Captive rearing of the endangered weevil Hadramphus tuberculatus (Pascoe, 1877) (Coleoptera: Curculionidae: Molytinae) for ex-situ conservation

ABSTRACT Captive rearing can be a successful short-term strategy for protecting species threatened with extinction, by bolstering existing populations, or establishing new ones. Improving the success of captive rearing requires specific prior ecological knowledge, for example habitat and climatic requirements. Here, we report on the captive rearing of the critically endangered Canterbury knobbled weevil Hadramphus tuberculatus (Pascoe, 1877). Only a single population of H. tuberculatus is known, with an estimated population size of fewer than 100 individuals; as such, captive rearing provides an opportunity to augment the remaining population and potentially to allow the establishment of new populations, if suitable sites can be found. We successfully reared two F1 generation adults and two live larvae were recovered at the end of the project. We use a qualitative spatial analysis to determine the location of possible sites for reintroduction of H. tuberculatus. The spatial analysis suggests that there is little suitable habitat remaining for new H. tuberculatus populations. Our study provides guidelines for future captive breeding programmes and highlights the risks of removing individuals from an already vulnerable, small population.