Diets and Reproductive Phenologies of the Introduced Ground Beetles Harpalus-Affinis and Clivina-Australasiae (Coleoptera, Carabidae) in New-Zealand

Abstract

The diet and reproductive periods of Harpalus affinis (= Harpalus aeneus) and Clivina australasiae, collected by pitfall trapping from graminaceous and legume crops at four sites on the North Island of New Zealand, were determined by dissection. H. affinis was predominantly phytophagous, with a liking for weed seeds; its main animal foods were Aphididae and Diptera. Females were gravid in spring (September-November) and summer (December-February) whilst tenerals were found mainly in autumn (March-May). Diet and phenology were similar in New Zealand, Europe and North America. C. australasiae was a polyphagous carnivore, consuming 11 categories of animal food (the most frequent being Enchytraeidae and Lumbricidae) and six categories of plant food. Females contained eggs from August to March. The food and reproductive period of C. australasiae in New Zealand were similar to those previously reported for Clivina fossor in Europe and North America. Overall, both species are considered likely to play a beneficial role in New Zealand agriculture. Opportunities are identified to study further the biocontrol potential and role in ecosystem function (e.g. community assembly rules) of these species, by means of translocation experiments.