P 4 - Role of container periphyton as oviposition attractant to female Aedes aegypti

Aedes aegypti females use different chemosensory cues to select oviposition sites. These cues are thought to give Ae. aegypti females information on food availability, presence of pathogens, competitors, and risk of predation among other factors. Most research on stimuli attracting female Ae. aegypti to oviposit in natural or artificial containers have focused on the properties of the vessel and contained water, such as size (perimeter, volume), color, water quality, and the concentration of dissolved organic matter and microorganisms in the form of plant infusions. One component of the aquatic habitat that has not been studied is the community of microorganisms that grow on inner walls of containers where Ae. aegypti gravid females stand to lay eggs, usually right above the water line. Depending on sun exposure algae can grow on the submerged wall surfaces, and other micro-organisms such as bacteria and fungi can grow as organic matter accumulates. These micro-organisms form the periphyton community which Ae. aegypti larvae feed on by browsing on submerged surfaces.  The question of interest is whether Ae. aegypti females are attracted to periphyton stimuli and what factors facilitate the attraction.  To answer this question, we conducted behavioral experiments where we: 1- Compared Ae. aegypti oviposition rates between containers with periphyton, and similar containers whose inner walls were periphyton free, and 2- Characterized the periphyton community richness and diversity. We found significantly higher oviposition rates in containers with periphyton compared to containers without, and we found the periphyton community in our experiments was mostly composed of Bacteria, followed by Archaea, Viridiplantae, Eukaryota and Fungi. Understanding how periphyton mediates oviposition behavior and what variables make periphyton attractive can help us in the formulation of new attractants directed for mosquito control.