Evolutionary investigations into insect olfaction and host choice using a mosquito model system

A project undertaken at the School of Biological Sciences, University of Queensland, and supervised by Dr Nigel Beebe

Summary

A malaria mosquito host feeding shift was observed in closely related species of the Anopheles punctulatus group in the southwest Pacific islands, where a loss of the ability of these mosquitoes to cue to humans has occurred. As olfaction plays a central role in the host preference this unique situation provides a rich opportunity to investigate the genetic basis of human host cueing in malaria mosquitoes. Comparative genomic and RNAseq approaches will be used to determine the molecular genetics and evolution of olfaction using the An. punctulatus group as a model system.

This research will be undertaken as a PhD project for Mr Luke Ambrose to:

  1. generate genomic and transcriptomic data from species/population pairs of closely related mosquito species exhibiting fixed differences in host feeding behaviour;
  2. through comparative genomics and transcriptomics, identify the genes involved in human seeking olfaction and describe their evolution; and
  3. use RNA interference (RNAi) gene knockdown methods to validate candidate genes' involvement in host seeking.
Anticipated outcomes
  1. Novel genome and transcriptome data on two mosquitoes (Anopheles hinesorum and An. irenicus) that show rare biological phenotypes – not cueing to either carbon dioxide or humans – that will provide a remarkable resource for on-going studies on the evolution of olfaction.
  2. A deeper understanding of the molecular mechanisms underpinning olfactory driven host seeking behaviour (in particular human seeking) including the identification and experimental validation of candidate genes involved in this significant behaviour.
  3. The application of this knowledge is likely to lead to the design of better spatial repellents and attractants for biting insects like mosquitoes and provide important insights into insect olfactory architecture that may have applications across other insects such as those involved in agricultural as well as those that provide ecosystem services       


Figure 1. Anopheles farauit feeding.