What is it about?
Mosquito bites spread disease-causing pathogens that sicken millions of people each year. However, this dangerous biting behavior occurs mainly during specific and predictable times of the day, and Aedes aegypti, the species we studied here, mostly bites at dawn and dusk. Our study reveals that mosquitoes use their internal “clocks” to modulate their drive to bite according to the time of day. A brief pulse of CO2, mimicking human presence, leads to more than 10 minutes of flight activity in the dengue vector mosquitoes around dawn and dusk, mirroring biting patterns seen in field studies. To disrupt these internal clocks, we mutated the gene for the circadian neuropeptide Pigment-Dispersing Factor (PDF). Mutant mosquitoes lacking PDF cannot properly time their morning activity and lose biting efficiency in the morning. This shows that mosquitoes have daily rhythms in their response to human cues that may contribute to their ability to find and bite us at particular times.
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Photo by National Institute of Allergy and Infectious Diseases on Unsplash
Why is it important?
Mosquitoes use robust navigation strategies to find and bite humans, but biting activity is usually restricted to just a few hours of the day. We aimed to understand how mosquito behavior changes at different times of day and how this intrinsic modulation “shuts down” biting for most of the day. Our results reveal the neuropeptide regulation of how persistently mosquitoes respond to the same human host cue, which provides explanation for how they may optimize their ability to hunt humans at dawn and dusk and could open new avenues to control the spread of mosquito-borne pathogens by exploiting endogenous periods of low biting drive.
Perspectives
This work represents the core of my PhD research. In collaboration with Rick Hormigo, I spent more than a year developing the MozzieDrome system, which ultimately gave us the technical leverage to uncover how mosquitoes strategize and restrict persistent CO₂ responsiveness to just a few hours of the day. It is deeply satisfying to see the genetic mutant I generated play such an important role in behavioral timing. This paper feels like a culmination of the diverse techniques I learned and developed throughout my PhD, and it is immensely rewarding to see how they came together to give us these exciting insights on the temporal regulation of mosquito biting.
Linhan Dong
Columbia University
Read the Original
This page is a summary of: Time-of-day modulation in mosquito response persistence to carbon dioxide is controlled by Pigment-Dispersing Factor, Proceedings of the National Academy of Sciences, November 2025, Proceedings of the National Academy of Sciences,
DOI: 10.1073/pnas.2520826122.
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