Heterocypris incongruens maintains an egg bank in stormwater habitats and influences the development of larval mosquito, Culex restuans

Authors: TRUJILO, JACQUELINE - University Of Illinois; SCHWING, CAMERON - University Of Illinois; Muturi, Ephantus; CACERES, CARLA - University Of Illinois

Submitted to: Ecology and Evolution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/8/2023
Publication Date: 8/22/2023
Citation: Trujilo, J., Schwing, C., Muturi, E.J., Caceres, C.E. 2023. Heterocypris incongruens maintains an egg bank in stormwater habitats and influences the development of larval mosquito, Culex restuans. Ecology and Evolution. 13(8) Article e10354. https://doi.org/10.1002/ece3.10354.
DOI: https://doi.org/10.1002/ece3.10354

Interpretive Summary: Stormwater systems, such as drainage ditches, host a community of mosquitoes including important vectors of diseases such as West Nile virus. These systems are also home to a variety of planktonic communities that compete for food with mosquito larvae. Understanding how mosquito larvae interact with these planktonic communities in stormwater systems can inform development of environmentally friendly strategies for mosquito control. We investigated how larvae of a West Nile virus vector mosquito interacts with one of the most abundant planktonic species in stormwater systems. Higher mosquito larval density was associated with lower survivorship to adulthood. Mosquito larvae reared in the presence of planktons had shorter development time to adulthood, larger adult body size, and were female-biased. These findings suggest that interspecific interactions between larvae of West Nile virus vector and planktons may increase the risk of West Nile virus by shortening the duration of mosquito development and promoting production of more and larger female mosquitoes.

Technical Abstract: Dormant propagules can provide a rapid colonization source for temporary aquatic habitats and set the trajectory for community dynamics, yet the egg banks of stormwater management systems have received little attention. We asked which species hatched from the sediment of drainage ditches in Champaign County, IL, and found bdelloid rotifers and ostracods (Heterocypris incongruens) to be the most common taxa. These sites also are colonized by mosquitoes, and we established laboratory experiments to examine interspecific interactions between common co-occurring taxa. Culex restuans larvae were reared in the presence or absence of H. incongruens at two intra- and interspecific densities (20 or 40 total individuals) and their survivorship to adulthood, development time to adulthood, adult body size, and sex ratio were determined. Survival for Cx. restuans was significantly lower at high larval density than at low larval density in both treatments. Culex restuans larvae reared in the presence of H. incongruens had a shorter development time to adulthood and emerged as larger adults compared to those reared in the absence of H. incongruens. The sex ratios in the H. incongruens treatments were female-biased whereas those in the Culex-only treatments were male-biased. These differences may have epidemiological implications, as only female mosquitoes serve as disease vectors. Our results emphasize the importance of understanding interspecific interactions in influencing larval mosquito development traits.