Effect of mating disruption on reproductive behavior in the European pine sawfly, <i>Neodiprion sertifer</i> (Hymenoptera : Diprionidae)

Abstract:
Females of the European pine sawfly, Neodiprion sertifer (Geoffr) (Hymenoptera: Diprionidae), were released and observed inside and outside (=control) of areas treated with their sex pheromone for the purpose of mating disruption. In 1992 and 1993, respectively, 0 and 2.5% of the females were observed mating in the pheromone treated area during the first day compared with 28 and 26% in the control area. Of the females that mated, approximately 50% stayed on their twigs and oviposited, while the remaining 50% disappeared Significantly more females disappeared from their twigs inside the treated area compared to the control area in both years. No difference was found in the proportion of unmated females ovipositing (2-12%) between the treated and the control area. Predation was responsible for much of the disappearance, but deliberate dispersal was also noted. Mating and dispersal in female N. sertifer are discussed in relation to population density and overall fitness.