The effect of larval temperature and photoperiod on the incidence of larval diapause in the blowfly, Calliphora vicina

Abstract

ABSTRACT. The blowfly, Calliphora vicina Meigen (Diptera: Calliphoridae), displays a maternally induced larval diapause. Progeny of adults exposed to short days enter diapause if the larval temperature is 15d̀C or below; exposing adults to long days, or larvae to temperatures above 15d̀C, results in non‐diapause. By keeping progeny from short‐day parents at the parental temperature of 23.5d̀C for various lengths of time before transfer to 11d̀C, it could be shown that the diapause‐averting effect of high temperature operates in the late wandering stage of larva, possibly at the moment of the decision for the brain‐ring gland complex to release PTTH/ecdysone at the diapause/non‐diapause stage.Although photoperiodic induction in the blowfly is maternal, previous work had shown that the larvae were also slightly sensitive to photoperiod. From the present study it is evident that also the eggs are photo‐sensitive.