1 Canterbury Museum, Christchurch
2 AgResearch, Lincoln
PCR (polymerase chain reaction) analysis of gut contents can be used to determine what arthropods are feeding on in ecosystems as DNA from the food ingested by an arthropod will be present in the gut for a certain amount of time before digestion takes place. PCR gut analysis was conducted on specimens of the introduced spider Tenuiphantes tenuis collected from pasture in Canterbury, New Zealand. PCR primers were specifically designed to amplify a fragment of the mitochondrial gene cytochrome c oxidase subunit 1 (COI) from Listronotus bonariensis and revealed that this major pasture pest species is consumed in the field by T. tenuis. The field predation rate of L. bonariensis by T. tenuis was estimated from our PCR results together with published data on the degradation of DNA and the density of T. tenuis in Canterbury pastures. We found that T. tenuis is a potentially significant predator of L. bonariensis in New Zealand pastures.