Flight behaviour of the manuka chafers, Pyronota festiva (Fabricius) and Pyronota setosa (Given) (Coleoptera: Melolonthinae), on the flipped soils of Cape Foulwind on the West Coast of New Zealand

The flight behaviour of two species of manuka beetle, Pyronota festiva and P. setosa was monitored in young dairy pastures established on the recently flipped soils of Cape Foulwind, Buller from 2008-2012. Adults of both species flew in the day during late spring /early summer (Nov-Dec) of each year. Flight behaviour was monitored by fixed vane traps, sweep netting and observation. Seasonal flight timing was consistent between years. Pyronota festiva exhibited flight patterns broadly similar to that previously reported in the literature. The P. setosa flights started 1-2 weeks in advance of P. festiva and trap catch were predominately male (95%). Female P. setosa were rarely observed flying and were rarely caught in sweep net samples. Unlike P. festiva, P. setosa adults were never observed swarming or congregating and feeding on the foliage of manuka or any of the other native or exotic tree species which were sporadically present within the wider study area. These differences in flight behaviour appear to explain the ability of P. festiva to rapidly invade and cause damage in new pastures, while P. setosa populations build up and spread slowly from patches of damage in infested pastures.