Larval habitat microbiota influences male Aedes aegypti life history traits
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Date
2022-05
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Publisher
The Ohio State University
Abstract
Sterile insect technique (SIT) is an insect control method that has seen historical success in controlling arthropod pests such as the screw-worm fly and other fruit fly pests. This method utilizes induced-sterility of mass-reared insects, typically males, that are released to mate with wild individuals and produce nonviable offspring, thereby decreasing target insect populations. For programs employing SIT to control mosquitoes like the yellow fever mosquito Aedes aegypti, which is a vector for pathogens causing diseases like dengue and yellow fever, released males must have comparable biological fitness levels to wild males. Microbes have been shown to be critical for mosquito development. Differential levels of biological fitness imparted by microbes would thus have implications for mass-rearing processes required of SIT and the reproductive success of sterile insects. In this experiment, we investigated the effects that the microbiota associated with the larval habitat had on life history traits used to estimate biological fitness of adult male Ae. aegypti. Ae. aegypti eggs were hatched, and larvae were placed into four different trays containing water for development. Three trays were treated with different bacteria from the genera Cedecea, Asaia, or Kocuria that were added to the conventional larval habitat microbiota, creating three treatments and a control group. The larvae from each group developed into pupae and then adults. Adult male mosquitoes from each group were placed into cups to measure longevity, and the right wings of all remaining adult male mosquitoes were measured. Adult males from the Cedecea treatment showed a statistically significant decrease in body size and longevity when compared to the control, while adult males from the other treatments had comparable life history trait phenotypes to the control. These findings emphasize the effects that microbes encountered by larvae in aquatic habitats have on subsequent adult stages. In the context of SIT, mass rearing programs should take precautions to exclude Cedecea from their facilities. Samples of container water for each treatment were taken and are being analyzed to determine the microbial composition of the larval habitat for each treatment. Effects of additional bacteria are being investigated.
Description
Honorable Mention - Denman Undergraduate Research Forum
Keywords
Mosquitoes, Microbiota, Sterile insect technique, Insects, Bacteria, Life history traits