Antennal sensilla of specialist and generalist Anastrepha species

The antennal sensilla of generalist and specialist species of fruit flies Anastrepha (Diptera Tephritidae) were analysed by scanning electron microscopy. The antennae of species in this genus have three segments, scape, pedicel and flagellum (or funiculus) and a long filamentous arista protruding from the flagellum. The antennal flagellum is covered by microtrichia, and four types of olfactory sensilla, basiconica, clavate, coeloconica and trichoidea. Although the total number (weighted by the flagellar area) of sensilla is similar in the generalist and specialist species, differences do exist. Basiconica and trichoidea sensilla are the most abundant in both, generalist and specialist species. Trichoidea occur in similar number in both group of species while basiconica is more numerous in the specialist one differing from the general claim that this sensilla are more abundant in generalist species. There are no significant differences in the number of the clavate and coeloconica sensilla in both group of species. The sensilla are not evenly distributed along the antennal flagella, and positive correlations were found between the number of each type of sensilla and the size of the flagella.