Anaerobic bacteria isolated from the alimentary canals of alfalfa leafcutting bee larvae

Abstract - Microorganisms were isolated from the alimentary canals of third-instar alfalfa leafcutting bee (Megachile rotundata) larvae under strict anaerobic conditions. In all 3 years of the study, small populations (8.0 colony-forming units per gut) of a limited number of bacterial taxa (primarily the facultatively anaerobic bacteria Paenibacillus macerans, Bacillus licheniformis, B. brevis, B. mycoides and P. polymyxa) were isolated. With the exception of three isolates of Clostridium longisporum recovered in 1993, no obligate anaerobic bacteria were isolated. The small size of populations and the inconsistency of recovery of bacteria in different years suggest that anaerobic microorganisms are not common inhabitants of leafcutting bee larval guts. Consequently they could not have a significant impact on the ecology of the alimentary canal nor influence the development of chalkbrood disease caused by the entompathogenic fungus, Ascosphaera aggregata. © Inra/DIB/AGIB/Elsevier, Paris