Cellulolytic bacteria in the digestive system of Prostephanus truncatus (Coleoptera: Bostrichidae)

Bacteria from the digestive system of larvae and adults of the larger grain borer, Prostephanus truncatus (Horn), from Mexico, Tanzania, and Togo were isolated and identified. Alcaligenes faecalis (Castellani & Chalmers), Chromobacterium violaceum (Bergonzini), and Pseudomonas fluorescens variety cellulosa (Trevisan) were only detected in the guts of P. truncatus from Tanzania, these bacteria showed a high capacity to digest carboxymethyl cellulose. The growth rate, antibiotic susceptibility, and effect of 2 pH values (4.5 and 6.5) on the growth of the 9 bacteria isolated from the 3 colonies of P. truncatus under aerobic and anaerobic conditions also were studied. Using transmission electron microscopy, the bacterial microenvironment was established in the hindgut (ileum) of the larger grain borer. The presence of cellulolytic bacteria in the alimentary tract suggests that this beetle has the potential to survive under varied environmental conditions and in a variety of commodities, including wooden structures in rural areas of most African and North and Central American countries that are used as dwellings or for maize storage. The presence of cellulolytic bacteria in the larger grain borer also suggests that cellulolytic capacity could be one of the phylogenetic similarities shared with some species of the Anobiidae.