Hymenoptera associated with marine strandlines at Christchurch and Banks Peninsula

ABSTRACT A number of species of Hymenoptera are associated with marine strandlines or wrack, where they are generally parasitoids of dipteran larvae and/or pupae. However, few records appear to exist of Hymenoptera associated with strandlines in New Zealand. We recorded the adult Hymenoptera obtained in 30 minute hand searches in strandlines at 36 sites at Christchurch and Banks Peninsula over the course of 3 years. Twenty-five species were recorded, consisting of four species of ants, one sawfly, one bee and 19 parasitoid wasps. The most commonly encountered species, in terms of both numbers collected and sites recorded, was Kleidotoma subantarcticana (Figitidae: Eucoilinae). Trichomalopsis sp. (Pteromalidae), two species of Spilomicrus (Diapriidae) and Trichopria sp. (Diapriidae) were also relatively widespread. There were no statistical differences in the number of Hymenoptera species recorded on sandy, shingle or boulder beaches on Banks Peninsula. Adult wasps were collected in all calendar months, although there was a decrease in occurrence in autumn and early winter. Hand searching proved a valuable method to obtain adult specimens of wasps for information on biogeography and seasonality. However, the rearing of wasps from different species of dipteran larvae or pupae is required to provide details of host species usage and attribute specific ecological functions of parasitoids within the strandline habitat.