Adult mortality and minimum lifespan of the ground beetle Harpalus affinis (Coleoptera: Carabidae) in New Zealand

To describe mortality patterns of the introduced ground beetle, Harpalus affinis (Schrank), field-collected individuals were kept in the laboratory under natural photoperiod in New Zealand. Two cohorts of adults survived for up to 2 years. Collecting time (spring versus late summer) had a significant effect on the survival, but not on the maximum lifespan observed. Up to 20-30% of individuals of both sexes lived longer than a year after collection. Carabids can develop from egg to adult in one season, or they spend the winter period hibernating as larvae or pupae, emerging the following spring. They are thought to be semelparous (the adults die after a single reproductive season) but several species survive longer and are iteroparous (Lovei & Sunderland 1996). However, data on lifespan, in the laboratory or the field, are still scarce for carabid species and none are known from New Zealand. In this publication we report on the adult lifespan of a New Zealand population of the non-native ground beetle Harpalus affinis (Schrank).