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

Area of Science:

• Vector-borne disease ecology
• Insect behavior and physiology
• Chronobiology and chemical ecology

Background:

• Anthropophilic mosquitoes like *Aedes aegypti* rely on host-seeking for survival and reproduction.
• Daily cycles influence mosquito activity and olfactory responses, but host odor rhythms and mosquito adaptations are poorly understood.
• Temporal synchronization between vectors and hosts could optimize foraging and interaction success.

Purpose of the Study:

• To investigate whether human body odor composition changes daily and if mosquitoes adjust their sensory responses.
• To determine the role of mosquito circadian genes, specifically 'timeless', in mediating host odor preference.
• To uncover the molecular basis of temporal synchronization in mosquito-host interactions.

Main Methods:

• Gas chromatography-mass spectrometry (GC-MS) to analyze daily shifts in human body odor.
• Behavioral assays to assess mosquito preference for host odors under different light-dark conditions.
• Genetic manipulation (gene silencing, mutant generation) of the 'timeless' gene in mosquitoes.
• Transcriptomic analysis of mosquito head and antennal tissues to identify rhythmic gene expression.

Main Results:

• Human body odor composition exhibits systematic daily variations between morning and evening.
• Mosquitoes show a preference for host odors that align with their active phase, which is dependent on light-dark cycles and the 'timeless' gene.
• Rhythmic expression of sensory and neuromodulatory genes in mosquitoes is driven by circadian and light-dark cycles, peaking during active periods.
• Disruption of the 'timeless' gene abolishes rhythmic gene expression and alters host odor preference.

Conclusions:

• Mosquito attraction to humans is temporally tuned by synchronized rhythms in host odor and mosquito sensory perception.
• The 'timeless' gene plays a crucial role in mediating mosquito responses to host cues based on time of day.
• This study reveals a novel form of interspecific temporal synchronization critical for vector-host interactions.