Ultrastructure of the antennal sensilla of Queensland fruit fly, Bactrocera tryoni (Froggatt) (Diptera: Tephritidae)

Antennal sensilla of the Queensland fruit fly, Bactrocera tryoni (Froggatt) (Diptera: Tephritidae) were examined using transmission electron microscopy. Six sensillar types were recognised: a multiporous double-walled type (Mp-dw), multiporous single-walled types (Mp-sw) (4 subtypes) and no-pore sensilla with inflexible sockets (Np-is). The Mp-sw sensilla were categorised on the basis of wall thickness and differences in wall, pore and dendrite structure. The Mp-dw sensilla are innervated by 2 or 3 unbranched dendrites. The Mp-sw thick-walled sensilla have I or 2 sensory cells, whose dendrites,show limited branching within the shaft. The Mp-sw thin-walled sensilla are innervated by 2 or 3 sensory cells with dendrites that branch extensively within the shaft. The Np-is sensilla have not previously been described from tephritid antennae, and are found only in the antennal sensory pit. They have a granular appearance to the exterior walls and are innervated by 3 sensory cells, only 2 of which project dendrites into the hair lumen. The proposed functions of the sensilla are discussed. (C) 1997 Elsevier Science Ltd.