Functional Anatomy of Split Compound Eyes of the Whirligig Beetles Dineutus mellyi (Coleoptera: Gyrinidae).

The functional anatomy of the split compound eyes of whirligig beetles Dineutus mellyi (Coleoptera: Gyrinidae) was examined by advanced microscopy and microcomputed tomography. We report the first 3D visualization and analysis of the split compound eyes. On average, the dorsal and ventral eyes contain 1913 ± 44.5 facets and 3099 ± 86.2 facets, respectively. The larger area of ventral eyes ensures a higher field of vision underwater. The ommatidium of the split compound eyes is made up of laminated cornea lenses that offer protection against mechanical injuries, bullet-shaped crystalline cones that guide light to the photoreceptive regions, and screening pigments that ensure directional light passage. The photoreceptive elements, made up of eight retinular cells, exhibit a tri-tiered rhabdom structure, including the upper distal rhabdom, a clear zone that ensures maximum light passage, and an enlarged lower distal rhabdom that ensures optimal photon capture.

The Morphological Transformation of the Thorax during the Eclosion of Drosophila melanogaster (Diptera: Drosophilidae).

The model organism Drosophila melanogaster, as a species of Holometabola, undergoes a series of transformations during metamorphosis. To deeply understand its development, it is crucial to study its anatomy during the key developmental stages. We describe the anatomical systems of the thorax, including the endoskeleton, musculature, nervous ganglion, and digestive system, from the late pupal stage to the adult stage, based on micro-CT and 3D visualizations. The development of the endoskeleton causes original and insertional changes in muscles. Several muscles change their shape during development in a non-uniform manner with respect to both absolute and relative size; some become longer and broader, while others shorten and become narrower. Muscular shape may vary during development. The number of muscular bundles also increases or decreases. Growing muscles are probably anchored by the tissues in the stroma. Some muscles and tendons are absent in the adult stage, possibly due to the hardened sclerites. Nearly all flight muscles are present by the third day of the pupal stage, which may be due to the presence of more myofibers with enough mitochondria to support flight power. There are sexual differences in the same developmental period. In contrast to the endodermal digestive system, the functions of most thoracic muscles change in the development from the larva to the adult in order to support more complex locomotion under the control of a more structured ventral nerve cord based on the serial homology proposed herein.

The morphology and spectral characteristics of the compound eye of Agasicleshygrophila (Selman & Vogt, 1971) (Coleoptera, Chrysomelidae, Galerucinae, Alticini).

The first exploratory study was conducted on the compound eye morphology and spectral characteristics of Agasicleshygrophila (Selman & Vogt, 1971) to clarify its eye structure and its spectral sensitivity. Scanning electron microscopy, paraffin sectioning, and transmission electron microscopy revealed that A.hygrophila has apposition compound eyes with both eucones and open rhabdom. The micro-computed tomography (CT) results after 3D reconstruction demonstrated the precise position of the compound eyes in the insect's head and suggested that the visual range was mainly concentrated in the front and on both sides of the head. The electroretinogram (ERG) experiment showed that red, yellow, green, blue, and ultraviolet light could stimulate the compound eyes of A.hygrophila to produce electrical signals. The behavioural experiment results showed that both males and females had the strongest phototaxis to yellow light and positive phototaxis to red, green, and blue light but negative phototaxis to UV light. This study of the compound eyes of A.hygrophila will be helpful for decoding its visual mechanism in future studies.

The fecal shield is a double-edged sword for larvae of a leaf beetle.

Larvae of some leaf beetles carry masses of feces covering parts or all of the body, which is called a "fecal shield". In general, the shield is thought to be a defense structure against natural enemies. However, some studies have suggested that defense effectiveness varies depending on the natural enemy. In this study, we used a fecal retention leaf beetle Ophrida xanthospilota (Coleoptera: Chrysomelidae), and 2 local generalist predators (an ant, Camponotus japonicus (Hymenoptera: Formicidae) and a stinkbug, Arma custos [Hemiptera: Pentatomidae]) as a system to test the hypothesis that the fecal shield of O. xanthospilota plays different roles in predation behavior of different predators and can provide multiple chemical communication signals in predator-prey interactions. Prey bioassays showed that the fecal shield of O. xanthospilota larvae repelled the ant C. japonicus while attracting the stinkbug A. custos. The results also strongly demonstrated that hexane extracts of the fecal shield significantly repelled C. japonicus, while dichloromethane (DCM) extracts did not inhibit ant predation. Interestingly, DCM extracts attracted A. custos, but hexane extracts did not. Therefore, we suggest that the fecal shield is a double-edged sword for the larvae of O. xanthospilota. Our results also indicated that the risk-benefit tradeoff of an insect should be estimated at a community level involving multiple enemies (predators and parasites) and herbivores, rather than in a single prey-predator pair.

Mitochondrial genomes of Sternochetus species (Coleoptera: Curculionidae) and the phylogenetic implications.

The three weevil species, Sternochetus gravis, S. mangiferae, and S. olivieri, have all been reported to be serious pests of mango fruits. Morphology, biology, and various management approaches of these economically important weevils have been well studied. However, no mitochondrial genomes have been reported from the genus Sternochetus. Herein, we assembled mitogenomes of all the three Sternochetus species to reveal their mitogenomic characteristics. A DNA library of 350 bp insert size was constructed and sequenced in Illumina's HiSeq 6000 platform with a pair-end 150 bp sequencing strategy by Novogene. The sequence reads were assembled using GetOrganelle v1.7.1 and the genes were annotated by Geneious Prime 2021.0.3 and MITOS Web Server. Coupled with 61 published mitogenomes from 13 subfamilies of Curculionidae, we reconstructed phylogenetic trees to resolve evolutionary relationships of these closely related species and also examined subfamily-level classification among Curculionidae. All three mitogenomes are double-stranded circular molecules with 22 transfer RNA genes, 13 protein-coding genes (PCGs), 2 ribosomal RNA genes, and 1 noncoding control region as in other insects. Higher interspecific nucleotide divergence (about 10%) of 13 PCGs indicated these three Sternochetus species diverged a long time ago. Phylogenetic analyses using both maximum likelihood and Bayesian inference methods showed that Sternochetus falls into the basal clade of Cryptorhynchini, a tribe in the subfamily Molytinae. The relationship of S. olivieri as a sister species to S. gravis + S. mangiferae was strongly supported. The monophyly of Cryptorhynchini was also well supported whereas Molytinae was suggested to be a polyphyletic group.

Tsounkranaglenea hefferni gen. et sp. nov. from Sabah, Malaysia (Coleoptera, Cerambycidae, Lamiinae: Saperdini).

A new saperdine species belonging to a new genus, Tsounkranaglenea hefferni gen. et sp. nov., is described from Sabah, Malaysia. The new genus differs from other genera of the tribe Saperdini by the special male sternite VII modified into a rake-shape, with the apex of the ventral plate of the median lobe unusually emarginated.

Biochemical, molecular, and morphological variations of flight muscles before and after dispersal flight in a eusocial termite, Reticulitermes chinensis.

Swarming behavior facilitates pair formation, and therefore mating, in many eusocial termites. However, the physiological adjustments and morphological transformations of the flight muscles involved in flying and flightless insect forms are still unclear. Here, we found that the dispersal flight of the eusocial termite Reticulitermes chinensis Snyder led to a gradual decrease in adenosine triphosphate supply from oxidative phosphorylation, as well as a reduction in the activities of critical mitochondrial respiratory enzymes from preflight to dealation. Correspondingly, using three-dimensional reconstruction and transmission electron microscopy (TEM), the flight muscles were found to be gradually deteriorated during this process. In particular, two tergo-pleural muscles (IItpm5 and III-tpm5) necessary to adjust the rotation of wings for wing shedding behavior were present only in flying alates. These findings suggest that flight muscle systems vary in function and morphology to facilitate the swarming flight procedure, which sheds light on the important role of swarming in successful extension and fecundity of eusocial termites.

A new genus of Languriinae from Mexico (Coleoptera, Erotylidae), with comments on the potential mimic phenomenon of some languriines.

A new genus of Languriinae, Tomolanguria Huang, gen. nov. is erected for a single species, Languria aculeata Gorham, 1887 from Mexico. It is similar to the Neotropical genus Languria Latreille, 1802. The differential diagnosis of this new genus is based on the structural features of the elytral apices and slight impressions present on each elytron. Languria aculeata is designated as the type species of the new genus. This species is redescribed and illustrated (all the three specimens examined are shown in the dorsal, ventral, and lateral views). Finally, a mimic relationship between this new genus and genus Paederus Fabricius, 1775 (Staphylinidae) is discussed.

Aurivillius's "Neue oder wenig bekannte ColeopteraLongicornia" (1886-1927), the correct years and page numbers.

Aurivillius's work entitled "Neue oder wenig bekannte ColeopteraLongicornia" was published in parts over a period of over four decades. There were two page numbers on most pages of these publications, one ordered by Aurivillius, the other by the journal. Historically, different authors have used different page numbers, and sometimes different years for these publications, which has caused chaos in the citations. Herein, accurate dates of publications for this work, and correct page numbers that should be used are provided and discussed.

The thoracic morphology of cave-dwelling and free-living ground beetles from China (Coleoptera, Carabidae, Trechinae).

External and internal thoracic structures of two carabid species (Trechini) were examined and documented with different techniques. The study has a main focus on the eyeless cave-dwelling specialist Sinaphaenops wangorum, but detailed information is also provided for a species occurring in cave entrances. The phylogenetic background of the structural features of the thoracic skeletomuscular system was addressed. The thoracic morphology of the examined species was compared to conditions observed in previously studied carabids and non-related subterranean leiodids (Staphylinoidea) in order to identify cave adaptations. Main thoracic character complexes linked with cavernicolous habits in Trechini are elongation of the pro- and mesothorax and the legs, and a complete and irreversible reduction of the flight apparatus. The lost flight capacity is linked with a far reaching modification of skeletal elements of the metathorax including a strongly shortened and simplified metanotum, a shortened metaventrite, and completely reduced wings and sclerites of the wing base. The elongate prothorax together with the long and slender head and elongated legs distinctly increases the activity range in the subterranean lightless environment, which likely facilitates foraging of the carnivorous beetles. Some of the observed features like wing loss and elongation of the anterior thorax and legs are also found in some cave-dwelling Leiodidae (Leptodirini), whereas some other subterranean members of the staphylinoid family have a compact body and legs of normal length. In contrast to the predaceous Trechini, Leptodirini are scavengers.

Geometric morphometrics analysis of the hind wing of leaf beetles: proximal and distal parts are separate modules.

The success of beetles is mainly attributed to the possibility to hide the hindwings under the sclerotised elytra. The acquisition of the transverse folding function of the hind wing is an important event in the evolutionary history of beetles. In this study, the morphological and functional variances in the hind wings of 94 leaf beetle species (Coleoptera: Chrysomelinae) is explored using geometric morphometrics based on 36 landmarks. Principal component analysis and Canonical variate analysis indicate that changes of apical area, anal area, and middle area are three useful phylogenetic features at a subtribe level of leaf beetles. Variances of the apical area are the most obvious, which strongly influence the entire venation variance. Partial least squares analysis indicates that the proximal and distal parts of hind wings are weakly associated. Modularity tests confirm that the proximal and distal compartments of hind wings are separate modules. It is deduced that for leaf beetles, or even other beetles, the hind wing possibly exhibits significant functional divergences that occurred during the evolution of transverse folding that resulted in the proximal and distal compartments of hind wings evolving into separate functional modules.

Penghou, a new genus of flea beetles from China (Coleoptera: Chrysomelidae: Galerucinae: Alticini).

A new genus (Penghou) with a single new species (P. yulongshan) from Yunnan Province in China is described and illustrated. It is compared to Hespera Weise, Hesperomorpha Ogloblin, Laotzeus Chen, Luperomorpha Weise, Mandarella Duvivier, Omeiana Chen, Stenoluperus Ogloblin and Taiwanohespera Kimoto.

The thorax of Mantophasmatodea, the morphology of flightlessness, and the evolution of the neopteran insects.

Mantophasmatodea was described as a new insect order in 2002. Since then, this small group of wingless insects has developed into one of the best investigated insect taxa. Nevertheless, many aspects of mantophasmatodean morphology as well as their evolutionary relationships remain ambiguous. To determine the phylogenetic relationships of Mantophasmatodea based on an extended character set and to elucidate possible morphological adaptions towards flightlessness, we investigated the thoracic morphology of two species, Austrophasma caledonensis and Mantophasma sp. The morphological similarity between these two species is striking and no differences in musculature were found. The mantophasmatodean thorax strongly resembles that of ice crawlers (Grylloblattodea), especially with respect to the presence of pleural processes in the meso- and metathorax, branched furcae in all segments, and similar muscle equipment. In a cladistic analysis containing all major lineages of Neoptera, the monophyly of Polyneoptera is supported by the presence of an anal fan and several modifications of the wing joint. Within Polyneoptera, a sister-group relationship between stoneflies and the remaining Polyneoptera is supported. A clade comprising Mantophasmatodea and the Grylloblattodea gains strong support from thoracic morphology and can be considered assured. Potential thoracic apomorphies include prothoracic paracoxal invaginations, pterothoracic pleural arms that originate from the epimeron, and a unique metathoracic sterno-coxal musculature. The monophyly of Orthoptera and Dictyoptera is further supported while the deeper polyneopteran nodes remain unresolved. Among the wingless taxa investigated we found few general morphological adaptations whereas, in other aspects, especially in the musculature, strong differences could be observed. However, much more research on the strongly neglected topic of flightlessness is required to make reliable statements.

The larval head structures of Podagricomela shirahatai (Chûjô) (Chrysomelidae, Galerucinae, Alticini) and morphological effects of leaf mining.

Head structures of the leaf mining larva of the chrysomelid species Podagricomela shirahatai are described and illustrated. Internal and external structures were reconstructed three dimensionally based on image stacks obtained with microcomputed tomography. The larval head is characterized by prognathism, a dorsoventrally compressed shape, a flattened maxillolabial complex, a completely reduced coronal suture, and the presence of a deep, V-shaped posterior emargination of the head capsule. Internal structures are not distinctly affected by leaf mining. The cephalic features are compared with conditions found in surface feeding and root feeding alticine larvae and also with characters of chrysomeline larvae of Chrysomela populi Linnaeus. Possible correlations between modifications of the larval head and different feeding behaviors are discussed. Characters are also discussed with respect to possible phylogenetic implications. Some derived features are apparently due to phylogenetic constraints. Apomorphies characterizing alticine larvae with distinctly different life habits are the loss of M. frontoepharyngalis (M. 9), the origin of M. tentoriostipitalis (M. 18) from the head capsule, two insertions of M. tentoriopraementalis inferior (M. 29) and the reduction of stemmata. The study underlines that the anatomical study of chrysomeloid larvae is not only highly desirable in a phylogenetic context, but also crucial for understanding the evolution of different life strategies in this extremely successful group of Coleoptera.

On the phylogeny and evolution of Mesozoic and extant lineages of Adephaga (Coleoptera, Insecta).

The relationships of extant and extinct lineages of Adephaga were analysed formally for the first time. Emphasis is placed on the aquatic and semiaquatic groups and their evolution in the Mesozoic. †Triadogyrus and †Mesodineutus belong to Gyrinidae, the sister group of the remaining families. †Triaplidae are the sister group of the following groups (Haliplidae, Geadephaga, Dytiscoidea incl. †Liadytidae, †Parahygrobiidae and †Coptoclavidae [major part]). The lack of a ventral procoxal joint and a very short prosternal process are plesiomorphies of †Triaplidae. †Coptoclavidae and †Timarchopsinae are paraphyletic. †Timarchopsis is placed in a geadephagan clade. In contrast to other coptoclavids, its metathorax is close to the condition found in Haliplidae, with a complete transverse ridge and coxae with large plates and free mesal walls. †Coptoclavidae s.str., i.e. excl. †Timarchopsis, is a dytiscoid subgroup. The mesal metacoxal walls are fused, the coxal plates are reduced, and the transverse ridge is absent. †Stygeonectes belongs to this dytiscoid coptoclavid unit and is therefore misplaced in †Timarchopsinae. †Liadytidae belongs to a dytiscoid subgroup, which also comprises the extant families Aspidytidae, Amphizoidae, Hygrobiidae and Dytiscidae. †Parahygrobia is the sister group of Hygrobiidae. The larvae are characterized by a broad gula, the absence of the lacinia, retractile maxillary bases and very long urogomphi set with long setae. †Liadytiscinae is the sister group of extant Dytiscidae. There is no support for a clade †Eodromeinae and for Trachypachidae incl. †Eodromeinae. †Fortiseode is nested within Carabidae. The exclusion of fossil taxa has no effect on the branching pattern. The evolution of Adephaga in the Mesozoic is discussed. Possible reasons for the extinction of †Coptoclavidae are the rise of teleost fish and the competition of Gyrinidae and Dytiscidae, which possess efficient defensive glands and larval mandibular sucking channels.

The larvae of Altica koreana (Ogloblin) and A. viridicyanea (Baly) (Coleoptera: Chrysomelidae: Galerucinae: Alticini).

The first instar and mature larvae of Altica koreana (Ogloblin) and A. viridicyanea (Baly) are described and illustrated for the first time and compared with larvae of Altica caerulescens (Baly), A. cirsicola Ohno, and A. fragariae (Nakane). A key to the five related Altica species is also given.

The first complete 3D reconstruction of a Spanish fly primary larva (Lytta vesicatoria, Meloidae, Coleoptera).

The first detailed anatomical study of a primary larva of Meloidae is presented. Thereby techniques such as three-dimensional reconstructions, microtome sections, SEM (scanning electronic microscopy) and CLSM (confocal laser scanning microscopy) are applied. The structural features are discussed in the context of phylogeny, but also possible correlations with parasitism, phoresy and miniaturisation. The triungulin first instar larva is likely an apomorphy of Meloidae excl. Eleticinae and linked with a specialisation on acridoid eggs or larvae and provisions of bees. The campodeid body shape of Lytta and Meloinae is a groundplan feature of Meloidae, whereas a navicular body is an autapomorphy of the generally phoretic larvae of Nemognathinae. Head structures of Lytta and features of the postcephalic body are largely plesiomorphic. The musculature of the head is only moderately simplified while the one of the postcephalic body is well developed. Its thorax is largely characterised by plesiomorphies. The characteristics of the legs suggest phoretic habits, even though this does not apply to larvae of Lytta. It is conceivable that a phoretic behaviour is secondarily lost, together with some but not all morphological modifications related to it. Derived features of the abdomen of Meloidae are the complete loss of the fixed urogomphi (also missing in Rhipiphoridae and other related groups) and the presence of one or two conspicuous caudal bristles. Only few features of Lytta are shared with the parasitic larvae of Rhipiphoridae and Strepsiptera. These characteristics, which are possibly linked with specialised life habits, have obviously evolved independently. Miniaturisation effects are minimal in the larvae of Lytta.

The larval head of Raphidia (Raphidioptera, Insecta) and its phylogenetic significance.

External and internal head structures of larval representatives of Raphidiidae are described. The obtained data were compared to characters of other neuropterid larvae and to larval characters of representatives of other endopterygote lineages. Characters potentially relevant for phylogenetic reconstruction are listed and discussed. The larvae of Raphidioptera differ distinctly from other neuropterid larvae in their morphology. They are mainly characterised by autapomorphic and plesiomorphic character states and few features indicate systematic affinities with other groups. Endopterygote groundplan features maintained in Raphidioptera are the complete tentorium, the free labrum, the full set of labral muscles, the presence of four extrinsic antennal muscles, the three-segmented labial palpi, the presence of a full set of extrinsic maxillary and labial muscles, the presence of a salivarium, and possibly the high number of stemmata. Apomorphies likely correlated with predaceous habits are the long gula, the protracted maxillae, the longitudinal arrangement of extrinsic maxillary muscles, and the elongated prepharyngeal tube. Highly unusual, potentially autapomorphic features are the presence of a dorsal ligament of the tentorium and paired gland-like structures below the pharynx. A prognathous or very slightly inclined head and slender mandibles without mola are features shared by larvae of all orders of Neuropterida. The parallel-sided head is a potential synapomorphy of Raphidioptera and Megaloptera. A fully prognathous head with anteriorly shifted posterior tentorial grooves and the presence of a parietal ridge and a distinct neck region are features shared with Corydalidae. Characters of the larval head are not sufficient for a reliable placement of Raphidioptera.