Neuronal basis of pheromone perception in mosquitoes

Motivation for the project. Anopheles mosquitoes are the vectors of malaria that affects half of the world population (WHO 2019). Mosquitoes heavily rely on their sense of smell to find a human for a blood meal (Konopka et al, 2021). Surprisingly, reports of chemical communication in Anopheles are very scarce and recent, and the use of pheromones is not universally established for any mosquitoes. In contrast to mosquitoes, most other insects are well known to use volatile and non-volatile pheromones (Blomquist and Bagnerés, 2010). We were intrigued by the obvious lack of information about mosquito pheromones, and thus the implicit assumption that mosquitoes, in contrast to other insects, don't produce and use chemical cues to communicate intraspecifically. We employed novel methods and techniques for our pilot studies, and identified 17 potential male and female pheromone candidates in Anopheles gambiae. This project will verify and strengthen our preliminary findings, and will explore how Anopheles gambiae respond to pheromone candidates at the levels of cells, organs and the entire organism. We will employ cutting edge techniques of insect neuroscience and genetic engineering to achieve our aims.

Aims. 1) To verify pheromone candidates and identify olfactory receptors that detect pheromone candidates in male and female mosquitoes; 2) To create a transgenic mosquito line targeting neurons that specifically respond to the pheromones; 3) To genetically manipulate the pheromone neurons and test their effect on mosquito mating behaviours.

Methodology. Pheromone candidates will be verified by GC/MS coupled with thermodesorption. Olfactory receptors will be identified via live calcium imaging from mosquito and Drosophila olfactory neurons. New transgenic lines will be generated by using CRISPR/Cas9 to replace the stop codon of the candidate OR genes with a T2A-QF2 construct. Panel of olfactory preference, flight activity and mating and behavioural assays will be developed and conducted on male and female An.gambiae.

Timetable. Year1: Aim 1 in Durham and Wuerzburg; conference ECRO/ESITO in Europe; Year2: Aims 1 and 2 in Durham; SfN conference/Neuroethology Congress; Optical Imaging and Electrophysiological Recordings in Neuroscience School, Paris; Year3: Aim 3 in Newcastle and Durham; PIPS placement; ESA conference; Year4: MBL course "Neural System and Behavior", Woods Hole, USA; finishing up experiments and writing up.


Novelty. This project will involve cutting edge techniques of insect neuroethology, neuroscience and genetics that the supervisors are world leaders in. In addition, understanding mosquito sexual communication has profound implications for mosquito and malaria control.