Scanning electron microscope observations on the antennal sensilla of two stored grain pests Trogoderma granarium and Trogoderma variabile (Coleoptera: Dermestidae)

Abstract

In this study both adult male and female antennal sensilla of Trogoderma granarium Everts, 1896 and Trogoderma variabile Ballion, 1878 (Coleoptera: Dermestidae) were observed by scanning electron microscope. The antennae of both species were found to consist of a scape, a pedicel and a flagellum with 9 subsegments, i.e., flagellomeres. Four categories of antennal sensilla including 10 types were found in these 2 species. The sensilla were designated, sensilla chaetica I, sensilla chaetica II, sensilla chaetica III, sensilla basiconica I, sensilla basiconica II, sensilla basiconica III, sensilla basiconica IV, sensilla basiconica V, sensilla coeloconica and Böhm bristles. The characteristics and distribution of these antennal sensilla were described, and relevant differences between the male and the female were compared. Finally, the probable functions and their applications in taxonomy were briefly discussed. These findings provide an improved understanding of the morphology of the antennae in these 2 species and can help to distinguish them clearly. Besides, these results also will support investigations into adaptions of these Trogoderma species to storage environments.