REAPPRAISAL OF THE PORE CHANNEL SYSTEM IN THE GROOVED PEGS OF AEDES-AEGYPTI

Pore channels occur along the grooves of lactic acid-receptive grooved pegs on the antennae of female Aedes aegypti. There are about 38 pore openings per groove or about 456 per peg. This finding is in conflict with the previous report that pore channels were extremely rare, The pore channels are of a similar electron density to the cuticle of the peg, making them difficult to see. For this reason many of the pore ch annels were probably overlooked in the previous study. We could not fi nd a terminal pore in the grooved peg as has been reported. Scanning e lectron microscopy and negative staining of the pegs revealed a tip of variable shape, usually without a pore, It is possible that 'edge eff ect' (more secondary electrons escape from edges of objects, making th em appear brighter than central regions) leads to an apparent terminal pore. Occasionally pegs have a number of small (20-40 nm) pores in th e tip region and these might also have been misinterpreted as a termin al pore. Pore channels appear to be the primary means of entry for air -borne stimuli in these grooved pegs.