Microscopic Structure of the Genitals and Thoracic Legs Sensilla of Arma chinensis under the Scanning Electron Microscopy

Purpose Arma chinensis (Fallou) is an important predatory natural enemy insect. Observing its genital organs, thoracic legs sensilla types and morphological characteristics is helpful to explore the mechanism of host selection and other behaviors.

Method The types and morphology of sensilla on genitalia and thoracic legs were observed by scanning electron microscopy.

Result Scanning electron microscopy (SEM) showed that there were four kinds of sensilla on the genitals of A. chinensis: sensilla trichodea, sensilla cheatica, sensilla coeloconica and sensilla basiconica. The length of sensilla trichodea, sensilla cheatica on the ovipositor of female insects is longer than that on the mating organ of male insects. There were five kinds of sensilla on the thoracic legs of A. chinensis: sensilla trichodea, sensilla cheatica, sensilla coeloconica, sensilla basiconica and Böhm’s bristle sensilla. However, there are some differences in the size of the sensilla on the thoracic legs between male and female: the length of the sensilla cheatica on the mid-hind foot is longer in female than in male, the length of sensilla Trichodea Ⅰ and Ⅱ on the hind foot is longer in female than in male, and the length of Böhm’s bristle sensilla on the forefoot is longer in male than in female.

Conclusion There are many types of sensilla on the genital organs and thoracic legs of A. chinensis. There are no significant differences in morphology and species, but only some of the receptors are different in size.