The response of the egg parasitoid, Trissolcus semistriatus (Nees) (Hymenoptera: Scelionidae) to metathoracic scent gland extract from Eurygaster maura (L.) (Hemiptera: Scutelleridae)

Abstract

ABSTRACT This study was conducted in 2013–2014 in order to determine the response of the egg parasitoid, Trissolcus semistriatus (Nees) (Hymenoptera: Scelionidae) to metathoracic scent gland (MSG) extract from Eurygaster maura (L.) (Hemiptera: Scutelleridae) in laboratory conditions. For this purpose, the MSG extracts obtained separately from males and females were diluted with hexane and six different concentrations were prepared. Naïve, mated parasitoids (2-3 days old) were used in the experiments. Hexane and distilled water were used as control treatments. In a Y-tube olfactometer, low concentrations of MSG extract from both sexes attracted the T. semistriatus but the preference for MSG extract was reduced with the increase in extract concentration and parasitoids oriented towards clean air. In order to determine the effect of MSG extract of E. maura on parasitisation and emergence rates of T. semistriatus, a single parasitoid was presented with two egg masses on blotting paper treated with MSG extract and two on blotting paper treated with hexane 4 cm apart in a Petri dish. The parasitoid was allowed 24 h for parasitisation. Parasitisation rates were higher than control at low concentrations of MSG extract of both sexes. There was no effect of MSG extracts on the emergence rates of parasitoids from eggs. According to the present results, the performance of the egg parasitoid, T. semistriatus in the control of the sunn pest, E. maura, can be enhanced by MSG extracts of the pest.