Effects of larval density on the size of Aedes polynesiensis adults (Diptera: Culicidae)

Replicated cohorts of a Tahitian laboratory strain of Aedes polynesiensis Marks were reared at 3 larval densities with a fixed amount of food. For larvae provided with limiting per capita food (i.e., 400 larvae per pan with 500 mg liver powder) relative to standard rearing conditions (i.e., 200 larvae per pan), mean pupal survival as well as male and female mean adult dry weights were significantly reduced and median developmental times were significantly prolonged. However, excess per capita food did not allow low density cohorts (i.e., 100 larvae per pan) to increase adult production, developmental rate, or adult dry weight compared with cohorts reared under standard rearing conditions. Male and female pupal wet weights, adult dry weights, and adult wing lengths all were correlated for Ae. polynesiensis collected as pupae from natural habitats near Papara Commune, Tahiti. Mean adult dry weights of host-seeking females from the same and a neighboring location did not differ significantly from weights of females emerging from field-collected pupae. The comparison of mean adult dry weight of these adults with adults reared at different densities in the laboratory indicated that field populations develop under food-limited conditions. Aedes polynesiensis responds to intraspecific larval competition by producing small adults over elongated developmental periods. Pupal wet weights, adult dry weights, and adult wing lengths are equally acceptable measures of mosquito size for vector and fecundity studies.