Ultrastructural morphology on antennal sensilla of the adult Diorhabda rybakowi on grassland

The leaf beetle Diorhabda rybakowi is an important insect pest that seriously damages pioneer plants for windbreak and sand fixation in the desert-steppes of northwest China. The ultrastructure of its antennal sensillas were observed by using scanning electron microscopy, and also compared the differences between females and males. The results showed that the antennae of both female and male adults of D. rybakowi were filamentous, and the flagellum was divided into nine subsections. Additionally, the male antennae (4 174.5 µm) were significantly longer than female antennae (3 780.5 µm) (P = 0.006). Both females and males have a large number of cuticular pores and appendages of cuticular plates distributed on the antennal surface. A total of six sensillums were identified in both male and female antennae, namely sensilla chaetica, sensilla trichodea, sensilla basiconca, sensilla coeloconica, sensilla auricillica, and Böhm’s bristle. The sensilla coeloconica was only found in a small number of male pedicel. This has provided the basic foundation for a deeper understanding of the molecular mechanisms of leaf beetle olfaction for sensing host volatiles or sex pheromones, and also for its integrated control.