蚊の体内時計を変えて刺されないようにすることはできるのか?(Could We Alter Mosquitos’ Internal Clocks to Stop Them From Biting?)

2025-11-11 コロンビア大学

<関連情報>

• https://news.columbia.edu/news/could-we-alter-mosquitos-internal-clocks-stop-them-biting
• https://www.pnas.org/doi/10.1073/pnas.2520826122

二酸化炭素に対する蚊の反応持続における時間帯による調節は色素分散因子によって制御される Time-of-day modulation in mosquito response persistence to carbon dioxide is controlled by Pigment-Dispersing Factor

Linhan Dong, Richard Hormigo, Jord M. Barnett, +1 , and Laura B. Duvall
Proceedings of the National Academy of Sciences  Published:November 11, 2025
DOI:https://doi.org/10.1073/pnas.2520826122

Significance

Mosquitoes use rhythmic sensory responses to find human hosts, but the role of circadian rhythms in this behavior is not well understood. Using an automated assay, we show that Aedes aegypti mosquitoes’ responses to CO₂, a critical host cue, vary with time of day. While activation is stable during daylight, persistence peaks at dawn and dusk, matching natural biting times. At night, activation is suppressed, suggesting internal circadian gating of host-seeking. We identify the neuropeptide Pigment-Dispersing Factor (PDF) as crucial in regulating this rhythm. Loss of PDF disrupts blood feeding success in the morning and impairs the mosquito circadian clock. These findings offer insights for vector control strategies that target natural periods of reduced biting to fight mosquito-borne diseases.

Abstract

Each year, hundreds of millions of people are sickened by diseases that are transmitted through mosquito bites, including dengue, Zika, and malaria. Mosquito biting does not occur uniformly throughout the day and peak biting times follow species-specific patterns. While host-associated cues, like carbon dioxide (CO₂), behaviorally activate human-biting mosquitoes to search for a host, the mechanisms that regulate these responses throughout the day remain poorly understood. Here, we introduce an automated behavioral tracking system to investigate time-of-day variation of CO₂ responsiveness in Aedes aegypti. We find that while acute responses to CO₂ remain consistently high throughout the light phase, response persistence peaks only at dawn and dusk, in alignment with field-observed biting rhythms. We identify the circadian neuropeptide Pigment-Dispersing Factor (PDF) as a key regulator in the daily timing of spontaneous locomotor activity and CO₂ response persistence. Mosquitoes lacking PDF show reduced activity and CO₂ persistence in the morning. In response to a blood meal baited with heat and human odorants, pdf mutants also show reduced feeding in the morning and midday. Additionally, loss of pdf impacts the spatial pattern of PDF immunostaining and cell-autonomous clock gene oscillation in the central circadian system. Notably, acute CO₂ responsiveness remains rhythmic without external zeitgeber cues and is unaffected in pdf mutants, suggesting distinct regulatory mechanisms for acute CO₂ activation versus response persistence. These findings reveal a circadian layer of control of mosquito activity pattern that temporally modulate host-seeking drive.