Sex Ratio of Episyrphus balteatus (Diptera : Syrphidae) in the Field and Laboratory Population

Abstract

Adult syrphids (hover flies) are nectar and pollen feeders and most important pollinators in agroecosystem while the larval stages are predators on the aphids and are used as bioagent in their biocontrol programme. Episyrphus balteatus (De Geer) is the most common and abundant species in northeast Bihar. Hence, its sex ratio was observed under the natural environment (field) and the laboratory conditions. The sex ratio in the field population was observed as male biased (1:1.25) but in the laboratory it was female biased (1: 0.78). The differences between the sex ratio in the field population as well as in the laboratory population are insignificant.