关键词: 黄翅大白蚁, 双工土白蚁, 触角, 感器, 扫描电镜

Abstract: As social insects，termites depend on olfactory perception to mediate intraspecific information communication，and antennal sensilla serve as crucial structures for detecting chemical cues.Investigating the morphological diversity and functional adaptation of antennal sensilla is fundamental to unraveling chemical communication mechanisms in termites. In this study，scanning electron microscopy（SEM） was employed to characterize the morphological features and spatial distribution patterns of antennal sensilla in Macrotermes barneyi and Odontotermes dimorphus.The results indicated that wing⁃budded reproductives possessed the longest antennae，whereas nymphs had the shortest antennae in both species. The antennal lengths of soldiers in M.barneyi were significantly greater than soldiers in O.dimorphus.From the scape to flagellum，the length and width of each antennomere initially decreased，then increased and subsequently plateaued. In total，11 sensillum types were identified across the two termite species，consisting of three subtypes of sensilla chaetica，two subtypes of sensilla trichodea，sensilla basiconica，Böhm’s bristles，sensilla globularia，sensilla spinosa，sensilla campaniformia，and sensilla bacilliformia.Clear variations in sensillum abundance were detected in the two termites species.Sensilla trichodea were the most numerous，followed by sensilla chaetica，while sensilla campaniformia were the rarest. In terms of distribution，sensilla chaetica Ⅰ，Ⅱ，sensilla trichodea and sensilla basiconica were predominantly distributed on the flagellomeres，with their quantities increasing toward the apical segments.By contrast，sensilla chaetica Ⅲ，Böhm’s bristles and sensilla campaniformia were largely confined to the scape and pedicel.Significant interspecific and inter⁃caste divergences were observed in the quantity and composition of antennal sensilla.Through interspecific comparisons among workers，O.dimorphus exhibited higher absolute and relative abundance of sensilla chaetica Ⅱ，while M.barneyi possessed more sensilla trichodea Ⅰ and sensilla basiconica；among soldiers，O.dimorphus had a higher proportion of sensilla trichodea Ⅰ，and M.barneyi was characterized by greater proportions of sensilla chaetica Ⅱ and sensilla basiconica.Intraspecific comparisons revealed that workers of O.dimorphus had significantly more sensilla chaetica Ⅰ and Ⅱ but fewer sensilla trichodea than soldiers.For M.barneyi，workers possessed more sensilla chaetica Ⅰ and sensilla trichodea Ⅰ，yet fewer sensilla chaetica Ⅱ and sensilla basiconica compared with soldiers.Overall，the present study describes the morphological structure，spatial distribution，as well as interspecific and inter⁃caste differences of antennal sensilla in the two termite species，providing solid morphological evidence for identifying pheromone receptor regions and exploring the olfactory communication network of termites.

Key words: Macrotermes barneyi, Odontotermes dimorphus, Antenna, Sensilla, Scanning electron microscopy（SEM）