| The Carabidae is a large family of beetles with 33,920 valid species world-wide. While the specific diets of many of these species are known, especially among the Carabinae, the feeding preferences of the majority of species are unknown. Attempts to determine the food preferences have been made relying upon morphological characters of the head and mouthparts but not in a quantitative manner. A literature review of morphological characters of the Carabidae in 2002 showed that no consistent morphological character would predict the feeding preferences of all species. In this study, twenty morphological measurements and character conditions from the adults of fourteen species of carabids representing five subfamilies and ten tribes were evaluated to determine whether there is a correlation between the morphology of the mandibles and proventriculus, the gut contents and field observations. Using cluster analysis the measurement means and the presence or absence of structures of all twenty characteristics were evaluated. Five characters were found to provide the most information and provided logical groupings. However, it was apparent that predicting specific food preferences was not possible. Instead the analysis indicated the type of feeding, that is, fluid feeding with extra-oral digestion, particulate feeding or mixed feeding incorporating both fluid feeding, and particulate feeding. Fluid and mixed feeding species (Cicindela punctulata Oliver and Calosoma calidum F., Paraclivina bipustulata (F.)) were predaceous while particulate feeders (primarily carnivorous: Omophron labiatum F., Bembidion quadrimaculatum L., Poecilus chalcites (Say), Stenocrepis duodecimstriata Chevrolet, Lebia grandis Hentz, and Calathus gregarius Say; primarily herbivorous: Harpalus caliginosus F., Geopinus incrassatus Dej., Stenolophus lineola F., Zabrus tenebroides Goeze, and Anisodactylus laetus Dej.) could be both predaceous and herbivorous to varying degrees. Lack of field observations or conflicting evidence of other workers makes some of the designations questionable. Convergent evolution seemed a likely mechanism in unrelated groups in the development of the proventriculus. Harpalus caliginosus demonstrated that although the members of the genus Harpalus are widely regarded to be seed eaters, H. caliginosus is at least a scavenger, if not predator, despite having mandibles appropriate for eating seeds. |
