Antennal sensilla of the ground beetle Platynus dorsalis (Pontoppidan, 1763) (Coleoptera, carabidae)

The typology, number, and distribution pattern of antennal sensilla of the ground beetle Platynus dorsalis (Pontoppidan) (Coleoptera, Carabidae) were studied using scanning electron microscopy. The 4.3-4.6-mm-long filiform an tennae of the beetles consist of the scape, pedicel, and nine flagellomeres . In both sexes, four subtypes of sensilla chaetica, five subtypes of sensi lla basiconica, sensilla trichodea, two subtypes of sensilla campaniformia, sensilla auricillica, and sensilla coeloconica were distinguished. The pos sible function of the sensilla was discussed and three types of sensilla we re considered as olfactory, sensilla trichodea and sensilla basiconica type s 1 and 2. Olfactory sensilla form two separate, dorsal and ventral, fields of sensilla on the flagellomeres, which seems to be common in ground beetl es. The total numbers of olfactory trichoid (approximately 1,000 hairs) and basiconic sensilla type 1 (1,700-1,800 pegs) on the antennae of P. dorsali s are 5-7 times higher than on the antennae of the ground beetle Bembidion lampros, suggesting that nocturnally active P. dorsalis is much more sensit ive to odours perceived by these sensilla than B. lampros with diurnal acti vity and hunting predominantly by sight. No remarkable sexual differences i n the types, numbers, and distribution of antennal sensilla were found in P . dorsalis. (C) 2001 Wiley-Liss, Inc.