Student Theses and Dissertations

Date of Award

2019

Document Type

Thesis

Degree Name

Doctor of Philosophy (PhD)

RU Laboratory

Vosshall Laboratory

Abstract

Mosquitoes use multiple sensory modalities, including olfaction, thermosensation, and vision, to hunt human hosts and obtain a blood-meal for egg production. Any individual sensory cue is an incomplete signal of a human host, and so a mosquito must integrate multimodal sensory information before committing to approaching and biting a person. Mosquito host-seeking behavior is thus a particularly fruitful model for studying multimodal integration because of its robustness, intricacy, and public health importance. Using tethered and free flight assays, we have teased apart responses to attractive visual and thermal cues in female Aedes aegypti, the yellow fever mosquito, uncovering their contributions to host-seeking decisions and distinctions in how they modulate their responses to those cues depending on CO₂, the most salient cue in human breath. We show that mosquitoes orient towards visual contrast in flight, regardless of CO₂ concentration, and then sense CO₂ to unlock thermotaxis towards potential hosts. Mosquitoes across their evolutionary lineage display an impressive variety of host choices, from mammals to cold-blooded frogs to leeches and earthworms, and the algorithms they use to weigh sensory host cues likely vary just as much. Our results illustrate how such weighting is performed in one species, providing a first glimpse into how general and contingent cues are integrated to produce host-seeking behavior in mosquitoes. With the rapid development of genetic and neuroscience tools in mosquitoes, we are poised to uncover the neuronal mechanisms underlying multimodal integration in these charismatic and deadly insects.

Comments

A Thesis Presented to the Faculty of The Rockefeller University in Partial Fulfillment of the Requirements for the degree of Doctor of Philosophy

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