SEASONAL-VARIATION IN BODY-SIZE OF MOSQUITOS (DIPTERA, CULICIDAE) IN A RICE CULTURE AGROECOSYSTEM

We determined whether wing lengths of Culex tarsalis (Coquillett) and Anopheles freeborni (Aitken) varied seasonally; whether size was assoc iated with abundance; and if individuals of a particular size could be associated with riparian, pasture, or rice field habitats within the rice culture agroecosystem of northern California. Significantly, the size of both male and female Cx. tarsalis increased as the season prog ressed. The size of female An. freeborni also increased significantly throughout the season, but the size of males did not. Abundance was no t correlated with average wing length nor could any habitat be signifi cantly associated with a particular size group. We conclude that for t he species studied here, environmental effects (such as water temperat ure and seasonal availability of larval nutrients) are more important in determining individual size than the density-dependent processes th at regulate the size of mosquitoes that breed in small containers.