Phoretic mites associated to Bombus pauloensis and Bombus bellicosus (Hymenoptera: Apidae) from Uruguay

Bumble bees (Bombus spp.), considered as important angiosperm pollinators, harbor several mite species associated with their nests. In the present study, 403 bumble bees - B. pauloensis (n = 285) and B. bellicosus (n = 118) - were surveyed at five departments from Uruguay: Canelones, Colonia, Montevideo, Florida and Soriano. The mite species Kuzinia spp. Pneumolaelaps longanalis, P. longipilus, Scutacarus acarorum, and Tyrophagus putrescentiae were found associated with both bumble bee species. At least one mite was present on 30% of the bumble bees. We compared the mite prevalence, abundance, intensity and Simpson's diversity index between bumble bee species and castes. Bumble bee caste was the most influential factor on mite presence, and also on the composition of the phoretic mite community. The assemblages described here could be relevant for future studies focusing on potential threatens for native bumble bees. In combination with a pathogen screening, this data could be proposed as a relevant approach for monitoring native pollinators, especially in areas where they are threatened. The establishment of descriptive indices for threatened and healthy populations would be then of great value for species conservation.