Antennal sensilla of the armoured ground cricket, Eugaster powysi Kirby, 1891 (Orthoptera, Tettigoniidae, Hetrodinae)

Sensilla on the antennae of the adult armoured ground cricket, Eugaster powysi, were studied using scanning electron microscopy to determine the sensilla morphology and their possible chemo- and mechanoreceptive functions for food detection. Twelve types or subtypes occur in males and thirteen in females: aporous sensilla chaetica (62.6 % of total sensilla in males, 63.5% in females) with a tactile mechanoreceptive function; uniporous sensilla chaetica of three subtypes (12.5-12.7%) with a contact chemoreceptive function; multiporous sensilla trichodea (5.6-7.9%); multiporous sensilla basiconica of three subtypes (13.1-13.9%); multiporous sensilla coeloconica (0.8-0.9%), all multiporous sensilla being olfactory receptors; aporous sensilla coeloconica (2.2%) and aporous sensilla coelocapitula (0.1% in female) with a possible thermo- hygroreceptive function; aporous Böhm sensilla (0.4-0.5%) and sensilla campaniformia (0.5-0.6%) which are proprioceptors. These results are related to the behaviour of Eugaster and compared with those obtained in other Orthoptera, Mantodea and Blattodea.