2026-05-28 バージニア工科大学（VirginiaTech）
Mosquitoes can learn to like DEET, the world’s most powerful insect repellent, according to a new study by Virginia Tech and University of Tours researchers. Photo courtesy of Adobe Stock.
＜関連情報＞
- https://news.vt.edu/articles/2026/05/cals-vinauger-mosquitoes-DEET.html
- https://journals.biologists.com/jeb/article-abstract/229/10/jeb251935/371741/Associative-learning-switches-DEET-valence-from
- https://medibio.tiisys.com/111007/
- https://www.cell.com/current-biology/fulltext/S0960-9822(19)30770-5
- https://www.cell.com/current-biology/fulltext/S0960-9822(17)31617-2
連合学習により、ネッタイシマカにおけるDEETの価が嫌悪感から嗜好感へと変化する Associative learning switches DEET valence from aversive to appetitive in Aedes aegypti
Claudio R. Lazzari ,David De Luca,Ayelén Nally,Charly Dufour,Clément Vinauger
Journal of Experimental Biology Published:28 May 2026
DOI:https://doi.org/10.1242/jeb.251935
ABSTRACT
Repellents are central to personal protection and to reducing transmission of mosquito-borne diseases. Although substantial effort has been devoted to identifying the sensory and molecular pathways underlying repellent detection, the diversity of reported modes of action has hindered the development of a unified framework. It is generally assumed that insects respond to repellents in a fixed, aversive manner. However, an unexplored possibility is how plastic the innate meaning of repellents may be. We present experiments testing whether the innate response of Aedes aegypti to DEET (the gold-standard repellent) can be shifted from aversion to attraction. First, we identified and validated an appetitive behavioural response in mosquitoes equivalent to PER conditioning in flies and bees: the biting attempt response (BAR). Next, we trained individual mosquitoes to associate DEET with a blood meal using Pavlovian conditioning. We then examined whether mosquitoes trained with blood as a positive reinforcer would display the BAR when presented with DEET alone or on host skin. Finally, we trained females to associate DEET with sugar and tested their subsequent response to DEET alone. Across all experiments, trained mosquitoes showed a reversal in the valence of DEET, shifting from innate avoidance to a learned appetitive response. These results demonstrate that experience can render DEET attractive by establishing associations with two rewarding contexts: vertebrate blood feeding and plant sugar feeding. We discuss the implications of this learned attraction for understanding repellent mechanisms and for designing strategies to improve personal protection.
ヒトの病原体媒介蚊であるネッタイシマカにおける視覚・嗅覚統合 Visual-Olfactory Integration in the Human Disease Vector Mosquito Aedes aegypti
Clément Vinauger ∙ Floris Van Breugel ∙ Lauren T. Locke ∙ … ∙ Adrienne L. Fairhall ∙ Omar S. Akbari ∙ Jeffrey A. Riffell
Current Biology Published: July 18, 2019
DOI:https://doi.org/10.1016/j.cub.2019.06.043
Highlights
- CO2 modulates mosquito behavioral responses to discrete visual stimuli
- CO2 modulates lobula neuropil responses to discrete visual stimuli
- Visual stimuli do not modulate responses to CO2 in olfactory glomeruli
- Modulation of peripheral visual and olfactory sensory stimuli is asymmetric
Summary
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 behaviors in mediating mosquito-host interactions [1], the role of visual cues is 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 light-emitting diode (LED) arena, which allowed for quantitative control over the stimuli, and a control theoretic model to show that CO2 modulates mosquito steering responses toward vertical bars. 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 neuropil regions within the lobula exhibited strong responses to objects, such as a bar, but showed little response to a large-field motion. Approximately 20% of the lobula neuropil we imaged were modulated when CO2 preceded the presentation of a moving bar. By contrast, responses in the antennal (olfactory) lobe were not modulated by visual stimuli presented before or after an olfactory stimulus. Together, our results suggest that asymmetric coupling between these sensory systems provides enhanced steering responses to discrete objects.
ネッタイシマカにおける宿主学習の調節 Modulation of Host Learning in Aedes aegypti Mosquitoes
Clément Vinauger ∙ Chloé Lahondère ∙ Gabriella H. Wolff ∙ … ∙ Omar S. Akbari ∙ Michael H. Dickinson ∙ Jeffrey A. Riffell
Current Biology Published: January 25, 2018
DOI:https://doi.org/10.1016/j.cub.2017.12.015
Highlights
- Aversive learning by mosquitoes suppresses responses to human hosts
- Mosquitoes can learn the association between mechanical shock and certain odorants
- CRISPR/Cas9 modification of the dopamine-1 receptor prevents learning
- Dopamine causes heterogeneous modulation of antennal lobe neurons
Summary
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. Mosquitoes will also blood feed from other hosts when their preferred is no longer abundant, but the mechanisms mediating these shifts between hosts, and preferences for certain individuals within a host species, remain unclear. Here, we show that olfactory learning may contribute to Aedes aegypti mosquito biting preferences and host shifts. Training and testing to scents of humans and other host species showed that mosquitoes can aversively learn the scent of specific humans and single odorants and learn to avoid the scent of rats (but not chickens). Using pharmacological interventions, RNAi, and CRISPR gene editing, we found that modification of the dopamine-1 receptor suppressed their learning abilities. We further show through combined electrophysiological and behavioral recordings from tethered flying mosquitoes that these odors evoke changes in both behavior and antennal lobe (AL) neuronal responses and that dopamine strongly modulates odor-evoked responses in AL neurons. Not only do these results provide direct experimental evidence that olfactory learning in mosquitoes can play an epidemiological role, but collectively, they also provide neuroanatomical and functional demonstration of the role of dopamine in mediating this learning-induced plasticity, for the first time in a disease vector insect.
