Imperial College London

DrLaurenCator

Faculty of Natural SciencesDepartment of Life Sciences (Silwood Park)

Senior Lecturer
 
 
 
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Contact

 

+44 (0)20 7594 1785l.cator Website

 
 
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Location

 

2.6MunroSilwood Park

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Summary

 

Publications

Publication Type
Year
to

33 results found

Pawar S, Huxley PJ, Smallwood TRC, Nesbit ML, Chan AHH, Shocket MS, Johnson LR, Kontopoulos D-G, Cator LJet al., 2024, Variation in temperature of peak trait performance constrains adaptation of arthropod populations to climatic warming., Nat Ecol Evol, Vol: 8, Pages: 500-510

The capacity of arthropod populations to adapt to long-term climatic warming is currently uncertain. Here we combine theory and extensive data to show that the rate of their thermal adaptation to climatic warming will be constrained in two fundamental ways. First, the rate of thermal adaptation of an arthropod population is predicted to be limited by changes in the temperatures at which the performance of four key life-history traits can peak, in a specific order of declining importance: juvenile development, adult fecundity, juvenile mortality and adult mortality. Second, directional thermal adaptation is constrained due to differences in the temperature of the peak performance of these four traits, with these differences expected to persist because of energetic allocation and life-history trade-offs. We compile a new global dataset of 61 diverse arthropod species which provides strong empirical evidence to support these predictions, demonstrating that contemporary populations have indeed evolved under these constraints. Our results provide a basis for using relatively feasible trait measurements to predict the adaptive capacity of diverse arthropod populations to geographic temperature gradients, as well as ongoing and future climatic warming.

Journal article

Wyer C, Brian H, Cator L, 2023, Release from sexual selection leads to rapid genome-wide evolution in Aedes aegypti, Current Biology, Vol: 33, Pages: 1351-1357.e5, ISSN: 0960-9822

The yellow fever mosquito, Aedes aegypti, mates in flight as part of ephemeral aggregations termed swarms. Swarms contain many more males than females, and males are thought to be subject to intense sexual selection.1,2 However, which male traits are involved in mating success and the genetic basis of these traits remains unclear. We used an experimental evolution approach to measure genome-wide responses of Ae. aegypti evolved in the presence and absence of sexual selection. These data revealed for the first time how sexual selection shapes the genome of this important species. We found that populations evolved under sexual selection retained greater genetic similarity to the ancestral population and a higher effective population size than populations evolving without sexual selection. When we compared evolutionary regimes, we found that genes associated with chemosensation responded rapidly to the elimination of sexual selection. Knockdown of one high-confidence candidate gene identified in our analysis significantly decreased male insemination success, further suggesting that genes related to male sensory perception are under sexual selection. Several mosquito control technologies involve the release of males from captive populations into the wild. For these interventions to work, a released male must compete against wild males to successfully inseminate a female. Our results suggest that maintaining the intensity of sexual selection in captive populations used in mass-releases is important for sustaining both male competitive ability and overall genetic similarity to field populations.

Journal article

Qureshi A, Keen E, Brown G, Cator Let al., 2023, The size of larval rearing container modulates the effects of diet amount and larval density on larval development in Aedes aegypti, PLoS One, Vol: 18, Pages: 1-18, ISSN: 1932-6203

Mass-rearing of mosquitoes under laboratory conditions is an important part of several new control techniques that rely on the release of males to control mosquito populations. While previous work has investigated the effect of larval density and diet amount on colony productivity, the role of the size of the container in which larval development takes place has been relatively ignored. We investigated the role of container size in shaping life history and how this varied with density and food availability in Aedes aegypti, an important disease vector and target of mass-rearing operations. For each treatment combination, immature development time and survival and adult body size and fecundity were measured, and then combined into a measure of productivity. We additionally investigated how larval aggregation behaviour varied with container size. Container size had important effects on life history traits and overall productivity. In particular, increasing container size intensified density and diet effects on immature development time. Productivity was also impacted by container size when larvae were reared at high densities (1.4 larva/ml). In these treatments, the productivity metric of large containers was estimated to be significantly lower than medium or small containers. Regardless of container size, larvae were more likely to be observed at the outer edges of containers, even when this led to extremely high localized densities. We discuss how container size and larval aggregation responses may alter the balance of energy input and output to shape development and productivity.

Journal article

Gregory N, Ewers RM, Chung AYC, Cator LJet al., 2022, Oil palm expansion increases the vectorial capacity of dengue vectors in Malaysian Borneo, PLoS Neglected Tropical Diseases, Vol: 16, ISSN: 1935-2727

Changes in land-use and the associated shifts in environmental conditions can have large effects on the transmission and emergence of mosquito-borne disease. Mosquito-borne disease are particularly sensitive to these changes because mosquito growth, reproduction, survival and susceptibility to infection are all thermally sensitive traits, and land use change dramatically alters local microclimate. Predicting disease transmission under environmental change is increasingly critical for targeting mosquito-borne disease control and for identifying hotspots of disease emergence. Mechanistic models offer a powerful tool for improving these predictions. However, these approaches are limited by the quality and scale of temperature data and the thermal response curves that underlie predictions. Here, we used fine-scale temperature monitoring and a combination of empirical, laboratory and temperature-dependent estimates to estimate the vectorial capacity of Aedes albopictus mosquitoes across a tropical forest-oil palm plantation conversion gradient in Malaysian Borneo. We found that fine-scale differences in temperature between logged forest and oil palm plantation sites were not sufficient to produce differences in temperature-dependent demographic trait estimates using published thermal performance curves. However, when measured under field conditions a key parameter, adult abundance, differed significantly between land-use types, resulting in estimates of vectorial capacity that were 1.5 times higher in plantations than in forests. The prediction that oil palm plantations would support mosquito populations with higher vectorial capacity was robust to uncertainties in our adult survival estimates. These results provide a mechanistic basis for understanding the effects of forest conversion to agriculture on mosquito-borne disease risk, and a framework for interpreting emergent relationships between land-use and disease transmission. As the burden of Ae. albopictus-vectored d

Journal article

Russell M, Cator L, 2022, No impact of biocontrol agent’s predation cues on development time or size of surviving Aedes al-bopictus under optimal nutritional availability, Insects, Vol: 13, ISSN: 2075-4450

Cyclopoid copepods have been applied successfully to limit populations of highly invasive Aedes albopictus mosquitoes that can transmit diseases of public health importance. However, there is concern that changes in certain mosquito traits, induced by exposure to copepod predation, might increase the risk of disease transmission. In this study, third instar Ae. albopictus larvae (focal individuals) were exposed to Megacyclops viridis predator cues associated with both the consumption of newly hatched mosquito larvae and attacks on focal individuals. The number of newly hatched larvae surrounding each focal larva was held constant to control for density effects on size, and the focal individual’s day of pupation and wing length were recorded for each replicate. Exposing late instar Ae. albopictus to predation decreased their chances of surviving to adulthood, and three focal larvae that died in the predator treatment showed signs of melanisation, indicative of wounding. Among surviving focal Ae. albopictus, no significant difference in either pupation day or wing length was observed due to copepod predation. The absence of significant sublethal impacts from M. viridis copepod predation on surviving later stage larvae in this analysis supports the use of M. viridis as a biocontrol agent against Ae. albopictus.

Journal article

Huxley PJ, Murray KA, Pawar S, Cator LJet al., 2022, Competition and resource depletion shape the thermal response of population fitness in <i>Aedes aegypti</i>, COMMUNICATIONS BIOLOGY, Vol: 5

Journal article

Russell MC, Herzog CM, Gajewski Z, Ramsay C, El Moustaid F, Evans MV, Desai T, Gottdenker NL, Hermann SL, Power AG, McCall ACet al., 2022, Both consumptive and non-consumptive effects of predators impact mosquito populations and have implications for disease transmission, eLife, Vol: 11, Pages: 1-23, ISSN: 2050-084X

Predator-prey interactions influence prey traits through both consumptive and non-consumptive effects, and variation in these traits can shape vector-borne disease dynamics. Meta-analysis methods were employed to generate predation effect sizes by different categories of predators and mosquito prey. This analysis showed that multiple families of aquatic predators are effective in consumptively reducing mosquito survival, and that the survival of Aedes, Anopheles, and Culex mosquitoes is negatively impacted by consumptive effects of predators. Mosquito larval size was found to play a more important role in explaining the heterogeneity of consumptive effects from predators than mosquito genus. Mosquito survival and body size were reduced by non-consumptive effects of predators, but development time was not significantly impacted. In addition, Culex vectors demonstrated predator avoidance behavior during oviposition. The results of this meta-analysis suggest that predators limit disease transmission by reducing both vector survival and vector size, and that associations between drought and human West Nile virus cases could be driven by the vector behavior of predator avoidance during oviposition. These findings are likely to be useful to infectious disease modelers who rely on vector traits as predictors of transmission.

Journal article

Huxley P, Murray K, Pawar S, Cator Let al., 2021, Competition in depleting resource environments shapes the thermal response of population fitness in a disease vector, Communications Biology, ISSN: 2399-3642

Mathematical models that incorporate the temperature dependence of lab-measured life history traits are increasingly used to predict how climatic warming will affect ectotherms, including disease vectors and other arthropods. These temperature-trait relationships are typically measured under laboratory conditions that ignore how conspecific competition in depleting resource environments—a commonly occurring scenario in nature—regulates natural populations. Here, we used laboratory experiments on the mosquito Aedes aegypti, combined with a stage-structured population model, to show that intensified larval competition in ecologically-realistic depleting resource environments can significantly diminish the vector’s maximal population-level fitness across the entire temperature range, cause a 6°C decrease in the optimal temperature for fitness, and contract its thermal niche width by 10°C. Our results provide evidence for future studies to consider competition dynamics under depleting resources when predicting how eukaryotic ectotherms will respond to climatic warming.

Journal article

League G, Pitch S, Geyer J, Baxter L, Montijo J, Rowland J, Johnson L, Murdock C, Cator Let al., 2021, Sexual selection theory meets disease vector control: Testing harmonic convergence as a “good genes” signal in Aedes aegypti mosquitoes, PLoS Neglected Tropical Diseases, ISSN: 1935-2727

Background:The mosquito Aedes aegypti is a medically important, globally distributed vector of the viruses that cause dengue, yellow fever, chikungunya, and Zika. Although reproduction and mate choice are key components of vector population dynamics and control, our understanding of the mechanisms of sexual selection in mosquitoes remains poor. In “good genes” models of sexual selection, females use male cues as an indicator of both mate and offspring genetic quality. Recent studies in Ae. aegypti provide evidence that male wingbeats may signal aspects of offspring quality and performance during mate selection in a process known as harmonic convergence. However, the extent to which harmonic convergence may signal overall inherent quality of mates and their offspring remains unknown.Methodology/Principal findings:To examine this, we measured the relationship between acoustic signaling and a broad panel of parent and offspring fitness traits in two generations of field-derived Ae. aegypti originating from dengue-endemic field sites in Thailand. Our data show that in this population of mosquitoes, harmonic convergence does not signal male fertility, female fecundity, or male flight performance traits, which despite displaying robust variability in both parents and their offspring were only weakly heritable.Conclusions/Significance:Together, our findings suggest that vector reproductive control programs should treat harmonic convergence as an indicator of some, but not all aspects of inherent quality, and that sexual selection likely affects Ae. aegypti in a trait-, population-, and environment-dependent manner.

Journal article

Huxley PJ, Murray KA, Pawar S, Cator LJet al., 2021, The effect of resource limitation on the temperature-dependence of mosquito population fitness, Proceedings of the Royal Society B: Biological Sciences, Vol: 288, ISSN: 0962-8452

Laboratory-derived temperature dependencies of life history traits are increasingly being usedto make mechanistic predictions for how climatic warming will affect vector-borne diseasedynamics, partially by affecting abundance dynamics of the vector population. Thesetemperature-trait relationships are typically estimated from juvenile populations reared onoptimal resource supply, even though natural populations of vectors are expected toexperience variation in resource supply, including intermittent resource limitation. Usinglaboratory experiments on the mosquito Aedes aegypti, a principal arbovirus vector,combined with stage-structured population modelling, we show that low-resource supply inthe juvenile life stages significantly depresses the vector’s maximal population growth rateacross the entire temperature range (22–32°C) and causes it to peak at a lower temperaturethan at high-resource supply. This effect is primarily driven by an increase in juvenilemortality and development time, combined with a decrease in adult size with temperature atlow-resource supply. Our study suggests that most projections of temperature-dependentvector abundance and disease transmission are likely to be biased because they are based ontraits measured under optimal resource supply. Our results provide compelling evidence forfuture studies to consider resource supply when predicting the effects of climate and habitatchange on vector-borne disease transmission, disease vectors and other arthropods.

Journal article

Cator L, Wyer C, Harrington L, 2021, Mosquito Sexual Selection and Reproductive Control Programs, Trends in Parasitology, Vol: 37, Pages: 330-339, ISSN: 0169-4758

The field of mosquito mating biology has experienced a considerable expansion in the past decade. Recent work has generated many key insights about specific aspects of mating behavior and physiology. Here, we synthesize these findings and classify swarming mosquito systems as polygynous. Male mating success is highly variable in swarms and evidence suggests that it is likely determined by both scramble competition between males and female choice. Incorporating this new understanding will improve both implementation and long-term stability of reproductive control tools.

Journal article

Russell M, Qureshi A, Wilson C, Cator Let al., 2021, Size, not temperature, drives cyclopoid copepod predation of invasive mosquito larvae, PLoS One, Vol: 16, ISSN: 1932-6203

During range expansion, invasive species can experience new thermal regimes. Differences between the thermal performance of local and invasive species can alter species interactions, including predator-prey interactions. The Asian tiger mosquito, Aedes albopictus, is a known vector of several viral diseases of public health importance. It has successfully invaded many regions across the globe and currently threatens to invade regions of the UK where conditions would support seasonal activity. We assessed the functional response and predation efficiency (percentage of prey consumed) of the cyclopoid copepods Macrocyclops albidus and Megacyclops viridis from South East England, UK against newly-hatched French Ae. albopictus larvae across a relevant temperature range (15, 20, and 25°C). Predator-absent controls were included in all experiments to account for background prey mortality. We found that both M. albidus and M. viridis display type II functional response curves, and that both would therefore be suitable biocontrol agents in the event of an Ae. albopictus invasion in the UK. No significant effect of temperature on the predation interaction was detected by either type of analysis. However, the predation efficiency analysis did show differences due to predator species. The results suggest that M. viridis would be a superior predator against invasive Ae. albopictus larvae due to the larger size of this copepod species, relative to M. albidus. Our work highlights the importance of size relationships in predicting interactions between invading prey and local predators.

Journal article

Andrés M, Su M, Albert J, Cator Let al., 2020, Buzzkill: targeting the mosquito auditory system, Current Opinion in Insect Science, Vol: 40, Pages: 11-17, ISSN: 2214-5745

Sound plays an important role in mosquito sensory ecology. Acoustic perception and acoustically-driven behaviours therefore represent potentially effective control targets. Previous scientific efforts around acoustic-based control and surveillance have not been systematic and ambiguity around the exact role of acoustic communication in conspecific interactions remains. Here, we briefly review recent advances in mosquito auditory physiology and behavioural ecology as well as ongoing activities to incorporate sound into control and surveillance tools. We highlight areas where increased collaboration between physiologists, molecular biologists, behavioural ecologists, and control experts is needed to capitalize on this progress and realize the potential of sound-based technologies and strategies.

Journal article

Cator L, Johnson LR, Mordecai EA, El Moustaid F, Smallwood TRC, LaDeau SL, Johansson MA, Hudson PJ, Boots M, Thomas MB, Power AG, Pawar Set al., 2020, The role of vector trait variation in vector-borne disease dynamics, Frontiers in Ecology and Evolution, Vol: 8, ISSN: 2296-701X

Many important endemic and emerging diseases are transmitted by vectorsthat are biting arthropods. The functional traits of vectors can affect pathogen transmission ratesdirectly andalso through their effect on vector population dynamics. Increasing empirical evidence shows that vector traits vary significantlyacross individuals, populations, and environmental conditions, andat time scales relevant to disease transmission dynamics. Here, we review empirical evidence for variation invector traits and how this trait variation is currentlyincorporated into mathematical modelsof vector-borne disease transmission. We argue that mechanistically incorporating trait variationinto these models, by explicitly capturingits effects on vector fitness and abundance, can improve the reliability oftheir predictions in a changing world. We provide a conceptual framework for incorporating trait variation into vector-borne disease transmission models,and highlight key empirical and theoretical challenges.This framework provides a means to conceptualize how traits can be incorporated in Vector Borne Disease systems,and identifies key areas in which trait variation can be explored. Determining when and to what extent it is important to incorporate trait variation into vector borne disease models remainsan important, outstanding question.

Journal article

Gregory N, 2020, Vectorial capacity across an environmental gradient

Disease transmitted by mosquitoes present some of the most pressing challenges facing human health today. Land-use change is a key driver of disease emergence, however the mechanisms linking environmental covariates of change, such as temperature, to the transmission potential of mosquitoes is poorly understood. Studies exploring these relationships have largely been correlative in nature, and thus have limited capacity to predict dynamics through space and time. Mechanistic approaches provide a valuable framework for understanding the processes underlying transmission, however they suffer from a dearth of field data on fundamental mosquito ecology. In both approaches, the environmental data used is typically coarse in scale and interpolated from weather stations located in open areas. In reality, local climatic conditions can vary considerably over fine spatial and temporal scales, particularly in dynamic working landscapes. Wild mosquitoes experience and respond to this highly dynamic environment, and failing to account for this variation may have significant implications for the accuracy of epidemiological models. This thesis uses an established epidemiological framework to explore the effects of tropical forest conversion to oil palm plantation on the potential for Ae. albopictus mosquitoes to transmit disease. Using field-derived microclimate data and published thermal responses of mosquito traits, I first examine how the scale of environmental data affects predictions of mosquito demography under land-use change. Next, I conduct field experiments to investigate whether microclimate heterogeneity across a land-use gradient drives variation in the rates of larval development. By pairing fine-scale microclimate data with temperature-dependent trait estimates, I find that forest conversion significantly increases the potential of Ae. albopictus to transmit disease. Together, these findings advance our understanding of Ae. albopictus ecology, and highlight the impo

Thesis dissertation

Gregory N, 2020, Vectorial capacity across an environmental gradient

Disease transmitted by mosquitoes present some of the most pressing challenges facing human health today. Land-use change is a key driver of disease emergence, however the mechanisms linking environmental covariates of change, such as temperature, to the transmission potential of mosquitoes is poorly understood. Studies exploring these relationships have largely been correlative in nature, and thus have limited capacity to predict dynamics through space and time. Mechanistic approaches provide a valuable framework for understanding the processes underlying transmission, however they suffer from a dearth of field data on fundamental mosquito ecology. In both approaches, the environmental data used is typically coarse in scale and interpolated from weather stations located in open areas. In reality, local climatic conditions can vary considerably over fine spatial and temporal scales, particularly in dynamic working landscapes. Wild mosquitoes experience and respond to this highly dynamic environment, and failing to account for this variation may have significant implications for the accuracy of epidemiological models. This thesis uses an established epidemiological framework to explore the effects of tropical forest conversion to oil palm plantation on the potential for Ae. albopictus mosquitoes to transmit disease. Using field-derived microclimate data and published thermal responses of mosquito traits, I first examine how the scale of environmental data affects predictions of mosquito demography under land-use change. Next, I conduct field experiments to investigate whether microclimate heterogeneity across a land-use gradient drives variation in the rates of larval development. By pairing fine-scale microclimate data with temperature-dependent trait estimates, I find that forest conversion significantly increases the potential of Ae. albopictus to transmit disease. Together, these findings advance our understanding of Ae. albopictus ecology, and highlight the impo

Thesis dissertation

Aldersley AA, Pongsiri A, Bunmee K, Kijchalao U, Chittham W, Fansiri T, Pathawong N, Qureshi A, Harrington LC, Ponlawat A, Cator Let al., 2019, Too “sexy” for the field? Paired measures of laboratory and semi-field performance highlight variability in the apparent mating fitness of Aedes aegypti transgenic strains, Parasites and Vectors, Vol: 12, ISSN: 1756-3305

BackgroundEvaluating and improving mating success and competitive ability of laboratory-reared transgenic mosquito strains will enhance the effectiveness of proposed disease-control strategies that involve deployment of transgenic strains. Two components of the mosquito rearing process, larval diet quantity and aquatic environment - which are linked to physiological and behavioural differences in adults - are both relatively easy to manipulate. In mosquitoes, as for many other arthropod species, the quality of the juvenile habitat is strongly associated with adult fitness characteristics, such as longevity and fecundity. However, the influence of larval conditioning on mating performance is poorly understood. Here, we investigated the combined effects of larval diet amount and environmental water source on adult male mating success in a genetically modified strain of Aedes aegypti mosquitoes in competition with wild-type conspecifics. Importantly, this research was conducted in a field setting using low generation laboratory and wild-type lines.ResultsBy controlling larval diet (high and low) and rearing water source (field-collected and laboratory water), we generated four treatment lines of a genetically modified strain of Ae. aegypti tagged with fluorescent sperm. Laboratory reared mosquitoes were then competed against a low generation wild-type colony in a series of laboratory and semi-field mating experiments. While neither food quantity nor larval aquatic environment were found to affect male mating fitness, the transgenic lines consistently outperformed wild-types in laboratory competition assays, an advantage that was not conferred to semi-field tests.ConclusionsUsing a model transgenic system, our results indicate that differences in the experimental conditions of laboratory- and field-based measures of mating success can lead to variation in the perceived performance ability of modified strains if they are only tested in certain environments. While there a

Journal article

Qureshi A, Aldersley A, Hollis B, Ponlawat A, Cator Let al., 2019, Male competition and the evolution of mating and life history traits in experimental populations of Aedes aegypti, Proceedings of the Royal Society B: Biological Sciences, Vol: 286, Pages: 1-8, ISSN: 1471-2954

Aedes aegypti is an important disease vector and a major target of reproductive control efforts. We manipulated the opportunity for sexual selection in populations of Ae. aegypti by controlling the number of males competing for a single female. Populations exposed to higher levels of male competition rapidly evolved higher male competitive mating success relative to populations evolved in the absence of competition, with an evolutionary response visible after only five generations. We also detected correlated evolution in other important mating and life history traits, such as acoustic signalling, fecundity and body size. Our results indicate that there is ample segregating variation for determinants of male mating competitiveness in wild populations and that increased male mating success trades-off with other important life history traits. The mating conditions imposed on laboratory-reared mosquitoes are likely a significant determinant of male mating success in populations destined for release.

Journal article

Aldersley A, Cator L, 2019, Female resistance and harmonic convergence influence male mating success in Aedes aegypti, Scientific Reports, Vol: 9, ISSN: 2045-2322

Despite the importance of mosquito mating biology to reproductive control strategies, a mechanistic understanding of individual mating interactions is currently lacking. Using synchronised high-speed video and audio recordings, we quantified behavioural and acoustic features of mating attempts between tethered female and free-flying male Aedes aegypti. In most couplings, males were actively displaced by female kicks in the early phases of the interaction, while flight cessation prior to adoption of the pre-copulatory mating pose also inhibited copulation. Successful males were kicked at a reduced rate and sustained paired contact-flight for longer than those that were rejected. We identified two distinct phases of acoustic interaction. Rapid frequency modulation of flight tones was observed in all interactions up to acceptance of the male. Harmonic convergence (wingbeat frequency matching) was detected more often in successful attempts, coinciding with the transition to stabilised paired flight and subsequent genital contact. Our findings provide a clearer understanding of the relationship between acoustic interactions and mating performance in mosquitoes, offering insights which may be used to target improvements in laboratory reared lines.

Journal article

Lang B, Idugoe S, McManus K, Drury F, Qureshi A, Cator LJet al., 2017, The effect of larval diet on adult survival, swarming activity and copulation success in male Aedes aegypti (Diptera: Culicidae), Journal of Medical Entomology, Vol: 55, Pages: 29-35, ISSN: 0022-2585

Control of Aedes aegypti (L.) (Diptera: Culicidae) populations is vital for reducing the transmission of several pervasive human diseases. The success of new vector control technologies will be influenced by the fitness of laboratory-reared transgenic males. However, there has been relatively little published data on how rearing practices influence male fitness in Aedes mosquitoes. In the laboratory, the effect of larval food availability on adult male fitness was tested, using a range of different fitness measures. Larval food availability was demonstrated to be positively correlated with adult body size. Larger males survived longer and exhibited greater swarming activity. As a consequence, larger males may have more mating opportunities in the wild. However, we also found that within a swarm larger males did not have an increased likelihood of copulating with a female. The outcome of the mating competition experiments depended on the methodology used to mark the males. These results show that fitness assessment can vary depending on the measure analyzed, and the methodology used to determine it. Continued investigation into these fitness measures and methodologies, and critically, their utility for predicting male performance in the field, will increase the efficiency of vector control programs.

Journal article

Cator LJ, 2017, Host attractiveness and malaria transmission to mosquitoes, Journal of Infectious Diseases, Vol: 216, Pages: 289-290, ISSN: 1537-6613

Journal article

Cator LJ, 2017, Malaria altering host attractiveness and mosquito feeding, Trends in Parasitology, Vol: 33, Pages: 338-339, ISSN: 1471-5007

Several studies have suggested that malaria parasites stack the odds of transmission in their favour by manipulating the attraction profiles of their hosts. A recent study provides evidence that a specific parasite factor, (E)-4-hydroxy-3-methyl-but-2-enyl pyrophosphate, may increase both the attractiveness of infected vertebrates and the susceptibility of mosquitoes to infection.

Journal article

Murdock CC, Luckhart S, Cator LJ, 2017, Immunity, host physiology, and behaviour in infected vectors, Current Opinion in Insect Science, Vol: 20, Pages: 28-33, ISSN: 2214-5753

When infection alters host behaviour such that the pathogen benefits, the behaviour is termed a manipulation. There are several examples of this fascinating phenomenon in many different systems. Vector-borne diseases are no exception. In some instances, as the term implies, pathogens directly interfere with host processes to control behaviour. However, host response to infection and host physiology are likely to play important roles in these phenotypes. We highlight the importance of considering host response and physiology from recent work on altered host-seeking in malaria parasite-infected mosquitoes and argue that this general approach will provide useful insights across vector-borne disease systems.

Journal article

Cator LJ, Zacharo Z, 2016, Size, sounds, and sex: interactions between body size and harmonic convergence signals determine mating success in Aedes aegypti, Parasites & Vectors, Vol: 9, ISSN: 1756-3305

Background: Several new mosquito control strategies will involve the release of laboratory reared males which will be required to compete with wild males for mates. Currently, the determinants of male mating success remain unclear. The presence of convergence between male and female harmonic flight tone frequencies during a mating attempt have been found to increase male mating success in the yellow fever mosquito, Aedes aegypti. Size has also been implicated as a factor in male mating success. Here we investigated the relationships between body size, harmonic convergence signalling, and mating success. We predicted that harmonic convergence would be an important determinant of mating success and that large individuals would be more likely to converge. Methods: We used diet to manipulate male and female body size and then measured acoustic interactions during mating attempts between pairs of different body sizes. Additionally, we used playback experiments to measure the direct effect of size on signalling performance. Results: In live pair interactions, harmonic convergence was again found to be a significant predictor of copula formation. However, we additionally found interactions between harmonic convergence behaviour and body size. The probability that a given male successfully formed a copula was a consequence of his size, the size of the female encountered, and whether or not they converged. While convergence appears to be predictive of mating success regardless of size, the positive effect of convergence was modulated by size combinations. In playbacks, adult body size did not affect the probability of harmonic convergence responses. Conclusions: Both body size and harmonic convergence signalling were found to be determinants of male mating success. Our results suggest that in addition to measuring convergence ability of mass release lines that the size distribution of released males may need to be adjusted to complement the size distribution of females. We

Journal article

Cator LJ, Pietri JE, Murdock CC, Ohm JR, Lewis EE, Read AF, Luckhart S, Thomas MBet al., 2015, Immune response and insulin signalling alter mosquito feeding behaviour to enhance malaria transmission potential, Scientific Reports, Vol: 5, ISSN: 2045-2322

Malaria parasites alter mosquito feeding behaviour in a way that enhances parasite transmission. This is widely considered a prime example of manipulation of host behaviour to increase onward transmission, but transient immune challenge in the absence of parasites can induce the same behavioural phenotype. Here, we show that alterations in feeding behaviour depend on the timing and dose of immune challenge relative to blood ingestion and that these changes are functionally linked to changes in insulin signalling in the mosquito gut. These results suggest that altered phenotypes derive from insulin signalling-dependent host resource allocation among immunity, blood feeding, and reproduction in a manner that is not specific to malaria parasite infection. We measured large increases in mosquito survival and subsequent transmission potential when feeding patterns are altered. Leveraging these changes in physiology, behaviour and life history could promote effective and sustainable control of female mosquitoes responsible for transmission.

Journal article

Cator LJ, Lynch PA, Thomas MB, Read AFet al., 2014, Alterations in mosquito behaviour by malaria parasites: potential impact on force of infection, Malaria Journal, Vol: 13, ISSN: 1475-2875

Journal article

Cator LJ, Thomas S, Paaijmans KP, Ravishankaran S, Justin JA, Mathai MT, Read AF, Thomas MB, Eapen Aet al., 2013, Characterizing microclimate in urban malaria transmission settings: a case study from Chennai, India, Malaria Journal, Vol: 12

<jats:title>Abstract</jats:title> <jats:sec> <jats:title>Background</jats:title> <jats:p>Environmental temperature is an important driver of malaria transmission dynamics. Both the parasite and vector are sensitive to mean ambient temperatures and daily temperature variation. To understand transmission ecology, therefore, it is important to determine the range of microclimatic temperatures experienced by malaria vectors in the field.</jats:p> </jats:sec> <jats:sec> <jats:title>Methods</jats:title> <jats:p>A pilot study was conducted in the Indian city of Chennai to determine the temperature variation in urban microclimates and characterize the thermal ecology of the local transmission setting. Temperatures were measured in a range of probable indoor and outdoor resting habitats of <jats:italic>Anopheles stephensi</jats:italic> in two urban slum malaria sites. Mean temperatures and daily temperature fluctuations in local transmission sites were compared with standard temperature measures from the local weather station. The biological implications of the different temperatures were explored using temperature-dependent parasite development models to provide estimates of the extrinsic incubation period (EIP) of <jats:italic>Plasmodium vivax</jats:italic> and <jats:italic>Plasmodium falciparum</jats:italic>.</jats:p> </jats:sec> <jats:sec> <jats:title>Results</jats:title> <jats:p>Mean daily temperatures within the urban transmission sites were generally warmer than those recorded at the local weather station. The main reason was that night-time temperatures were higher (and hence diurnal temperature ranges smaller) in the urban settings. Mean temperatures and temperature variation also differed between specific resting s

Journal article

Cator LJ, George J, Blanford S, Murdock CC, Baker TC, Read AF, Thomas MBet al., 2013, ‘Manipulation’ without the parasite: altered feeding behaviour of mosquitoes is not dependent on infection with malaria parasites, Proceedings of the Royal Society B: Biological Sciences, Vol: 280, Pages: 20130711-20130711, ISSN: 0962-8452

<jats:p> Previous studies have suggested that <jats:italic>Plasmodium</jats:italic> parasites can manipulate mosquito feeding behaviours such as probing, persistence and engorgement rate in order to enhance transmission success. Here, we broaden analysis of this ‘manipulation phenotype’ to consider proximate foraging behaviours, including responsiveness to host odours and host location. Using <jats:italic>Anopheles stephensi</jats:italic> and <jats:italic>Plasmodium yoelii</jats:italic> as a model system, we demonstrate that mosquitoes with early stage infections (i.e. non-infectious oocysts) exhibit reduced attraction to a human host, whereas those with late-stage infections (i.e. infectious sporozoites) exhibit increased attraction. These stage-specific changes in behaviour were paralleled by changes in the responsiveness of mosquito odourant receptors, providing a possible neurophysiological mechanism for the responses. However, we also found that both the behavioural and neurophysiological changes could be generated by immune challenge with heat-killed <jats:italic>Escherichia coli</jats:italic> and were thus not tied explicitly to the presence of malaria parasites. Our results support the hypothesis that the feeding behaviour of female mosquitoes is altered by <jats:italic>Plasmodium</jats:italic> , but question the extent to which this is owing to active manipulation by malaria parasites of host behaviour. </jats:p>

Journal article

Cator LJ, Lynch PA, Read AF, Thomas MBet al., 2012, Do malaria parasites manipulate mosquitoes?, Trends in Parasitology, Vol: 28, Pages: 466-470, ISSN: 1471-4922

Journal article

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