A COMPARISON OF THE MOLAR EFFICIENCY OF 2 INSECT-EATING MAMMALS

The extent to which the different molar morphologies of two similar-si zed mammals, Petaurus breviceps (sugar glider) and Dasyuroides byrnei (kowari), could affect the digestion of larval insect nitrogen was inv estigated. Nitrogen digestibility of Tenebrio larvae treated with a pr oteolytic enzyme (trypsin) increased with decreasing larval piece size . However, it was found that the molars of P. breviceps, with their mi nimal shearing capacity compared with D. byrnei, can only compress rat her than finely comminute Tenebrio larvae. As a result, P. breviceps h ave less efficient nitrogen digestibility than D. byrnei whose shearin g molars can finely comminute larvae. Petaurus breviceps molars are in efficient at breaking down insects possibly because of functional cons traints, where the molars must perform several different tasks with co mpeting morphological demands, or because of phylogenetic constraints.