Abstract
Sex pheromone specific antennal sensilla of the male corn stemborer, Chilo partellus (Swinhoe), were studied by electrophysiological and electronmicroscopical techniques. Electroantennographic measurements showed that the two pheromone components, (Z)-11-hexadecenal and (Z)-11-hexadecenol, elicited the highest responses together with a third potential pheromone component, (Z)-10-pentadecenal. Two physiological types of pheromone detecting sensilla trichodea were identified in the single sensillum measurements, In one sensillum type (type I), a receptor neuron characterized by a large action potential amplitude responded to (Z)-11-hexadecenal, and a neuron with a small spike amplitude responded to (Z)-11-hexadecenol, The receptor neurons present in this sensillum type also responded to other pheromone-like compounds produced in the female C, partellus pheromone gland. In a second sensillum type (type II), a single receptor neuron responded exclusively to (Z)-9-tetradecenal, a fourth potential pheromone component. The morphological investigation confirmed the presence of different types of sensilla trichodea. Sensilla trichodea containing one-to-three receptor neurons were observed. These sensillar types could however not be distinguished based on external morphology. The results from the investigation of antennal function and morphology in the corn stemborer, provides one of the first examples of relatively non-specific pheromone detecting receptor neurons. The study also confirms the pattern of morphologically distinct sensillum trichodeum subtypes on male pyralid antennae
