Ultrastructural observations on antennal sensilla of Coleophora obducta (Meyrick) (Lepidoptera: Coleophoridae).

Coleophora obducta (Meyrick) is an important defoliator of larch in northeast China. To further describe the mechanism of insect-plant chemical communication, we observed the antennae and their sensilla of C. obducta by scanning and transmission electron microscopy. In both sexes, antennae were threadlike, and in total there were eight types of sensilla found on the antennae: Sensilla placodea, Sensilla basiconica, Sensilla coeloconica, Sensilla styloconica, Sensilla trichodea, Sensilla squamiformia, Sensilla furcatea and Böhm bristles, respectively. We described ultrastructures and discussed possible functions. We inferred from their ultrastructures as chemoreceptors that S. placodea, S. basiconica and S. trichodea were innervated by sensory neurons. The neuron of S. styloconica terminated in a tubular structure which suggested gustatory/mechanosensory function, and the terminal sensory pegs might function as contact-chemoreceptors depending on their locations.