Adaptative significance of a temperature induced diapause in a cosmopolitan parasitoid of <i>Drosophila</i>

Abstract

Abstract. 1. We have previously demonstrated pre‐pupal diapause in a tropical population of Leptopilima boulardi Barbotin, Carton and Kelner‐Pillault (Cynipidae, Hymenoptera), a larval parasitoid of Drosophila melanogaster Meigen. Prepupal diapause was induced by low temperature (17.5°C) but absent at 25°C; it was independent of photoperiod. 2. Four populations which originated from different latitudes (4°S to 44°N) exhibit the same response to temperature without any major genetic geographical variation. 3. In temperate areas, this diapause may permit a phenological and temporal coincidence between the parasitoid and its host whose larval growth is only possible for temperatures above 13°C. 4. The significance of the persistence of this diapause in tropical areas is discussed.