External morphology ofXyleborus ferrugineus (Fabr.) (Coleoptera: Scolytidae). I. Head and prothorax of adult males and females

Abstract

The overall body dimensions and external morphology of the head, head appendages, prothorax, and prothoracic legs of the adult haploid male and diploid female Xyleborus ferrugineus (Fabricius) were examined by scanning electron microscopy and light microscopy, and analyzed for variation. The female is significantly larger (1.26 X) than the male. The length/width ratio of both the pronotum and elytron, and the pronotum-length/elytron-length ratio are significantly different in the male and female. These findings indicate a distinct sexual dimorphism in general body form. There is significantly greater variability in pronotal length and width in the male than the female. There are sexual differences in setal patterns and setal size variabilities on the dorsal pronotum and the terminus of the antennae.