Comparative anatomical and histological study of the alimentary canal of the Dendroctonus frontalis (Coleoptera : Scolytidae) complex

In this study we compared the anatomy and histology of the alimentary canal of Dentroctonus approximatus Dietz, D. mexicanus Hopkins, D. frontalis Zim mermann, and D. brevicomis LeConte, The results show that these species sha re similar characteristics, and their structural pattern is comparable to t hat observed in other Dendroctonus species. These 4 species have characteri stics not found in other bark beetle genera in the esophagus, crop, provent riculus, and hindgut. The close relationship of the Malpighian tubules to p osterior foregut, anterior midgut, and distal hindgut is also different. Ad ditionally, the midgut of the D. frontalis complex species shows a great ce llular diversity, which suggests that this region may Lf involved ill phero mone production.