The role of container periphyton as an oviposition attractant for female Aedes aegypti

Abstract Background Aedes aegypti mosquitoes use diverse chemosensory cues to select an oviposition site. These cues are thought to provide information on factors such as food availability, predators, pathogens, and competitors. Most research on the stimuli attracting female Ae. aegypti to oviposit in natural or artificial containers has focused on the properties of the vessel and water, such as size, color, water quality, concentration of dissolved organic matter, and microorganisms. One understudied aspect of oviposition containers is periphyton, the complex community of microorganisms that can grow on the inner walls of containers where gravid Ae. aegypti females lay their eggs. Periphyton can potentially act as an indicator of the container’s suitability for females looking for an oviposition site, and as a source of food for future mosquito larvae. We were interested in understanding whether container periphyton attracts gravid Ae . aegypti females for oviposition and to assess the microbial composition of the periphyton community. Methods To answer these questions, we collected periphyton from an artificial water-collecting container that had visible Ae. aegypti larvae and pupae. We propagated this periphyton in 36 plastic buckets with water, and once the periphyton was established, we conducted a series of attraction and oviposition choice experiments within a semi-field cage where gravid Ae. aegypti were released and presented with buckets with and without periphyton, periphyton-exposed water, or dechlorinated water. Additionally, we collected samples from the periphyton used in these assays for 16s rRNA microbial fingerprinting. Results Across the 2 different experiments, encompassing 11 replicate trials, female Ae. aegypti consistently laid more eggs in buckets with periphyton compared to the controls, demonstrating that periphyton promotes Ae. aegypti oviposition. Results from 16s rRNA fingerprinting of periphyton specimens revealed that these communities are complex but predominantly composed of microbial taxa from the phyla Bacteroidetes, Cyanobacteria, and Pseudomonadota. Conclusions Periphyton in artificial containers had attractive properties for Ae. aegypti oviposition and is composed by complex microbial communities. Understanding periphyton’s attractive properties could prompt the development and formulation of novel attractants useful in mosquito control.