Parasites and Parasitization Rates in Bumble Bee Queens, Bombus spp. (Hymenoptera: Apidae), in Southwestern Virginia

Several parasites were found affecting foraging bumble bee queens collected in the spring of 1982 and 1983 at three locations in southwestern Virginia. Sphaerularia bombi Dufour (Nematoda: Tylenchida) occurred at low levels in all areas sampled, infestation rates ranging between 1.7 and 7.9% during the 2-year period. Parasitization by Locustacarus buchneri (Stammer) (Acari: Podapolipidae) ranged from 0 to 29.3%, and the mite appeared to be host-specific for Bombus bimaculatus Cresson and Bombus vegans Smith. Gregarious endoparasitic larvae, probably Syntretus sp. (Hymenoptera: Braconidae), were seen at levels ranging from 0 to 11.8%. Two types of phoretic mites were also common. Kuzinia americana Delfinado and Baker (Acari: Acaridae) were generally abundant at rates ranging from 12.3 to 69.6%. Parasitus spp. mites (Acari: Parasitidae) were carried by 4.9 to 37.2% of the queens. Bumble bee populations in southwestern Virginia probably are not seriously reduced by any of the parasites or commensals.