Ultra-structure of antenna, eye, mouthparts and sensilla of Cheilomenes sexmaculata Fabricius, 1781 (Coccinellidae: Coleoptera)

Cheilomenes sexmaculata Fabricius, 1781 is a well-known ladybird beetle that feeds primarily on aphids, mealy bugs, phytophagous mites, scale insects, and other small insects and is an important bio-control agent of aphids. Evolution in the structure of mouthparts is known to be associated with the composition of food material and feeding behaviour. The sensilla present on mouthparts plays a pivotal role in feeding mechanisms. Feeding mechanism of ladybird beetles will be better understood if the fine structure of mouthparts, modifications in the structures, and presence of different sensilla on the mouthparts of C. sexmaculata are understood. Using scanning electron microscopy, the functional morphology of mouthparts of C. sexmaculata was studied and compared with the fine structures with those of other Lady Beetles. The labrum, mandibles, maxillae, labium, and hypopharynx make up the mouthpart of C. sexmaculata. This study includes a thorough description of each mouthpart and the different kinds of sensilla. In the current study, three types of sensilla chaetica, four types of sensilla basiconica, two types of sensilla styloconica, one type of sensilla placodea, one type of sensilla coeloconica, one type of sensilla campaniformia, and one type of cuticular pore using characters like the length, morphology, and distribution of the sensilla were studied. The structure of the mouthparts and the purposes of the sensilla on them is discussed with reference to other coleopterans. The results obtained in the current study will provide better insights into the functional morphology of lady beetles.