Sex, age, and acoustic mating interactions affect the immunity of Aedes aegypti offspring

Aedes aegypti is an important vector of several pathogenic arboviruses
including dengue, chikungunya and Zika. Innovative approaches to control
Aedes populations, involving synthetic transgenic modifications as well as
Wolbachia bacteria, appear promising. For the various techniques requiring
offspring inheritance of a trait, released males must successfully compete
for mating partners against wildtype males. However, very little is known
about mechanisms of mate selection in mosquitoes in general and in
particular about potential correlations between mating success and
offspring immune performance. Harmonic convergence signals have been
proposed as a cue for females to predict male quality. We investigated
whether offspring of converging parental pairs showed differences in
immune competence compared to offspring derived from non-converging
parental pairs using three different types of immune assays. We found that
offspring immune responses (melanization response and response to a
bacterial challenge) differed between offspring from converging and
non-converging parents. However, immune responses were shaped by several
interacting factors such as sex, age, reproductive status, and parental
mating behavior. Parental mating behavior had a stronger effect on the
immune response of male offspring than on female offspring. Further, a
population of female offspring derived from converging parental pairs
reached their peak dengue virus dissemination rate earlier compared to a
population of offspring derived from non-converging parental pairs. Our
results provide insight into a wide range of selective pressures shaping
mosquito immune function. Evolutionary trade-offs between naturally and
sexually selected traits can have important implications for disease
transmission and control and should be considered in the development of
reproductive control strategies.