Abstract: 【Aim】 The aim of this study is to observe the morphological characteristics of the main antennal sensilla of the blister beetle Epicauta impressicornis (Coleoptera, Meloidae) so as to provide a reference basis for further studying the biology and behavioral mechanisms of E. impressicornis, and a prerequisite for future electrophysiological studies of its antennal sensilla. 【Methods】 The morphology of the antennal sensilla of E. impressicornis adults was observed under scanning electron microscopy, and the quantity, distribution and the difference in antennal sensilla between the male and female were statistically and comparatively analyzed. 【Results】 The results revealed that the antennal sensilla of E. impressicornis adults show sexual dimorphism, and their type, abundance, and distribution have similarities and differences between both sexes. Seven types of sensilla, including sensilla chaetica type 1 (CH1), sensilla chaetica type 2 (CH2), sensilla basiconica type 1 (SB1), sensilla basiconica type 2 (SB2), Böhm sensilla (BB), sensilla auricillica (SA), and sensilla campaniformia (CA) were found on the antennae of both sexes. In addition, there are some unique sensilla including sensilla chaetica type 3 (CH3) and sensilla basiconica type 3 (SB3) on the male antennae, and sensilla basiconica type 4 (SB4), sensilla basiconica type 5 (SB5) and grooved pegs (GP) on the female antennae. 【Conclusion】 The types of antennal sensilla of E. impressicornis are rich and diverse. These antennal sensilla are speculated to function as pheromone receptors (CH1), chemoreceptors (CH2 and GP), olfactory receptors (CH3, SB1-SB5, SA and CA), mechanoreceptors (BB) and thermoreceptors (CA and GP) according to their morphology and distribution, as well as based on comparative analyses with the previously reported results.

Key words: Epicauta impressicornis, sexual dimorphism, antennal sensilla, morphology, distribution, scanning electron microscopy