Interspecific Competition, Parasitism, and Predation Affect Development of Aedes hendersoni and A. triseriatus (Diptera: Culicidae) in Artificial Treeholes

Abstract

Experiments were conducted in simulated treehole microcosms to determine the effects of interspecific competition, parasitism, and predation on development of the sibling species Aedes hendersoni Cockerell and Aedes triseriatus (Say). The results of competition between the two species were asymmetrical. A. hendersoni larvae competed better against conspecifics than they did against A. triseriatus larvae. The reverse was true for A. triseriatus . Infection with Ascogregarina barretti (Vavra), a natural protozoan parasite of A. triseriatus , negatively affected development of A. hendersoni but had no effect on the natural host. Infected A. hendersoni larvae were more likely than uninfected larvae to compete poorly against A. triseriatus . Mortality of infected A. hendersoni was significantly higher than that of their uninfected counterparts, but infected survivors were not released from the effects of competition. Predation by fourth instar Anopheles barberi Coquillett was equal on prey larvae of both Aedes species . Surviving larvae were released from competition. These results suggest that interspecific competition, parasitism, and predation may be important factors in the life histories of treehole Aedes .