Molecular correlates of swarming behaviour in Aedes aegypti males

Abstract

Mosquitoes are the deadliest vectors of diseases. They impose a huge health burden on human populations spreading parasites as disparate as protozoans (malaria), viruses (yellow fever and more) and nematodes (filariasis) that cause life-threatening conditions. In recent years, mating has been proposed as a putative target for population control. Mosquitoes mate mid-air, in swarms initiated by males and triggered by a combination of internal and external stimuli. As the number of females in a swarm is limited, there is intense competition among males, and they 'retune' their physiology for this demanding behaviour. There is limited knowledge on the 'genetic reprogramming' required to enable swarming. Interestingly, recent evidence indicates that the upregulation of circadian clock genes may be involved in the swarming of malaria mosquitoes of the genus Anopheles. Here, we use whole-head RNA-seq to identify gene expression changes in Aedes aegypti males that are engaged in swarming in a laboratory setting. Our results suggest that in preparation to swarming, males tend to lower some housekeeping functions while increasing remodelling of the cytoskeleton and neuronal connectivity; the transcription of circadian clock genes is unaffected.

Keywords: Aedes aegypti; circadian clock; swarming; transcriptomics.

Figure 1.

(a) Experimental design. Swarming males (flying) are attracted to a human host. Non-swarming males are irresponsive to the host and rest on the walls of the cage. (b) Volcano plot showing transcripts differentially expressed in swarming males (in red) (p < 0.05, log₂FC > |0.75|). Transcripts of the circadian genes period (per) and timeless (tim) and are not differentially expressed and are shown in blue and green, respectively.