Abstract
Mutillid wasps are ectoparasitic insects that parasitize the enclosed developmental stages of their hosts. Adults are sexually dimorphic, with brilliantly colored and hardened cuticles. The biology of parasitic mutillid wasps has rarely been addressed. Here, we investigated the parasitization by Mutilla europaea on an important pollinator, Bombus breviceps. The parasitic biology and dispersal ability of M. europaea were observed and tested under experimental conditions. We provide the first record of M. europaea parasitizing B. breviceps in southwestern China. As is the case with other bumblebee species, M. europaea mainly parasitized the puparia of males. The dispersal and invasion ability of this parasite under experimental conditions indicates that it spreads rapidly, as far as 20 m in one week, and invades different hosts (B. breviceps and Bombus haemorrhoidalis). This report not only clarifies the parasitic relationship between M. europaea and B. breviceps, but also has important ecological implications for the conservation of bumblebees in China.