Sexual Differences in Larval Molting Rates in a Protandrous Mosquito (Diptera: Culicidae) Species,Aedes sierrensis

Abstract

Day-old larval Aedes sierrensis collected from six newly flooded treeholes in northern California were reared individually in the laboratory under simulated field conditions to compare larval developmental rates of males and females. Time to adult eclosion ranged from 133 to 219 d for this generally univoltine, winter-developing species. Males experienced significantly shorter first, second, and third larval instars than females. Females spent significantly less time as fourth instars (whose endpoint is determined by photoperiod). Length of pupal stage was equal for males and females. Time to mean adult eclosion differed among treeholes but was not determined by latitudinal position of treehole. Wing lengths were shorter for males than females in this sexually dimorphic species and also differed significantly among treeholes. Wing lengths were significantly correlated with total developmental time, but females spending more time in the fourth instar did not emerge as larger adults. In natural treeholes, resource utilization during rapid development by Ae. sierrensis males may limit the size and number of females produced from the same cohort if resources are limiting.

Testing Developmental Plasticity in Aquatic Larvae ofCorethrella appendiculata(Diptera: Corethrellidae)

“…Male precedence in molting from the third to the fourth instar has been recorded previously in mosquitoes such as Aedes sierrensis (Ludlow) (Mercer et al 2008). Protandry, the eclosion of male adults before females, has been observed in many insect species and is reported here for C. appendiculata.…”

WolbachiaInfection and Resource Competition Effects on ImmatureAedes albopictus(Diptera: Culicidae)

“…Such sexually asymmetric competition has been observed for other mosquito species including Aedes polynesiensis Marks (Mercer 1999) and Aedes aegypti L. (Bedhomme et al 2003) and seems to be a widespread occurrence among mosquito species (Mercer et al 2008). Whatever the starting conditions, males (with about half the adult biomass of females) consume fewer resources and emerge earlier than their sisters.…”

Context-dependent interactive effects of non-lethal predation on larvae impact adult longevity and body composition

“…Theories on sexual and natural selection predict differential adaptive benefits of protandry for both males and females; males benefit by mating multiple times and females by enhanced fecundity [ 68 , 73 ]. Previous studies have shown sex-specific responses to biological interactions in protandrous insects [ 75 , 83 , 84 ]. Development time for males was not strongly affected by nutrition and density, but adult size and size-dependent body composition changed dramatically as evident in larvae exposed to ‘low’ and ‘medium’ nutrition and ‘high’ intraspecific competition (Figs 2 and 4 ).…”