Search Results (101)

Comparative morphological analysis of the labrum and labium among nine aphid species—Uroleucon sp., Glyphina betulae, Myzus cerasi, Panaphis juglandis, Chaitophorus sp., Lachnus roboris, Forda sp., Paracletus cimiciformis, and Trama sp., belonging to six subfamilies—reveals marked interspecific variation in structure, segmentation, and sensilla equipment. The labrum is generally triangular and plate-like, ranging from 88.8 μm (M. cerasi) to 358.1 μm (L. roboris). However, Trama sp. exhibits a distinctive conical labrum (311.1 μm) bearing three pairs of sensilla trichodea (St2)—unique among the examined taxa. Most species possess a four-segmented labium, while Trama sp. and L. roboris exhibit five segments. The second segment is the longest and most elaborate, bearing dense arrays of sensilla or spiniform tubercles in several species. Sensilla trichodea (St1–St5) are widespread across taxa, showing the highest densities in Chaitophorus sp St1, Trama and L. roboris St2, Uroleucon sp St3, and P. cimiciformis St4, whereas Trama sp. uniquely combines sensilla St2, St3, St5, and sensilla basiconica (Sb2). Sensilla basiconica (Sb1) are consistently positioned at the base of the labrum and the fourth labial segment, except in Trama sp., which presents sensilla St3. Distinct cuticular modifications—including apical cuticular processes and granular protrusions—occur only in Trama sp. and L. roboris, suggesting lineage-specific adaptations. These morphological patterns indicate that aphid mouthpart diversity reflects functional specialisation linked to host-plant structural variation. Full article

Larvae of lacewings (Neuroptera) are (mostly) ferocious predators, and the most well known are the larvae of antlions. In the larger group of antlion-like lacewings, the larvae resemble those of antlions to a certain degree but have certain peculiarities. Larvae of the group Nemopteridae can be easily separated into two groups: the larvae of Crocinae (thread-winged lacewings), also known as long-necked antlions, have relatively slender mouthparts and long necks, as the name suggests; the larvae of Nemopterinae (spoon-winged lacewings) have stout mouthparts and bodies. We here report new lacewing larvae of the group Nemopteridae from about 100-million-year-old Kachin amber, Myanmar. The new findings significantly expand the dataset of these animals in the fossil record. Quantitative analyses comparing the fossil and extant larvae support earlier indications that the morphological diversity of the fossils was in fact larger, yet the results are not as conclusive as in other ingroups of Neuroptera. The comparison also indicates that convergent evolution played an important role in the evolution of larvae of antlion-like lacewings. Full article

The mortality rate of first- to second-instar horseshoe crabs during molting is extremely high under culture conditions (pH of 7.6 ± 0.1, salinity of 27 ± 2, temperature of 26–32 °C), and we preliminarily speculate that it is related to disease. Our team found that Ectoplana limuli was attached to the ventral limbs of adult horseshoe crabs during culture. Parasite samples were collected from the external appendages and mouthparts of adult Tachypleus tridentatus for classification and identification. The primary objective of this experiment was to identify the species of this parasite and determine its taxonomic status. To this end, the experiment employed a combination of morphological methods and 18S rDNA gene molecular markers. The obtained sequences showed over 99% homology with Ectoplana limuli. Sequence alignment and phylogenetic tree results indicated that Ectoplana limuli showed a closer genetic relationship with Nerpa fistulata, but more distant relationships with Paucumara and Baikalobia. This is the first time that this parasite has been found in China, providing additional information for the study of horseshoe crab diseases. Full article

This study presents detailed microstructural observations of the mouthparts and sensory organs of adult cicadomorphan species, obtained using scanning electron microscopy (SEM). Despite microstructural variation, the overall morphology of the mouthparts, comprising a three-segmented labium and a bundle of interlocking stylets (maxillae and mandibles), is highly conserved across species, supporting its evolutionary significance in sap feeding from floem, xylem, or epidermis cells. Variations in the number and shape of mandibular stylet barbs likely reflect adaptations to different host plant tissues. The presence of an identical dual interlocking system between the maxillary stylets, which is found consistently across taxa, enhances functional stability during feeding and indicates a conserved mechanism among cicadomorphans. The species studied exhibit two distinct types of salivary canal closure: hooked and T-shaped. The latter potentially represents a state linked to specialised feeding strategies, such as sap xylem feeding. On the labial tip, there are different shapes of the anterior sensory fields. This area hosts a complex array of sensilla of different numbers, including gustatory (sensilla peg, PS1 and PS2, basiconica, BS3, double basiconica, DB), olfactory (finger–like, FLS) and thermo-hygroreceptive (sensillum dome-shaped, DS, and coeloconicum, CS) types, which facilitate host detection and feeding site selection. In the posterior sensory field, sensilla contact-chemosensory (sensilla basiconica, BS1 and BS2, and sensillum trichoideum, TS) are present. Mechanosensilla chaetica (CH1–CH3) are widely distributed on the last labial segment and may contribute to labium positioning. These findings emphasise the presence of both conserved and specialised morphological traits reflecting evolutionary and ecological diversification within Cicadomorpha. Full article

The sexual generation of Schlechtendalia chinensis (Bell) is pivotal for gallnut yield yet cannot feed due to mouthpart degeneration. Could respiratory metabolic rate (RMR) modulation compensate for nutritional deficits? We quantified the RMR across key developmental stages of sexual morphs (including parental sexuparae and progeny fundatrices) using an LI-6400XT portable photosynthesis system equipped with a customized insect respiration chamber (6400-89). All morphotypes exhibited significantly lower nocturnal RMRs compared to their diurnal rates (p < 0.05), while RMRs did not differ significantly between morning (9:00–12:00) and afternoon (14:00–17:00) (p > 0.05). Significant RMR variation occurred among morphotypes: females and sexuparae displayed the lowest rates, fundatrices were intermediate, and males exhibited remarkably elevated rates (2–3 times higher than those of females or sexuparae). Both sexes showed a characteristic RMR trajectory: elevated at birth and declining during early postnatal development, followed by a gradual resurgence that culminated in peak values on postnatal day 8, coinciding with mating. This physiological zenith was immediately succeeded by marked respiratory metabolic downregulation following copulation, with RMRs decreasing substantially during the post-copulatory phase. Our findings demonstrate significant intergenerational and intersexual RMR differentiation. This research addresses critical knowledge gaps in the respiratory metabolism of S. chinensis, is the first to elucidate a nutrient adaptation strategy through respiratory metabolic regulation under non-trophic conditions, and provides actionable insights for optimizing gallnut production in controlled cultivation systems. Full article

Monkey beetles (Hopliini, Scarabaeoidea) are a species-rich group of flower-visiting insects that are specialized to feed on floral tissue, pollen and/or nectar. We studied ten South African species, examining morphological features associated with their specific feeding preferences. This is the first attempt in a limited number of beetle species to comparatively investigate both the mouthparts and the alimentary tract in relation to ingested food. Using light microscopy, we found cutting edges on the mandibles and galea teeth in flower tissue-feeding species. Pollen feeders have numerous bristles on the maxillae and a prominent mola on the mandibles that are likely used for gathering and grinding pollen. The elongate heads and mouthparts of the nectar feeders are considered an adaptation that enable these species to mop up nectar while probing flowers. Using µCT imaging and reconstructions of the entire alimentary tract, our morphometric results suggest that food preferences are not related to total relative gut length, although the ratio of foregut to body length was greater in pollen- and nectar-feeding monkey beetles than in floral tissue-feeders. The midgut of females tends to be longer relative to body size compared to males. Our work serves as a basis for generating hypotheses for future research that includes gut morphology in flower-visiting insects. Full article

The Raspy crickets are an interesting group of nocturnal animals that bear femoral-abdominal stridulation and spin silk from the mouthparts. Gryllacridid classification is the subject of ongoing discussion. Here, we present the first mitogenomic sequences for three Ocellarnaca taxa: O. braueri (15,597 bp), O. fuscotessellata (15,607 bp), and O. emeiensis (16,510 bp). Three mitochondrial genomes exhibited the conventional metazoan gene and conserved the characteristic gene order across Gryllacrididae species. Evolutionary selection analyses showed that atp8 was the least evolutionarily constrained mitochondrial gene, whereas cox1 was the most conserved across lineages. The three Ocellarnaca species harbored 5–8 mitochondrial DNA sequence repeats (mtSSRs), falling within the 1–8 range detected in all analyzed Gryllacrididae species. Magnigryllacris and Ocellarnaca exhibited higher mtSSR counts than related genera sharing analogous male abdominal apex morphology. Phylogenomic analyses of 35 mitogenomes from 21 Gryllacrididae species supported Ocellarnaca as monophyletic and a sister to Magnigryllacris (bootstrap = 100%), with O. fuscotessellata resolved as sister to the clade (O. sp. + (O. emeiensis + O. braueri)). This study expands the mitogenomic resources for Ocellarnaca, which will facilitate further resolution of phylogenetic reconstruction within this genus and across Gryllacrididae genera. Full article

Tomicus pilifer is a major pest that threatens Pinus koraiensis forests in the northeast region of China. In this study, we employed scanning electron microscopy (SEM) to observe the sensilla on the antennae, mouthparts, and legs of both male and female T. pilifer adults, analyzing the differences in sensillum types, external morphology, and quantities between sexes. The results revealed six types of sensilla on the antennae of both males and females, including sensilla trichoidea, sensilla zigzag, sensilla coeloconica, sensilla chaetica, Böhm bristles, and sensilla basiconica. Among these, sensilla basiconica was the most abundant, with four subtypes identified, and sensilla basiconica III was observed only on the male antennae, indicating sexual dimorphism in sensillum types. The mouthparts exhibited the greatest diversity in sensilla, with seven types identified: sensilla basiconica, sensilla twig basiconica, sensilla coeloconica, sensilla trichoidea, sensilla chaetica, sensilla zigzag, and sensilla digitiformia. Of these, sensilla basiconica and sensilla twig basiconica, responsible for olfactory or gustatory functions, were concentrated at the distal ends of the maxillary palps and labial palps. On the legs, sensilla trichoidea, sensilla zigzag, and sensilla chaetica were distributed on all segments. The findings of this study provide a scientific basis for further research into the olfactory and feeding behaviors, as well as electrophysiological studies, of T. pilifer. Full article

Some Cretaceous ants belonging to the stem group of Formicidae exhibit bizarre morphology. This wide range of unusual adaptive features is primarily related to the mouthparts and clypeus. The researchers were perplexed by their specific ecology, as modern ant lineages do not exhibit anything similar. Here, we report and describe a new genus based on an extraordinary and mysterious alate ant from Late Eocene Baltic amber. Undoubtedly, the new ant is classified within the subfamily Formicinae (one of the crown groups), yet it displays a highly specialised morphology and an unusual array of features that are not observed in any extant ant lineages. Neither recent nor extinct ants have such a combination of features. While the exact phylogenetic placement of the new ant remains uncertain, we offer a discussion of its potential affinities based on our constrained phylogenetic analyses. We propose that †Eridanomyrma gen. n. should be considered in the new tribe †Eridanomyrmini trib. n. This new taxon highlights the adaptive diversity of a highly specialised, extinct lineage of Eocene crown-group ants. We also present a 3D model based on X-ray computed microtomography (µCT). Full article

Calyptra Ochsenheimer, 1816 is an important genus of fruit piercers and blood feeders with 18 described species worldwide. Both sexes of all Calyptra species pierce fruit. Adults feed upon and damage soft-skinned (e.g., Rubus and Vitis) and thicker-skinned fruits (e.g., Ficus and Citrus) in subtropical and tropical Asia. These moths are rare examples of a lepidopteran lineage that uses its fruit-piercing mouthparts to pierce the skin of vertebrate animals occasionally. In China, 10 species of this genus have been reported. Here, we identified seven species of the genus Calyptra Ochsenheimer, 1816 from Chinese fauna, including C. gruesa, C. thalictri, C. hokkaida, C. albivirgata, C. orthograpta, C. fletcheri, and C. lata. Detailed illustrations of male and female external morphology and genital structures are provided. A comprehensive worldwide checklist of the genus Calyptra is also included. This study highlights significant taxonomic revisions and morphological features for this genus within Chinese fauna. Full article

Chrysomya nigripes Aubertin, 1932, is a species of Calliphoridae widely distributed in Southeast Asia, with studies and case reports confirming the value of this species in estimating the minimum postmortem interval (PMI_min). However, data on the growth and development of this species’ intra-puparial age are not yet complete. Here, we investigated the intra-puparial morphological changes of C. nigripes at seven temperatures, ranging from 16 °C to 34 °C. We also investigated the potential value of Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) coupled with chemometric methods for the intra-puparial age estimation of C. nigripes at 19 °C, 25 °C, and 31 °C. The spectral data within the wavenumber range of 1800–900 cm⁻¹, collected from the second thoracic segment of all puparia, were processed. Through this procedure, the mean values of ATR-FTIR spectra of C. nigripes of puparia at each intra-puparial age under various constant temperature conditions were obtained. The results showed that at 16 °C, C. nigripes could not complete its developmental process, while it could do so at the remaining six constant temperatures. With an increase in temperature, the average duration of the intra-puparial period was reduced from the longest at 19 °C of 192 ± 0 h to 77.3 ± 4.6 h at 34 °C. The intra-puparial morphological changes were divided into 12 sub-stages, and the development of the compound eyes, mouthparts, antennae, thorax, legs, wings, and abdomen were divided into 6–8 sub-stages. The Partial Least Squares Discriminant Analysis (PLS-DA) classification model predicted better results compared to the Random Forest (RF) classification model, with an accuracy of 58.3%, 77.8%, and 100% at 19 °C, 25 °C, and 31 °C, respectively. In this study, each sub-stage of the C. nigripes pupa and the time range of structure emergence were recorded, and it was concluded that the spectral trends were time-dependent. Thus, ATR-FTIR combined with chemometrics could also be used as a tool to assist in estimating the intra-puparial stage of C. nigripes and provide a reference value for PMI_min. Full article

Few traits exhibit a more diverse collection of exemplary structure–function relationships than the mouthparts of insects. The global dominance of insects is attributed to their diverse food sources, which are matched by an array of morphological and chemical adaptations: a ‘tool kit’ for biomimicry. This review provides an overview of insect mouthparts that have contributed to biomimetics, including information about morphology and functionality in relation to particular feeding mechanisms. Themes in the groups of insects employed for particular biomimetic studies, including their lineages and feeding strategies, are identified along with suggestions for future studies, which together underscore the importance and promise of the development of novel engineered devices inspired by the unique ‘tools’ of insect mouthparts. Full article

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. Full article

This study investigated the characteristics of the digestive system in adult Japanese mantis shrimp (Oratosquilla oratoria), which is a species of carnivorous crustacean, with a focus on morphological and histological analysis. The digestive system of O. oratoria includes the mouthparts, the esophagus, cardiac stomach, pyloric stomach, midgut, hindgut, anus and hepatopancreas. The histological structure of each organ is composed of the mucosal epithelial layer, submucous layer, muscularis, and outer membrane. Besides, the foregut is covered with a diverse chitinous layer. The labrum is densely populated with minor salivary glands. The mandibular-gastric mill apparatus and evenly arranged bifurcated setae are observed in the cardiac stomach. The secondary filter of the pyloric stomach is subtly intricate, with fine spicules and seta plate. The midgut, being the longest segment of the digestive tract and accounting for 59.39% of body length, has villi covered with dense microvilli. The hindgut also forms villi, but the height of the villi (695.96 μm) is 3.20 times that of the midgut (217.41 μm). The hepatopancreas encircles the entire pyloric stomach, midgut, and hindgut. The hepatosomatic index is approximately 3.83%. Full article

Hyphantria cunea is a widespread pest that causes significant issues in forestry and agriculture, with a far-reaching global impact. However, ultramorphological studies of H. cunea, especially in terms of ultramorphological changes, are far from in-depth. Therefore, we investigated the ultrastructure of its eggs, larvae, and pupae using scanning electron microscopy, focusing on ultrastructural changes in larvae across different instars. The eggs have rough surfaces, and the micropylar region consists of rosette cells. The larval head chaetotaxy is symmetrically arranged, and there are three types of sensilla on the antennae and mouthparts. The abdominal and anal prolegs feature a uniordinal heteroideus midband of crochets. The pupal abdomen has ten segments; in females, the genital slit (Fgs) is located at the anterior edge of abdominal segment VIII, while in males, the genital slit (Mgs) is situated in the middle of abdominal segment IX. First-instar larvae exhibit only primary setae, and secondary setae emerge in the second instar. As the larvae mature, the head, thoracic legs, and abdominal and anal prolegs all become larger overall. The surface of the verrucae is initially smooth, with microtrichia appearing from the fourth instar onwards, and the setae on the verrucae gradually increase in size. These findings provide additional features for larval species identification and contribute to the morphological study of H. cunea. Full article