Kodamaea ohmeri (Ascomycota: Saccharomycotina) presence in commercial Bombus impatiens Cresson and feral Bombus pensylvanicus DeGeer  (Hymenoptera: Apidae) colonies

In this study, eight commercial and three feral bumble bee (Bombus impatiens Cresson and Bombus pensylvanicus DeGeer respectively, Hymenoptera: Apidae) colonies were tested for the presence of Kodamaea ohmeri (Ascomycota: Saccharomycotina), a yeast known to attract small hive beetles (SHB) (Aethina tumida Murray, Coleoptera: Nitidulidae) to honey bee (Apis mellifera L., Hymenoptera: Apidae) colonies. Swabs of commercial bumble bee colonies and homogenates of bumble bee colony components (adults, brood, honey, pollen and wax) were plated on selective media. The resulting yeast isolates were compared to K. ohmeri previously isolated from SHB. Yeasts were detected in all of the commercial bumble bee colony swab samples (n = 56) and a selected subsample was shown through molecular, chemical, and microbiological evidence to be K. ohmeri. For the second part of the study, feral bumble bee colonies were excavated and evaluated for the presence of any SHB life stage (none was found). Adult bees and swabs from the colonies were plated on selective media. Kodamaea ohmeri was isolated in all samples collected from the feral bumble bee colonies. The presence of K. ohmeri in commercial and feral bumble bee colonies is of concern, as SHB, which harbour K. ohmeri, are attracted to the volatiles produced by K. ohmeri growing on bee collected pollen.