Sensilla on antenna and maxillary palp of Neoceratitis asiatica (Diptera: Tephritidae)

Abstract

Neoceratitis asiatica (Diptera: Tephritidae) is a disastrous pest for wolfberry production in China. In our preliminary field trapping experiment, both female and male N. asiatica adults were captured by male-produced sex attractant. To provide a solid background for studying mechanism of olfaction, the sensilla of antenna and maxillary palp of N. asiatica adults were studied by means of scanning electron microscopy. Both sexes have 3 antennal segments, including scape, pedicel, and flagellum, while arista is arisen from the proximal dorsal ridge of the flagellum. Two types of sensilla were found on the scape and pedicel, sensilla microtrichia (AnMi) and sensilla chaetica (AnCh). There are five types of sensilla on the flagellum, sensilla basiconica (AnB), clavate sensilla (AnCl), sensilla trichoidea (AnTr), sensilla coeloconica (AnCo), and AnMi. Three types of sensilla were observed on maxillary palp, sensilla basiconica (MpB), sensilla microtrichia (MpMi), and sensilla chaetica (MpCh). AnMi and MpMi are the most abundant sensilla type on antenna and maxillary palp, respectively. With the exception of having longer flagellum in females, the dimension of antennal segments, type and number of sensilla, density of pores on the shaft of AnCl, AnCh, AnB and MpB, and at the base area of AnCh and MpCh didn't show differences between sexes. This lack of inter-sexual differences may be related to chemoreception of male-emitted sex pheromone and of host plant volatiles by both female and male adults.

Keywords: Antennal morphology; Chemoreceptor; Fruit fly; Olfaction; Scanning electron microscopy; Sensory organ.