Biology subjects

Vinauger, C.

Publications and source records attributed to Vinauger, C..

16 recordsLinked to original sources

bioRxiv2026

Rapid phase resetting of Aedes aegypti circadian rhythms by transient alterations in light exposure

Circadian clocks enable mosquitoes to anticipate recurring environmental variations and coordinate behaviors critical for survival and disease transmission, such as locomotion, reproduction, host-seeking, and blood-feeding, with times of day when performance is maximal. In Aedes aegypti, locomotor activity follows a robust diurnal rhythm shaped by endogenous circadian clocks and environmental cues, among which light has been shown to be the primary source of temporal information. While early studies established the role of light in regulating locomotor activity, behavior, oviposition and pupation, it remains unclear which features of a light cycle drive changes in circadian rhythms. This question is increasingly relevant as Ae. aegypti is frequently exposed to artificial and dynamic lighting conditions in urban environments. Here, we investigated how transient changes in light schedules influence circadian rhythms in locomotor activity by systematically manipulating the timing, duration, and direction of light exposure. Using a high-throughput assay, we tested over 1900 individuals, including wild-type and timeless knockout mutants, and showed that a single day of al tered lighting is sufficient to induce robust phase shifts, with no evidence of masking effects. A 6-hour light pulse was sufficient to re-entrain mosquitoes regardless of the timing of the pulse, and phase shifts were primarily driven by the offset time of the light pulse, indicating that light-offset acts as a major zeitgeber. Together, these findings challenge conventional assumptions about the timescale of circadian synchronization and highlight the remarkable plasticity of mosquito behavior in response to anthropogenic light. Eventually, these effects could explain the rapid adaptation of the species to urban environments and have potential consequences for disease transmission dynamics.

animal behavior and cognition↗

bioRxiv2026

Temporal synchrony between human odor rhythms and mosquito olfactory preference shapes host attraction

For anthropophilic mosquitoes such as Aedes aegypti, aligning host-seeking with human availability enhances foraging efficiency and reproductive success. Although time of day modulates mosquito activity and olfactory sensitivity, it remains unknown whether human hosts display rhythmic changes in odor cues and whether mosquitoes adjust their sensory responses accordingly. Here, we combine chemical, behavioral, genetic, and transcriptomic approaches to reveal that both mosquitoes and their human hosts in this interaction are temporally synchronized. Gas chromatography-mass spectrometry showed systematic daily shifts in human body odor composition between morning and evening. Correspondingly, mosquitoes prefer host odors that match their own active phase--a time-specific preference abolished in timeless mutants and under constant darkness. Silencing the timeless gene further induced an aversion for the host scent under light-dark conditions. Transcriptomic analysis of mosquito heads and antennae uncovered rhythmic expression of sensory and neuromodulatory genes, driven by both circadian and light-dark cycles and which peaks during mosquitoes active periods, with rhythmic co-expression networks collapsing in timeless knockouts. Together, these results show that mosquito attraction to humans is temporally tuned by the interplay of host odor rhythms and mosquito sensory rhythms, revealing a previously unrecognized form of interspecific temporal synchronization in vector-host interactions.

animal behavior and cognition↗

bioRxiv2025

YOLito: A generalizable model for automated mosquito detection

Understanding mosquito behavior is key to advancing research in ecology, evolution, and disease control, yet most behavioral assays rely on human-dependent methods, such as real-time observation or manual frame-by-frame annotation, limiting throughput and reproducibility. We present YOLito, a domain-generalized AI model for automated mosquito detection and behavioral quantification. Built on the Ultralytics YOLO framework and enhanced with Slicing-Aided Hyper Inference (SAHI), YOLito accurately detects multiple mosquitoes across diverse backgrounds and imaging conditions. Trained on a globally assembled dataset of 38,547 annotated images from 35 experimental setups across six laboratories and three public datasets, YOLito achieved high performance on unseen data (precision = 0.95; recall = 0.91) and generalized across mosquito species (Aedes, Anopheles, Culex) and assay types, including blood-feeding, sugar-feeding, and oviposition. By automating behavioral scoring, YOLito transforms traditional assays into scalable and reproducible experimental platforms. The accompanying open-source toolkit enables high-throughput extraction of metrics such as visit frequency, duration, and distance traveled, providing a standardized and extensible framework that bridges computer vision and vector biology.

animal behavior and cognition↗

bioRxiv2025

Hemoglobin in the diet modulates post-blood feeding behavioral rhythms and gene expression in Aedes aegypti

Female Aedes aegypti mosquitoes rely on blood meals to acquire nutrients essential for egg development. However, blood ingestion also introduces physiological stressors--including thermal, osmotic, and oxidative stress--particularly during the digestion of heme-containing proteins. In Drosophila melanogaster, oxidative stress response genes are regulated by the circadian clock, and core circadian transcription factors are redox-sensitive. Additionally, sufficient iron ingestion is necessary to maintain normal circadian behaviors, as iron metabolism genes influence circadian behaviors, and flies lacking iron storage and transport are arrhythmic. However, whether similar interactions between iron metabolism and circadian rhythms exist in mosquitoes remains unclear. Here, we leverage the known alteration of mosquitoes activity rhythms following a bloodmeal to investigate whether dietary hemoglobin contributes to post-feeding activity suppression and gene regulation in the female Ae. aegypti. Using vertebrate blood and artificial blood mimic diets of equal nutritional values but with and without hemoglobin, we compared mosquito egg production, locomotor activity, sleep profiles, and transcript abundance of genes involved in circadian regulation and host-seeking behavior. Hemoglobin intake significantly reduced post-feeding activity, increased sleep amounts, and suppressed transcription of the core circadian gene period in mosquito heads. Short periods of sleep deprivation during the post-blood feeding period of inactivity did not alter egg production, timing of deposition, or viability. Our findings reveal that hemoglobin-derived heme influences behavioral and molecular responses in Ae. aegypti after a blood meal, pointing to a complex regulatory network linking heme acquisition, oxidative stress, daily rhythms, and behavior.

animal behavior and cognition↗

bioRxiv2025

Larval environment reshapes mosquito disease risk via phenotypic and molecular plasticity

Early-life environmental conditions can exert profound, lasting effects on adult phenotypes, with major consequences for fitness and disease transmission, especially in holometabolous insects like mosquitoes, which are a key vector species. Yet, the molecular mechanisms through which juvenile environments shape adult physiology and behavior via transstadial effects remain largely unresolved. Here, we demonstrate that larval competition, a key ecological stressor, profoundly alters adult body size, survival, reproductive output, host-seeking behavior, olfactory neurophysiology, and vector competence in the mosquito Aedes aegypti. Crucially, using transcriptomic profiling and integrative network analyses, we identify seven regulatory hub genes whose expression is strongly associated with size-dependent variation in olfactory behavior, reproductive investment, and Zika virus transmission potential. These hub genes belong to gene modules enriched for functions in chemosensory processing, metabolic regulation, and signal transduction, revealing a molecular framework mediating environmentally induced plasticity across metamorphosis. Integrating these empirical findings into a transmission model, we show that incomplete larval control can inadvertently increase outbreak risk by producing larger, longer-lived, and more competent vectors. Our results uncover molecular mechanisms underpinning phenotypic plasticity in disease vectors and highlight the critical need to account for transstadial effects in models of vector-borne disease transmission.

physiology↗

bioRxiv2025

A microbiome-derived transfer RNA modification underlies behavioral optimums and predator avoidance in mosquito larvae

The gut microbiome is a rich source of nutrients that are critical to the development and biology of eukaryotes. Transfer RNAs (tRNAs) are essential components of protein synthesis, and some chemical modifications to tRNA rely on the availability of microbiome-derived nutrients. In eukaryotes, the micronutrient queuosine (Q) is salvaged from the microbiome or diet and then incorporated into eukaryotic tRNA to influence the speed and efficiency of protein synthesis. Here, we examine the role of microbiome-derived Q in mosquito larval development and behavior. When mosquito larvae are grown with a microbiome incapable of synthesizing Q, there is a significant impact on tyrosine levels and processes, which correlate with defects in behavior and cuticle formation. Due to defects in movement and behavioral responses, Q-deficient larvae demonstrate impaired predator evasion, leading to higher instances of capture by predaceous beetle larvae. The broad effects of Q-deficiency in mosquito larvae highlight the importance of microbiome-derived nutrients for eukaryotic physiology and behavior.

physiology↗

bioRxiv2024

Intra-species quantification reveals differences in activity and sleep levels in the yellow fever mosquito, Aedes aegypti

Aedes aegypti is an important mosquito vector of human disease with a wide distribution across the globe. Climatic conditions and ecological pressure drive differences in the biology of several populations of this mosquito, including blood-feeding behavior and vector competence. However, no study has compared activity and/or sleep among different populations/lineages of Ae. aegypti. Having recently established sleep-like states in three mosquito species with observable differences in timing and amount of sleep among species, we investigated differences in activity and sleep levels among 17 Ae. aegypti lines drawn from both its native range in Africa and its invasive range across the global tropics. Activity monitoring indicates that all the lines show consistent diurnal activity, but significant differences in activity level, sleep amount, number of sleep bouts, and bout duration were observed among the lines. Variations in specific activity and sleep parameters were explained by differences in host preference, ancestry, and human population density for the lineages collected in Africa. This study provides evidence that the diurnal sleep and activity profiles for Ae. aegypti are consistent, but there are significant population differences for Ae. aegypti sleep and activity levels and interactions with humans may significantly impact mosquito activity and sleep.

physiology↗

bioRxiv2024

Aedes albopictus colonies from different geographic origins differ in their sleep and activity levels but not in the time of peak activity

Mosquitoes occupy a wide range of habitats where they experience various environmental conditions. The ability of some species, such as the tiger mosquito, Aedes albopictus, to adapt to local conditions certainly contributes to their invasive success. Among traits that remain to be examined, mosquitoes ability to time their activity with that of the local host population has been suggested to be of significant epidemiological importance. However, whether different populations display heritable differences in their chronotype has not been examined. Here, we compared laboratory strains originating from 8 populations from 3 continents, monitored their spontaneous locomotor activity patterns, and analyzed their sleep-like states. Overall, all strains showed conserved diurnal activity concentrated in the hours preceding the crepuscule. Similarly, they all showed increased sleep levels during the morning and night hours. However, we observed strain-specific differences in the activity levels at each phase of the day. We also observed differences in the fraction of time that each strain spends in a sleep-like state, explained by variations in the sleep architecture across strains. Human population density and the latitude of the site of geographic origin of the tested strain showed significant effects on sleep and activity patterns. Altogether, these results suggest that Ae. albopictus mosquitoes adapt to local environmental conditions via heritable adaptations of their chronotype.

animal behavior and cognition↗

bioRxiv2023

Effect of temperature on mosquito olfaction

Mosquitoes use a wide range of cues to find a host to feed on, eventually leading to the transmission of pathogens. Among them, olfactory cues (e.g., host emitted odors, including CO2, and skin volatiles) play a central role in mediating host seeking behaviors. While mosquito olfaction can be impacted by many factors, such as the physiological state of the insect (e.g., age, reproductive state), the impact of environmental temperature on the olfactory system remains unknown. In this study, we quantified the behavioral responses of Aedes aegypti mosquitoes, vectors of dengue, yellow fever and Zika viruses, to host and plant related odors under different environmental temperatures.

neuroscience↗

bioRxiv2022

Visual threats reduce blood-feeding and trigger escape responses in Aedes aegypti mosquitoes.

The diurnal mosquitoes Aedes aegypti are vectors of several arboviruses, including dengue, yellow fever, and Zika viruses. To find a host to feed on, they rely on the sophisticated integration of olfactory, visual, thermal, and gustatory cues reluctantly emitted by the hosts. If detected by their target, this latter may display defensive behaviors that mosquitoes need to be able to detect and escape. In humans, a typical response is a swat of the hand, which generates both mechanical and visual perturbations aimed at a mosquito. While the neuro-sensory mechanisms underlying the approach to the host have been the focus of numerous studies, the cues used by mosquitoes to detect and identify a potential threat remain largely understudied. In particular, the role of vision in mediating mosquitoes ability to escape defensive hosts has yet to be analyzed. Here, we used programmable visual displays to generate expanding objects sharing characteristics with the visual component of an approaching hand and quantified the behavioral response of female mosquitoes. Results show that Ae. aegypti is capable of using visual information to decide whether to feed on an artificial host mimic. Stimulations delivered in a LED flight arena further reveal that landed females Ae. aegypti display a stereotypical escape strategy by taking off at an angle that is a function of the distance and direction of stimulus introduction. Altogether, this study demonstrates mosquitoes can use isolated visual cues to detect and avoid a potential threat. Summary StatementIn isolation, visual stimuli programmed to mimic a human swat prevent mosquitoes from blood-feeding by triggering take-offs and escape responses.

animal behavior and cognition↗

bioRxiv2021

Behavioral and postural analyses establish sleep-like states for mosquitoes that can impact interactions with hosts

Sleep is an evolutionarily conserved process that has been described in different animal systems. For insects, sleep characterization has been primarily achieved using behavioral and electrophysiological correlates in a few systems. Sleep in mosquitoes, which are important vectors of disease-causing pathogens, has not been directly examined. This is surprising as circadian rhythms, which have been well studied in mosquitoes, influence sleep in other systems. In this study, we characterized sleep in mosquitoes using body posture analysis and behavioral correlates, and quantified the effect of sleep deprivation on sleep rebound, host landing and blood-feeding propensity. Body and appendage position metrics revealed a clear distinction between the posture of mosquitoes in their putative sleep and awake states for multiple species, which correlate with a reduction in responsiveness to host cues. Sleep assessment informed by these posture analyses indicated significantly more sleep during periods of low activity. Nighttime and daytime sleep deprivation resulting from the delivery of vibration stimuli induced sleep rebound in the subsequent phase in day and night active mosquitoes, respectively. Lastly, sleep deprivation suppressed host landing in both laboratory and field settings and also impaired blood feeding of a human host when mosquitoes would normally be active. These results suggest that quantifiable sleep states occur in mosquitoes, and highlight the potential epidemiological importance of mosquito sleep.

physiology↗

bioRxiv2021

Modeling the effects of Aedes aegypti's larval environment on adult body mass at emergence

Mosquitoes vector harmful pathogens that infect millions of people every year, and developing approaches to effectively control mosquitoes is a topic of great interest. However, the success of many control measures is highly dependent upon ecological, physiological, and life history traits of the mosquito species. The behavior of mosquitoes and their potential to vector pathogens can also be impacted by these traits. One trait of interest is mosquito body mass, which depends upon many factors associated with the environment in which juvenile mosquitoes develop. Our experiments examined the impact of larval density on the body mass of Aedes aegypti mosquitoes, which are important vectors of dengue, Zika, yellow fever, and other pathogens. To investigate the interactions between the larval environment and mosquito body mass, we built a discrete time mathematical model that incorporates body mass, larval density, and food availability and fit the model to our experimental data. We considered three categories of model complexity informed by data, and selected the best model within each category using Akaikes Information Criterion. We found that the larval environment is an important determinant of the body mass of mosquitoes upon emergence. Furthermore, we found that larval density has greater impact on body mass of adults at emergence than on development time, and that inclusion of density dependence in the survival of female aquatic stages in models is important. We discuss the implications of our results for the control of Aedes mosquitoes and on their potential to spread disease. Author summaryIn this work we examined how the environment in which young mosquitoes develop affects their adult body size as measured by adult body mass. Adult size has potential impacts on mosquito behavior and the ability of mosquitoes to transmit disease. We used a combination of experimental work and mathematical modeling to determine important factors affecting adult mosquito body size. In our model, we incorporated potentially interacting aspects of the mosquito life cycle and traits that affect mosquito growth as juveniles. These aspects include body mass, density of the population, and level of available resource. We compared different models to determine the one that best describes the data. As mass at emergence is linked to the success of adult mosquitoes to produce offspring and to their ability transmit pathogens, we discuss how important influences on development and survival of young mosquitoes affect mosquito control and disease spread.

ecology↗

bioRxiv2019

Neuromodulation and Differential Learning Across Mosquito Species

Mosquitoes can learn to change their host-feeding behaviors, such as shifting activity times to avoid bednets or switching from biting animals to biting humans, leading to the transfer of zoonotic diseases. Dopamine is critical for insect learning, but its role in the antennal lobe remains unclear, and it is unknown whether different mosquito species learn the same odor cues. We assayed aversive olfactory learning and dopaminergic brain innervation in four mosquito species with different host preferences and report here that they differentially learn odors salient to their preferred host and innervation patterns vary across species. Using genetically-encoded GCaMP6s Aedes aegypti, we mapped odor-evoked antennal lobe activity and report that glomeruli tuned to \"learnable\" odors have significantly higher dopaminergic innervation. Changes in dopamine expression in the antennal lobes of diverse invertebrate species may be an evolutionary mechanism to adapt olfactory learning circuitry without changing brain structure and for mosquitoes an ability to adapt to other hosts when their preferred are no longer present.

neuroscience↗

bioRxiv2019

The olfactory basis of orchid pollination by mosquitoes

Mosquitoes are important vectors of disease and require sources of carbohydrates for reproduction and survival. Unlike host-related behaviors of mosquitoes, comparatively less is understood about the mechanisms involved in nectar-feeding decisions, or how this sensory information is processed in the mosquito brain. Here we show that Aedes spp. mosquitoes, including Aedes aegypti, are effective pollinators of the Platanthera obtusata orchid, and demonstrate this mutualism is mediated by the orchids scent and the balance of excitation and inhibition in the mosquitos antennal lobe (AL). The P. obtusata orchid emits an attractive, nonanal-rich scent, whereas related Platanthera species - not visited by mosquitoes - emit scents dominated by lilac aldehyde. Calcium imaging experiments in the mosquito AL revealed that nonanal and lilac aldehyde each respectively activate the LC2 and AM2 glomerulus, and remarkably, the AM2 glomerulus is also sensitive to DEET, a mosquito repellent. Lateral inhibition between these two glomeruli reflects the level of attraction to the orchid scents: whereas the enriched nonanal scent of P. obtusata activates the LC2 and suppresses AM2, the high level of lilac aldehyde in the other orchid scents inverts this pattern of glomerular activity, and behavioral attraction is lost. These results demonstrate the ecological importance of mosquitoes beyond operating as disease vectors and open the door towards understanding the neural basis of mosquito nectar-seeking behaviors.\n\nSignificance StatementNectar-feeding by mosquitoes is important for survival and reproduction, and hence disease transmission. However, we know little about the sensory mechanisms that mediate mosquito attraction to sources of nectar, like those of flowers, or how this information is processed in the mosquito brain. Using a unique mutualism between Aedes mosquitoes and Platanthera obtusata orchids, we reveal that this mutualism is mediated by the orchids scent. Furthermore, lateral inhibition in the mosquitos antennal (olfactory) lobe - via the neurotransmitter GABA - is critical for the representation of the scent. These results have implications toward understanding the olfactory basis of mosquito-nectar-seeking behaviors.

neuroscience↗

bioRxiv2019

Visual-olfactory integration in the human disease vector mosquito, Aedes aegypti

Mosquitoes rely on the integration of multiple sensory cues, including olfactory, visual, and thermal stimuli, to detect, identify and locate their hosts [1-4]. Although we increasingly know more about the role of chemosensory behaviours in mediating mosquito-host interactions [1], the role of visual cues remains comparatively less studied [3], and how the combination of olfactory and visual information is integrated in the mosquito brain remains unknown. In the present study, we used a tethered-flight LED arena, which allowed for quantitative control over the stimuli, to show that CO2 exposure affects target-tracking responses, but not responses to large-field visual stimuli. In addition, we show that CO2 modulates behavioural responses to visual objects in a time-dependent manner. To gain insight into the neural basis of this olfactory and visual coupling, we conducted two-photon microscopy experiments in a new GCaMP6s-expressing mosquito line. Imaging revealed that the majority of ROIs in the lobula region of the optic lobe exhibited strong responses to small-field stimuli, but showed little response to a large-field stimulus. Approximately 20% of the neurons we imaged were modulated when an attractive odour preceded the visual stimulus; these same neurons also elicited a small response when the odour was presented alone. By contrast, imaging in the antennal lobe revealed no modulation when visual stimuli were presented before or after the olfactory stimulus. Together, our results are the first to reveal the dynamics of olfactory modulation in visually evoked behaviours of mosquitoes, and suggest that coupling between these sensory systems is asymmetrical and time-dependent.

neuroscience↗

bioRxiv2017

Modulation of host learning in Aedes aegypti mosquitoes

How mosquitoes determine which individuals to bite has important epidemiological consequences. This choice is not random; most mosquitoes specialize in one or a few vertebrate host species, and some individuals in a host population are preferred over others. Here we show that aversive olfactory learning contributes to mosquito preference both between and within host species. Combined electrophysiological and behavioural recordings from tethered flying mosquitoes demonstrated that these odours evoke changes in both behaviour and antennal lobe (AL) neuronal responses. Using electrophysiological and behavioural approaches, and CRISPR gene editing, we demonstrate that dopamine plays a critical role in aversive olfactory learning and modulating odour-evoked responses in AL neurons. Collectively, these results provide the first experimental evidence that olfactory learning in mosquitoes can play an epidemiological role.

neuroscience↗