Functional morphology of the mouthparts of lady beetle Hippodamia variegata (Coleoptera: Coccinellidae), with reference to their feeding mechanism

The lady beetle Hippodamia variegata (Goeze, 1777) is widely distributed around the world and reported as an important natural enemy of aphids, noctuid larvae, leafhoppers, and psyllids. As feeding organs, the mouthparts of H. variegata must play important roles in the feeding process and study on their morphologies will provide insight into their feeding mechanisms. In this study, we examined the fine morphology of the mouthpart of H. variegata in detail, especially the various kinds of sensilla and the comparison with other lady beetles. We found that the basic components are the same as those in other lady beetles, which are labrum, mandible, maxillae, labium, and hypopharynx and the morphologies of these structures are also quite similar to other species; in total, seven kinds of sensilla were identified, and on the basis of their lengths and distribution, 14 types of sensilla can be identified. Specially, the differences between H. variegata and other beetles were compared and the functions of each part, as well as different kinds of sensilla were discussed.