Orientation and Behavioural Responses of Cotesia plutellae (Kurdjumov) (Hymenoptera: Braconidae) Towards Honey and Sucrose

Abstract

: In present study effect of sucrose, honey odour and its different fractions on orientation and behaviour of Cotesia plutellae (K) (Hymenoptera: Braconidae) , a larval endoparasitoid of Plutella xylostella (L) (Lepidoptera: Plutellidae), was studied under laboratory conditions. Orientation responses of naïve, unmated and unfed adults of C. plutellae were tested in a T-shaped tunnel. Female wasps showed attraction, antennation and mouth parts extension to honey at a distance in response to its odour. Attraction of females to honey was innate because the wasps derived from sucrose-fed parents showed same level of attraction to honey as those derived from honey-fed parents. Hexane fraction of hexane-extracted honey attracted females, but did not elicit antennation and mouthparts extension. Aqueous fraction of hexane-extracted honey elicited latter two responses but no attraction. Male wasps showed antennation and mouthparts extension but no responses to honey odour. A comparison of Preference Indices of the wasps for different fractions showed that their attraction to the hexane fraction and antennation/mouthparts extension to the aqueous fraction were significantly less than those to the un-extracted honey. The present study suggests that it may be helpful in biological control with C. plutellae to use honey odour in the background of an appropriate, nutritionally efficient, food like sucrose or a formulation of various nutrients which may itself be unattractive to the parasitoids.