Diurnal activities ofHalictus scabiosaebees and their nest parasites (major bee-flies, cuckoo wasps, ichneumon wasps,Sphecodesbees, and velvet ants) were investigated at a study site with 159 nests in Eastern Austria. Foraging activity correlated with ambient temperature only before midday and decreased in the afternoon. The activity of nest-infesting parasites increased during the day and correlated with ambient temperature. The match factorfmbetween the ratios of the foraging activities ofH. scabiosaeand the ratios of aspects of morning temperature was assessed on three consecutive days with different weather. The activity patterns of halictine bees and their nest parasites differed: the parasites exhibited only small time windows in which their activities were synchronised with those of their hosts. The bees exhibited an anticyclic behaviour and collected food in times of low parasite pressure and decreased foraging activity when parasite pressure increased.
Cryptic species and hidden ecological interactions of halictine bees along an elevational gradient
