Ultra Morphological Structre of Sensory Sensillae on the Legs and External Genitalia of the Red Palm Weevil Rhynchophorus ferrugineus (Oliv.)

The Red Palm Weevil (RPW) is a major pest infesting date trees in the Gulf region. Chemoreceptors play an important role for insects behaviour in detecting their defined host for feeding, egg laying or mating. The present study is aimed to study morphological structure of sensillae on different legs and external genitalia of both sexes. Three kinds of sensillae are found on the different parts of the three pairs of fore, mid and hind legs, these sensillae are identified as ( Trichoid in three types, coeloconic in two types and one type of Basiconic sensillae). Fore legs bear the highest number of different forms of sensillae, males contained realatively greater number than females. Mid femur only in female bears a dense hair of trichoid sensillae, while they are found on fore- mid and hind femur of males, this may be used for differentiating two sexes. Female ovipositor contained trichoid sensilla can be subdivided into three distinct type I, II, and III in addition placoid sensillae, it could be identified four types of trichoid sensilla on the male external genitalia and numerous of placoid sensillae.These may be for hygroreception.