STRUCTURE AND DISTRIBUTION OF TACTILE AND BIMODAL TASTE TACTILE SENSILLA ON THE OVIPOSITOR, TARSI AND ANTENNAE OF THE FLOUR MOTH, EPHESTIA-KUEHNIELLA (ZELLER) (LEPIDOPTERA, PYRALIDAE)

The bimodal taste/tactile sensilla on ovipositor, tarsi and antennae and the tactile sensilla on ovipositor and tarsi of the flour moth, Ephestia kuehniella (Zeller) (Lepidoptera : Pyralidae), were studied with electron microscopy to provide a structural base for further physiological and behavioural studies. These sensilla can be involved in the perception of the oviposition-deterring pheromone secreted by the larvae, as well as for the general assessment of the oviposition site. The taste/tactile sensilla in the 3 different positions have slightly divergent morphological characteristics; on the antennae and tarsi, there are 4 chemosensory neurons, while on the ovipositor there are 5. There is also a mechano-sensory unit connected to the base of the bristle of these sensilla. Tactile sensilla, innervated by one sensory cell, are present on the tarsi and on 2 different positions of the ovipositor. Freeze-substitution technique for transmission electron microscopy was employed on the tarsi and yielded superior results compared with conventional chemical fixation. © 1990.