Kairomonal response of the parasitoid Anagyrus spec. nov. near pseudococci to the sex pheromone of the vine mealybug

Abstract

The occurrence of a kairomonal response of the parasitoid Anagyrus spec. nov. near pseudococci (Hymenoptera: Encyrtidae) to (+)-(1 R, 3 R )- cis -2,2-dimethyl-3-isopropenyl-cyclobutanemethanol acetate (PcA, namely, planococcyl acetate) and ( S )-(+)-lavandulyl senecioate (LS), the respective female sex pheromones of its hosts, the citrus mealybug, Planococcus citri (Risso) and the vine mealybug, Planococcus ficus (Signoret) (Homoptera: Pseudococcidae) was investigated. Attraction to the pheromones was tested by employing pheromone traps in field trials and by static air olfactometer bioassays in the laboratory. Female wasps showed a significant response to LS, in both field and olfactometer experiments. No significant response was registered to the sex pheromone of P. citri. Despite the similarity between the structures of LS and its analogue ( S ) - (+)-lavandulyl isovalerate (LI), no significant response to the latter compound was observed. It seems that differences between the structures of the carboxylate moiety of the respective molecules (LS and LI) markedly affect the kairomonal attractiveness to the parasitoid. The kairomonal response of Anagyrus spec. nov. near pseudococci was neither influenced by the host habitat nor by the host species on which it developed. This suggested innate behaviour of Anagyrus spec. nov. near pseudococci , possibly derived from evolutionary relationships between the parasitoid and P. ficus . The practical implications of the results are discussed.