helps time Aedes aegypti mosquito persistence after carbon dioxide cues, especially around morning host seeking.
Evidence
This automated behavioral and mutant mosquito study measured time-of-day CO2 responses, blood-meal feeding, PDF staining, and clock-gene oscillation in Aedes aegypti.
Caveat
The work is a mosquito model of host-seeking behavior, and acute CO2 responsiveness appeared regulated separately from PDF-dependent response persistence.
Simplified
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 (CO), 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 COresponsiveness in. We find that while acute responses to COremain 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 (PDF) as a key regulator in the daily timing of spontaneous locomotor activity and COresponse persistence. Mosquitoes lacking PDF show reduced activity and COpersistence in the morning. In response to a blood meal baited with heat and human odorants,mutants also show reduced feeding in the morning and midday. Additionally, loss ofimpacts the spatial pattern of PDF immunostaining and cell-autonomous clock gene oscillation in the central circadian system. Notably, acute COresponsiveness remains rhythmic without external zeitgeber cues and is unaffected inmutants, suggesting distinct regulatory mechanisms for acute COactivation versus response persistence. These findings reveal a circadian layer of control of mosquito activity pattern that temporally modulate host-seeking drive. 2 2 2 2 2 2 2Aedes aegypti pdf pdf pdf
Key numbers
>10 min
Sustained Activity Duration
Duration of sustained activity post-CO exposure at dawn and dusk.
3.23 ± 0.50 min
Activity Reduction
Time taken for activity to cease after lights-off in homozygous mutants.
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