Egg Hatchability and Diapause in Aedes triseriatus (Diptera: Culicidae): Temperature- and Photoperiod-induced Latencies1

Egg diapause in the mosquito Aedes triseriatus (Say) is a hatching latency induced by photoperiod. Fully-formed embryos are sensitive to diapause-inducing daylengths, and only 3–6 short-day cycles (10 h light/24 h) are required to block the hatching reflex. Photoperiodic response of Ae. triseriatus from 42°N latitude is identical whether exposure occurs during embryogenesis or after its completion. Diapause can be repeatedly induced and terminated in the same egg. A 2nd type of hatching latency can be induced in Ae triseriatus. At an optimal photoperiod (16 h light/24 h), embryos transferred from 21°–10°C become unresponsive to hatching stimuli after 7–14 days. This temperature-induced latency is completely terminated 13 days after return to 21°C.