Report

Mosquito heat seeking is driven by an ancestral cooling receptor

See allHide authors and affiliations

Science  07 Feb 2020:
Vol. 367, Issue 6478, pp. 681-684
DOI: 10.1126/science.aay9847

You are currently viewing the abstract.

View Full Text

Log in to view the full text

Log in through your institution

Log in through your institution

Heat seeking is cool

Mosquitoes seek hosts using several cues, one of which is body heat. Greppi et al. hypothesized that cooling-activated receptors could be used for locating mammalian hosts if they were rewired downstream for repulsion responses (see the Perspective by Lazzari). A gene family conserved in insects and known to be responsible for sensing changes in temperature in fruit flies was the starting point. Genome-wide analyses and labeled CRISPR-Cas9 mutants allowed visualization of the receptor in neurons of Anopheles gambiae mosquitoes' antennae and assessment of adult female mosquitoes with a disrupted copy of the receptor. This ancestral insect temperature regulatory system has been repurposed for host-finding by malaria mosquitoes.

Science, this issue p. 681; see also p. 628

Abstract

Mosquitoes transmit pathogens that kill >700,000 people annually. These insects use body heat to locate and feed on warm-blooded hosts, but the molecular basis of such behavior is unknown. Here, we identify ionotropic receptor IR21a, a receptor conserved throughout insects, as a key mediator of heat seeking in the malaria vector Anopheles gambiae. Although Ir21a mediates heat avoidance in Drosophila, we find it drives heat seeking and heat-stimulated blood feeding in Anopheles. At a cellular level, Ir21a is essential for the detection of cooling, suggesting that during evolution mosquito heat seeking relied on cooling-mediated repulsion. Our data indicate that the evolution of blood feeding in Anopheles involves repurposing an ancestral thermoreceptor from non–blood-feeding Diptera.

View Full Text

Stay Connected to Science