Behavioural consequences of cold exposure on males and females of Aphidius rhopalosiphi De Stephani Perez (Hymenoptera: Braconidae)

Cold storage of insect parasitoids is currently used before mass release in the field in biological control programmes. The physiological consequences of constant cold storage are known in various species of parasitic wasps, but there are few reports on the behaviour of survivors and even fewer reports where both sexes were tested. In this study, we observed the consequences of a long storage of Aphidius rhopalosiphi De Stephani Perez (Hymenoptera: Braconidae), a parasitoid of the cereal aphid Sitobion avenae Fabricius (Hemiptera: Aphididae), at low temperature on some key behavioural decisions that both sexes will make when released in the field. Males are less tolerant than females and both sexes suffer from a long exposure (28 days or more) at 4°C during the pupal stage: alteration of olfactory responses, decrease in mating capacity and decrease in the efficiency of patch exploitation by females.