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.