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Statistics of Statisticians: Critical Masses for Research Groups

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Ralph Kenna, Bertrand Berche, Statistics of Statisticians: Critical Masses for Research Groups, Significance , Volume 9, Issue 6, December 2012, Pages 22–25, https://doi.org/10.1111/j.1740-9713.2012.00617.x

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If you work in a group of researchers, how big should your group be? Too small, and you have no one to bounce ideas off – and you may face extinction by funding cuts. Big groups bring fertile interactions and better-quality work. So is bigger always better? And does it depend on what you are researching? Ralph Kenna and Bertrand Berche have found out …

Do big groups do better research than small ones? Funders believe so – but is it true?

The notion of critical mass in research has been around for a long time 1 but it has recently become much more important. Policy makers, university managers – and, let's face it, the people who allocate funds – want research to be efficient; they want value for their money. They want the best research possible out of the researchers they have or pay for. So they look for indicators of the quality of academic research – and the simpler those indicators, in their view, the better. One simple indicator, so it has been claimed, is the size of the research group – the number of people involved in it. So this has become an issue to funders and to managers, and notions associated with critical mass have become increasingly important. It is perhaps surprising, therefore, that until very recently critical mass has lacked proper definition and measurement, and even understanding 2,3 .

The old notion of critical mass was of some sort of threshold group or department size, below which research quality tends to be poor and above which research standards start to improve. The idea has been extended to, and perhaps beyond, its logical conclusion: that “the bigger the group, the better”, and that “benefit continues to accrue through increasing scale”. And this belief has had consequences. It has brought calls from some lobbyists to concentrate resources into a small number of elite research institutions, where the groups will be big and the research correspondingly better. However, despite analyses based on counting citations of research papers, no evidence for such a threshold has ever been found 4 . Is the idea actually true?

To test it, we need a mathematical model for the relationship between research quality and group quantity. Happily, such a model has recently been developed 1 . It is a model that belongs, with many others, to the new and popular discipline known as sociophysics, in which physical principles are applied to social phenomena, and it uses ideas imported from statistical mechanics. The new model turns the old idea of critical mass on its head. Rather than a minimum group size required for quality research, critical mass emerges as an upper limit, above which research quality either tends not to improve or the rate of improvement starts to level out. This levelling out of research quality is due to communication limits and is known as the Ringelmann effect in sociology 5 . Ringelmann published his work in 1913, so the idea is approaching its hundredth birthday. Only now is it being tested mathematically in this context.

Group thinking can bring quality results… © iStockphoto.com/LifesizeImages

Typically for sociophysics models, the new theory has a very simple basis. One could assume that the strength of a research group or department is a simple sum of the strengths of the individuals comprising it. If the mean strength of the individuals in a group is a , and if the group has N members, then the strength of the group would be aN , a linear function of group size. But our assumption is a naïve one. Research groups are complex systems, in which interactions between individuals play crucial roles – so we need a better model which takes account of the interactions. Suppose an interaction between researchers gives an added effect, and the mean strength of that effect is b for each interaction. In a group of N people there are N ( N − 1)/2 possible two-way communication links; then the group strength becomes aN + bN ( N − 1)/2. This has an N 2 term in it, so the strength of the group as a whole is quadratically related to the number of people in it. If we then define quality as strength per head, we end up with a linear relation between quality and quantity. As an equation, average quality 〈 s 〉 can be written, when N is below the critical mass, as

… but a one-man band can seek inspiration unhindered. © iStockphoto.com/Peter Booth

In apes, chimpanzees and man there is a limit to the number of individuals who can communicate with each other

However, within a given discipline, one may expect there to be a limit to the number of colleagues with whom one can meaningfully communicate. In social groups, this limit is known as the Dunbar number 6 . Dunbar found it in chimpanzees and apes as well as in human beings. For research groups (who of course do not want to be confused with Dunbar's other primates) it is called the upper critical mass 1 . Its size turns out to depend on the discipline involved – chemistry, physics, archaeology and mathematics, for example, all have different upper critical masses. Once the group exceeds this size it tends to fragment into subgroups. The quadratic term associated with interactions between individuals is no more, as scientists cannot interact meaningfully across the entire department. Instead there is a quadratic term associated with the number of interactions between the various subgroups. However, this tends to be weaker than the interactions between individuals, decreasing as the upper critical mass increases 1 . Beyond the upper critical mass the dependency of quality on quantity is much reduced. The model thus predicts an average or expected piecewise linear relationship between quality s and quantity N in research,

where now N is above the critical mass. The a 2 and b 2 here are different from the a and b in equation (1); the line has a much shallower slope.

Since these equations only predict the average dependencies of research quality on group size, and since they take account of average interactions between agents, it is common to speak of mean field theory (borrowing parlance from statistical physics).

Theory is all very well; but this is a theory which it is possible to test. To test it, empirical data are required. Happily, the UK's Research Assessment Exercise (RAE) provides plenty.

For those not familiar with it, the RAE takes place about every 5 years. It is an assessment of the quality of university research which the government uses to decide how funds should be allocated between different universities, institutions and departments. Not surprisingly, it is taken very seriously indeed by university managers and by researchers themselves.

Figure 1 . Quality as a function of quantity for research groups in (a) statistics and operational research and (b) applied mathematics, with best fits to the expected behaviour discussed in the text. (The dashed curves represent 95% confidence intervals for these fits.) The black dot in (a) represents a joint submission by Edinburgh and Heriot-Watt universities and is considered an outlier. The coefficients of determination are R 2 = 0.60 and 0.74 and the data pass the Kolmogorov–Smirnov normality test. The breakpoint or upper critical mass is N c = 17 ± 6 for statistics and operational research, compared to N c = 13 ± 2 for applied mathematics

The most recent RAE, in 2008, sought to measure the quality of research coming from various groups in 67 academic disciplines in universities and research institutes across the country. Research was scrutinised to determine the proportions carried out at each of five levels:

4 * : World-leading research;

3 * : Internationally excellent research;

2 * : Research that is internationally recognised;

1 * : research recognised at a national level;

unclassified research.

A policy of concentrating resources into a few larger groups is unjustified

Following the RAE, a formula is used to determine how funding is distributed to higher education institutes for the subsequent years. The original formula used by the Higher Education Funding Council for England valued 4 * and 3 * research seven and three times more highly than 2 * research and allocated no funding to lower-quality research.

So how large should a group of (say) statisticians be before communication problems start to set in? One of the assessment divisions of the 2008 RAE was the Statistics and Operational Research unit. It received 30 submissions, comprising 389 individuals in groups of sizes ranging from N = 2 to N = 30. The mean group size was 13. It is useful to compare it to the Applied Mathematics unit, because of the similarities between the disciplines. Plots of quality of research, as assessed by the RAE, against number of people in the research groups are given in Figure 1 . There are clear correlations between quality and quantity in each case, and each of them fits our theory very nicely. For each discipline we see, as predicted, two straight lines, of differing slopes. The point at which they intersect is N , the upper critical mass. Below the critical mass, quality of research increases rapidly with the size of the group; above the critical mass the increase is much slower.

Upper critical mass estimates for a selection of academic disciplines. When there are more than N c researchers in a group, quality improvement per head starts to decline

And, as we can see, the upper critical mass for statisticians is 17 (plus or minus 6). This is the best size for any statistical research group. For applied mathematicians it is 13 (plus or minus 2). Once a research group has attained this size, it does not really help much (nor does it hurt) to add more and more researchers. In other words, a continual policy of concentrating resources into fewer, larger groups is unjustified.

It is, of course, possible to fit the data to other mathematical formulae. But the fits described above have the advantage of being sourced in a microscopic, agent-based model, permitting an interpretation of cause and effect. A short list of estimates for the upper critical masses of a selection of science disciplines is given in Table 1 . (See Harrison 1 and Kenna and Berche 2 , 7 for more extensive lists and for fits to other functional forms.)

It is perhaps worth noting that the table agrees, to some extent, with preconceived notions of the way that different academic disciplines behave. Pure mathematicians have the smallest “best group size”; and they are typically pictured as loners, sometimes antisocial ones. Perhaps less expected is the position of foreign language research, which also seems to work best in very small groups. The biggest “best group size” belongs to the medical sciences, and the complexity of much medical research also makes this expected. The number of co-authors of medical papers is also typically large, which is anecdotal confirmation of the result.

The RAE and its successor, the Research Excellence Framework, which will replace it in 2014, are of enormous importance to the entire academic research community in the UK. Under the Research Excellence Framework statistics and operational research will be considered as part of the overall mathematical sciences unit of assessment, which also includes pure and applied mathematics. Thus RAE 2008 provided the only opportunity to measure critical mass for statistics and operational research as a single discipline, distinct from their mathematics cousins.

(a) Quality measurements normalised to the overall mean for statistics and operational research groups at RAE 2008. (b) The same data normalised to the expectation 〈s〉, taking size into account. Here distance along the x-axis corresponds to alphabetical listing of the universities to which the groups belong

After the RAE, universities and research groups are ranked in the media according to performance. The ranking, though, is done without taking size of the group into account. Figure 2 (a) illustrates such a ranking; the different research groups are ranged above or below an average irrespective of how big each group is. But as we have seen, it is clear that such plots (and rankings) do not compare like with like: they do not take size into account. It is perhaps more sensible – and fairer – to take the expected performance related to their size into account as well; this is shown in Figure 2 (b). The data is more tightly distributed; the variation caused by different group size has been eliminated. The tighter distribution of Figure 2 (b) (where the range is 26.1 and standard deviation is 6.7) illustrates the superiority of the underlying size-based model over that of Figure 2 (a) (with range 43.6 and standard deviation 10.7).

By considering how the strength of research groups might be expected to improve by either adding more researchers or transferring researchers between groups, one can show that there is also a lower critical mass , which more closely corresponds to the traditional notion, although it is not a threshold 1 . This may be interpreted as the minimum size a group or department should achieve for it to be viable in the long term. The lower critical mass turns out to be pleasantly simple: it is half the value of the upper critical mass. Groups whose size is smaller than this are vulnerable and should seek to achieve the lower critical mass to avoid extinction. Therefore, statistics and operational research groups should strive to achieve a size of at least N c /2 ≈ 9 members, and should be happy if they have over N c ≈ 17 staff. But beyond that, it does not much matter how many staff the group has – more staff beyond the critical number will tend only to increase the quantity of research, but not its quality.

So what lessons can be drawn from this type of analysis? It is worth reiterating that there is no threshold group size beyond which research quality significantly improves. On the contrary, there is a measurable upper critical mass, beyond which the Ringelmann effect kicks in. Secondly, having established that a community of researchers is greater than the sum of its parts, it is clear that facilitation of communication should form an important management policy in academia. For example, while modern managerial experiments such as distance working or “hotdesking” may be reasonably employed in certain industries, these would have a negative effect for researchers. Instead, for them, putting individuals’ office spaces close to each other to facilitate spontaneous two-way interaction between as many people as possible is important. Researchers have always known this to be the case. Critical mass analyses along the lines presented here may help them take this message to university managers and to policy makers.

In short, then, bigger is indeed better, but only up to a point. Give us sufficient staff and help us communicate with each other. But there is no need to take this policy to extremes.

Harrison M. ( 2009 ) Does high-quality research require “critical mass”? In D. Pontikakis , D. Kyriakou and R. van Baval (eds), The Question of R&D Specialisation: Perspectives and Policy Implications , pp. 53 – 54 . Luxembourg: JRC Scientific and Technical Reports for European Commission .

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Kenna , R. and Berche , B. ( 2010 ) The extensive nature of group quality . Europhysics Letters , 90 , 58002 .

Kenna , R. and Berche , B. ( 2010 ) The critical mass and the dependency of research quality on group size . Scientometrics , 86 , 527 – 540 .

Evidence ( 2010 ) The Future of the UK University Research Base . Report for Universities UK. Available at http://www.universitiesuk.ac.uk/Publications/Documents/UUK-FutureOfResearch-LiteratureReview.pdf .

Ringelmann , M. ( 1913 ) Recherches sur les moteurs animés: travails de l'homme . Annales del'Institut National Agronomique , 2 , 2 – 39 .

Dunbar , R. I. M. ( 1992 ) Neocortex size as a constraint on group size in primates . Journal of Human Evolution , 22 , 469 – 493 .

Kenna , R. and Berche , B. ( 2011 ) Statistics of statisticians: Critical mass of statistics and operational research groups in the UK . Accepted for publication in International Journal of Modern Physics . (An earlier version is available at http://arxiv.org/abs/1102.4914 ).

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Higher Education Management and Policy

Critical masses for academic research groups and consequences for higher education research policy and management, institutional management in higher education.

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Previously published as Higher Education Management, Higher Education Management and Policy (HEMP) is published three times each year and is edited by the OECD’s Programme on Institutional Management in Higher Education. It covers the field through articles and reports on such issues as quality assurance, human resources, funding, and internationalisation. It also is a source of information on activities and events organised by OECD’s IMHE Programme.

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Smaller universities may produce research which is on a par with larger, elite establishments. This is confirmed by a recently developed mathematical model, supported by data from British and French higher education research-evaluation exercises. The detailed nature of the UK system, in particular, allows quantification of the notion of critical mass in research. It is shown that research quality increases with group quantity, but only up to a limiting size referred to as the upper critical mass. The condition for smaller universities to produce top-quality research is that they contain research groups of sizes above the upper critical masses appropriate to their respective disciplines. Policies which concentrate support into progressively fewer, larger institutions are therefore unjustified for high-quality academic research. Instead, to amplify overall research strength, support for medium-sized groups should be prioritised to help them attain upper critical mass.

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Author(s) Ralph Kenna and Bertrand Berche

02 Dec 2011

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Higher Education Management and Policy, Volume 23 Issue 3

Critical masses for academic research groups and consequences for higher education research policy and management.

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Title: critical mass and the dependency of research quality on group size.

Abstract: Academic research groups are treated as complex systems and their cooperative behaviour is analysed from a mathematical and statistical viewpoint. Contrary to the naive expectation that the quality of a research group is simply given by the mean calibre of its individual scientists, we show that intra-group interactions play a dominant role. Our model manifests phenomena akin to phase transitions which are brought about by these interactions, and which facilitate the quantification of the notion of critical mass for research groups. We present these critical masses for many academic areas. A consequence of our analysis is that overall research performance of a given discipline is improved by supporting medium-sized groups over large ones, while small groups must strive to achieve critical mass.

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June 8, 2018

The 25% Revolution—How Big Does a Minority Have to Be to Reshape Society?

A committed few can influence the many and sweep away social conventions, new research shows

By David Noonan

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Social change—from evolving attitudes toward gender and marijuana to the rise of Donald Trump to the emergence of the Black Lives Matter and #MeToo movements—is a constant. It is also mysterious, or so it can seem. For example, “How exactly did we get here?” might be asked by anyone who lived through decades of fierce prohibition and now buys pot at one of the more than 2,000 licensed dispensaries across the U.S.

A new study about the power of committed minorities to shift conventional thinking offers some surprising possible answers. Published this week in Science , the paper describes an online experiment in which researchers sought to determine what percentage of total population a minority needs to reach the critical mass necessary to reverse a majority viewpoint. The tipping point, they found, is just 25 percent. At and slightly above that level, contrarians were able to “convert” anywhere from 72 to 100 percent of the population of their respective groups. Prior to the efforts of the minority, the population had been in 100 percent agreement about their original position.

“This is not about a small elite with disproportionate resources,” says Arnout van de Rijt, a sociologist at Utrecht University in the Netherlands who studies social networks and collective action, and was not involved in the study. “It's not about the Koch brothers influencing American public opinion. Rather, this is about a minority trying to change the status quo, and succeeding by being unrelenting. By committing to a new behavior, they repeatedly expose others to that new behavior until they start to copy it.”

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The experiment was designed and led by Damon Centola, associate professor in the Annenberg School of Communications at the University of Pennsylvania. It involved 194 people randomly assigned to 10 “independent online groups,” which varied in size from 20 to 30 people. In the first step group members were shown an image of a face and told to name it. They interacted with one another in rotating pairs until they all agreed on a name. In the second step Centola and his colleagues seeded each group with “a small number of confederates…who attempted to overturn the established convention (the agreed-on name) by advancing a novel alternative.”

For the second step, as Centola explains it, the researchers began with a 15 percent minority model and gradually increased it to 35 percent. Nothing changed at 15 percent, and the established norm remained in place all the way up to 24 percent.

The magic number, the tipping point, turned out to be 25 percent. Minority groups smaller than that converted, on average, just 6 percent of the population. Among other things, Centola says, that 25 percent figure refutes a century of economic theory. “The classic economic model—the main thing we are responding to with this study—basically says that once an equilibrium is established, in order to change it you need 51 percent. And what these results say is no, a small minority can be really effective, even when people resist the minority view.” The team’s computer modeling indicated a 25 percent minority would retain its power to reverse social convention for populations as large as 100,000.

But the proportion has to be just right: One of the groups in the study consisted of 20 members, with four contrarians. Another group had 20 members and five contrarians—and that one extra person made all the difference. “In the group with four, nothing happens,” Centola says, “and with five you get complete conversion to the alternative norm.” The five, neatly enough, represented 25 percent of the group population. “One of the most interesting empirical, practical insights from these results is that at 24 percent—just below the threshold—you don’t see very much effect,” adds Centola, whose first book, How Behavior Spreads: The Science of Complex Contagions , comes out this month. “If you are those people trying to create change, it can be really disheartening.” When a committed minority effort starts to falter there is what Centola calls “a convention to give up,” and people start to call it quits. And of course members have no way to know when their group is just short of critical mass. They can be very close and simply not realize it. “So I would say to Black Lives Matter, #MeToo and all of these social change movements that approaching that tipping point is slow going, and you can see backsliding. But once you get over it, you’ll see a really large-scale impact.”

Real-life factors that can work against committed minorities—even when they reach or exceed critical mass—include a lack of interaction with other members, as well as competing committed minorities and what’s called “active resistance”—which pretty well describes the way many people in 2018 respond to political ideas with which they disagree. But even with such obstacles, Centola says the tipping point predicted in his model remains well below 50 percent.

Certain settings lend themselves to the group dynamics Centola describes in his study, and that includes the workplace. “Businesses are really great for this kind of thing,” he says, “because people in firms spend most of their day trying to coordinate with other people, and they exhibit the conventions that other people exhibit because they want to show that they’re good workers and members of the firm. So you can see very strong effects of a minority group committed to changing the culture of the population.”

The other environment in which the 25 percent effect is particularly evident, Centola says, is online—where people have large numbers of interactions with lots of other people, many of them strangers. This raises some tricky questions: Can a bot stand in for a member of a committed minority? And can a committed minority be composed of bots and the real people the bots influence, so that bots are actually driving the change? According to Centola, “In a space where people can’t distinguish people from bots, yes. If you get a concerted, focused effort by a group of agents acting as a minority view, they can be really effective.”

Yale sociologist Emily Erikson, who also studies social networks but was not involved with the study, sees the new paper partly as a warning. “In some sense it’s saying extreme voices can quickly take over public discourse,” she says. “Perhaps if we’re aware of that fact, we can guard against it.”

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It is no coincidence that the universities were pioneers of the internet, for the medium lends itself uniquely well to academic debate and collaboration. We call this process of sharing ideas in cyberspace “virtual learning”, and the main goal of any such community is to create a shared understanding that will inspire research and development. This paper describes trends and issues in creating a Virtual Learning Community in systems engineering, drawing upon the results of an European ALFA‐funded project named COSME.

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Molina, A. , Bremer, C.F. and Eversheim, W. (2001), "Achieving critical mass: a global research network in systems engineering", Foresight , Vol. 3 No. 1, pp. 59-65. https://doi.org/10.1108/14636680110802996

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What is Critical Research? | Definition, Examples & Methods

Introduction

What does critical research mean, what is an example of critical qualitative research, approaches to critical theory.

Critical research was created out of a need to examine power , inequities, and the resulting societal implications on the status quo in society. It is a necessary departure from traditional scientific research in that it looks beyond what is directly observable to analyze the social world and develop social theory from novel perspectives to address previous injustices. In this article, we'll look at what critical theory entails for qualitative research , as well as the different strands that make up critical research.

In specific terms, critical research examines the nature of power dynamics influencing the social world. More broadly, this has implications for understanding inequality and disparity across cleavages of race, gender, ethnicity, sexual orientation, and economic class, among other differences in identity.

While there are many different strands to critical research, there are a number of common characteristics that are shared by scholars of critical theory:

• Contextualization : Traditional research assumes a singular, almost absolutist approach to knowledge. In contrast, critical theory challenges the positivist outlook on scientific research and assumes a more sociocultural outlook to the social world. In adopting a more contextualized approach to any particular social phenomenon, scholars look to making propositions specific to different contexts rather than defining grand, unifying theories that explain socially constructed concepts regardless of individual or cultural circumstances.
• Subjectivity : Unlike more positivist approaches to research, critical research presupposes a lack of an ability to directly observe physical reality. Moreover, a researcher's perception is often confounded by culturally-reinforced presumptions such as stereotypes and other biases that privilege those in power. The possibility that the social world can be subjectively construed directly challenges assumptions of a positivist understanding of social phenomena. Instead, critical research encourages scholars and laypeople alike to consider the world from different points of view in order to identify problems and inequities that are otherwise invisible within traditional worldviews.
• Social change : Critical research is seldom interested in generating insights purely out of intellectual curiosity. Critical scholars tend to adopt a philosophy of social justice where research is aimed at benefiting marginalized or oppressed populations who lack the same opportunities and benefits that are otherwise granted to those in mainstream society. In this respect, research and analysis within a critical paradigm are merely preliminary steps in a process that appeals to institutions, stakeholders, and social activists to draw on actionable insights from the research and make tangible proposals for enacting change.
• Transformation : Similar to the imperative of social change, transformation deals with fundamentally altering contemporary paradigms. However, this aspect to critical research is more concerned with problematizing traditional perspectives of the social world and the phenomena within it, both from a layperson's point of view and from the view of traditional academic institutions that perpetuate mainstream scientific inquiry. Rather than simply acknowledge the subjective nature of the social world, critical research calls for fundamentally transforming perceptions and attitudes in a manner that views marginalized populations more equitably.

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One of the more famous studies to produce a critical analysis is the doll test first devised by Mamie Clark, then conducted with husband Kenneth Clark starting in the 1940s and replicated in later years. In the doll test, children were asked how they felt about dolls that were put in front of them. The children preferred to play with the dolls that looked white rather than the dolls that looked black, and had more positive views about the white-looking dolls. Children who were black also tended to share the same perception of black-looking dolls, which suggested that their surrounding environment - particularly the school system but more broadly the culture around them - profoundly impacted them by reinforcing negative stereotypes about racial minorities.

Critical theorists argue that such stereotypes, especially when perpetuated by institutions like education and mass media, further contribute to economic and social disparities when children of color experience exposure to negative attitudes about race and ethnicity. This novel research provided fundamental insights that led to the following real-world changes:

• Desegregation of schools : This research took place in the era where public schools in the United States were separated by race. The findings from the doll test helped make the case that institutionalized discrimination had effects on the educational and emotional development of children of color, ultimately leading to judicial rulings that contributed to school desegregation.
• Educational reforms : Subsequent discussions of racial stereotypes have helped to further promote initiatives for racial equity and equality in public education. While still undoubtedly controversial to this day, efforts to promote diversity training for teachers, multicultural curriculum development, and other policies to address racial disparities can be partly attributed to the findings of the doll test.
• Anti-discrimination policies : The findings from the doll test form a scientific basis for anti-discrimination frameworks for public policy, workplace organization, and other formal institutions. Where racism and equality might otherwise be abstract, potentially vague concepts, a scientific framework regarding discriminatory attitudes provides a language for discussing practical implications addressing racism.

Here are some of the various forms of critical research. Keep in mind that these approaches are not exclusive to each other, though they have their own distinct focus to shed light on specific issues relevant to the social sciences, nor are they exhaustive of the entire array of critical theory.

• Critical discourse analysis : Researchers who critically analyze communication look at how people exercise power through speech to manipulate or control others. This analytical method connects theories from linguistics, sociology, and anthropology to look at the power of language in constructing social reality.
• Critical ethnography : Ethnography is an all-encompassing approach to research aimed at capturing relationships, practices, and behaviors within any given context. Beyond a comprehensive examination of cultures, critical ethnographers use the resulting findings to advocate for social change.
• Critical methodology : Critical scholars may also look at how methods are used to construct scholars' epistemology about scientific knowledge and question approaches to science that emphasize objectivity to a fault. Critical methodology advocates for reflexivity and participatory research as a departure from traditional research methods.
• Critical race theory : Scholars engaged in critical race theory look at longstanding racial disparities to examine how institutions and power structures perpetuate racism and how people of color can challenge those structures from legal and advocacy standpoints in order to foster equity and equality.
• Decolonizing research : Focusing on the critique that most established research comes from a Western-based perspective, research on decolonization seeks to deconstruct established philosophical paradigms that disadvantage perspectives of indigenous populations, cultures from the Global South, and other communities that have long been ignored by mainstream scholarship.

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Critical Mass is a term often used but rarely defined: when enough members of a society or community have adopted an interactive innovation so that the further rate of adoption becomes self-sustaining. It is clearly closely related to network effects – there is little point joining a social network when there are no other members of one’s community there; but when enough people are there that others feel they are missing the interaction that happens on the network, they will be more inclined to join. Interactive innovations , according to Markus, 1 are those where “widespread usage creates universal access, a public good that individuals cannot be prevented from enjoying even if they have not contributed to it.” Later adopters are influenced by the early adopters of interactive innovations, while early adopters also benefit from the later adopters’ usage. Markus terms this reciprocal interdependence ; for example, an early adopter of the telephone probably didn’t have much fun until more people adopted the innovation and they had, therefore, more people to call.

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Markus, M.L. (1987) “Toward a ‘Critical Mass’ Theory of Interactive Media Universal Access, Interdependence and Diffusion” Communication Research 14 (5): 491–511.

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Gladwell, M. (2000) The Tipping Point: How Little Things Can Make a Big Difference . London: Abacus.

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Shirky C. (2008) Here Comes EveryBody: The Power of Organising without Organizations . London: Penguin Books.

Dunbar, P.R. (2004) Grooming, Gossip and the Evolution of Language (2 nd edn). London: Faber and Faber.

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Gruenbaum, R. (2015). Critical Mass. In: Making Social Technologies Work. Palgrave Pocket Consultants. Palgrave Macmillan, London. https://doi.org/10.1057/9781137024824_21

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Conducting research to identify key features and critical nodes in the coalescence and instability of pre-fabricated jointed rock.

1. Introduction

2. experimental research, 2.1. preparation of pre-fabricated jointed red sandstone, 2.2. design of experimental plan, 2.3. test equipment and system, 3. test results and discussion, 3.1. analysis of strength variation and failure characteristics in jointed red sandstone, 3.2. analysis of cooperative failure characteristics in jointed rock mass during the instability process, 3.2.1. characteristics of accelerated interaction zones during the instability process, 3.2.2. analysis of cooperative failure characteristics in jointed red sandstone, 3.3. sub-instability stage zoning characteristics in pre-fabricated jointed red sandstone, 3.4. analysis of strain variation in the intact region of rock mass under the influence of joints, 3.5. analysis of acoustic emission characteristics during the instability process of jointed red sandstone, 4. detailed mechanical response of jointed red sandstone model specimens, 4.1. validation and application of fractals, 4.2. modeling and simulation results, 5. conclusions, author contributions, institutional review board statement, informed consent statement, data availability statement, conflicts of interest.

• Jiao, F.; Xu, J.; Guo, B.; Peng, S.; Yan, F.; Chen, Y. Shear test on the influence of filling thickness on the shear strength of rock joints. J. Min. Saf. Eng. 2022 , 39 , 405–412. [ Google Scholar ]
• Indraratna, B.; Premadasa, W.; Brown, E.T.; Gens, A.; Heitor, A. Shear strength of rock joints influenced by compacted infill. Int. J. Rock Mech. Min. 2014 , 70 , 296–307. [ Google Scholar ] [ CrossRef ]
• She, C.X.; Sun, F.T. Study of the Peak Shear Strength of a Cement-Filled Hard Rock Joint. Rock Mech. Rock Eng. 2018 , 51 , 713–728. [ Google Scholar ] [ CrossRef ]
• Xiao, W.; Yu, H.; Zhu, Z.; Li, Y.; Liu, W. Experimental study on the dilatancy characteristics of thin-bedded filling rock joints. Chin. J. Geotech. Eng. 2020 , 42 , 1499–1508. [ Google Scholar ]
• Chai, S.; Wang, H.; Jing, Y.; Jia, N. Experimental study on dynamic compression characteristics of cumulative damage of filled jointed rock. Chin. J. Rock Mech. Eng. 2020 , 39 , 2025–2037. [ Google Scholar ]
• Wang, G.; Cao, T.; Wen, X.; Sun, F.; Zhang, L. Evolution law of pre-peak energy self-inhibition of single-joint sandstone under uniaxial compression. J. China Coal Soc. 2021 , 46 (Suppl. S1), 211–221. [ Google Scholar ]
• Ma, Q.; Su, Q.; Ma, D.; Yuan, P. Experimental study on SHPB dynamic mechanical failure characteristics of sandstone in deep roadway with different joint dip angles. Chin. J. Rock Mech. Eng. 2020 , 39 , 1104–1116. [ Google Scholar ]
• Jin, A.; Lu, T.; Wang, B.; Chen, S.; Zhang, J. Experimental study on dip angle characteristics of key joints in rock mass based on improved mechanical equivalence. Chin. J. Rock Mech. Eng. 2023 , 42 , 76–87. [ Google Scholar ]
• Liu, T.; Yang, R.; Ding, L.; Li, X.; Zeng, L. Study on mechanical properties and meso-cracking mechanism of granite with non-interpenetrated joints. Chin. J. Rock Mech. Eng. 2023 , 42 , 1070–1082. [ Google Scholar ]
• Deng, Z.; Wu, J.; Shang, J.; Xie, L. The equivalent elastic model and strength characteristics of rock mass with transfixion-non-transfixion cross joints. J. China Coal Soc. 2018 , 43 , 3098–3106. [ Google Scholar ]
• Li, S.; Lin, H.; Lin, Q.; Wang, Y.; Zhao, Y.; Hu, H. Mechanical behavior and failure characteristics of double-layer composite rock-like specimens with coplanar double joints under uniaxial loading. Trans. Nonferrous Met. Soc. China 2023 , 33 , 2815–2831. [ Google Scholar ] [ CrossRef ]
• Zhao, Y.; Liu, J.; Jin, A.; Sun, H.; Wang, B.; Wei, Y. Study on failure characteristics of non-interpenetrated jointed rock mass under loading and unloading conditions. J. Cent. South Univ. (Nat. Sci. Ed.) 2020 , 51 , 1893–1901. [ Google Scholar ]
• Wang, G.; Zhang, L.; Xu, M.; Liang, Z.; Ran, L. Study on energy evolution mechanism of damage and failure of non-interpenetrated jointed rock mass under uniaxial compression. Chin. J. Geotech. Eng. 2019 , 41 , 639–647. [ Google Scholar ]
• Wang, Q.; Xia, K.; Wu, B.; Xu, Y.; Liu, F. Experimental study on dynamic failure of prefabricated parallel double jointed rock-like material plate. J. Tianjin Univ. (Nat. Sci. Eng.) 2019 , 52 , 1099–1108. [ Google Scholar ]
• Zare, S.; Karimi-Nasab, S.; Jalalifar, H. Analysis and determination of the behavioral mechanism of rock bridges using experimental and numerical modeling of non-persistent rock joints. Int. J. Rock Mech. Min. 2021 , 141 , 104714. [ Google Scholar ] [ CrossRef ]
• Wang, J.; Li, J.; Zhou, K.; Jiang, C.; Shen, Y.; Jia, H. Fracture mechanical properties of sandstone with pre-fabricated cracks under freeze-thaw cycles. Theor. Appl. Fract. Mech. 2024 , 131 , 104444. [ Google Scholar ] [ CrossRef ]
• Yin, T.; Yin, J.; Wu, Y.; Yang, Z.; Liu, X.; Zhuang, D. Water saturation effects on the mechanical characteristics and fracture evolution of sandstone containing pre-existing flaws. Theor. Appl. Fract. Mech. 2022 , 122 , 103605. [ Google Scholar ] [ CrossRef ]
• Yuan, H.; Xiao, T.; She, H.; Huang, M. Crack propagation law of rock with single fissure based on PFC2D. Front. Earth Sci. 2023 , 10 , 977054. [ Google Scholar ] [ CrossRef ]
• Jin, M.A.; Guo, Y.S. Accelerated synergism prior to fault instability: Evidence from laboratory experiments and an earthquake case. Seismol. Geol. 2014 , 36 , 547–561. [ Google Scholar ]
• Jin, M.A.; Sherman, S.I.; Guo, Y.S. Identification of meta-instable stress state based on experimental study of evolution of the temperature field during stick-slip instability on a 5° bending fault. Sci. China Earth Sci. 2012 , 55 , 869–881. [ Google Scholar ] [ CrossRef ]

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Zhang, B.; Zhang, S.; Shen, B.; Li, Y.; Song, S.; Han, X. Conducting Research to Identify Key Features and Critical Nodes in the Coalescence and Instability of Pre-Fabricated Jointed Rock. Appl. Sci. 2024 , 14 , 7905. https://doi.org/10.3390/app14177905

Zhang B, Zhang S, Shen B, Li Y, Song S, Han X. Conducting Research to Identify Key Features and Critical Nodes in the Coalescence and Instability of Pre-Fabricated Jointed Rock. Applied Sciences . 2024; 14(17):7905. https://doi.org/10.3390/app14177905

Zhang, Buchu, Shichuan Zhang, Baotang Shen, Yangyang Li, Shilong Song, and Xuexian Han. 2024. "Conducting Research to Identify Key Features and Critical Nodes in the Coalescence and Instability of Pre-Fabricated Jointed Rock" Applied Sciences 14, no. 17: 7905. https://doi.org/10.3390/app14177905

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• Published: 05 September 2024

Larvicidal potential of Trachyspermum ammi essential oil and Delphinium speciosum extract against malaria, dengue, and filariasis mosquito vectors

• Alireza Sanei‑Dehkordi 1 ,
• Amir Masoud Tagizadeh 2 ,
• Mir Babak Bahadori 3 ,
• Elhameh Nikkhah 3 ,
• Masoumeh Pirmohammadi 4 ,
• Sara Rahimi 3   na1 &
• Hossein Nazemiyeh 5   na1  

Scientific Reports volume  14 , Article number:  20677 ( 2024 ) Cite this article

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• Drug discovery
• Medical research
• Microbiology
• Parasitic infection
• Pathogenesis
• Plant sciences
• Viral infection

Mosquito-borne diseases, such as malaria, dengue, and Zika, pose major public health challenges globally, affecting millions of people. The growing resistance of mosquito populations to synthetic insecticides underscores the critical need for effective and environmentally friendly larvicides. Although chemical pesticides can initially be effective, they often lead to negative environmental consequences and health hazards for non-target species, including humans. This study aimed to evaluate the larvicidal effects of Trachyspermum ammi essential oil and Delphinium speciosum extract on the larvae of three major mosquito species: Aedes aegypti , Anopheles stephensi , and Culex quinquefasciatus . Mosquito larvae of Ae. aegypti , An. stephensi , and Cx. quinquefasciatus were reared under controlled laboratory conditions. The larvicidal activity of T. ammi essential oil and D. speciosum extract was evaluated through standard bioassays, using various concentrations of essential oils (10, 20, 40, 80, and 160 ppm) and extracts (160, 320, 640, 1280, and 2560 ppm) to determine the lethal concentration (LC 50 ) values after 24 h of exposure. Fresh plant materials were collected, with the essential oil extracted via hydro-distillation, and the extract prepared using methanol solvent extraction. The chemical composition of T. ammi essential oil was examined using gas chromatography-mass spectrometry (GC-MS). Additionally, the preliminary analysis of the chemical compounds in D. speciosum extract was carried out using thin layer chromatography (TLC) and nuclear magnetic resonance spectroscopy (NMR) techniques. The results indicated that the essential oil of T. ammi exhibited more effective larvicidal activity compared to the D. speciosum extract. Specifically, the essential oil demonstrated LC 50 values of 18 ppm for Cx. quinquefasciatus and 19 ppm for Ae. aegypti . In contrast, the D. speciosum extract showed the strongest larvicidal effect against An. stephensi , with an LC 50 of 517 ppm. Concentrations of 40 ppm of the essential oil and 1280 ppm of the extract resulted in 100% mortality across all three species. Both the essential oil of T. ammi and the D. speciosum extract exhibited concentration-dependent larvicidal activity, and these results were statistically significant ( p  < 0.001) compared to the no-treatment group. GC-MS analysis revealed thymol (88.95%), o-cymen-5-ol (4.11%), and γ-terpinene (2.10%) as the major constituents of the T. ammi essential oil. Additionally, TLC verified the presence of alkaloids in both chloroform and methanolic extracts. Proton NMR identified a diterpene structure for these alkaloids. These findings suggest that T. ammi essential oil is a promising candidate for natural mosquito control strategies. Given its efficacy, further research is warranted to explore its potential in integrated vector management programs.

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Ovicidal toxicity of plant essential oils and their major constituents against two mosquito vectors and their non-target aquatic predators

Evaluating larvicidal, ovicidal and growth inhibiting activity of five medicinal plant extracts on Culex pipiens (Diptera: Culicidae), the West Nile virus vector

Introduction.

Mosquitoes (Diptera: Culicidae ) are responsible for spreading important human parasites and microbes 1 , leading to major diseases and death, which impose a substantial economic burden globally 2 . Mosquitoes pose significant public health risks by transmitting diseases such as lymphatic filariasis, malaria, dengue fever, yellow fever, and Zika virus 3 . This emphasizes the crucial role of mosquito vector control in tropical and subtropical regions worldwide 4 , 5 , 6 .

Cx. quinquefasciatus plays a crucial role as a vector for both lymphatic filariasis and West Nile virus (WNV) 7 . Lymphatic filariasis, commonly referred to as elephantiasis, is recognized as one of the most significant neglected infectious diseases 8 and the second most common global mosquito-borne disease 9 . Over 882 million people in 44 countries worldwide remain threatened by lymphatic filariasis 10 .

Malaria is primarily transmitted to humans through the bites of infected female Anopheles stephensi 11 . In 2022, approximately 249 million cases of malaria were reported worldwide, resulting in 608000 malaria-related deaths across 85 countries 12 .

Dengue fever is a mosquito-borne viral infection that spreads to humans through the bites of infected mosquitoes, primarily Aedes aegypti mosquito 13 . Dengue has become a major global health issue, affecting approximately four billion people across 130 countries 14 . Annually, approximately 100–400 million infections occur, putting a significant portion of the world’s population at risk 14 .

While the treatment of these diseases is challenging, prevention offers a viable and effective strategy to reduce the burden of these disease and address the economic, emotional, and health consequences. Various approaches have been developed to manage vector populations and curb disease transmission in regions where these diseases are endemic 15 . Over the past several decades, synthetic insecticides have been employed to manage vectors and break the transmission cycle of vector-borne diseases 16 . However, the extensive use of synthetic pesticides to control mosquitoes presents significant risks, including toxicity to non-target organisms and potential harm to environmental and human health 17 , 18 . Additionally, the use of these synthetic chemicals contributes to the development of resistance in mosquito populations 19 .

Recent strategies to control mosquito vectors involve eco-friendly approaches, including the use of botanical insecticides. It is essential to explore environmentally friendly alternatives in botanicals, such as plant extracts and essential oils (EO) 20 . EOs are volatile compounds present in various plant families, including Asteraceae , Rutaceae , Myrtaceae , Lauraceae , Lamiaceae , Apiaceae , Piperaceae , Poaceae , Zingiberaceae , and Cupressaceae 21 . These natural insecticides are specifically toxic to mosquito pests while being environmentally beneficial. It is well-known that plant metabolites are toxic to mosquitoes and can effectively manage their populations 22 .

Botanical components possess antifungal, antibacterial, antileishmanial, antimalarial, and insecticidal properties 23 , 24 , 25 , 26 . Natural substances, such as EO and plant extracts, exhibit a wide range of biological effects, including insecticidal, acaricidal, repellent, antifeedant, ovipositional deterrent, and growth inhibiting properties against insect pests, including mosquitos 27 , 28 , 29 , 30 . EOs represent a substantial source of biologically active monoterpenes and have been extensively documented for their bioactivities against insect pests. Several EOs and extracts with notable potential for mosquito control originate from the plant genera Tagetes spp. 31 , Mentha spp. 32 , Citrus spp. 33 , Trachyspermum spp. 34 , and Delphinium spp. 35 . The larvicidal potency of extract from Thymus plant 36 , Satureja species 37 , Pelargonium roseum 38 , Carum copticum 39 , Citrus aurantifolia 40 against Cx. quinquefasciatus, An. stephensi, Ae, aegypti have been reported. Also, EOs derived from cassia, camphor, wintergreen, pine, and eucalyptus are already being utilized in various commercial products intended for mosquito control 41 .

Trachyspermum ammi is taxonomically classified under the Apiaceae family, which comprises approximately 347 genera and 12,816 species. The plant is widely distributed and cultivated in various regions, including Iran, Pakistan, Afghanistan, and India. The grayish-brown seeds (fruits) of T. ammi are commonly used for biomedical and nutritional proposes. The EO extracted from the seeds is a volatile oil possessing distinctive organoleptic and physicochemical characteristics 42 , 43 .

The Delphinium genus (Ranunculaceae) encompasses around 300 species globally, with 28 species found in Iran, including 9 species endemics to the region 44 . D. speciosum , a perennial herb found in Northwestern region of Iran, features villous stems that can grow up to 80 cm in height. These stems may be either simple or branched and are supported by woody roots. The leaves of this plant are rounded-pentagonal in shape, measuring between 3–12 mm in width, and are covered with villous hairs on both surfaces 44 . For many years, plants from the Delphinium genus have been traditionally used as herbal remedies, including insecticides, larvicides, antibacterial, and lice treatment 35 , 45 , 46 , 47 .

Despite the limited knowledge of the larvicidal properties of T. ammi and D. speciosum endemic to Iran, our study represents the first investigation into their effects against C. quinquefasciatus , An. stephensi , and Ae. aegypti . We also examined their chemical profiles, which could potentially be utilized for future biopesticide development.

Materials & methods

Mosquitoes rearing.

The mosquito larvae employed in larvicidal tests including Ae. aegypti , An. stephensi , and Cx. quinquefasciatus, were sourced from a laboratory colony at the Department of Biology and Control of Disease Vectors, Faculty of Health, Hormozgan University of Medical Sciences in Bandar Abbas, Iran. These colonies were consistently maintained at 27 ± 1 °C, with a 12:12 light and dark photoperiod, and 65 ± 5% relative humidity. The larvae were fed daily with powdered fish food until pupation, ensuring a continuous supply for mosquito larvicidal experiments.

Collection of plants material

The D. speciosum plant which was collected in May 2023 from the Sahand Mountain in the Sprakhon region of East Azarbaijan Province (37 °82′N, 46 °40′E; altitude of 2480 m), and a voucher specimen (TBZMED 5004) was deposited in the Herbarium of the Faculty of Pharmacy, Tabriz University of Medical Sciences. The T. ammi seeds were procured from Shafa Pajohan Sabz, a knowledge-based firm located in Tabriz, Iran. The collected plants were identified by Dr. Atefeh Ebrahimi, a botanist at the Herbarium of the Faculty of Pharmacy, Tabriz University of Medical Sciences. Harvesting of the plants was conducted in accordance with the regulations issued by the Natural Resources & Watershed Management Organization-I.R. of Iran and the Research Institute of Forests and Rangelands. According to these regulations, the harvesting of Delphinium plants for laboratory purposes is permitted without restrictions.

Plant extract preparation

Following the collection and washing of D. speciosum , the plant was subjected to a drying process under laboratory conditions. The aerial parts of the plant were then pulverized and subjected to extraction via the Soxhlet method, utilizing petroleum ether, chloroform, and methanol sequentially. A portion of the resulting crude methanolic extract, weighing 5 g, was subsequently employed for bioassay analysis. Different concentrations (160, 320, 640, 1280, and 2560 ppm) were derived from the stock solution 48 , 49 .

Essential oil extraction

The T. ammi seeds were pulverized, and their essential oil was extracted using hydro-distillation with a Clevenger apparatus over a period of 3 h. The essential oil was subsequently dried using anhydrous sodium sulphate and preserved at a temperature of −4 °C for use in larvicidal bioassay tests 50 .

Larvicidal bioassay

Bioassay tests were conducted in accordance with the World Health Organization’s standard method 51 . Total T. ammi essential oil and D. speciosum extract were initially dissolved in 99% ethanol and 99% methanol, respectively, as co-solvents. The solutions were stirred for 30 s with a glass rod. For the larval test, 25 larvae at the late 3rd and early 4th instars of Ae. aegypti , An. stephensi , and Cx. quinquefasciatus were collected using a fine mesh strainer and then gently transferred by tapping into four 400-mL glass beakers containing 249 mL of dechlorinated tap water. Each concentration was replicated at least four times, comprising a total of 100 larvae. The test medium was prepared by combining 1 mL of the appropriate dilution of essential oil or total extract in co-solvents with 249 mL of water. Controls included batches of mosquitoes from the colony exposed to water and the solvents alone. The larvae were exposed to different concentrations of 10, 20, 40, 80, and 160 ppm of essential oil, and 160, 320, 640, 1280, and 2560 ppm of total extract in dechlorinated tap water for 24 h, with no provision of food during this period.

Gas chromatography/Mass spectroscopy analysis

The composition of T. ammi EO was analyzed using a chromatography-mass spectrometry instrument (Shimadzu, QP-5050 A) equipped with a DB-1 capillary column (60 m length, 0.25 mm inner diameter, and 0.25 μm film thickness). An electron impact ionization (EI) system applying 70 eV ionization energy was used for the identification of the essential oil’s volatile components. Helium was employed as the carrier gas at a flow rate of 1 mL/min, operating in constant linear velocity mode. The injector and detector temperatures were set at 250 °C. The oven temperature was held at 50 °C for 3 min and then was programed from 50 to 265 °C at the rate of 2.5 °C/min, and was kept at this temperature for 6 min. After dilution of the essential oil in n-hexane (1:100), 1 µL of essential oil solution was injected manually.

Identification of each volatile component was carried out using calculated retention indices (RI) based on n-alkanes chromatogram (C 8 –C 24 ) under the same gas chromatography condition. The EO constituents were identified by comparing their RI values and mass spectra with those in several Mass Spectral libraries such as Wiley and NIST. The results are presented as the area of Mass response in relative percentages 52 .

NMR analysis of extracts

Since Delphinium species are mainly known for having diterpene alkaloids, and most published sources consider these compounds responsible for the anti-parasitic effects of these plants, so it was tried to check the presence or absence of alkaloid compounds in the used extracts. A preliminary study was conducted to determine the alkaloid content of the extracts using TLC on precoated-silica gel plate (TLC Silica gel 60 F254, Merck). Additionally, NMR spectroscopy was used to determine the nature of alkaloids in the extracts. It should be noted that the NMR guided isolation method is a valuable technique that has been widely used by researchers in metabolomic studies and drug discovery. This very powerful tool provides the ability to detect different categories of chemical compounds in the extract at the same time 53 , 54 , 55 , 56 , 57 . NMR experiments were recorded with a Bruker UltraShield-400 spectrometer (Bruker, Germany) in deuterated chloroform and TMS used as an internal standard.

Statistical analysis

In the current study, the independent variables include different larval species and treatment groups exposed to various concentrations of essential oils and plant extracts, while the dependent variable is the mosquito mortality rate. All experiments were conducted in quadruplicate, data are expressed as mean ± standard deviation. We assessed the normality of the dependent variable using graphical methods and statistical tests. Due to the large sample size, the central limit theorem supports the assumption of normality in the data 58 . Lethal concentrations (LC 50 and LC 90 ), along with 95% confidence intervals and probit equations, were determined through probit regression analysis. A Three-Way ANOVA followed by Tukey’s HSD test (95% confidence interval, SPSS v.25) was used to compare larvicidal activity. Graphs were generated using GraphPad Prism v.8. Statistical significance was defined as p  < 0.05. The effect size (ES) was calculated using Cohen's d, which is defined as the difference between two means divided by the pooled standard deviation. Cohen's guidelines for interpreting effect size are: small effect: d ≈0.2, Medium effect: d ≈0.5, Large effect: d ≈0.8. This quantification provided an objective measure of the practical significance of the findings 59 .

Larvicidal effect of samples

In this study, we examined the larvicidal effect of T. ammi essential oil at different concentrations ranging from 10 to 160 ppm and D. speciosum extract at various concentrations between 160 and 2560 ppm on three mosquito species: An. stephensi , Cx. quinquefasciatus and Ae. aegypti . The findings are summarized in (Table 1 ).

As shown in Table 1 , The An. stephensi demonstrated the highest larval mortality rate when treated with D. speciosum extract, reaching 100% mortality at a concentration of 1280 ppm. For Cx. quinquefasciatus and Ae. aegypti larvae treated with this extract, mortality rates at the highest concentration of 2560 ppm were 98 and 99%, respectively. The lowest mortality rate was observed in Cx. quinquefasciatus larvae treated with D. speciosum extract, showing only 5% mortality at a concentration of 160 ppm. For larvae treated with T. ammi EO, the highest mortality rates were observed in Cx. quinquefasciatus and Ae. aegypti , with mortality rates of 96% and 94%, respectively, at a concentration of 40 ppm. In contrast, the mortality rate for An. stephensi larvae treated with 40 ppm of T. ammi EO was reported to be 45%. The lowest larval mortality rates at 10 ppm of T. ammi EO were recorded as 6% for An. stephensi , 13% for Cx. quinquefasciatus , and 11% for Ae. aegypti .

A clear dose-dependent relationship was observed between the concentration of T. ammi EO and D. speciosum extract and the mortality rates of mosquito larvae. As the concentration of T. ammi EO increased, the mortality rates among An. stephensi , Cx. quinquefasciatus , and Ae. aegypti also increased significantly. Specifically, at lower concentrations (10 and 20 ppm), mortality rates ranged from 13 to 54%, while at higher concentrations (160 ppm), mortality rates reached up to 99% for An. stephensi and 100% for Cx. quinquefasciatus and Ae. aegypti . Similarly, D. speciosum extract exhibited a dose-dependent effect, with mortality rates increasing from 10, 5, and 6% at 160 ppm to 100% at 2560 ppm for An. stephensi , Cx. quinquefasciatus , and Ae. aegypti . Statistical analysis confirmed a significant dose-dependent relationship ( p  < 0.05) between the concentration of T. ammi EO and D. speciosum extract and larval mortality, indicating that both are effective larvicides, with higher concentrations leading to increased mortality in mosquito populations (Table 2 ).

The results of this study also revealed that the average mortality rates differed significantly among the various larval species ( p  < 0.02). The ANOVA test indicated statistically significant differences in average mortality rates between An. stephensi and Cx. quinquefasciatus ( p  = 0.03), as well as between An. stephensi and Ae. aegypt ( p  = 0.04). However, the difference in average mortality rates between Cx. quinquefasciatus and Ae. aegypti was not statistically significant ( p  = 0.06( (Table 3 ).

A significant difference in the average larval mortality percentage was observed among the treatment groups ( p  = 0.001). The post-hoc ANOVA tests revealed a significant difference between the groups treated with T. ammi EO and D. speciosum extract ( p  = 0.02). Additionally, the average mortality percentage in the groups treated with either T. ammi EO or D. speciosum extract was significantly higher compared to the untreated group ( p  < 0.001) (Table 3 ).

The average mortality percentage varied across groups with different therapeutic concentrations, and this variation was statistically significant ( p  = 0.001). In the T. ammi EO treatment group, concentrations ranging from 20 to 160 ppm showed a significant difference compared to the untreated group ( p  < 0.001), while the 10 ppm concentration did not exhibit a statistically significant difference ( p  = 1.00).

In the group treated with D. speciosum extract, concentrations between 640 and 2560 ppm exhibited a significant difference compared to the untreated group ( p  < 0.001), while the 10 ppm concentration did not show a significant difference from the untreated group ( p  = 0.98) (Table 3 ).

The comparison of larval mortality percentages at different concentrations in the two treatment groups, T. ammi and D. speciosum , indicated no statistically significant difference between the highest concentration of D. speciosum (2560 ppm) and the concentrations of 40, 80, and 160 ppm of T. ammi ( p  > 0.05). Additionally, the lowest concentration of T. ammi (10 ppm) did not show a statistically significant difference compared to the concentrations of 160 to 640 ppm of D. speciosum ( p  > 0.05). However, the mortality percentages at other concentrations in the two treatment groups differred significantly ( p  < 0.05).

The mean difference (MD) and standardized mean difference (SMD) values, as well as the interpretation areas of the effect size, have been calculated and presented in (Tables 4 , 5 ). The effect size interpretation showed that concentrations of 1280 and 2560 ppm of D. speciosum were more effective in increasing larval mortality rate compared to other concentrations tested (Table 4 ). Additionally, the concentrations of 40, 80 and 160 ppm of T. ammi were identified as highly effective (Table 5 ).

According to the dose-response curve shown in (Fig.  1 ), the LC 50 value for the essential oil derived from T. ammi was calculated as 48.7, 18.3, and 19.7 ppm for An. stephensi , Cx. quinquefasciatus and Ae. aegypti , respectively. The LC 50 value for the extract of D. speciosum was determined as 517, 991.5, and 887.4 ppm for An. stephensi , Cx. quinquefasciatus and Ae. aegypti , respectively.

Dose-response curves depicting the larvicidal activity. ( a ) extract of D. speciosum ( b ) EOs of T. ammi .

Probit regression analysis of larvicidal data, shown in (Table 6 ), determined the LC 50 and LC 90 values for D. speciosum ’s extract and EO of T. ammi . The LC 90 value for the EO was calculated as 143.3, 35.8, and 40.2 ppm for An. stephensi , Cx. quinquefasciatus and Ae. aegypti , respectively. The LC 90 value for the extract was determined as 1157, 2662, and 2530 ppm for An. stephensi , Cx. quinquefasciatus and Ae. aegypti , respectively.

Essential oil composition

Chemical compounds of the EO of T. ammi are presented in (Table 7 ). The volatile oil was characterized by the presence of 6 constituents, representing 98.09% of the total compounds. Thymol (88.95%), o-cymen-5-ol (4.11%), and γ‑terpinene (2.10%) were identified as the most abundant phytochemicals. All of the compounds belong to monoterpenes. Oxygenated monoterpenes are the main class of compounds in EO composition. The remaining compounds belong to hydrocarbon monoterpenes (Table 7 ).

Extract composition

TLC method was used to confirm the presence of alkaloids. Spraying the dragendroff reagent on the TLC surface revealed the orange spots of alkaloids (Fig.  2 ). The resulting chromatogram showed that alkaloids are present only in the chloroform and methanolic extracts, and the petroleum ether extract does not contain these compounds. Examination of proton NMR spectra showed that the alkaloids in the chloroform and methanol extracts have a diterpene structure (Fig.  3 ).

TLC profile of alkaloids in different extract of Delphinium speciosum aerial part: 1- MeOH, 2-Chloroform extracts on Silica gel GF254 using Hexane: Chloroform: Methanol (11.5; 5: 0.5) as developing solvent mixtures. A dragendorff spsray reagent was used for detection of alkaloids.

NMR chromatogram of alkaloids in different extract of Delphinium speciosum aerial part ( a ) chloroformic ectract; ( b ) methanolic extract. The 1H-NMR spectra were recorded in CDCl3 in 400 MHz.

The development of eco-friendly and safe insecticides derived from natural sources, such as plants, is vital due to their precise targeting abilities and reduced risk of bioaccumulation. Utilizing natural control methods, like biopesticides, offers an effective strategy to combat insecticide resistance in mosquitoes 60 , 61 . In this study, we evaluated the efficacy of T. ammi essential oil and D. speciosum extract as larvicides against mosquito vectors of malaria, dengue fever, and filariasis.

Our study demonstrated the strong larvicidal effects of D. speciosum extract and T. ammi EO against three primary mosquito vectors: An. stephensi , Cx quinquefasciatus , and Ae. aegypti . These results are consistent with previous studies that investigated the toxic activity of Delphinium cardiopetalum extract against agricultural pest larvae 62 . Similar studies have demonstrated that extracts from Delphinium cultorum exhibit strong larvicidal effects on Ae. aegypti larvae 63 . The current study found mortality ratees ranging from 6 to 99% in Ae. aegypti , 10 to 100% in An. stephensi , and 5 to 98% in Cx. quinquefasciatus larvae treated with D. speciosum extracts at concentrations of 160 to 2560 ppm. These findings align with the 30–90% mortality observed in studies that reported significant larvicidal activity of 31 Delphinium species extracts against mosquito larvae 64 . Also, the findings of this study are consistent with previous research that reported significant larvicidal effects of Delphinium staphisagria against Leishmania spp, with a 100% mortality rate at 400 ppm 65 , which is higher than the 30–87% mortality rate at 200–1600 ppm observed in Ae. aegypti 35 , 66 .

In contrast to previous studies that indicated minimal insecticidal activity of Delphinium staphisagria against Pediculus species 67 , our study revealed a strong efficacy of D. speciosum extract against Ae. Aegypti, achieving a mortality rate of 99% at 2000 ppm. Our findings are also consistent with studies showing that the green synthesis of silver nanoparticles using Delphinium denudatum root extract possesses both antibacterial and mosquito larvicidal properties, with reported mortality rates of 95% at 4000 ppm in mosquito larvae 47 .

Many other studies have also shown that extracts from different plants have strong larvicidal effects on An. stephensi and Cx. quinquefasciatus , with reported mortality percentages ranging from 5 to 90%, which closely align with the results of our study 20 , 68 , 69 , 70 , 71 , 72 .

The results of previous studies showed that the EO of T. ammi seeds has moderate larvicidal effects on small hive beetles ( Aethina tumida), with a mortality rate of 36.25% at the highest concentration (48 ppm). In contrast, the results of our study shows that the mortality rate of the important vector species at a concentration of 40 ppm was 96% 73 . T. ammi exhibited high potency against larvae in this study, with a similar effect recorded against Cx. quinquefasciatus , Ae. aegypti , and An. stephensi, achieving mortality rates of 90, 97, 100%, respectively 41 , 43 , 74 . While only a few studies have explored the larvicidal effects of D. speciosum extract and T. ammi EO, many studies have focused on the larvicidal properties of EOs from other plants on important vector species. A similar finding has been recorded for Cx. quinquefasciatus , Ae. aegypti , and An. stephensi 20 , 71 , 75 ,

Consistent with our results, several past studies have reported statistically significant variations in the susceptibility of different mosquito larvae to plant-derived larvicides 33 , 76 , 77 , 78 . However, in contrast to our findings, a few previous research have reported no statistically significant differences in the larvicidal efficacy of plant extracts across different mosquito species 79 , 80 .

The statistically significant differences in the average larval mortality can be attributed to several factors. First, there is a variation in larval physiology and biochemistry, meaning different larval species may have different physiological and biochemical responses to the same treatment. Second, there is a differential penetration or mode of action of the larvicides, which means that the effectiveness of the larvicides can vary depending on how they penetrate the larvae or their mode of action 81 , 82 . These statistically significant differences in the average larval mortality underscore the importance of considering species-specific responses when developing and deploying plant-derived larvicides.

The results of our study indicated that T. ammi EO demonstrated stronger larvicidal activity than D. speciosum extract against all tested species. This increased effectiveness is attributed to its higher concentration of bioactive compounds. These EOs disrupt larval physiological processes and possess antimicrobial properties, which may enhance their effectiveness 72 . This finding aligns with previous studies, further confirming the superior efficacy of essential oil 83 , 84 . EO with an LC 50 value less than 50 ppm are deemed very active, those between 50 and 100 ppm as active, and those over 100 ppm are considered weak or inactive 85 . For extracts, toxicity varies with LC 50 values: under 100 ppm is highly toxic, 100–500 ppm is moderately toxic, 500–1000 ppm is low toxicity, and above 1000 ppm is non-toxic 86 . Based on this classification, the LC 50 of T. ammi EO and D. speciosum extract from our study categorizes them as highly toxic and moderately toxic against all three vector species, respectively.

Our findings revealed that both plant-derived larvicides exhibited significant, dose-dependent larvicidal activities across all tested mosquito species, which are in line with the results of previous studies 33 , 72 , 78 , 83 . The LC 50 of the T. ammi EO against An. stephensi larvae was 49 ppm, which is lower than the LC 50 (81 ppm) reported for the same EOs in a previous study 41 . Similarly, the LC 50 values of the EO from T. ammi against Ceratitis capitata , Tribolium castaneum , and Aethina tumidawas were reported to be 46, 15, and 52 ppm, respectively 34 , 73 , 87 , and the LC 50 of the D. speciosum extract against Aedes larvae was 887 ppm, which is notably higher than the LC 50 (244 ppm) documented for the same crude extract in another investigation 35 .

The effect size analysis of this study revealed that D. speciosum extract exhibited potent effects solely at concentrations of 1280 and 2560 ppm. In contrast, T . ammi essential oil demonstrated effects ranging from moderate to strong at concentrations between 20 and 160 ppm. Moreover, based on our knowledge, there were no reports found on the effect size of the larvicidal impact of D. speciosum extract and T. ammi EO against An. stephensi , Cx. quinquefasciatus , and Ae. aegypti . The findings on effect size and effective concentration were highly beneficial for enhancing larval mortality rates and applying them in real-world scenarios. In this research, the practical concentrations used were 1280 ppm for D. speciosum and 40 ppm for T. ammi .

Previous studies reported that γ‑terpinene, carvacrol, p-cymene, and thymol were the main phytochemicals in the EO of T. ammi 52 , 88 , 89 , 90 , 91 , 92 , 93 , 94 , 95 . These studies investigated different chemotypes of T. ammi from different localities using various extraction methods. Our findings on the chemical constituents of the plant are consistent with previous findings. The minor differences in the chemical compositions reported by different studies may be associated with variable climate, geographical conditions, genetics, and extraction techniques. Previous studies show that most of the alkaloids in the genus Delphinium have diterpene structures 96 . As shown in our results, several alkaloid compounds were observed in chloroform and methanolic extracts.

The mechanisms of action of essential oils and total plant extracts against mosquito larvae are multifaceted and distinct. Essential oils primarily exert their larvicidal effects through contact toxicity, neurotoxicity, and enzyme inhibition. Upon contact, essential oils disrupt the larvae’s cuticle, leading to desiccation and death. Neurotoxic components, such as monoterpenes and sesquiterpenes, interfere with the nervous system, causing paralysis and mortality. Additionally, some essential oils inhibit acetylcholinesterase, an enzyme crucial for nerve signal transmission, further disrupting larval neural functions. In contrast, total plant extracts, which encompass a broader range of bioactive compounds, act through multiple mechanisms including growth disruption, metabolic inhibition, and oviposition deterrence. The diverse chemical constituents in plant extracts, such as alkaloids, flavonoids, and saponins, interfere with larval development and molting processes, disrupt energy metabolism, and deter female mosquitoes from laying eggs in treated water. These combined actions make both essential oils and plant extracts effective larvicides, though their specific mechanisms and applications may vary depending on the plant species and extraction methods used 97 , 98 , 99 , 100 .

Botanically derived natural larvicides are gaining attention as safety and environmentally friendly alternatives to synthetic insecticides for mosquito control. Despite their benefits, such as lower chemical residues and reduced toxicity to non-target organisms, there are still potential environmental impacts and safety concerns that must be considered. Additionally, the persistence and degradation of these natural compounds in the environment are not always well understood. While the safety profile of natural larvicides for humans and animals is generally better than that of synthetic insecticides, some natural compounds can still pose risks. Furthermore, the variability in the composition of natural extracts can lead to inconsistent efficacy and safety profiles. Standardization and rigorous testing are essential to ensure the safe use of these products 101 , 102 , 103 .

Our study offers encouraging indications of the larvicidal potential of D. speciosum extract and T. ammi EO. However, it’s crucial to recognize some limitations. The experiments were carried out in a controlled laboratory environment. To evaluate the effectiveness and practicality of these plant-derived compounds in real-world vector control programs, additional field-based assessments are required. Furthermore, identifying and characterizing the specific phytochemicals that contribute to the observed larvicidal activities calls for more in-depth investigation.

Our study has highlighted the substantial larvicidal effects of D. speciosum extract and T. ammi EO against three primary disease vector mosquitoes. The larvicidal activity of T. ammi essential oil surpasses that of D. speciosum extract, with the optimal concentration being 40 ppm. Additionally, among the species studied, Cx. quinquefasciatus exhibits the highest sensitivity to these plant-derived treatments. Thymol is the main component of T. ammi EO, and the alkaloids in D. speciosum extract have diterpene structures. Considering the effect size values, along with the dose-dependent trends and species-specific responses can help researchers gain a more comprehensive understanding of the real-world implications and potential utility of the plant-derived larvicides investigated in this study. Future studies should include both laboratory and field trials to evaluate their effectiveness against diverse mosquito populations, assess its environmental impact, and determine optimal application methods for their practical use in vector control.

Data availability

The datasets used and/or analysed during the current study available from the corresponding author on reasonable request.

Reinhold, J. M., Lazzari, C. R. & Lahondère, C. Effects of the environmental temperature on Aedes aegypti and Aedes albopictus mosquitoes: A review. Insects 9 , 158 (2018).

Article   PubMed   PubMed Central   Google Scholar  

Gabrieli, P., Smidler, A. & Catteruccia, F. Engineering the control of mosquito-borne infectious diseases. Genome Biol. 15 , 1–9 (2014).

Article   Google Scholar  

CDC. Centers for Disease Control and Prevention. Where mosquitoes live 2024. https://www.cdc.gov/mosquitoes/about/where-mosquitoes-live_1.html . (accessed 22 June 2024).

Wilder-Smith, A. et al. Epidemic arboviral diseases: Priorities for research and public health. Lancet Infect. Dis. 17 , e101–e106 (2017).

Article   PubMed   Google Scholar  

Benelli, G. & Mehlhorn, H. Declining malaria, rising of dengue and Zika virus: insights for mosquito vector control. Parasitol. Res. 115 , 1747–1754 (2016).

Benelli, G. Research in mosquito control: Current challenges for a brighter future. Parasitol. Res. 114 , 2801–2805 (2015).

Samy, A. M. et al. Climate change influences on the global potential distribution of the mosquito Culex quinquefasciatus , vector of West Nile virus and lymphatic filariasis. PLoS ONE 11 , e0163863 (2016).

Benelli, G. et al. Acute larvicidal toxicity of five essential oils ( Pinus nigra , Hyssopus officinalis , Satureja montana , Aloysia citrodora and Pelargonium graveolens ) against the filariasis vector Culex quinquefasciatus : Synergistic and antagonistic effects. Parasitol. Int. 66 , 166–171 (2017).

Article   CAS   PubMed   Google Scholar  

Thandapani, K. et al. Enhanced larvicidal, antibacterial, and photocatalytic efficacy of TiO 2 nanohybrids green synthesized using the aqueous leaf extract of Parthenium hysterophorus . Environ. Sci. Pollut. Res. 25 , 10328–10339 (2018).

Article   CAS   Google Scholar  

WHO. World Health Organisation. lymphatic philariasis key facts 2023 https://www.who.int/news-room/fact-sheets/detail/lymphatic-filariasis . (accessed 1 June 2023).

Liu, Q. et al. Possible potential spread of Anopheles stephensi , the Asian malaria vector. BMC Infect. Dis. 24 , 333 (2024).

WHO. World Health Organisation. Malaria key facts 2023 https://www.who.int/news-room/fact-sheets/detail/malaria . (accessed 4 December 2023).

Brady, O. J. et al. Refining the global spatial limits of dengue virus transmission by evidence-based consensus. PLoS Negl. Trop. Dis. 6 , e1760 (2012).

WHO. World Health Organisation. Dengue and severe dengue https://www.who.int/news-room/fact-sheets/detail/dengue-and-severe-dengue . (accessed 17 March 2023).

Laith, A. E., Alnimri, M., Ali, H., Alkhawaldeh, M. & Mihyar, A. Mosquito-borne diseases: assessing risk and strategies to control their spread in the Middle East. J. Biosaf. Biosecur. 6 , 1–12 (2024).

Floore, T. G. Mosquito larval control practices: Past and present. J. Am. Mosq. Control Assoc. 22 , 527–533 (2006).

Naqqash, M. N., Gökçe, A., Bakhsh, A. & Salim, M. Insecticide resistance and its molecular basis in urban insect pests. Parasitol. Res. 115 , 1363–1373 (2016).

Mansouri, A. et al. The environmental issues of DDT pollution and bioremediation: A multidisciplinary review. Appl. Biochem. Biotechnol. 181 , 309–339 (2017).

Serrão, J. E., Plata-Rueda, A., Martínez, L. C. & Zanuncio, J. C. Side-effects of pesticides on non-target insects in agriculture: A mini-review. Sci. Nat. 109 , 17 (2022).

Selvakumaran, J. et al. Evaluation of mosquitocidal, histopathological and non-target effect of botanical pesticides from Stemodia viscosa and their mixtures against immature stages of Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus . . Biologia 79 , 1425–1437 (2024).

Khater, H. F. Prospects of botanical biopesticides in insect pest management. Pharmacologia 3 , 641–656 (2012).

Govindarajan, M., Rajeswary, M. & Benelli, G. Chemical composition, toxicity and non-target effects of Pinus kesiya essential oil: An eco-friendly and novel larvicide against malaria, dengue and lymphatic filariasis mosquito vectors. Ecotoxicol. Environ. Saf. 129 , 85–90 (2016).

Nenaah, G. E. & Ibrahim, S. I. Chemical composition and the insecticidal activity of certain plants applied as powders and essential oils against two stored-products coleopteran beetles. J. Pest Sci. 84 , 393–402 (2011).

Sousa, Z. L. et al. Biological activities of extracts from Chenopodium ambrosioides Lineu and Kielmeyera neglecta Saddi . Ann. Clin. Microbiol. Antimicrob. 11 , 1–7 (2012).

Article   ADS   Google Scholar  

Pavela, R. et al. Clausena anisata and Dysphania ambrosioides essential oils: From ethno-medicine to modern uses as effective insecticides. Environ. Sci. Pollut. Res. 25 , 10493–10503 (2018).

Kavallieratos, N. G. et al. Effectiveness of eight essential oils against two key stored-product beetles, Prostephanus truncatus (Horn) and Trogoderma granarium everts. Food Chem. Toxicol. 139 , 111255 (2020).

Haddi, K. et al. Rethinking biorational insecticides for pest management: Unintended effects and consequences. Pest Manag. Sci. 76 , 2286–2293 (2020).

Article   ADS   CAS   PubMed   Google Scholar  

Dai, D. N. et al. Chemical compositions, mosquito larvicidal and antimicrobial activities of essential oils from five species of cinnamomum growing wild in north central Vietnam. Molecules 25 , 1303 (2020).

Article   CAS   PubMed   PubMed Central   Google Scholar  

Eden, W. T., Alighiri, D., Supardi, K. I. & Cahyono, E. The mosquito repellent activity of the active component of air freshener gel from java citronella oil ( Cymbopogon winterianus ). J. Parasitol. Res. 202 , 1–5 (2020).

Silvério, M. R. S., Espindola, L. S., Lopes, N. P. & Vieira, P. C. Plant natural products for the control of Aedes aegypti : The main vector of important arboviruses. Molecules 25 , 3484 (2020).

Vasudevan, P., Kashyap, S. & Sharma, S. Tagetes: A multipurpose plant. Bioresour. Technol. 62 , 29–35 (1997).

Ansari, M., Vasudevan, P., Tandon, M. & Razdan, R. Larvicidal and mosquito repellent action of peppermint ( Mentha piperita ) oil. Bioresour. Technol. 71 , 267–271 (2000).

Sanei-Dehkordi, A., Moemenbellah-Fard, M. D., Saffari, M., Zarenezhad, E. & Osanloo, M. Nanoliposomes containing limonene and limonene-rich essential oils as novel larvicides against malaria and filariasis mosquito vectors. BMC Complement. Med. Ther. 22 , 140 (2022).

Benelli, G. et al. Carlina acaulis and Trachyspermum ammi essential oils formulated in protein baits are highly toxic and reduce aggressiveness in the medfly Ceratitis capitata . Ind. Crops Prod. 161 , 113191 (2021).

Sen-Utsukarci, B. et al. The cytotoxicity and insecticidal activity of extracts from Delphinium formosum boiss. & huet. Istanb. J. Pharm. 49 , 148–153 (2019).

Google Scholar  

Pitarokili, D., Michaelakis, A., Koliopoulos, G., Giatropoulos, A. & Tzakou, O. Chemical composition, larvicidal evaluation, and adult repellency of endemic Greek Thymus essential oils against the mosquito vector of West Nile virus. Parasitol. Res. 109 , 425–430 (2011).

Michaelakis, A., Theotokatos, S. A., Koliopoulos, G. & Chorianopoulos, N. G. Essential oils of Satureja species: insecticidal effect on Culex pipiens larvae ( Diptera : Culicidae ). Molecules 12 , 2567–2578 (2007).

Tabari, M. A., Youssefi, M. R., Esfandiari, A. & Benelli, G. Toxicity of β-citronellol, geraniol and linalool from Pelargonium roseum essential oil against the West Nile and filariasis vector Culex pipiens ( Diptera : Culicidae ). Res. Vet. Sci. 114 , 36–40 (2017).

Al-Mekhlafi, F. A. Larvicidal, ovicidal activities and histopathological alterations induced by Carum copticum ( Apiaceae ) extract against Culex pipiens ( Diptera : Culicidae ). Saudi J. Biol. Sci. 25 , 52–56 (2018).

Andrade-Ochoa, S. et al. Oviposition deterrent and larvicidal and pupaecidal activity of seven essential oils and their major components against Culex quinquefasciatus Say ( Diptera : Culicidae ): synergism–antagonism effects. Insects 9 , 25 (2018).

Pandey, S., Upadhyay, S. & Tripathi, A. Insecticidal and repellent activities of thymol from the essential oil of Trachyspermum ammi (Linn) sprague seeds against Anopheles stephensi . Parasitol. Res. 105 , 507–512 (2009).

Kadam, S. S., More, S. B. & Waghmare, J. S. Tranchyspermum Ammi : Natural pesticides. J. Biopest. 10 , 90–98 (2017).

Bhadra, P. An overview of Ajwain ( Trachyspermum ammi ). Indian J. Nat. Sci. 10 , 18466–182474 (2020).

Gheybi, S., Asnaashari, S., Moghaddam, S. B., Ebrahimi, A. & Afshar, F. H. Volatile components of aerial parts of Delphinium speciosum MB growing in Iran. J. Rep. Pharm. Sci. 4 , 191–195 (2015).

Vicentini, C. B., Manfredini, S. & Contini, C. Ancient treatment for lice: A source of suggestions for carriers of other infectious diseases?. Infez. Med. 26 , 181–192 (2018).

PubMed   Google Scholar  

Shan, L., Chen, L., Gao, F. & Zhou, X. Diterpenoid alkaloids from Delphinium naviculare var. lasiocarpum with their antifeedant activity on Spodoptera exigua . Nat. Prod. Res. 33 , 3254–3259 (2019).

Suresh, G. et al. Green synthesis of silver nanoparticles using Delphinium denudatum root extract exhibits antibacterial and mosquito larvicidal activities. Spectrochim. Acta Part A Mol. Biomol. Spectrosc. 127 , 61–66 (2014).

Article   ADS   CAS   Google Scholar  

Dey, P. et al. Recent Advances in Natural Products Analysis (Elsevier, 2020).

Pereira, A. G. et al. Natural Secondary Metabolites: From Nature, Through Science, to Industry (Springer, 2023).

Kumar, A., Shukla, R., Singh, P. & Dubey, N. K. Chemical composition, antifungal and antiaflatoxigenic activities of Ocimum sanctum L. essential oil and its safety assessment as plant based antimicrobial. Food Chem. Toxicol. 48 , 539–543 (2010).

WHO. World Health Organization. Guidelines for laboratory and field testing of mosquito larvicides (No. WHO/CDS/WHOPES/GCDPP/2005.13).

Bahadori, M. B., Asnaashari, S. & Nazemiyeh, H. Fatty acid profile of roots and aerial parts of Ruscus hyrcanus Woronow. Pharma. Sci. 25 , 78–81 (2019).

Wei, Y. et al. 1H NMR guided isolation of 3-arylisoquinoline alkaloids from Hypecoum erectum L. and their anti-inflammation activity. Phytochemistry 222 , 114093 (2024).

Xiao, J. et al. 1H NMR-guided isolation of hasubanan alkaloids from the alkaloidal extract of Stephania longa . Bioorg. Chem. 139 , 106717 (2023).

Zhao, C.-X. et al. 1H-NMR-guided isolation of enantiomeric coumarin-monoterpenes with anti-inflammatory activity from Gerbera piloselloides . Phytochemistry 203 , 113346 (2022).

Wang, A. D. et al. Isolation and structure determination of new saponins from Pulsatilla cernua based on an NMR-guided method and their anti-proliferative activities. Phytochem. Lett. 27 , 9–14 (2018).

Zhang, Y. et al. Isolation of a new monoterpenoid glycoside from anhua dark tea based on an NMR-guided method and its cytotoxic activity against MDA-MB-231 and SH-SY5Y cell lines. Nat. Prod. Res. 36 , 2015–2020 (2022).

Elliott, A. C. & Woodward, W. A. Statistical Analysis Quick Reference Guidebook: with SPSS Examples (Sage, 2007).

Book   Google Scholar  

Cohen, J. Statistical Power Analysis for the Behavioral Sciences (Routledge, 2013).

Rahimi, S., Vatandoost, H., Abai, M. R., Raeisi, A. & Hanafi-Bojd, A. A. Status of resistant and knockdown of West Nile vector, Culex pipiens complex to different pesticides in Iran. J. Arthropod Borne Dis. 13 , 284 (2019).

PubMed   PubMed Central   Google Scholar  

Rahimi, S. et al. Resistant status of Culex pipiens complex species to different imagicides in Tehran Iran. J.Vect. Borne Dis. 57 , 47–51 (2020).

González-Coloma, A. et al. Antifeedant delphinium diterpenoid alkaloids. Structure—Activity relationships. J. Agric. Food Chem. 46 , 286–290 (1998).

Miles, J. E., Ramsewak, R. S. & Nair, M. G. Antifeedant and mosquitocidal compounds from delphinium× cultorum Cv. magic fountains flowers. J. Agric. Food Chem. 48 , 503–506 (2000).

Ulubelen, A. et al. Insect repellent activity of diterpenoid alkaloids. Phytother. Res. 15 , 170–171 (2001).

Ramírez-Macías, I. et al. Leishmanicidal activity of nine novel flavonoids from Delphinium staphisagria . Sci. World J. 2012 , 203646 (2012).

Yan, Y., Li, X., Wang, Z., Yang, X. & Yin, T. C 18-diterpenoid alkaloids in tribe Delphineae ( Ranunculaceae ): Phytochemistry, chemotaxonomy, and bioactivities. RSC Adv. 12 , 395–405 (2022).

Vicentini, C. B., Manfredini, S. & Contini, C. Ancient treatment for lice: A source of suggestions for carriers of other infectious diseases?. Le Infez. Med. 26 , 181–192 (2018).

Alghamdi, A. A. & Basher, N. S. Efficacy of leaves and flowers ethanol extracts of the invasive species Lantana camara Linn as a mosquito larvicidal. Int. J. Mosq. Res. 7 , 43–47 (2020).

Fasasi, K., Olawoyin, M. O., Rufai, A. M. & Iwalewa, Z. O. Anales de Biología (Servicio de Publicaciones de la Universidad de Murcia, 2024).

Mandal, P. & Chandra, G. Casearia tomentosa fruit extracts exposed larvicidal activity and morphological alterations in Culex q uinquefasciatus and Aedes albopictus under in vitro and semi field conditions. BMC Res. Notes 17 , 6 (2024).

Pirmohammadi, M. et al. Influence of agro-climatic conditions on chemical compositions and repellency effect of Mentha longifolia plant against malaria vector Anopheles stephensi . Toxin Rev. 42 , 115–121 (2023).

Baz, M. M., Selim, A., Radwan, I. T., Alkhaibari, A. M. & Khater, H. F. Larvicidal and adulticidal effects of some Egyptian oils against Culex pipiens . Sci. Rep. 12 , 4406 (2022).

Article   ADS   CAS   PubMed   PubMed Central   Google Scholar  

Bisrat, D. & Jung, C. Insecticidal toxicities of three main constituents derived from T rachyspermum ammi (L.) Sprague ex turrill fruits against the small hive beetles, Aethina tumida murray. Molecules 25 , 1100 (2020).

Seo, S. M., Park, H. M. & Park, I. K. Larvicidal activity of ajowan ( Trachyspermum ammi ) and Peru balsam ( Myroxylon pereira ) oils and blends of their constituents against mosquito, Aedes aegypti , acute toxicity on water flea, Daphnia magna , and aqueous residue. J. Agric. Food Chem. 60 , 5909–5914 (2012).

Kusman, I. T. et al. The potentials of Ageratum conyzoides and other plants from Asteraceae as an antiplasmodial and insecticidal for malaria vector: An article review. Infect. Drug Resist. 16 , 7109–7138 (2023).

Ammar, S. et al. Essential oils from three Algerian medicinal plants ( Artemisia campestris , Pulicaria arabica , and Saccocalyx satureioides ) as new botanical insecticides?. Environ. Sci. Pollut. Res. 27 , 26594–26604 (2020).

Benelli, G. et al. Ascaridole-rich essential oil from marsh rosemary ( Ledum palustre ) growing in Poland exerts insecticidal activity on mosquitoes, moths and flies without serious effects on non-target organisms and human cells. Food Chem. Toxicol. 138 , 111184 (2020).

Žabka, M. et al. Antifungal and insecticidal potential of the essential oil from Ocimum sanctum L. against dangerous fungal and insect species and its safety for non-target useful soil species Eisenia fetida (Savigny, 1826). Plants 10 , 2180 (2021).

Huong, L. T. et al. Essential oils of Zingiber species from Vietnam: Chemical compositions and biological activities. Plants 9 , 1269 (2020).

An, N. T. G. et al. Mosquito larvicidal activity, antimicrobial activity, and chemical compositions of essential oils from four species of Myrtaceae from central Vietnam. Plants 9 , 544 (2020).

Inaba, K. et al. Molecular action of larvicidal flavonoids on ecdysteroidogenic glutathione S-transferase Noppera-bo in Aedes aegypti . BMC Biol. 20 , 43 (2022).

Antonio-Nkondjio, C., Sandjo, N. N., Awono-Ambene, P. & Wondji, C. S. Implementing a larviciding efficacy or effectiveness control intervention against malaria vectors: Key parameters for success. Parasites Vect. 11 , 1–12 (2018).

García-Díaz, J. et al. Larvicidal and adulticidal activity of essential oils from four cuban plants against three mosquito vector species. Plants 12 , 4009 (2023).

Chaves, R. D. S. B. et al. Evaluation of larvicidal potential against larvae of Aedes aegypti ( Linnaeus , 1762) and of the antimicrobial activity of essential oil obtained from the leaves of Origanum majorana L.. PLoS ONE 15 , e0235740 (2020).

Kiran, S. R., Bhavani, K., Devi, P. S., Rao, B. R. & Reddy, K. J. Composition and larvicidal activity of leaves and stem essential oils of Chloroxylon swietenia DC against Aedes aegypti and Anopheles stephensi . Bioresour. Technol. 97 , 2481–2484 (2006).

Nguta, J. et al. Biological screening of Kenya medicinal plants using Artemia salina L. ( Artemiidae ). Pharmacologyonline 2 , 458–478 (2011).

Chaubey, M. K. Insecticidal activity of Trachyspermum ammi ( Umbelliferae ), Anethum graveolens (Umbelliferae) and Nigella sativa ( Ranunculaceae ) essential oils against stored-product beetle Tribolium castaneum herbst ( Coleoptera : Tenebrionidae ). Afr. J. Agric. Res. 2 , 596–600 (2007).

Sahaf, B. Z., Moharramipour, S. & Meshkatalsadat, M. H. Chemical constituents and fumigant toxicity of essential oil from Carum copticum against two stored product beetles. Insect Sci. 14 , 213–218 (2007).

Moein, M. R. et al. Trachyspermum ammi (L.) sprague: Chemical composition of essential oil and antimicrobial activities of respective fractions. J. Evid. Based Complement. Altern. Med. 20 , 50–56 (2015).

Rasooli, I. et al. Antimycotoxigenic characteristics of Rosmarinus officinalis and Trachyspermum copticum L. essential oils. Int. J. Food Microbiol. 122 , 135–139 (2008).

Khajeh, M., Yamini, Y., Sefidkon, F. & Bahramifar, N. Comparison of essential oil composition of Carum copticum obtained by supercritical carbon dioxide extraction and hydrodistillation methods. Food Chem. 86 , 587–591 (2004).

Srivastava, M., Baby, P. & Saxena, A. GC-MS investigation and antimicrobial activity of the essential oil of Carum c opticum benth & hook. Acta Aliment. 28 , 291–295 (1999).

Mohagheghzadeh, A., Faridi, P. & Ghasemi, Y. Carum copticum Benth & Hook essential oil chemotypes. Food Chem. 100 , 1217–1219 (2007).

Shojaaddini, M., Moharramipour, S. & Sahaf, B. Fumigant toxicity of essential oil from Carum copticum against Indian meal moth, Plodia interpunctella . J. Plant Protect. Res. https://doi.org/10.2478/v10045-008-0050-5 (2008).

Dhaiwal, K., Chahal, K. K., Kataria, D. & Kumar, A. Gas chromatography-mass spectrometry analysis and in vitro antioxidant potential of ajwain seed ( Trachyspermum ammi L.) essential oil and its extracts. J. Food Biochem. 41 , e12364 (2017).

Lotfaliani, M., Ayatollahi, S. A., Kobarfard, F. & Pour, P. M. Chemistry, biological activities and toxic effects of alkaloidal constituents of genus Delphinium —A mini review. J. Herbmed. Pharmacol. 10 , 486–499 (2021).

Kelly, P. H., Yingling, A. V., Ahmed, A., Hurwitz, I. & Ramalho-Ortigao, M. Defining the mechanisms of action and mosquito larva midgut response to a yeast-encapsulated orange oil larvicide. Parasites Vect. 15 , 183 (2022).

Cruz-Castillo, A. U. et al. Terpenic constituents of essential oils with larvicidal activity against Aedes Aegypti : A QSAR and docking molecular study. Molecules 28 , 2454 (2023).

Isman, M. B. & Tak, J. H. Inhibition of acetylcholinesterase by essential oils and monoterpenoids: a relevant mode of action for insecticidal essential oils? Biopest. Int. 13 , 71–78 (2017).

Pavela, R., Maggi, F., Iannarelli, R. & Benelli, G. Plant extracts for developing mosquito larvicides: From laboratory to the field, with insights on the modes of action. Acta Tropica 193 , 236–271 (2019).

Pavela, R. & Benelli, G. Essential oils as ecofriendly biopesticides? Challenges and constraints. Trends Plant Sci. 21 , 1000–1007 (2016).

Nawaz, M., Mabubu, J. I. & Hua, H. Current status and advancement of biopesticides: Microbial and botanical pesticides. J. Entomol. Zool. Stud. 4 , 241–246 (2016).

Mathew, L. K. Botanicals as biopesticides: A review. Int. J. Adv. Res. 4 , 1734–1739 (2016).

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Acknowledgements

Our appreciation goes to Dr. A.A. Keshtkar, Dr. A. Latifi, Dr. A. Ebrahimi, and Mr. A. Azadnia for his direction and counsel throughout the project.

This work was founded and supported by the Maragheh University of Medical Sciences (MRGUMS), (IR.MARAGHEHPHC.REC.1401.012) Maragheh, Iran.

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These authors contributed equally: Sara Rahimi and Hossein Nazemiyeh.

Authors and Affiliations

Infectious and Tropical Diseases Research Center, Hormozgan Health Institute, Hormozgan University of Medical Sciences, Bandar Abbas, Iran

Alireza Sanei‑Dehkordi

Student Research Committee, Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran

Amir Masoud Tagizadeh

Medicinal Plants Research Center, Maragheh University of Medical Sciences, Maragheh, Iran

Mir Babak Bahadori, Elhameh Nikkhah & Sara Rahimi

Department of Vector Biology and Control of Diseases, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran

Masoumeh Pirmohammadi

Department of Pharmacognosy, Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran

Hossein Nazemiyeh

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Contributions

Conceptualization, S.R., H.N., and A.S-D.; Methodology, H.N., M.P., and A.S-D.; Formal Analysis, S.R., and M-B.B.; Investigation, S.R., A-M.T., and H.N.; Data Curation, S.R., E.N., and M-B.B.; Writing—Original Draft Preparation, S.R., A.S-D., M-B.B., and A-M.T.; Writing—Review & Editing, S.R., H.N., A.S-D., M-B.B., A-M.T., E.N., and M.P.; Supervision, H.N.; Project Administration, S.R.; All authors have read and agreed to the published version of the manuscript.

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Sanei‑Dehkordi, A., Tagizadeh, A.M., Bahadori, M.B. et al. Larvicidal potential of Trachyspermum ammi essential oil and Delphinium speciosum extract against malaria, dengue, and filariasis mosquito vectors. Sci Rep 14 , 20677 (2024). https://doi.org/10.1038/s41598-024-71829-x

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Received : 11 July 2024

Accepted : 30 August 2024

Published : 05 September 2024

DOI : https://doi.org/10.1038/s41598-024-71829-x

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• Larvicidal activity
• Culex quinquefasciatus
• Aedes aegypti
• Anopheles stephensi
• Essential oil

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