Stimuli Affecting Selection of Oviposition Sites by Aedes Vexans (Diptera: Culicidae): Light1

Abstract

Light has a great influence on the selection of oviposition sites by Aedes vexans. Given a choice between shaded and unshaded locations, females strongly preferred to oviposit where there was shade. Since a mosquito on a shaded surface might sense reduced light from overhead or reduced light reflected from the surface itself, an experiment was performed to determine whether 1 or both of these aspects of shade influenced oviposition. In this experiment, females deposited the same number of eggs on highly reflective (white) and poorly reflective (black) surfaces, indicating that reduction of reflected light did not encourage oviposition. Therefore, reduction of overhead light was probably what stimulated oviposition at shaded sites. Mosquitoes exposed to a daily regime of 16 h of simulated daylight and 8 h of simulated nocturnal illumination deposited 4 times as many eggs per hour during the darker periods.