Functional morphology of the mouthparts of longhorn beetle adult Psacothea hilaris (Coleoptera: Cerambycidae) and sensilla comparisons between the sexes

Ultrastructure of the Sensilla on Antennae and Mouthparts of Larval and Adult Cylas formicarius (Coleoptera: Brentidae)

The quarantine pest, Cylas formicarius, is a key pest of sweet potatoes during both production and storage, posing a major threat to food security in various countries. To investigate behavioral mechanisms, the ultrastructure of the heads of larval and adult stages was analyzed using scanning electron microscopy, with an emphasis on the sensilla of the mouthparts and antennae. The results reveal degeneration of the antennae and ocelli in larvae. The larval mouthparts are equipped with three types and six subtypes of sensilla. Both male and female adults have four types and six subtypes of sensilla on their mouthparts. Compared to larvae, the adult mouthparts display a greater diversity of sensilla types and higher numbers of sensilla basicaonica (SB), sensilla chaetica (SC), and sensilla digitiformia (SD). Adult antennae consist of a scape, a pedicel, and eight flagellomeres (F1-F8), with F8 showing sexual dimorphism. Seven types of sensilla, excluding SB and sensilla ligulate (SL), each with two subtypes, were identified on the antennae of adults of both sexes. SC, sensilla furcatea, Böhm bristles, and SL were newly observed in the antennae of C. formicarius adults. Additionally, one type and seven subtypes of sensilla on the adult antennae exhibit distinct sexual dimorphism in terms of structure or number. The relationship between the head structure and adaptability of C. formicarius was examined, and the functions of each sensilla were discussed, providing a theoretical basis for future studies on the behavior of this pest.

Introduction to Scydmaeninae (Coleoptera, Staphylinidae): morphology of adults

Exo- and endoskeletal structures of Scydmaeninae are illustrated and described based on exemplary 351 species representing 116 genera and all tribes. Over 1700 illustrations show an unparallel morphological diversity of ant-like stone beetles, and introduce this group to coleopterists, setting standards for morphological descriptions. The morphological terminology is discussed and selected terms are defined or clarified, to ensure unambiguous understanding of terms used by various authors in a different sense. Several selected problems are discussed in detail, as the cephalic structures; a possible hypopharyngeal, and not prelabial, origin of the ligula in some beetles; structures that increase the mechanical robustness of the thorax; the astounding plasticity of evolutionary changes in the ventral prothoracic and pterothoracic pleural structures; novel discoveries in the elytral locking system (incl. elytral-metanepisternal locking device); multiple migrations of the aedeagal membranous area retractor; and a parallelism between Scydmaeninae and Pselaphinae in male secondary sexual characters. Moreover, synapomorphies of Scydmaeninae are discussed, and perspectives for future studies are outlined.

Using ecological niches to determine potential habitat suitability for Psacothea hilaris (Coleoptera: Cerambycidae) and its natural enemies in China under future climates

Climate change impacts the distribution of pests and its natural enemies, prompting this study to investigate the dynamics and shifts in distribution under current and future climate conditions. The spatial pattern of Psacothea hilaris (Pascoe) (Coleoptera: Cerambycidae) in China was analyzed, and the MaxEnt model was optimized to predict the potential geographic distribution of P. hilaris and its two natural enemies (Dastarcus helophoroides (Fairmaire) (Coleoptera: Bothrideridae) and Dendrocopos major (Linnaeus) (Piciformes: Picidae)) in China, to further analyze the key environmental factors affecting the survival of P. hilaris and its natural enemies, and to determine the potential of using D. helophoroides and D. major as natural enemies to control P. hilaris. The results showed that the suitable ranges of P. hilaris and natural enemies are expanding under the influence of climate change, and both have migrated to higher latitudes. The potential ranges of D. helophoroides, D. major, and P. hilaris are highly similar. It is noteworthy that the potential range of D. helophoroides completely covers the potential range of P. hilaris. This indicates that D. helophoroides and D. major can be employed as biological control agents to manage P. hilaris populations. This study provides a theoretical framework and empirical evidence for the development of early warning and green control strategies for P. hilaris.

Morphology of the Mouthparts of Ladybeetle Vibidia duodecimguttata (Coleoptera: Coccinellidae), with Emphasis on Their Sensilla

Mouthparts are the feeding organs of insects, which play vital roles in the feeding process. The morphology of insect mouthparts has greatly evolved according to different foods and feeding habits. Therefore, studying the structure of the mouthparts is the key to understanding their feeding mechanisms. Vibidia duodecimguttata is an important biological control agent for powdery fungus. In this study, the fine morphology of the mouthpart of V. duodecimguttata was studied by scanning electron microscopy. The basic components of mouthpart of V. duodecimguttata are similar to those of other ladybeetles, while the specific morphology of each part is different. In total, six kinds of sensilla were identified on mouthpart, and twelve types of sensilla were divided according to their morphology, length and distribution. In addition, two kinds of glandular structures were also found, namely perforated plates and cuticular pores. Finally, the morphological differences between mycetophagous and other feeding habits ladybeetles were compared, and the function of each kind of sensilla was discussed, which may establish a solid foundation for further understanding of the feeding mechanism of ladybirds.

Morphology and taxonomic significance of the labrum in the flea beetle genus Chaetocnema Stephens, 1831 (Coleoptera, Chrysomelidae, Galerucinae, Alticini)

The structure of labrum or upper lip in adult Coleoptera is only minimally investigated and used in classification and phylogeny. This study investigates the morphology of the labrum in the flea beetle genus Chaetocnema Stephens, 1831 (Chrysomelidae, Galerucinae, Alticini) to assess and develop a terminology and identify potential morphological characters useful to delimitation of species and species groups as well as phylogeny reconstruction in leaf beetles.

The Microscopic Morphology of Mouthparts and Their Sensilla in the Mycophagous Ladybeetle Illeis chinensis (Coleoptera: Coccinellidae)

The morphological diversity of insect mouthparts is closely related to changes in food sources and diets. Research into the structures of insect mouthparts may help to establish a fundamental basis for a better understanding of insect feeding mechanisms. In this study, we examined the fine morphology of the mouthparts of Illeis chinensis using scanning electron microscopy. We paid particular attention to the types, quantities, and distribution of sensilla on the mouthparts. Our results showed that the basic components of the mouthparts of I. chinensis are the same as those in other lady beetles, i.e., the labrum, mandible, maxillae, labium, and hypopharynx. We also found structural specialization indicating adaptation to fungal feeding. On the mouthparts, there are eight kinds of sensilla and two kinds of glandular structures, including sensilla chaetica, sensilla basiconica, sensilla styloconica, sensilla coeloconica, sensilla campaniformia, sensilla placodea, sensilla digitiformia, Böhm bristles, perforated plates, and cuticular pores. This is the first time that sensilla digitiformia has been reported in ladybirds. Finally, variations in mouthparts among ladybirds with differing diets, as well as the putative functions of each of the mouthparts and sensilla, were discussed. This research can provide a reference for understanding the functions of the mouthparts in ladybird feeding behavior and thereby contribute to the development of precise insect behavior regulation and management strategies.