Seasonality of crane flies (Diptera: Tipulidae) in South Island beech forest in relation to the abundance ofVespulawasps (Hymenoptera: Vespidae)

Abstract

Crane flies (Tipulidae) are common in the diet of native insectivores and introduced Vespula wasps. The seasonality of adult crane fly species was determined by Malaise trapping so that species potentially vulnerable to an impact from high wasp numbers could be identified as possible indicator species for analyzing the wider impacts of wasps in beech forest (Nothofagus spp.) ecosystems. Four sites in beech forest at Lake Rotoroa, Nelson Lakes National Park, were sampled over 2.5 years. The seasonality of 20 species of larger Tipulidae were plotted against three broad seasonal levels of wasp abundance identified from Malaise trap catches. Eleven species shared at least 40% of their flight period with high wasp numbers, with three of these restricted almost entirely to the period of high wasp abundance. These species may be the most vulnerable to an impact from wasp predation.