Functional morphology of the mouthparts of lady beetle Coccinella transversoguttata (Coccinellidae, Coleoptera), with reference to their feeding mechanism

Abstract

The lady beetle Coccinella transversoguttata is an important biocontrol agent of aphids. As the main the feeding apparatus, mouthparts play essential roles in feeding process, and the morphological variation of mouthparts is correlated with variation in food source and feeding behavior.To better understand the feeding behavior of C. transversoguttata, we studied the functional morphology of mouthparts, with special attention to the fine morphology of each part of mouthpart and various kinds of sensilla. The mouthpart of C. transversoguttata is typical mandibulate type that composed of labrum, mandible, maxillae, labium, and hypopharynx. Detailed descriptions were given about the fine morphology of each part, and various types of sensilla were identified and classified. In total, two types of sensilla chaetica, four types of sensilla basiconica, two types of sensilla styloconica, two types of sensilla placodea, and one type of cuticular pore were identified according to their length, morphology and distribution. Specially, the putative function of each part of mouthpart as well as each kind of sensilla and their coordinative mechanisms in feeding process were discussed. These results would lay a solid foundation for understanding the feeding mechanism of lady beetles. K E Y W O R D Schewing mouthpart, fine morphology, sensilla

Functional morphology of antennae and sensilla of Hippodamia variegata (Coleoptera: Coccinellidae)

“…However, in another study, the sensilla densities are very similar in two anopheline sibling species (Diptera) with different host preferences [60]. In Coleoptera, relevant studies were much rare, while the role of mouthpart sensilla in feeding process have been studied in several species [46,61,62]. We found that many types of sensilla are distributed both on antennae and mouthpart, thus more comparative studies should be done to conform if there is correlation between the number of sensilla and feeding preference.…”

“…Sensilla chaetica (Sch) is the most abundant sensilla in not only the antennae but also the mouthpart of H . variegata [ 46 ]. They are also universal on the antennae of many other insects [ 3 , 18 , 35 ].…”

“…Depend on their specific location, Bb are deduced to be mechanoreceptors that perceive antennal movement and position [3,35,[43][44][45]. Sensilla chaetica (Sch) is the most abundant sensilla in not only the antennae but also the mouthpart of H. variegata [46]. They are also universal on the antennae of many other insects [3,18,35].…”

“…In conclusion, the differences in shape are not always in accord with differences in functionally relevant internal structures. Thus, it is not enough to determine a name of sensilla relying on morphology alone [46]. Confirmation of sensilla function requires not only external morphology, but also more investigation on structural properties of functional relevance [38].…”

The mouthparts of the adult dragonfly Anax imperator (Insecta: Odonata), functional morphology and feeding kinematics

“…One example, covering all mouthparts, is the work of Schmitt et al (2014) on Periplaneta americana (Blattodea: Blattidae), describing movement patterns of the mouthparts using X-ray cinematography. Furthermore, Hao et al (2020) carried out an extensive study on the functional morphology of the mouthparts of the lady beetle Coccinella transversoguttata (Coleoptera: Coccinellidae). They focused on identifying different types of sensilla found on the mouthparts, subsequently drawing conclusions regarding their specific function.…”