Morphological comparison of proboscis sensilla between Plusiinae and Noctuinae (Lepidoptera: Noctuidae)

Abstract

In higher Lepidoptera the proboscis and its sensilla vary from species to species in different feeding guilds. However, whether such morphological differences have a phylogenetic significance remains unclear. Here we compared the morphology of proboscis sensilla in 19 representative species of Plusiinae and four of Noctuinae using scanning electron microscopy. In Plusiinae four types of sensilla (sensilla chaetica, sensilla basiconica, sensilla styloconica, and sensilla coeloconica) were present on the proboscis, with cuticular processes only in the proximal region. In Noctuinae three types of sensilla (sensilla chaetica, sensilla basiconica, and sensilla styloconica) were found on the proboscis, with cuticular processes on its whole length. Morphological differences of proboscis sensilla between Plusiinae and Noctuinae mainly involve the shape, number, and length of sensilla styloconica and sensilla chaetica. The sensilla styloconica of Plusiinae are significantly shorter and fewer than those of Noctuinae. The styli of sensilla styloconica are glabrous in Plusiinae and are longitudinally ribbed in Noctuinae. These significant morphological differences are useful in distinguishing the two subfamilies, suggesting that proboscis sensilla may provide useful characters in the systematic and phylogenetic analyses at the subfamily level within Noctuidae.