Photoperiod-induced diapause in a North Carolina strain of Aedes sollicitans: photosensitivity of fully formed and developing embryos.

The role of photoperiod in the induction of diapause in eggs laid by field-collected adult Aedes sollicitans mosquitoes was examined at different temperatures. Short-day photoperiods induced a much higher incidence of diapause at 15 degrees than at 22 degrees C, whether eggs were 0, 1, 2, 3, 4 or 5 days old postoviposition on exposure. A 6-week exposure to a 6:18 to 10:14 (L:D) photoperiod at 15 degrees caused 87-100% of the eggs tested to enter diapause. The diapause incidence was significantly different for 0- to 5-day-old eggs subjected to a 10:14 photoperiod at 15 degrees and to a combination of 10.5:13.5 photoperiod and a 21:5 degrees C thermoperiod. Hatchability of 0- to 5-day-old eggs did not differ significantly after a 6-week exposure to other photoperiod/temperature combinations tested. However, evidence of photoperiod/temperature interaction during embryogenesis was observed following exposure to different short-day photoperiods at both 22 and 15 degrees C.