Morphology and distribution of antennal sensilla of Plautia stali (Hemiptera: Pentatomidae)

Abstract

In this study, the morphology and distribution of antennal sensilla of male and female adults of Plautia stali were investigated using scanning electron microscopy. In both sexes, the antennae of P. stali were composed of a scape, two-segmented pedicels (P1 and P2) and two-segmented flagellomeres (F1 and F2). There were no differences in the overall length and shape between males and females. Four basic types of sensilla (s. trichodea, s. basiconica, s. chaetica and s. coeloconica) were identified in each sex. Sensilla basiconica and s. chaetica were further divided into four and two subtypes, respectively. Among the sensilla, s. trichodea and s. basiconica subtype 4 were multiporous, indicating that these two types are involved in olfactory functions. There was an apical pore on the tip of s. basiconica subtypes 2 and 3, suggesting that they have contact chemosensory function. There was no pore on the cuticular surface of the other types of sensilla, suggesting that these types may be mechano-, thermo- or hygroreceptors. Sexual dimorphism was not evident in the distribution of the four types of sensilla, although there were variations in the number and distribution of sensilla along with the antennae in both sexes. This study reveals information regarding the sensory function of each type of sensillum in P. stali.