Objective  Antennae of Dendrolimus houi were examined under a scanning electron microscope (SEM) for the morphological differences that might relate to functional differentiations between the male and female moths.

  Methods   SEM images of the antennae of newly emerged male and female D. houi were obtained for an ultrastructural comparison.

  Results  The yellowish brown antennae of the male pine moths had a feather-like appearance, while that of the female resembled a short-tooth-comb. They both had 13 distinctive types of sensilla in 6 classifications including 2 sensilla trichodea, 1 sensilla basiconica, 3 sensilla chaetica, 3 sensilla styloconica, 2 sensilla coeloconica, and 2 Bőhm bristles. The sexual dimorphism on adult D. houi was evident by the sensilla basiconica of the females and the sensilla trichodea Ⅱ of the males shown on the antenna surface. In addition, there were more numerous and longer 6-8 sensilla trichodea Ⅰ that were orderly aligned in a row with 1-2 sensilla trichodea Ⅱ in between on the abdomen of the lateral branches of the male antenna than those of the female organ (P＜0.05).

  Conclusion   The ultrastructure of the moth antennae revealed by SEM displayed the significant differences between the male and female D. houi on the length and quantity of the lateral branch sensilla trichodea Ⅰ. The fact that sensilla basiconica existed only on the female moths and the sensilla trichodea Ⅱ exclusively on the male adults might be indicative of distinctive roles of them in host-selection, mating behavior, or other biological functions of the insect species.