Antenna; Discotettiginae; Exoskeleton; Reception; Sensillum

The antennae of both sexes of the groundhopper Discotettix belzebuth (Serville, 1838) (Orthoptera: Tetrigidae) were examined using scanning electron microscopy. The antennae are composed of 13 segments that differ in their morphology, shape, and spatial distribution of the sensilla. We identified four types of sensilla (coeloconic, placoid, basiconic, and Böhm). Those particular numbers varied among the different antennal segments. The per-segment distributions of each type of sensillum did not differ between males and females, but the number of sensilla per mm2 of antennal surface was approximately 9% greater in females than in males. The specifically dilated and flattened middle antennal segments of D. belzebuth did not bear more sensilla than other filiform antennal segments. The surfaces of these conspicuous segments are composed of protuberances and cuticular plates, and sensilla occur only on their lateral margins. The possible functions of the particular antennal sensilla and the specifically dilated antennal segments are discussed in relation to their morphology, olfactory detection, contact chemoreception, hygroreception and in relation with the species habitat associations and potential anti-predatory adaptations.