Amazons Are Back: Absence of Males in a Praying Mantis from Uruguayan Savannas

With a broad distribution throughout South America, Brunneria subaptera (Saussure) (Coptopterygidae) is the most abundant praying mantis species in Uruguay, mostly associated with grassland vegetation. Their body coloration can vary between green or brown sepia. The recent catalog of Uruguayan mantids showed that all specimens of B. subaptera from the collections in Uruguay were females, suggesting an absence of males in natural populations. The aim of this study was to determine the occurrence of female-only populations of B. subaptera in Uruguay. Moreover, we analyzed the genetic variation and estimated the time of the most recent common ancestor of the species. We performed bimonthly samplings in two localities in Uruguay for 1 year and we sexed the individuals. We extracted DNA from the abdominal tissue of adult females and sequenced a fragment of the mitochondrial cox1 gene to assess the genetic diversity and to estimate diversification times. We did not find any males in either of the studied localities. The age estimates revealed a recent origin of the species (2.33 Ma), and there was no genetic differentiation between the individuals from Uruguayan localities. This absence of males of B. subaptera documented in the sampled locations suggests that the species reproduces by thelytokous parthenogenesis. This study opens promising venues for future research into reproductive strategies and polymorphism in South-American praying mantises that inhabit one of the largest areas of grasslands in the world, currently under dramatic deterioration and reduction.

We know very little about pollination in the Platanthera Rich (Orchidaceae: Orchidoideae)

The Platanthera Rich. (Orchidoideae) comprise a speciose genus of orchids primarily in the northern hemisphere, with up to 200 known species worldwide. Individual species are known to self-pollinate, but many rely on insect pollinators with characteristics such as floral color, timing of floral odor emissions, nectar rewards, and spur length associated with particular pollination syndromes. As with many orchids, some orchid-pollinator associations are likely highly co-evolved, but we also know that some Platanthera spp. are the result of hybridization events, which implies a lack of pollinator fidelity in some cases. Some Platanthera spp. occur in large numbers which, coupled with the numerous Platanthera-pollinator systems, make them accessible as study species and useful for co-evolutionary studies. Due to the likely effects of climate change and ongoing development on Platanthera spp. habitats, these orchids and their associated pollinators should be a focus of conservation attention and management. However, while there is a fairly substantial literature coverage of Platanthera-pollinator occurrence and interactions, there are still wide gaps in our understanding of the species involved in these systems. In this systematic review, we outline what is current knowledge and provide guidance on further research that will increase our understanding of orchid-insect co-evolutionary relationships. Our review covers 157 orchid species and about 233 pollinator species interacting with 30 Platanthera spp. We provide analyses on aspects of these interactions such as flower morphology, known insect partners of Platanthera species, insect-Platanthera specificity, pollination visitor timing (diurnal vs. nocturnal), floral rewards, and insect behavior affecting pollination outcomes (e.g., pollinia placement). A substantial number of Platanthera spp. and at least a few of their known pollinators are of official (IUCN) conservation concern - and many of their pollinators remain unassessed or even currently unknown - which adds to the urgency of further research on these co-evolved relationships.

A crane fly of the genus Gynoplistia Macquart (Diptera, Limoniidae) from the early Miocene of New Zealand

The first fossil limoniid fly from the Miocene Fossil-Lagerstätte of Foulden Maar in New Zealand is described on the basis of an isolated well-preserved wing. The specimen is tentatively attributed to a new species Gynoplistiafouldensensissp. nov. in the large extant genus Gynoplistia, which is well diversified in the country. It is the second fossil record of this genus, the first one being an isolated wing from the Cretaceous Weald Clay Formation in the United Kingdom.

Retinal Adaptation in Response to Light and Dark Regimes in the Oriental Armyworm Mythimna separata (Lepidoptera: Noctuidae)

The oriental armyworm, Mythimna separata (Walker), is a well-known nocturnal migratory pest that relies on its exceptional nocturnal vision for navigation during long-distance flights. In this study, we investigated the ultrastructure of the compound eyes of adult M. separata using transmission electron microscopy and quantitatively evaluated adaptational changes in the retina under light and dark conditions. The compound eyes of M. separata are superposition eyes with a clear zone. The retina shows remarkable anatomical differences under light and dark adaptation, primarily characterized by distinct patterns of rhabdoms within the clear zone: the rhabdoms are nearly absent under light adaptation, but become more voluminous under dark adaptation. In the distal, middle, and proximal sections of the clear zone, the cross-sectional areas of retinulae and rhabdoms, as well as the rhabdom occupation ratio, are significantly larger under dark adaptation than under light adaptation. Conversely, the opposite trend is observed beneath the clear zone. These results indicate remarkable plasticity in the M. separata retina throughout a normal daily cycle, providing a theoretical basis for improving searchlight and ground light trap techniques for the management of this migratory species.

A comparison of dissection and 3D approaches to estimate muscle physiological cross-sectional area, validated by in vivo bite forces

Performance traits such as bite forces are crucial to fitness and relate to the niche and adaptation of species. However, for many insects it is not possible to directly measure bite forces because they are too small. Biomechanical models of bite forces are therefore relevant to test hypotheses of adaptation in insects and other small organisms. Although such models are based on classical mechanics, combining forces, material properties and laws of levers, it is currently unknown how various models relate to bite forces measured in vivo. One critical component of these models is the physiological cross-sectional area (PCSA) of muscles, which relates to the maximum amount of force they can produce. Here, using the grasshopper Schistocerca gregaria, we compare various ways to obtain PCSA values and use in vivo measurements of bite forces to validate the biomechanical models. We show that most approaches used to derive PCSA (dissection, 3D muscle convex hull volume, muscle attachment area) are consistent with the expected relationships between PCSA and bite force, as well as with the muscle stress values known for insects. The only exception to this are PCSA values estimated by direct 3D muscle volume computation, which could be explained by noisy variation produced by shrinkage. This method therefore produces PCSA values which are uncorrelated to in vivo bite forces. Furthermore, despite the fact that all other methods do not significantly differ from expectations, their derived PCSA values vary widely, suggesting a lack of comparability between studies relying on different methods.

New insights into immune genes and other expanded gene families of the house fly, Musca domestica, from an improved whole genome sequence

The house fly, Musca domestica, is a pest of livestock, transmits pathogens of human diseases, and is a model organism in multiple biological research areas. The first house fly genome assembly was published in 2014 and has been of tremendous use to the community of house fly biologists, but that genome is discontiguous and incomplete by contemporary standards. To improve the house fly reference genome, we sequenced, assembled, and annotated the house fly genome using improved techniques and technologies that were not available at the time of the original genome sequencing project. The new genome assembly is substantially more contiguous and complete than the previous genome. The new genome assembly has a scaffold N50 of 12.46 Mb, which is a 50-fold improvement over the previous assembly. In addition, the new genome assembly is within 1% of the estimated genome size based on flow cytometry, whereas the previous assembly was missing nearly one-third of the predicted genome sequence. The improved genome assembly has much more contiguous scaffolds containing large gene families. To provide an example of the benefit of the new genome, we used it to investigate tandemly arrayed immune gene families. The new contiguous assembly of these loci provides a clearer picture of the regulation of the expression of immune genes, and it leads to new insights into the selection pressures that shape their evolution.

Butterfly wing color made of pigmented liquid

A previously undescribed mechanism underlying butterfly wing coloration patterns was discovered in two distantly related butterfly species, Siproeta stelenes and Philaethria diatonica. These butterflies have bright green wings, but the color pattern is not derived from solid pigments or nanostructures of the scales or from the color of the cuticular membrane but rather from a liquid retained in the wing membrane. Wing structure differs between the green and non-green areas. In the non-green region, the upper and lower cuticular membranes are attached to each other, whereas in the green region, we observed a space of 5-10 μm where green liquid is held and living cells are present. A pigment analysis and tracer experiment revealed that the color of the liquid is derived from hemolymph components, bilin and carotenoid pigments. This discovery broadens our understanding of the diverse ways in which butterfly wings obtain their coloration and patterns.

First report of parasitism by Eutrichophilus cercolabes (Phthiraptera: Trichodectidae) on Coendou spinosus (Erethizontidae) in Rio Grande do Sul, Brazil - case report

Coendou spinosus is a species of rodent popularly known as porcupine, it has a great ability to adapt to different habitats and is found in tropical forests in countries such as Bolivia, Brazil, Venezuela and Guianas. This mammal has already been identified as a reservoir of several pathogenic agents for humans and other animals and has a variety of ectoparasites, endoparasites and hemoparasites little studied and described. Due to this, the objective was to report the parasitism by Eutrichophilus cercolabes in C. spinosus in the central region of Rio Grande do Sul, southern Brazil. In total, 16 lice were found, one male and 15 females of the species. This is the first report of the parasitism of this Phthiraptera on C. spinosus in Rio Grande do Sul. The scarcity of reports on the taxonomy and biotic characteristics, as well as the vector capacity of pathogens of most species of ectoparasites of wild animals, highlights the need for further studies on the distribution of these arthropods in different regions and host species.

First record of a rare case of accidental urinary myiasis by Telmatoscopus albipunctata (Diptera: Psychodidae), with morphological description, in a human in Brazil

Telmatoscopus albipunctata is an insect of the Psychodidae family, with a worldwide distribution, particularly in tropical and subtropical countries. Although it does not have hematophagous habits, it has veterinary medical importance due to the mechanical transmission of protozoa and bacteria, many of which cause nosocomial infections. This dipteran has been reported as one of the causative agents of accidental myiasis in humans in several countries, and since it has not been registered in South America, the objective of the present report was to describe a rare case of accidental urinary myiasis caused by T. albipunctata (Diptera: Psychodidae) in humans in Brazil. In the present report, a 25-year-old female patient, resident of the central region of the state of Rio Grande do Sul, Brazil, sought medical attention after finding larvae in her urine. She complained of vaginal itching and skin dermatitis. The larvae were sent to the Veterinary Parasitology Laboratory of the Federal University of Santa Maria, where they were mounted on permanent slides for further taxonomic identification. Morphological characteristics allowed the identification of fourth-stage larvae and pupae of T. albipunctata. Therefore, the present work reports the first record of accidental urinary myiasis caused by T. albipunctata infection in Brazil and South America.

First Report of Mitochondrial DNA Copy Number Variation in Opsius heydeni (Insecta, Hemiptera, Cicadellidae) from Polluted and Control Sites

Mitochondrial DNA easily undergoes alterations due to exposure to stress factors. In particular, mitochondrial DNA copy number (mtDNAcn) variation can be used as a biomarker of the effect of exposure to various environmental contaminants. In this study, a molecular investigation based on the evaluation of mtDNAcn variation was applied for the first time to individuals belonging to the species Opsius heydeni. A total of 20 samples were collected from two sites in eastern Sicily: Priolo Gargallo, a site with a strong anthropic impact, and the Simeto river Oasis, a control site. Specimens identified based on morphological traits were used to obtain COI gene sequences from this species that were not previously available in GenBank. After processing, the relative mtDNAcn was evaluated using real-time PCR of a portion of the COI and 18S genes. A decrease in the mtDNAcn in the specimens from the polluted site was observed. These results highlight how environmental contaminants can alter the mitochondrial genome and how Opsius heydeni can be considered a potential bioindicator species of environmental quality.

Insect fauna including unrecorded species in Ulleungdo, South Korea

Background

Ulleungdo harbours a unique ecosystem owing to its isolation from the mainland alongside its maritime climate. The island, formed via volcanic activity, is the largest island in the East Sea of Korea and retains a primeval forest. The ecosystems are being destroyed owing to increasing human activity on the island. Therefore, through the investigation of the insect fauna of Ulleungdo, we tried to provide information that can be the basis for understanding the island ecology of Ulleungdo. This survey was conducted four times between April and October in 2020 at Seonginbong.

New information

The findings of the survey regarding insect fauna at Seonginbong, Ulleungdo included 10 orders, 105 families, 216 genera and 212 species, of which 12 families, two subfamilies, 13 genera and 74 species were previously unrecorded. The data have been registered in the Global Biodiversity Information Facility (GBIF; www.GBIF.org).

Highly accurate long reads are crucial for realizing the potential of biodiversity genomics

BACKGROUND

Generating the most contiguous, accurate genome assemblies given available sequencing technologies is a long-standing challenge in genome science. With the rise of long-read sequencing, assembly challenges have shifted from merely increasing contiguity to correctly assembling complex, repetitive regions of interest, ideally in a phased manner. At present, researchers largely choose between two types of long read data: longer, but less accurate sequences, or highly accurate, but shorter reads (i.e., >Q20 or 99% accurate). To better understand how these types of long-read data as well as scale of data (i.e., mean length and sequencing depth) influence genome assembly outcomes, we compared genome assemblies for a caddisfly, Hesperophylax magnus, generated with longer, but less accurate, Oxford Nanopore (ONT) R9.4.1 and highly accurate PacBio HiFi (HiFi) data. Next, we expanded this comparison to consider the influence of highly accurate long-read sequence data on genome assemblies across 6750 plant and animal genomes. For this broader comparison, we used HiFi data as a surrogate for highly accurate long-reads broadly as we could identify when they were used from GenBank metadata.

RESULTS

HiFi reads outperformed ONT reads in all assembly metrics tested for the caddisfly data set and allowed for accurate assembly of the repetitive ~ 20 Kb H-fibroin gene. Across plants and animals, genome assemblies that incorporated HiFi reads were also more contiguous. For plants, the average HiFi assembly was 501% more contiguous (mean contig N50 = 20.5 Mb) than those generated with any other long-read data (mean contig N50 = 4.1 Mb). For animals, HiFi assemblies were 226% more contiguous (mean contig N50 = 20.9 Mb) versus other long-read assemblies (mean contig N50 = 9.3 Mb). In plants, we also found limited evidence that HiFi may offer a unique solution for overcoming genomic complexity that scales with assembly size.

CONCLUSIONS

Highly accurate long-reads generated with HiFi or analogous technologies represent a key tool for maximizing genome assembly quality for a wide swath of plants and animals. This finding is particularly important when resources only allow for one type of sequencing data to be generated. Ultimately, to realize the promise of biodiversity genomics, we call for greater uptake of highly accurate long-reads in future studies.

Diversity, Form, and Postembryonic Development of Paleozoic Insects

While Mesozoic, Paleogene, and Neogene insect faunas greatly resemble the modern one, the Paleozoic fauna provides unique insights into key innovations in insect evolution, such as the origin of wings and modifications of postembryonic development including holometaboly. Deep-divergence estimates suggest that the majority of contemporary insect orders originated in the Late Paleozoic, but these estimates reflect divergences between stem groups of each lineage rather than the later appearance of the crown groups. The fossil record shows the initial radiations of the extant hyperdiverse clades during the Early Permian, as well as the specialized fauna present before the End Permian mass extinction. This review summarizes the recent discoveries related to the documented diversity of Paleozoic hexapods, as well as current knowledge about what has actually been verified from fossil evidence as it relates to postembryonic development and the morphology of different body parts.

Composition and Dynamics of Hexapod Communities on Yushan Bamboo (Yushania niitakayamensis) in the Subtropical Montane Areas of Taiwan

Plant communities that colonize high-elevation zones generally have short growing seasons which lead to specialized adaptations in such zones. In montane areas of Taiwan, Yushan bamboo (YB, Yushania niitakayamensis) is dominant at elevations ranging from 2500 to 3300 m and grows in a grassland-like open habitat. In this study, hexapods were collected from YB bimonthly between 2009 and 2012 by using a sweeping net. The composition of and several bioindices for the hexapods were determined, and multivariate analyses were conducted to explore the dynamics and seasonal distribution of the hexapods. A total of 32,000 individuals belonging to 11 orders and 113 families were collected, with adult individuals being collected more frequently in warmer seasons (from June to October). Of the sampled individuals, 90% belonged to the orders Collembola (42%), Hemiptera (35%), and Hymenoptera (13%). The number of individuals belonging to Hemiptera were stable in all seasons, and the number of hymenopteran wasps was influenced by temperature and exhibited a stable dynamic pattern. The number of individuals belonging to Collembola fluctuated dramatically. The multivariate analyses revealed that the collected hexapods could be divided into two major family groups according to survey season (i.e., summer and winter groups). Several families were collected only in summer, but a few were collected only in winter. Eigenvalues obtained from a principal component analysis revealed that the families Chironomidae, Delphacidae, Entomobryidae, Hypogastruridae, Sminthuridae, and Thripidae (all dominant) were the major contributors to the winter group. These families were abundant all year, although some were more abundant during winter. The three dominant orders Collembola, Hemiptera, and Hymenoptera, each of which has a distinct community structure and dynamic pattern, may have their own adaptive mechanisms in the subtropical regions of Taiwan. Hemiptera individuals, which feed on YB, were most abundant in the adult stage in summer and in the nymphal stage in winter. The abundance of parasitic hymenopteran wasps, which had stable dynamic patterns, was associated with that of their host insects and temperature. The drastic fluctuations in the abundance of Collembola may have been caused by abiotic factors, such as precipitation and microhabitat factors. The early onset of spring and the late onset of winter might also affect the dynamics of the studied hexapods.

Genomic-Phenomic Reciprocal Illumination: Desyopone hereon gen. et sp. nov., an Exceptional Aneuretine-like Fossil Ant from Ethiopian Amber (Hymenoptera: Formicidae: Ponerinae)

Fossils are critical for understanding the evolutionary diversification, turnover, and morphological disparification of extant lineages. While fossils cannot be sequenced, phenome-scale data may be generated using micro-computed tomography (µ-CT), thus revealing hidden structures and internal anatomy, when preserved. Here, we adduce the male caste of a new fossil ant species from Miocene Ethiopian amber that resembles members of the Aneuretinae, matching the operational definition of the subfamily. Through the use of synchrotron radiation for µ-CT, we critically test the aneuretine-identity hypothesis. Our results indicate that the new fossils do not belong to the Aneuretinae, but rather the Ponerini (Ponerinae). Informed by recent phylogenomic studies, we were able to place the fossils close to the extant genus Cryptopone based on logical character analysis, with the two uniquely sharing absence of the subpetiolar process among all ponerine genera. Consequently, we: (1) revise the male-based key to the global ant subfamilies; (2) revise the definitions of Aneuretinae, Ponerinae, Platythyreini, and Ponerini; (3) discuss the evolution of ant mandibles; and (4) describe the fossils as †Desyopone hereon gen. et sp. nov. Our study highlights the value of males for ant systematics and the tremendous potential of phenomic imaging technologies for the study of ant evolution.

A New Genus of Spittlebugs (Hemiptera, Cercopidae) from the Eocene of Central Tibetan Plateau

The superfamily Cercopoidea is commonly named as "spittlebugs", as its nymphs produce a spittle mass to protect themselves. Cosmoscartini (Cercopoidea: Cercopidae) is a large and brightly colored Old World tropical tribe, including 11 genera. A new genus Nangamostethos gen. nov. (type species: Nangamostethostibetense sp. nov.) of Cosmoscartini is described from Niubao Formation, the late Eocene of central Tibetan Plateau (TP), China. Its placement is ensured by comparison with all the extant genera of the tribe Cosmoscartini. The new fossil represents one of few fossil Cercopidae species described from Asia. It is likely that Nangamostethos was extinct from the TP due to the regional aridification and an overturn of plant taxa in the late Paleogene.

Abdominal serial homologues of wings in Paleozoic insects

The Late Paleozoic acquisition of wings in insects represents one of the key steps in arthropod evolution. While the origin of wings has been a contentious matter for nearly two centuries, recent evolutionary developmental studies suggest either the participation of both tergal and pleural tissues in the formation of wings¹ or wings originated from exites of the most proximal leg podite incorporated into the insect body wall.² The so-called "dual hypothesis" for wing origins finds support from studies of embryology, evo-devo, and genomics, although the degree of the presumed contribution from tergal and pleural tissues differ.^3-6 Ohde et al.,⁷ confirmed a major role for tergal tissue in the formation of the cricket wing and suggested that "wings evolved from the pre-existing lateral terga of a wingless insect ancestor." Additional work has focused on identifying partial serially homologous structures of wings on the prothorax^8,9 and abdominal segments.¹⁰ Thus, several studies have suggested that the prothoracic horns in scarab beetles,⁹ gin traps of tenebrionid and scarab beetle pupae,^11,12 or abdominal tracheal gills of mayfly larvae^1,13 evolved from serial homologues of wings. Here, we present critical information from abdominal lateral outgrowths (flaps) of Paleozoic palaeodictyopteran larvae, which show comparable structure to thoracic wings, consisting of cordate lateral outgrowths antero-basally hinged by muscle attachments. These flaps therefore most likely represent wing serial homologues. The presence of these paired outgrowths on abdominal segments I-IX in early diverging Pterygota likely corresponds to crustacean epipods^14,15 and resembles a hypothesized ancestral body plan of a "protopterygote" model.

Exploring Large-Scale Patterns of Genetic Variation in the COI Gene among Insecta: Implications for DNA Barcoding and Threshold-Based Species Delimitation Studies

The genetic variation in the COI gene has had a great effect on the final results of species delimitation studies. However, little research has comprehensively investigated the genetic divergence in COI among Insecta. The fast-growing COI data in BOLD provide an opportunity for the comprehensive appraisal of the genetic variation in COI among Insecta. We calculated the K2P distance of 64,414 insect species downloaded from BOLD. The match ratios of the clustering analysis, based on different thresholds, were also compared among 4288 genera (35,068 species). The results indicate that approximately one-quarter of the species of Insecta showed high intraspecific genetic variation (>3%), and a conservative estimate of this proportion ranges from 12.05% to 22.58%. The application of empirical thresholds (e.g., 2% and 3%) in the clustering analysis may result in the overestimation of the species diversity. If the minimum interspecific genetic distance of the congeneric species is greater than or equal to 2%, it is possible to avoid overestimating the species diversity on the basis of the empirical thresholds. In comparison to the fixed thresholds, the “threshOpt” and “localMinima” algorithms are recommended for the provision of a reference threshold for threshold-based species delimitation studies.

The First Fossil Representatives of the Sawfly Genera Emphytus and Empria from the upper Miocene of France (Hymenoptera, Tenthredinidae)

Simple Summary

Two sawflies belonging to the tenthredinid genera Emphytus and Empria are described from upper Miocene diatomite paleolakes from Southern France. They are compared with all their extant and fossil relative genera. The previously described fossil representatives of these two genera are discussed. These fossils are of great interest for dating in future phylogenetic analyses of the Tenthredinidae.

Abstract

Emphytusmiocenicus sp. nov., first fossil representative of this genus, is described from the upper Miocene of the diatom paleolake of Montagne d’Andance (Ardèche, France). Its placement is ensured by an in-depth comparison with all the extant and fossil genera of the subfamily Allantinae. The representatives of Emphytus are distributed in the Palearctic, Nearctic, and Oriental regions. Empria sammuti sp. nov., second representative of the latter genus, is described from the latest Miocene of the diatom paleolake of Sainte-Reine (Cantal, France). The placement of this new species is based on a detailed comparison with the extant genera of the tribe Empriini. The larvae of the extant Emphytus and Empria spp. are known to be phytophagous on angiosperm leaves of several families, all present as fossils in the taphocenoses of la Montagne d’Andance and Sainte-Reine. Emphytus miocenicus sp. nov. represents the oldest record of this genus and of its crown group, corroborating the estimate of a middle Eocene–middle Oligocene age for its stem group. Throughout our study, it appears that the first described fossil of the genus Empria, E. oligocaenica, from the Oligocene of Germany, needs to be revised and redescribed. It should preferably be treated until the revision as incertae sedis in Allantinae sensu lato.

De Novo Genome Assembly and Annotation of an Andean Caddisfly, Atopsyche davidsoni Sykora, 1991, a Model for Genome Research of High-Elevation Adaptations

We sequence, assemble, and annotate the genome of Atopsyche davidsoni Sykora, 1991, the first whole-genome assembly for the caddisfly family Hydrobiosidae. This free-living and predatory caddisfly inhabits streams in the high-elevation Andes and is separated by more than 200 Myr of evolutionary history from the most closely related caddisfly species with genome assemblies available. We demonstrate the promise of PacBio HiFi reads by assembling the most contiguous caddisfly genome assembly to date with a contig N50 of 14 Mb, which is more than 6× more contiguous than the current most contiguous assembly for a caddisfly (Hydropsyche tenuis). We recover 98.8% of insect BUSCO genes indicating a high level of gene completeness. We also provide a genome annotation of 12,232 annotated proteins. This new genome assembly provides an important new resource for studying genomic adaptation of aquatic insects to harsh, high-altitude environments.

Loss of Timeless Underlies an Evolutionary Transition within the Circadian Clock

Most organisms possess time-keeping devices called circadian clocks. At the molecular level, circadian clocks consist of transcription-translation feedback loops. Although some components of the negative transcription-translation feedback loop are conserved across the animals, important differences exist between typical models, such as mouse and the fruit fly. In Drosophila, the key components are PERIOD (PER) and TIMELESS (TIM-d) proteins, whereas the mammalian clock relies on PER and CRYPTOCHROME (CRY-m). Importantly, how the clock has maintained functionality during evolutionary transitions between different states remains elusive. Therefore, we systematically described the circadian clock gene setup in major bilaterian lineages and identified marked lineage-specific differences in their clock constitution. Then we performed a thorough functional analysis of the linden bug Pyrrhocoris apterus, an insect species comprising features characteristic of both the Drosophila and the mammalian clocks. Unexpectedly, the knockout of timeless-d, a gene essential for the clock ticking in Drosophila, did not compromise rhythmicity in P. apterus, it only accelerated its pace. Furthermore, silencing timeless-m, the ancestral timeless type ubiquitously present across animals, resulted in a mild gradual loss of rhythmicity, supporting its possible participation in the linden bug clock, which is consistent with timeless-m role suggested by research on mammalian models. The dispensability of timeless-d in P. apterus allows drawing a scenario in which the clock has remained functional at each step of transition from an ancestral state to the TIM-d-independent PER+CRY-mammalian system operating in extant vertebrates, including humans.

Long Reads Are Revolutionizing 20 Years of Insect Genome Sequencing

The first insect genome assembly (Drosophila melanogaster) was published two decades ago. Today, nuclear genome assemblies are available for a staggering 601 insect species representing 20 orders. In this study, we analyzed the most-contiguous assembly for each species and provide a "state-of-the-field" perspective, emphasizing taxonomic representation, assembly quality, gene completeness, and sequencing technologies. Relative to species richness, genomic efforts have been biased toward four orders (Diptera, Hymenoptera, Collembola, and Phasmatodea), Coleoptera are underrepresented, and 11 orders still lack a publicly available genome assembly. The average insect genome assembly is 439.2 Mb in length with 87.5% of single-copy benchmarking genes intact. Most notable has been the impact of long-read sequencing; assemblies that incorporate long reads are ∼48× more contiguous than those that do not. We offer four recommendations as we collectively continue building insect genome resources: 1) seek better integration between independent research groups and consortia, 2) balance future sampling between filling taxonomic gaps and generating data for targeted questions, 3) take advantage of long-read sequencing technologies, and 4) expand and improve gene annotations.

Evidence for wing development in the Late Palaeozoic Palaeodictyoptera revisited

The numerous fossil specimens described as consecutive series of different larval stages of two species, Tchirkovaea guttata and Paimbia fenestrata (Palaeodictyoptera: Tchirkovaeidae), were reinvestigated with emphasis on comparing the development and growth of their wings with that of the wings of a recent mayfly, Cloeon dipterum. This unique fossil material was for a long time considered as undisputed evidence for an unusual type of wing development in Palaeozoic insects. The original idea was that the larvae of Palaeodictyopterida had wings, which were articulated and fully movable in their early stages of postembryonic development and that these gradually enlarging wings changed their position from longitudinal to perpendicular to the body axis. Moreover, the development of wings was supposed to include two or more subimaginal instars, implying that the fully winged instars moulted several times during their postembryonic development. The results of the present study revealed that there is no evidence that this series of nymphal, subimaginal and imaginal wings provide support for the original idea of wing development in Palaeozoic insects. On the contrary, our results indicate, that the supposed palaeodictyopteran larval wings are in fact wing pads with a wing developing inside the cuticular sheath as in recent hemimetabolous insects. Moreover, this study newly reinterpreted the wing pad base of Parathesoneura carpenteri and confirmed the presence of nygma like structures on wings and wing pads of palaeodictyopteran Tchirkovaeidae.

A review of the hexapod tracheal system with a focus on the apterygote groups

Respiratory systems are key innovations for the radiation of terrestrial arthropods. It is therefore surprising that there is still a considerable lack of knowledge. In this review of the available information on tracheal systems of hexapods (with a focus on the apterygote lineages Protura, Collembola, Diplura, Archaeognatha and Zygentoma), we summarize available data on the spiracles (number, position and morphology), the shape and variability of tracheal branching patterns including anastomoses, the tracheal fine structure and the respiratory proteins. The available data are strongly fragmented, and information for most subgroups is missing. In various cases, individual observations for one species account for the knowledge of the entire order. The available data show that there are strong differences between but also within apterygote orders. We conclude that the available data are insufficient to derive detailed conclusions on the hexapod ground plan and outline the possible evolutionary scenarios for the tracheal system in this group.

The role of bracket fungi in creating alpha diversity of invertebrates in the Białowieża National Park, Poland

Bracket fungi are seen mainly as the cause of economic losses in forestry, and their role as creators of biodiversity is relatively poorly understood. The aim of the study was defining the manner in which the degree of decay (DD) of the fruiting bodies determines the character of the invertebrate assemblages colonising them. The effect of this group of fungi on the modification of biodiversity of invertebrates (Aranae, Opiliones, Pseudoscorpionida, two groups of mites-Mesostigmata and Oribatida, and Collembola and Insecta) was investigated by analyzing 100 fruiting bodies of 10 species of bracket fungi divided into four DD classes. The material was collected at Białowieża National Park, which is considered to be the largest area of natural forests in the North European Plain. 16 068 invertebrate individuals classified into 224 species were obtained. Oribatid mites (12 543 individuals) constituted the largest group of individuals, which were classified into 115 species with the most numerous Carabodes femoralis (8,811 individuals). Representatives of this group of mites have been reported previously in the publications on bracket fungi; however, the contributions of Oribatida and other groups of invertebrates were not broadly compared. Moreover, the species such as Hoploseius mariae and H. oblongus, which were predominantly found in fruiting bodies of bracket fungi, have also been discerned. The invertebrate fauna differs depending on DD of the samples: In the more decayed samples, a higher number of both individuals and species were recorded compared to the samples with lower DDs; however, this trend proved to be nonlinear. The DCA and cluster analysis revealed a similarity of the invertebrate assemblages from the 2 DD and 4 DD samples. They also indicated that the group 3 DD differed the most from all the other samples. The indicator species analysis identified species characteristic to individual DDs: For group 1 DD, it was, for example, Hoploseius oblongus; for 2 DD-Orchesella bifasciata; and for 3 DD-Chernes cimicoides, while for 4 DD-Dinychus perforatus.

Filling in the gaps: A reevaluation of the Lygus hesperus peptidome using an expanded de novo assembled transcriptome and molecular cloning

Peptides are the largest and most diverse class of molecules modulating physiology and behavior. Previously, we predicted a peptidome for the western tarnished plant bug, Lygus hesperus, using transcriptomic data produced from whole individuals. A potential limitation of that analysis was the masking of underrepresented genes, in particular tissue-specific transcripts. Here, we reassessed the L. hesperus peptidome using a more comprehensive dataset comprised of the previous transcriptomic data as well as tissue-specific reads produced from heads and accessory glands. This augmented assembly significantly improves coverage depth providing confirmatory transcripts for essentially all of the previously identified families and new transcripts encoding a number of new peptide precursors corresponding to 14 peptide families. Several families not targeted in our initial study were identified in the expanded assembly, including agatoxin-like peptide, CNMamide, neuropeptide-like precursor 1, and periviscerokinin. To increase confidence in the in silico data, open reading frames of a subset of the newly identified transcripts were amplified using RT-PCR and sequence validated. Further PCR-based profiling of the putative L. hesperus agatoxin-like peptide precursor revealed evidence of alternative splicing with near ubiquitous expression across L. hesperus development, suggesting the peptide serves functional roles beyond that of a toxin. The peptides predicted here, in combination with those identified in our earlier study, expand the L. hesperus peptidome to 42 family members and provide an improved platform for initiating molecular and physiological investigations into peptidergic functionality in this non-model agricultural pest.

Universal fluorescence in situ hybridization (FISH) protocol for mapping repetitive DNAs in insects and other arthropods

Repetitive DNAs comprise large portion of eukaryote genomes. In genome projects, the assembly of repetitive DNAs is challenging due to the similarity between repeats, which generate ambiguities for alignment. Fluorescence in situ hybridization (FISH) is a powerful technique for the physical mapping of various sequences on chromosomes. This technique is thus very helpful in chromosome-based genome assemblies, providing information on the fine architecture of genomes and their evolution. However, various protocols are currently used for FISH mapping, most of which are relatively laborious and expensive, or work properly only with a specific type of probes or sequences, and there is a need for a universal and affordable FISH protocol. Here we tested a FISH protocol for mapping of different DNA repeats, such as multigene families (rDNAs, U snDNAs, histone genes), satellite DNAs, microsatellites, transposable elements, DOP-PCR products, and telomeric motif (TTAGG)_n, on the chromosomes of various insects and other arthropods. Different cell types and stages obtained from diverse tissues were used. The FISH procedure proved high quality and reliable results in all experiments performed. We obtained data on the chromosomal distribution of DNA repeats in representatives of insects and other arthropods. Thus, our results allow us to conclude that the protocol is universal and requires only time adjustment for chromosome/DNA denaturation. The use of this FISH protocol will facilitate studies focused on understanding the evolution and role of repetitive DNA in arthropod genomes.

Ecosystem Services Provided by Insects in Brazil: What Do We Really Know?

Insects are the most abundant and diverse organisms on Earth and provide essential ecosystem services. However, Brazilian society rarely consider the importance of insects in their diverse country. Therefore, in this review, we provide an overview of ecosystem services provided by insects in Brazil. A database search returned 136 articles, published in English or Portuguese, on ecosystem services provided by insects in Brazil. The first article was published in 1982, and majority of the studies were conducted in the Atlantic Forest or the Cerrado biomes. The most frequently studied insect-provided ecosystem services were pollination, decomposition, and biological control of pests. The studies focused primarily on natural and anthropic ecosystems, and most followed an experimental approach. We noted that the term "ecosystem services" was not used frequently in studies on insects in Brazil. The information available was mostly taxon-biased. We discuss the implications of these findings in relation to reconciling economic interests and the need for insect conservation for continued provision of ecosystem services in a broader perspective. In conclusion, we argue that the scientific community should focus on understanding the ecosystem services provided by insects other than those strictly related to economic activities, and on improving communication with policymakers and citizens. As a tropical and megadiverse country, Brazil has the potential to become a protagonist in conserving and using the ecosystem services provided by insects, both locally and internationally, by providing scientific information to policymakers and citizens.

Gastric canthariasis caused by invasion of mealworm beetle larvae in weaned pigs in large-scale farming

Background

Mealworm beetle T. molitor (Coleoptera: Tenebrionidae) (Linnaeus, 1758) is one of the most important cosmopolitan primary storage pests, scavenging on a variety of post-harvest grains and affecting the quality and safety of food and feed. In addition to being an important factor in feed hygiene, the insect can also be an epidemiological factor of canthariasis. Livestock infestations with T. molitor are rarely reported. This article describes T. molitor-caused canthariasis in pigs in large scale closed-cycle farming.

Results

In the spring, we registered a significantly increased mortality among weaned pigs. In autopsy, live 3–6 mm long T. molitor larvae were found in their stomachs, especially in the non-glandular oesophageal region, on average 2–3 larvae per 10 cm² of gastric mucosa. Corrective actions reduced the number of deaths back to basal levels.

Conclusions

This is the first documented case of potentially lethal gastric canthariasis in weaned pigs, caused by invasion of T. molitor larvae. Although canthariasis caused by T. molitor has not been a significant problem in farm animals so far, our case indicates that the presence of mealworm beetles is a potential threat to animal welfare and health.

Structural colours in diverse Mesozoic insects

Structural colours, nature's most pure and intense colours, originate when light is scattered via nanoscale modulations of the refractive index. Original colours in fossils illuminate the ecological interactions among extinct organisms and functional evolution of colours. Here, we report multiple examples of vivid metallic colours in diverse insects from mid-Cretaceous amber. Scanning and transmission electron microscopy revealed a smooth outer surface and five alternating electron-dense and electron-lucent layers in the epicuticle of a fossil wasp, suggesting that multilayer reflectors, the most common biophotonic nanostructure in animals and even plants, are responsible for the exceptional preservation of colour in amber fossils. Based on theoretical modelling of the reflectance spectra, a reflective peak of wavelength of 514 nm was calculated, corresponding to the bluish-green colour observed under white light. The green to blue structural colours in fossil wasps, beetles and a fly most likely functioned as camouflage, although other functions such as thermoregulation cannot be ruled out. This discovery not only provides critical evidence of evolution of structural colours in arthropods, but also sheds light on the preservation potential of nanostructures of ancient animals through geological time.

Male postabdomen reveals ancestral traits of Megasecoptera among winged insects

External male genitalia of insects are greatly diverse in form and frequently used in evolutionary context and taxonomy. Therefore, our proper recognition of homologous structures among various groups from Paleozoic and extant insect taxa is of crucial interest, allowing to understand the key steps in insect evolution. Here, we reveal structural details of two Late Carboniferous representatives of Megasecoptera (families Bardohymenidae and Brodiopteridae), such as the presence of separated coxal plates VIII and ventral expansions of coxal lobes IX. Together with the confirmed presence of abdominal styli in some other members of Palaeodictyopterida (Diaphanopterodea) this suggests that early pterygotes may have had traits more archaic than expected. Whether or not these traits point to a stem-group relationship of Palaeodictyopterida to all other Pterygota as suspected by earlier authors remains unclear at this stage. Furthermore, the present study provides an updated comparison of male postabdomen morphology among extant species of wingless Archaeognatha and representatives of early diverging groups of Pterygota from the Late Carboniferous and Early Permian, the Megasecoptera (Palaeodictyopterida), Permoplectoptera (Ephemeroptera) and Meganisoptera (Odonatoptera).

Multi-faceted analysis provides little evidence for recurrent whole-genome duplications during hexapod evolution

BACKGROUND

Gene duplication events play an important role in the evolution and adaptation of organisms. Duplicated genes can arise through different mechanisms, including whole-genome duplications (WGDs). Recently, WGD was suggested to be an important driver of evolution, also in hexapod animals.

RESULTS

Here, we analyzed 20 high-quality hexapod genomes using whole-paranome distributions of estimated synonymous distances (KS), patterns of within-genome co-linearity, and phylogenomic gene tree-species tree reconciliation methods. We observe an abundance of gene duplicates in the majority of these hexapod genomes, yet we find little evidence for WGD. The majority of gene duplicates seem to have originated through small-scale gene duplication processes. We did detect segmental duplications in six genomes, but these lacked the within-genome co-linearity signature typically associated with WGD, and the age of these duplications did not coincide with particular peaks in KS distributions. Furthermore, statistical gene tree-species tree reconciliation failed to support all but one of the previously hypothesized WGDs.

CONCLUSIONS

Our analyses therefore provide very limited evidence for WGD having played a significant role in the evolution of hexapods and suggest that alternative mechanisms drive gene duplication events in this group of animals. For instance, we propose that, along with small-scale gene duplication events, episodes of increased transposable element activity could have been an important source for gene duplicates in hexapods.

An unusual 100-million-year old holometabolan larva with a piercing mouth cone

Holometabola is a hyperdiverse group characterised by a strong morphological differentiation between early post-embryonic stages (= larvae) and adults. Adult forms of Holometabola, such as wasps, bees, beetles, butterflies, mosquitoes or flies, are strongly differentiated concerning their mouth parts. The larvae most often seem to retain rather plesiomorphic-appearing cutting-grinding mouth parts. Here we report a new unusual larva preserved in Burmese amber. Its mouth parts appear beak-like, forming a distinct piercing mouth cone. Such a morphology is extremely rare among larval forms, restricted to those of some beetles and lacewings. The mouth parts of the new fossil are forward oriented (prognathous). Additionally, the larva has distinct subdivisions of tergites and sternites into several sclerites. Also, the abdomen segments bear prominent protrusions. We discuss this unusual combination of characters in comparison to the many different types of holometabolan larvae. The here reported larva is a new addition to the 'unusual zoo' of the Cretaceous fauna including numerous, very unusual appearing forms that have gone extinct at the Cretaceous-Palaeogene boundary.

On the morphology of the Late Paleozoic insect families Bardohymenidae and Aspidothoracidae (Palaeodictyopterida: Megasecoptera)

Megasecoptera is a late Paleozoic order of herbivorous insects with rostrum-like mouthparts and slender homonomous outstretched wings. Our knowledge of their morphology is mainly based on wings while other body parts are scarcely documented. Here we focus on the families Bardohymenidae and Aspidothoracidae. A new well preserved specimen of Sylvohymen cf. sibiricus is described and illustrated, particularly the structures of the external male genitalia previously unknown for Bardohymenidae. Sylvohymen marginatussp. nov. is described from the early Permian of Tshekarda based on unique traits in the wing venation. The genera Paleohymen and Taigahymen are both removed from Bardohymenidae and the latter is transferred to Vorkutiidae. Alexahymen aestatis (Brauckmann, 1991) comb. nov. from Pennsylvanian at Piesberg is transferred from Aspidothoracidae to Bardohymenidae. Piesbergbrodiagen. nov. is designated for Piesbergbrodia tristrata (Brauckmann and Herd, 2003) comb. nov. as a member of Brodiidae and the first known record of this family from Piesberg quarry. The placement of Sylvohymen peckae in the Bardohymenidae is considered doubtful due to lack of significant characters in its venation. Furthermore, our study is focused on the form of the apical cell and the pattern of wing pigmentation. Peculiarities of the integumental outgrowths and external genitalia of representatives of Aspidothoracidae and Bardohymenidae, and other close relatives, are highlighted.

Unusual mechanism of emission of vibratory signals in pygmy grasshoppers Tetrix tenuicornis (Sahlberg, 1891) (Orthoptera: Tetrigidae)

Acoustic communication plays an important role in the life of insects and especially in representatives of the order Orthoptera. Their vibrational signalling, unlike signalling by sound, is poorly studied. The pygmy grasshoppers Tetrix tenuicornis (Sahlberg, 1891) belonging to the ancestral family Tetrigidae (Orthoptera) can produce several types of substrate-borne vibratory signals using their mid-legs. The emission of these signals is not accompanied by visible movements of any parts of the body. The goal of our study was to elucidate the mechanism of production of these vibrations. For this, we synchronously recorded the vibratory signals and the muscle activity in various regions of the legs and thorax in freely moving males. The obtained results revealed an unusual mechanism for the emission of acoustic signals. We found that the strongest muscle activity during the emission of the vibratory signals was recorded in the mesofemur and mesotibia. According to the position of the electrode, these muscles are the flexor and extensor of the tibia, levators and depressors of the tarsus, and probably pretarsus. The motor system employed during the emission of vibratory signals was most similar to that of the jump of locusts and probably is performed as a result of co-contraction of antagonistic muscles of the tibia, tarsus, and pretarsus. The data obtained make significant additions to the presentation of a variety of insect acoustic communication systems.

RNA virome screening in diverse but ecologically related citrus pests reveals potential virus-host interactions

As an evergreen ecosystem, citrus orchards have specialized pest species and stable ecological homeostasis; thus, they provide an ideal model for investigating RNA viromes in diverse but ecologically related species. For this purpose, we collected specialized citrus pests from three classes of invertebrates, Insecta, Arachnida, and Gastropoda and we constructed two kinds of libraries (RNA and small RNA) for the pests by deep sequencing. In total, six virus-derived sequences were identified, including four Picornavirales, one Jingchuvirales and one Nidovirales. The picornavirus-derived small RNAs showed significant small RNA peaks and symmetric distribution patterns along the genome, which suggests these viruses infected the hosts and triggered host antiviral immunity RNA interference. Screening of virus-derived sequences in multiple species of citrus pests (n = 10 per species) showed that Eotetranychus kankitus picorna-like virus and Tetranychus urticae mivirus may be present in multiple pests. Our investigation in citrus pests confirmed that RNA viruses revealed by metagenomics could impact host immunity (e.g. RNAi). An approach with parallel deep sequencing of RNAs and small RNAs is useful not only for viral discoveries but also for understanding virus-host interactions of ecologically related but divergent pest species.

A DNA Barcoding Survey of an Arctic Arthropod Community: Implications for Future Monitoring

Accurate and cost-effective methods for tracking changes in arthropod communities are needed to develop integrative environmental monitoring programs in the Arctic. To date, even baseline data on their species composition at established ecological monitoring sites are severely lacking. We present the results of a pilot assessment of non-marine arthropod diversity in a middle arctic tundra area near Ikaluktutiak (Cambridge Bay), Victoria Island, Nunavut, undertaken in 2018 using DNA barcodes. A total of 1264 Barcode Index Number (BIN) clusters, used as a proxy for species, were recorded. The efficacy of widely used sampling methods was assessed. Yellow pan traps captured 62% of the entire BIN diversity at the study sites. When complemented with soil and leaf litter sifting, the coverage rose up to 74.6%. Combining community-based data collection with high-throughput DNA barcoding has the potential to overcome many of the logistic, financial, and taxonomic obstacles for large-scale monitoring of the Arctic arthropod fauna.

Ultrastructural comparison of the compound eyes of the Asian corn borer Ostrinia furnacalis (Lepidoptera: Crambidae) under light/dark adaptation

The Asian corn borer Ostrinia furnacalis is one of the most destructive pests of maize throughout eastern Asia and the South Pacific. In the present study the fine structure of the compound eyes of adult O. furnacalis was investigated under light/dark adaptation using light and electron microscopy. The compound eyes of male and female O. furnacalis are superposition eyes with electron-lucent clear zones. The sexual differences of the compound eyes of O. furnacalis are mainly reflected in eye size rather than ommatidial ultrastructure. Each ommatidium of both sexes contains 12 retinula cells, one of which is the basal retinula cell. All the retinula cells form a centrally-fused, two-tiered rhabdom, whose distal layer passes through the clear zone and distally connects with the crystalline cone. The ultrastructural changes under light/dark conditions mainly involve the rhabdom occupation ratio to retinula cell volume in the proximal layer of the rhabdom as well as the dimensions of the subcorneal zone and the crystalline tract. Pigment movements occur within the retinula cells and primary pigment cells, but are undetectable within the secondary pigment cells. Regardless of light or dark adaptation, in other words, the pigments never migrate into the clear zone.

The complete mitochondrial genome of click beetle Chiagosnius vittiger (Coleoptera: Elateridae) and phylogenetic analysis

In this study, we determined the complete mitochondrial genome sequence of click beetle Chiagosnius vittiger (Heyden, 1887) (GenBank accession no. MN306531) using next-generation sequencing (NGS) method. The mitogenome is 15,842 bp in length, consisting of 13 protein-coding genes (PCGs), two ribosomal RNA genes (rRNAs), 22 transfer RNA genes (tRNAs), and one non-coding control region. The overall nucleotide composition was 41.6% A, 31.1% T, 16.9% C, and 10.4% G, with 72.7% AT, respectively. The gene arrangement is consistent with the typical insect mitochondrial genome. Phylogenetic analysis revealed that C. vittiger clustered into a clade with Chiagosnius sulcicollis with high bootstrap support.

Patterns and Constraints in the Evolution of Sperm Individualization Genes in Insects, with an Emphasis on Beetles

Gene expression profiles can change dramatically between sexes and sex bias may contribute specific macroevolutionary dynamics for sex-biased genes. However, these dynamics are poorly understood at large evolutionary scales due to the paucity of studies that have assessed orthology and functional homology for sex-biased genes and the pleiotropic effects possibly constraining their evolutionary potential. Here, we explore the correlation of sex-biased expression with macroevolutionary processes that are associated with sex-biased genes, including duplications and accelerated evolutionary rates. Specifically, we examined these traits in a group of 44 genes that orchestrate sperm individualization during spermatogenesis, with both unbiased and sex-biased expression. We studied these genes in the broad evolutionary framework of the Insecta, with a particular focus on beetles (order Coleoptera). We studied data mined from 119 insect genomes, including 6 beetle models, and from 19 additional beetle transcriptomes. For the subset of physically and/or genetically interacting proteins, we also analyzed how their network structure may condition the mode of gene evolution. The collection of genes was highly heterogeneous in duplication status, evolutionary rates, and rate stability, but there was statistical evidence for sex bias correlated with faster evolutionary rates, consistent with theoretical predictions. Faster rates were also correlated with clocklike (insect amino acids) and non-clocklike (beetle nucleotides) substitution patterns in these genes. Statistical associations (higher rates for central nodes) or lack thereof (centrality of duplicated genes) were in contrast to some current evolutionary hypotheses, highlighting the need for more research on these topics.

The complete mitochondrial genome of Melanotus cribricollis (Coleoptera: Elateridae) and phylogenetic analysis

We determined the complete mitogenome sequence of Melanotus cribricollis (Faldermann) (GenBank accession no. MK792748). The mitogenome is 15,908 bp in length, consisting of 13 protein-coding genes, 22 transfer RNA genes, two ribosomal RNA genes, and one non-coding control region. The overall nucleotide composition was 40.8% A, 31.5% T, 17.4% C, and 10.3% G, with 72.3% of AT, respectively. Phylogenetic analysis based on the 13 coding protein genes nucleotide sequences revealed that M. cribricollis clustered with the same genus species M. villosus, and the three genus Melanotus Eschscholtz, Agriotes Eschscholtz and Adrastus Eschscholtz had a close relationship.

Ecomorphological diversification of the Late Palaeozoic Palaeodictyopterida reveals different larval strategies and amphibious lifestyle in adults

The Late Palaeozoic insect superorder Palaeodictyopterida exhibits a remarkable disparity of larval ecomorphotypes, enabling these animals to occupy diverse ecological niches. The widely accepted hypothesis presumed that their immature stages only occupied terrestrial habitats, although authors more than a century ago hypothesized they had specializations for amphibious or even aquatic life histories. Here, we show that different species had a disparity of semiaquatic or aquatic specializations in larvae and even the supposed retention of abdominal tracheal gills by some adults. While a majority of mature larvae in Palaeodictyoptera lack unambiguous lateral tracheal gills, some recently discovered early instars had terminal appendages with prominent lateral lamellae like in living damselflies, allowing support in locomotion along with respiratory function. These results demonstrate that some species of Palaeodictyopterida had aquatic or semiaquatic larvae during at least a brief period of their post-embryonic development. The retention of functional gills or gill sockets by adults indicates their amphibious lifestyle and habitats tightly connected with a water environment as is analogously known for some modern Ephemeroptera or Plecoptera. Our study refutes an entirely terrestrial lifestyle for all representatives of the early diverging pterygote group of Palaeodictyopterida, a greatly varied and diverse lineage which probably encompassed many different biologies and life histories.

The complete mitochondrial genome of click beetle Chiagosnius sulcicollis (Coleoptera: Elateridae) and phylogenetic analysis

In this study, we determined the complete mitochondrial genome sequence of click beetle Chiagosnius sulcicollis (Candeze, 1878) (GenBank accession no. MK792747) using next-generation sequencing (NGS) method. The mitogenome is 15,848 bp in length, consisting of 13 protein-coding genes (PCGs), 2 ribosomal RNA genes, 22 transfer RNA genes, and 1 non-coding control region. The overall nucleotide composition was 41.6% A, 31.5% T, 16.6% C, and 10.3% G, with 73.1% AT, respectively. The gene arrangement is consistent with the typical insect mitochondrial genome. Phylogenetic analysis revealed that C. sulcicollis clustered into a clade with Melanotus villosus with high bootstrap support.

The complete mitochondrial genome of a blowfly Calliphora nigribarbis (Vollenhoven, 1863) (Insecta: Diptera: Calliphoridae)

In the present study, the complete mitochondrial genome of a blowfly Calliphora nigribarbis has been sequenced and analyzed. The length of complete the mitochondrial genome is 16,279 bp, with 39.50% A, 13.20% C, 9.30% G, and 38.0% T nucleotide distribution. The complete mitochondrial genome consists of 13 protein-coding genes, 22 transfer RNAs, and 2 ribosomal RNAs likewise the most metazoan mitochondrial genomes. Furthermore, phylogenetic relationships of C. nigribarbis in the subfamily Calliphorinae investigated. The results suggested that C. vomitoria is the most related species to C. nigribarbis and the genus Calliphora is not monophyletic. This study provides the first complete mitochondrial genome sequence for the species.

The abdomen of a free-living female of Strepsiptera and the evolution of the birth organs

Mengenillidae is a small, basal family of Strepsiptera, mainly characterized by free-living females in contrast to the endoparasitic females of Stylopidia. Here, we describe external and internal structures of the female abdomen of Eoxenos laboulbenei (Mengenillidae). The external morphology was examined and documented using microphotography. Internal structures were reconstructed three-dimensionally using a μCT-data set. The morphologically simplified abdomen comprises 10 segments. The integument is weakly sclerotized and flexible. Spiracles are present dorsolaterally on segments I-VII. Segment VII bears the posteroventral birth opening and the small abdominal segment X carries the anus at its apex. Numerous eggs float freely in the hemolymph. The musculature of segments I-IV is composed of ventral and dorsal longitudinal muscle bundles, strongly developed paramedial dorsoventral muscles and a complex meshwork of small pleural muscles, with minimal differences between the segments. Segments V-X contain more than 50 individual muscles, even though the musculature as a whole is weakly developed. Even though it is not involved in processing food, the digestive tract is well-developed. Its postabdominal section comprises a part of the midgut and the short hindgut. The midgut fills a large part of the postabdominal lumen. The lumina of the midgut and hindgut are not connected. Five or six nodular Malpighian tubules open into the digestive tract at the border region between the midgut and hindgut. The birth organ below the midgut releases the primary larvae after hatching via the birth opening at segment VII. It is likely derived from primary female genital ducts. The presence of six additional birth organs of segments I-VI are de novo formations and a groundplan apomorphy of Stylopidia, the large strepsipteran subgroup with endoparasitic females. The loss of the primary birth organ of segment VII is an apomorphy of Stylopiformia (Stylopidia excl. Corioxenidae).

The diversity of terrestrial arthropods in Canada

Based on data presented in 29 papers published in the Biota of Canada Special Issue of ZooKeys and data provided herein about Zygentoma, more than 44,100 described species of terrestrial arthropods (Arachnida, Myriapoda, Insecta, Entognatha) are now known from Canada. This represents more than a 34% increase in the number of described species reported 40 years ago (Danks 1979a). The most speciose groups are Diptera (9620 spp.), Hymenoptera (8757), and Coleoptera (8302). Less than 5% of the fauna has a natural Holarctic distribution and an additional 5.1% are non-native species. A conservatively estimated 27,000–42,600 additional species are expected to be eventually discovered in Canada, meaning that the total national species richness is ca. 71,100–86,700 and that currently 51–62% of the fauna is known. Of the most diverse groups, those that are least known, in terms of percent of the Canadian fauna that is documented, are Acari (31%), Thysanoptera (37%), Hymenoptera (46%), and Diptera (32–65%). All groups but Pauropoda have DNA barcodes based on Canadian material. More than 75,600 Barcode Index Numbers have been assigned to Canadian terrestrial arthropods, 63.5% of which are Diptera and Hymenoptera. Much work remains before the Canadian fauna is fully documented, and this will require decades to achieve. In particular, greater and more strategic investment in surveys and taxonomy (including DNA barcoding) is needed to adequately document the fauna.

DNA barcoding data release for Coleoptera from the Gunung Halimun canopy fogging workpackage of the Indonesian Biodiversity Information System (IndoBioSys) project

We present the results of a DNA barcoding pipeline that was established as part of the German-Indonesian IndobioSys project - Indonesian Biodiversity Information System. Our data release provides the first large-scale diversity assessment of Indonesian coleoptera obtained by canopy fogging. The project combined extensive fieldwork with databasing, DNA barcode based species delineation and the release of results in collaboration with Indonesian counterparts, aimed at supporting further analyses of the data. Canopy fogging on 28 trees was undertaken at two different sites, Cikaniki and Gunung Botol, in the south-eastern area of the Gunung Halimun-Salak National Park in West Java, Indonesia. In total, 7,447 specimens of Coleoptera were processed, of which 3,836 specimens produced DNA barcode sequences that were longer than 300 bp. A total of 3,750 specimens were assigned a Barcode Index Number (BIN), including 2,013 specimens from Cikaniki and 1,737 specimens from Gunung Botol. The 747 BINs, that were obtained, represented 39 families of Coleoptera. The distribution of specimens with BINs per tree was quite heterogeneous in both sites even in terms of the abundance of specimens or diversity of BINs. The specimen distribution per taxon was heterogeneous as well. Some 416 specimens could not be identified to family level, corresponding to 72 BINs that lack a family level identification. The data have shown a large heterogeneity in terms of abundance and distribution of BINs between sites, trees and families of Coleoptera. From the total of 747 BINs that were recovered, 421 (56%) are exclusive from a single tree. Although the two study sites were in close proximity and separated by a distance of only about five kilometres, the number of shared BINs between sites is low, with 81 of the 747 BINs. With this data release, we expect to shed some light on the largely hidden diversity in the canopy of tropical forests in Indonesia and elsewhere.

A comparison of tarsal morphology and traction force in the two burying beetles Nicrophorus nepalensis and Nicrophorus vespilloides (Coleoptera, Silphidae)

Our aim was to compare friction and traction forces between two burying beetle species of the genus Nicrophorus exhibiting different attachment abilities during climbing. Specifically, the interaction of adhesive hairs and claws during attachment with respect to various surface properties was investigated by using a 2 × 3 experimental design. Traction force was measured for two different surface energies (hydrophilic vs hydrophobic) varying in roughness from smooth to micro-rough to rough. Nanotribometric tests on single legs were also performed. The external morphology of the attachment devices investigated by scanning electron microscopy suggested higher intra-specific (intersexual) than inter-specific differences. Whereas differences between the two species in traction force were high on smooth surfaces, no differences could be detected between males and females within each species. With claws intact, both species showed the highest forces on rough surfaces, although N. nepalensis with clipped claws performed best on a smooth surface. However, N. nepalensis beetles outperformed N. vespilloides, which showed no differences between smooth and rough surfaces with clipped claws. Both species demonstrated poor traction forces on micro-rough surfaces. Results concerning the impact of surface polarity were inconclusive, whereas roughness more strongly affected the attachment performance in both species. Nanotribometric analyses of the fore tarsi performed on micro-rough and rough surfaces revealed higher friction in the proximal (pull) direction compared with the distal (push) direction. In these experiments, we detected neither differences in friction performance between the two species, nor clear trends concerning the influence of surface polarity. We conclude that the investigated morphological traits are not critical for the observed interspecific difference in attachment ability on smooth surfaces. Furthermore, interspecific differences in performance are only clear on smooth surfaces and vanish on micro-rough and rough surfaces. Our results suggest that even subtle differences in the adhesion-mediating secretion in closely related species might result in qualitative performance shifts.

Two new deraeocorine plant bug species from Japan (Heteroptera, Miridae, Deraeocorinae)

Two new deraeocorine plant bug species, Fingulushenrytomi and Stethoconustakaii, are described from Japan. A color habitus image of live individuals and scanning electron micrographs are shown for each taxon to aid an unequivocal identification. A checklist and keys to species are also provided for Japanese Fingulus and Stethoconus.

A general theory of genital homologies for the Hexapoda (Pancrustacea) derived from skeletomuscular correspondences, with emphasis on the Endopterygota

No consensus exists for the homology and terminology of the male genitalia of the Hexapoda despite over a century of debate. Based on dissections and the literature, genital skeletomusculature was compared across the Hexapoda and contrasted with the Remipedia, the closest pancrustacean outgroup. The pattern of origin and insertion for extrinsic and intrinsic genitalic musculature was found to be consistent among the Ectognatha, Protura, and the Remipedia, allowing for the inference of homologies given recent phylogenomic studies. The penis of the Hexapoda is inferred to be derived from medially-fused primary gonopods (gonopore-bearing limbs), while the genitalia of the Ectognatha are inferred to include both the tenth-segmental penis and the ninth-segmental secondary gonopods, similar to the genitalia of female insects which comprise gonopods of the eighth and ninth segments. A new nomenclatural system for hexapodan genitalic musculature is presented and applied, and a general list of anatomical concepts is provided. Novel and refined homologies are proposed for all hexapodan orders, and a series of groundplans are postulated. Emphasis is placed on the Endopterygota, for which fine-grained transition series are hypothesized given observed skeletomuscular correspondences.