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

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.