Scanning Electron Microscopy Observation on Antenna Sensilla in Adults of 2 Color Types of Coridius chinensis

To understand the type, distribution and ultrastructure of antennal sensilla of 2 color types of adults Coridius chinensis. The antennal morphology and ultrastructure of the female and male adults from 2 color types of C. chinensis were observed by scanning electron microscopy with brown and black C. chinensis in Dongshan Township, Tengchong City. The findings indicated that the antennae of C. chinensis were linear with 5 segments and composed by scape, pedicel and flagellum. The length of antennae was different between 2 color types and sexes. The antennal length of female from brown type was 8 433.88 μm, which was significantly longer than that of the male antennal length 8 162.21 μm, and the antennal length of female from black type was 8 315.41 μm that was also significantly longer than that of the male antennal length 8 106.54 μm. There was no significant difference in antennal length of female adults between 2 types while the antennal length of male adults between 2 types was significantly different. There were 7 antennal sensilla types from 2 color types of C. chinensis, including sensilla trichoidea, sensilla chaetica, sensilla basiconca, sensilla bent-tipped, sensilla cavity, sensilla cylindrical and sensilla coeloconica, among which 5 antennal sensilla types were shared by 2 color types. The sensilla trichoidea had the largest number and the widest distribution range. There were some differences on the antennae length, types and distribution of the antennal sensilla between 2 color types and sexes. Moreover, the sensilla cylindrical was observed for the first time on the antennae of Heteroptera insects. The results of this study provide a basic reference for further study of the relationship between C. chinensis and environment and the mechanism of host selection and the large-scale artificial breeding of C. chinensis.