Sensilla on six olfactory organs of male Eogystia hippophaecolus (Lepidoptera: Cossidae)

Abstract

Eogystia hippophaecolus (Hua et al.) is an important boring pest that primarily damages sea buckthorn, causing large ecological and economic damages in China. In this study, we used scanning electron microscopy to investigate the sensilla on six olfactory tissues of male E. hippophaecolus: antennae, labial palps, external genitals, propodeum, mesopodium, and metapedes. On the antennae, two types of sensillum trichodea, two types of sensillum basiconica, a type of sensillum coeloconica, and Böhm's bristles were found. The labial palps had sensilla trichodea and chaetica. On the external genitals, three types of sensilla trichodea were the only sensilla. Böhm bristles were found on the base of the tibia and at the terminus of the tarsus. Most sensilla were distributed on the tarsus of the three pairs of legs, and notably, a majority of which were sensilla trichodea and sensilla chaetica, were on the pretarsus and telotarsus of the three pairs of legs. In this study, the distribution, number, type, and morphology of the sensilla on six olfactory organs of E. hippophaecolus were determined, which established the foundation for a future immunohistochemical search of olfactory proteins. Research highlights Eogystia hippophaecolus is a serious pest of seabuckthorn. The distribution, number, type, and morphology of olfactory sensilla of E. hippophaecolus are determined. The function and distribution of sensilla are compared with those of other insects.

Gustatory function of sensilla chaetica on the labial palps and antennae of three tortricid moths (Lepidoptera: Tortricidae)

“…We do not know the extent of gustation in the labial palps of Lepidoptera because reports of uniporous sensilla chaetica (i.e., with a putative gustatory function) on the external part of labial palps are scarce. Chaetica-like sensilla with a terminal pore have been reported in a species of the Cossidae family 16 . Sensilla chaetica are described in other Cossidae and in members of the Tortricidae and Pyralidae families, but it is not indicated if they bear a pore at the tip, and thus they may not be gustative 15 , 26 , 27 .…”

“…CO 2 detection may help Lepidoptera in host-plant selection 14 . In some moth species, the labial palps bear chaetica-like sensilla 15 , 16 , which often have a gustatory function in other insect appendages 3 – 5 . The presence of putative gustatory receptors of the sugar clade in the labial palps of Helicoverpa armigera (Hübner) 17 further indicates the presence of gustation in the labial palps, but as far as we know, there is no physiological evidence that the labial palps of Lepidoptera have a gustatory function.…”