ULTRASTRUCTURE OF THE ANTENNAL SENSILLA OF QUEENSLAND FRUIT-FLY, BACTROCERA-TRYONI (FROGGATT) (DIPTERA, TEPHRITIDAE)

Antennal sensilla of the Queensland fruit fly, Bactrocera tryoni (Frog gatt) (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 subty pes) and no-pore sensilla with inflexible sockets (Np-is). The Mp-sw s ensilla were categorised on the basis of wall thickness and difference s in wall, pore and dendrite structure. The Mp-dw sensilla are innerva ted by 2 or 3 unbranched dendrites. The Mp-sw thick-walled sensilla ha ve 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 se nsory cells with dendrites that branch extensively within the shaft. T he Np-is sensilla have not previously been described from tephritid an tennae, and are found only in the antennal sensory pit. They have a gr anular appearance to the exterior walls and are innervated by 3 sensor y cells, only 2 of which project dendrites into the hair lumen. The pr oposed functions of the sensilla are discussed. (C) 1997 Elsevier Scie nce Ltd.