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The insect order Blattodea (cockroaches and termites) has drawn substantial research attention for their dietary habits and lifestyle of living with or around humans. In the present study, we focused on the discovery of RNA viruses hidden in Blattodea insects using the publicly available RNA sequencing datasets. Overall, 136 distinctive RNA viruses were identified from 36 Blattodea species, of which more than 70 % were most closely related to the invertebrate-associated viral groups within Picornavirales, Sobelivirales, Bunyaviricetes, Jingchuvirales, Durnavirales, Lispiviridae, Orthomyxoviridae, Permutotetraviridae, Flaviviridae and Muvirales. Several viruses were associated with pathogens of vertebrates (Paramyxoviridae), plants (Tymovirales), protozoa (Totiviridae), fungi (Narnaviridae) and bacteria (Norzivirales). Collectively, 93 complete or near-complete viral genomes were retrieved from the datasets, and several viruses appeared to have remarkable temporal and spatial distributions. Interestingly, the newly identified Periplaneta americana dicistrovirus displayed a remarkable distinct bicistronic genome arrangement from the well-recognized dicistroviruses with the translocated structural and non-structural polyprotein encoding open reading frames over the genome. These results significantly enhance our knowledge of RNA virosphere in Blattodea insects, and the novel genome architectures in dicistroviruses and other RNA viruses may break our stereotypes in the understanding of the genomic evolution and the emergence of potential novel viral species.

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Genetic changes that enabled the evolution of eusociality have long captivated biologists. More recently, attention has focussed on the consequences of eusociality on genome evolution. Studies have reported higher molecular evolutionary rates in eusocial hymenopteran insects compared with their solitary relatives. To investigate the genomic consequences of eusociality in termites, we analysed nine genomes, including newly sequenced genomes from three non-eusocial cockroaches. Using a phylogenomic approach, we found that termite genomes have experienced lower rates of synonymous substitutions than those of cockroaches, possibly as a result of longer generation times. We identified higher rates of non-synonymous substitutions in termite genomes than in cockroach genomes, and identified pervasive relaxed selection in the former (24-31% of the genes analysed) compared with the latter (2-4%). We infer that this is due to reductions in effective population size, rather than gene-specific effects (e.g. indirect selection of caste-biased genes). We found no obvious signature of increased genetic load in termites, and postulate efficient purging of deleterious alleles at the colony level. Additionally, we identified genomic adaptations that may underpin caste differentiation, such as genes involved in post-translational modifications. Our results provide insights into the evolution of termites and the genomic consequences of eusociality more broadly.

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The white-bellied pangolin Phataginus tricuspis (Rafinesque 1821) is a semiarboreal species occurring in tropical sub-Saharan Africa. It is the world's most trafficked African pangolin species based on volumes recorded in seizures. Reintroduction of confiscated live pangolins and ex-situ rearing are being explored worldwide as a conservation action. However, the husbandry of seized animals is challenging as the diet of the white-bellied pangolin is poorly known and little studied. We analyzed the stomach contents of dead white-bellied pangolins from two forest-savanna protected areas. Stomach content samples from 13 white-bellied pangolin specimens contained ~165,000 Arthropoda, mostly Hymenoptera (60.34%) and Blattodea (39.66%). Overall, we identified 39 termite and 105 ant species consumed as prey by pangolins. Individual pangolins examined had fed on a maximum of 31 ant species and 13 termite species. The termite and ant species richness varied significantly across the pangolins' last consumed meal. We recorded 24 ant genera dominated by Crematogaster (relative importance [RI] = 17.28). Out of 18 termite genera recorded, the genus Pseudacanthotermes (RI = 17.21) was the most important prey. Ten ant species were preferentially eaten by white-bellied pangolin, with Crematogaster acis being the most common prey species. Four species of termite were most frequently eaten with Pseudacanthotermes militaris being the most abundant. The mean abundance of ants and termites varied among pangolin individuals. The season did not influence the mean abundance of termites eaten by pangolin individuals. However, ant abundance in stomach contents was significantly higher in the dry season. An improved understanding of pangolin feeding behavior and prey selection may help inform conservation husbandry efforts. For example, nutritional analysis of the food eaten by wild pangolins can guide the development of nutritional diets for captive pangolins.

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Termites are dominant animals of tropical terrestrial ecosystems. Their success is due to their eusocial organization as well as their ability to digest dead plant tissues. While being extremely abundant, the termite diet is poor in crucial nutrients, such as fatty acids. Linoleic acid (LA) is a precursor for many vital biomolecules, and most animals depend on its dietary supply. Termites count among the exceptions known to produce LA de novo, presumably via the action of an unknown Δ12 fatty acyl desaturase (FAD) introducing the second double bond into monounsaturated oleic acid. Here, we search for the evolutionary origin of LA biosynthesis in termites. To this end, we compile the repertoire of FAD homologs from 57 species of termites and their closest relatives, the cockroaches, analyze FAD phylogeny, and identify a potential Δ12 FAD branch, which arose through duplication of a likely Δ9 FAD. We functionally characterize both paralogs and identify the Δ9 activity in the ancestral FAD-A1a and the Δ12 activity responsible for LA biosynthesis in FAD-A1b. Through the combination of homology modeling and site-directed mutagenesis, we pinpoint structural features possibly contributing to the distinct functions, regiospecificities, and substrate preferences of the two enzymes. We confirm the presence of both paralogs in all 36 studied species of the Blattoidea lineage (Blattidae, Lamproblattidae, Cryptocercidae, and termites) and conclude that we identified an evolutionary event important for the ecological success of termites, which took place in their cockroach ancestors roughly 160 My and remained conserved throughout termite diversification into 3,000 extant species.

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Many insects harbor bacterial endosymbionts that supply essential nutrients and enable their hosts to thrive on a nutritionally unbalanced diet. Comparisons of the genomes of endosymbionts and their insect hosts have revealed multiple cases of mutually-dependent metabolic pathways that require enzymes encoded in 2 genomes. Complementation of metabolic reactions at the pathway level has been described for hosts feeding on unbalanced diets, such as plant sap. However, the level of collaboration between symbionts and hosts that feed on more variable diets is largely unknown. In this study, we investigated amino acid and vitamin/cofactor biosynthetic pathways in Blattodea, which comprises cockroaches and termites, and their obligate endosymbiont Blattabacterium cuenoti (hereafter Blattabacterium). In contrast to other obligate symbiotic systems, we found no clear evidence of "collaborative pathways" for amino acid biosynthesis in the genomes of these taxa, with the exception of collaborative arginine biosynthesis in 2 taxa, Cryptocercus punctulatus and Mastotermes darwiniensis. Nevertheless, we found that several gaps specific to Blattabacterium in the folate biosynthetic pathway are likely to be complemented by their host. Comparisons with other insects revealed that, with the exception of the arginine biosynthetic pathway, collaborative pathways for essential amino acids are only observed in phloem-sap feeders. These results suggest that the host diet is an important driving factor of metabolic pathway evolution in obligate symbiotic systems. IMPORTANCE The long-term coevolution between insects and their obligate endosymbionts is accompanied by increasing levels of genome integration, sometimes to the point that metabolic pathways require enzymes encoded in two genomes, which we refer to as "collaborative pathways". To date, collaborative pathways have only been reported from sap-feeding insects. Here, we examined metabolic interactions between cockroaches, a group of detritivorous insects, and their obligate endosymbiont, Blattabacterium, and only found evidence of collaborative pathways for arginine biosynthesis. The rarity of collaborative pathways in cockroaches and Blattabacterium contrasts with their prevalence in insect hosts feeding on phloem-sap. Our results suggest that host diet is a factor affecting metabolic integration in obligate symbiotic systems.

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Manipulator modificaputis Vrsanský and Bechly, 2015 (Manipulatoridae, Corydioidea) is a purported predatory cockroach from Cretaceous Myanmar amber, based on a single male. It is distinctive by the nimble head, elongate pronotum and legs, and particularly by the extraordinarily long maxillary palpi. In the present study, we redescribe Manipulator modificaputis based on six new fossils including males and females, and comment on the original description. The closely related Manipulatoides obscura gen. & sp. nov. is proposed on the basis of five fossils, including males and females. It differs from Manipulator in weaker spination of the legs, including the type-C forefemoral spination instead of the type-A of Manipulator. Some undetermined adults and nymphs are also described. We discuss the ethology of Manipulatoridae and speculate that they might feed on flowers. They are unlikely to be specialized predators since they lack necessary weaponry for capturing prey; in contrast, their unique morphotype appears to be suitable for efficient foraging and locomotion amid flowering twigs. The possibility of being kleptoparasites of the spider-web is also discussed. In addition, regenerated four-segmented tarsi are found from the new species.

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Although 3105 termite species have been documented worldwide, little information is available on those in Thailand. In this review, the Google Scholar search platform and the Scopus and Science Direct databases were used to obtain information on termite species and for georeferencing. The QGIS software was used to create point localities that were overlaid on the Thailand administrative level 1 (province) to map the distribution of termite species in the country based on the World Geodetic System 1984. From the 19 reviewed sources, 44 defined coordinates were identified in 14 provinces across Thailand. Among these 44 coordinates, we found 75 termite species and 83 unknown species of termites; in total, 36 termite species were from the North (6 locations), 33 species were from the Northeast (10 locations), 34 species were from the West (4 locations), 29 species were from the Central region (3 locations), 44 species were from the East (8 locations), and 54 species were from the South (13 locations). The most predominant species in all regions were Globitermes sulphureus, Macrotermes gilvus, Microcerotermes crassus, and Microtermes obesi.

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The most diverse and abundant family of termites, the Termitidae, evolved in African tropical forests. They have since colonised grassy biomes such as savannas. These open environments have more extreme conditions than tropical forests, notably wider extremes of temperature and lower precipitation levels and greater temporal fluctuations (of both annual and diurnal variation). These conditions are challenging for soft-bodied ectotherms, such as termites, to survive in, let alone become as ecologically dominant as termites have. Here, we quantified termite thermal limits to test the hypothesis that these physiological limits are wider in savanna termite species to facilitate their existence in savanna environments. We sampled termites directly from mound structures, across an environmental gradient in Ghana, ranging from wet tropical forest through to savanna. At each location, we quantified both the Critical Thermal Maxima (CTmax ) and the Critical Thermal Minima (CTmin ) of all the most abundant mound-building Termitidae species in the study areas. We modelled the thermal limits in two separate mixed-effects models against canopy cover at the mound, temperature and rainfall, as fixed effects, with sampling location as a random intercept. For both CTmax and CTmin , savanna species had significantly more extreme thermal limits than forest species. Between and within environments, areas with higher amounts of canopy cover were significantly associated with lower CTmax values of the termite colonies. CTmin was significantly positively correlated with rainfall. Temperature was retained in both models; however, it did not have a significant relationship in either. Sampling location explained a large proportion of the residual variation, suggesting there are other environmental factors that could influence termite thermal limits. Our results suggest that savanna termite species have wider thermal limits than forest species. These physiological differences, in conjunction with other behavioural adaptations, are likely to have enabled termites to cope with the more extreme environmental conditions found in savanna environments and facilitated their expansion into open tropical environments.

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Most of our knowledge on insect cuticular hydrocarbons (CHCs) stems from analytical techniques based on gas-chromatography coupled with mass spectrometry (GC-MS). However, this method has its limits under standard conditions, particularly in detecting compounds beyond a chain length of around C40. Here, we compare the CHC chain length range detectable by GC-MS with the range assessed by silver-assisted laser desorption/ionization mass spectrometry (Ag-LDI-MS), a novel and rarely applied technique on insect CHCs, in seven species of the order Blattodea. For all tested species, we unveiled a considerable range of very long-chain CHCs up to C58, which are not detectable by standard GC-MS technology. This indicates that general studies on insect CHCs may frequently miss compounds in this range, and we encourage future studies to implement analytical techniques extending the conventionally accessed chain length range. Furthermore, we incorporate 3D scanned insect body surface areas as an additional factor for the comparative quantification of extracted CHC amounts between our study species. CHC quantity distributions differed considerably when adjusted for body surface areas as opposed to directly assessing extracted CHC amounts, suggesting that a more accurate evaluation of relative CHC quantities can be achieved by taking body surface areas into account.

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The present study shows an updated synoptic list of the 30 known Isoptera of the Arabian Peninsula which are classified under four families and nine genera. Twenty-seven species are hitherto known from the Kingdom of Saudi Arabia (KSA). The present inventory of the termites of Riyadh Province (KSA) indicated three species, Anacanthotermes ochraceous (Burmeister 1839), Psammotermes hypostoma Desneux, 1902 and a rare species, Coptotermes heimi (Wasmann 1902). We present an illustrated key to species based on the soldier caste. Anacanthotermes ochraceous, and P. hypostoma are widely distributed Palearctic species whereas C. heimi seems rare and is a new record for KSA. Distribution maps for the three species are provided based on recently collected material and literature records and remarks on species habitat preference are given.

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The purpose of this paper is to establish the orange head cockroach (Eublaberus posticus) as a useful insect subject for research in comparative psychology by investigating habituation of the light-startle response (LSR). While one goal of comparative psychology is to compare the behavior of a diversity of species, many taxa, including cockroaches, are grossly underrepresented. Our work serves to improve this deficit by investigating habituation learning in the orange head cockroach in four experiments. In our first experiment, we found that LSR, and habituation of LSR, occurs to both lights being turned on and lights being turned off. In our second experiment, we found that the duration of a light did not affect response, and that spontaneous recovery of LSR occurs after 24 h intervals. In our third experiment, we found that the presence of food inhibited LSR. In our final experiment, we found that the rate of LSR habituation decreased as intertrial interval increased, in a manner predicted by established principles of habituation. Our work lays a strong foundation for future research on the behavior of orange head cockroaches as well as learning in cockroaches in general. We hope that our findings help establish cockroaches as practical insect subjects for research in comparative psychology and related fields such as behavior analysis and behavioral ecology.

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The present paper is the third part of a revision of the genus Dziriblatta and treats the nominal subgenus Dziriblatta and its species. The subgenus contains 10 species of which 8 are new to science. The species can be distributed to two species groups: the bolivari-species group with Dz. (Dz.) algerica, Dz. (Dz.) bolivari, Dz. (Dz.) brevisacculata, spec. nov., Dz. (Dz.) curvisetosa, spec. nov., and Dz. (Dz.) pilleata, spec. nov.-and the lobososacculata-species group with Dz. (Dz.) altotuberculata, spec. nov., Dz. (Dz.) lobososacculata, spec. nov., Dz. (Dz.) planotuberculata, spec. nov., Dz. (Dz.) ramososacculata, spec. nov., and Dz. (Dz.) undulata, spec. nov.. The descriptions of the species are complemented by numerous images showing their most important structures, their distribution in southern Spain and Morocco, and their supposed phylogenetic relationships. A determination key allows the discrimination of the males.

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Reduced genetic diversity through inbreeding can negatively affect pathogen resistance. This relationship becomes more complicated in social species, such as social insects, since the chance of disease transmission increases with the frequency of interactions among individuals. However, social insects may benefit from social immunity, whereby individual physiological defenses may be bolstered by collective-level immune responses, such as grooming or sharing of antimicrobial substance through trophallaxis. We set out to determine whether differences in genetic diversity between colonies of the subterranean termite, Reticulitermes flavipes, accounts for colony survival against pathogens. We sampled colonies throughout the United States (Texas, North Carolina, Maryland, and Massachusetts) and determined the level of inbreeding of each colony. To assess whether genetically diverse colonies were better able to survive exposure to diverse pathogens, we challenged groups of termite workers with two strains of a pathogenic fungus, one local strain present in the soil surrounding sampled colonies and another naïve strain, collected outside the range of this species. We found natural variation in the level of inbreeding between colonies, but this variation did not explain differences in susceptibility to either pathogen. Although the naïve strain was found to be more hazardous than the local strain, colony resistance was correlated between two strains, meaning that colonies had either relatively high or low susceptibility to both strains regardless of their inbreeding coefficient. Overall, our findings may reflect differential virulence between the strains, immune priming of the colonies via prior exposure to the local strain, or a coevolved resistance toward this strain. They also suggest that colony survival may rely more upon additional factors, such as different behavioral response thresholds or the influence of a specific genetic background, rather than the overall genetic diversity of the colony.

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The known species of Allacta Saussure Zehntner, 1895 in India are reviewed. Three new species, A. jcenpro sp. nov., A. vellimalai sp. nov., and A. kollimalai sp. nov., are described. All are placed under hamifera species group. The new species can be differentiated from other members of hamifera species group by the pronotal and facial markings, the structure of the male genitalia and other morphological characters. Additional reports to A. kalakadensis Prabakaran Senraj 2019 and A. figurata (Walker, 1871) are provided. A key to the known species of Indian Allacta is provided.

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We describe the first two Blattodea from the early Eocene Palana Formation of the Gurha opencast lignite mine, western Rajasthan, India. Although it is not possible to attribute them to a precise family, these large wings suggest a warm and humid paleoclimate for the area at that time.

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We describe the endemic Tasmanian cockroach, Polyzosteria yingina sp. nov. (Henry), 78 years after it was first documented. Evidence from morphology, biogeography and CO1 barcodes is used to distinguish this species from related mainland Australian taxa it has previously been confused with. Polyzosteria yingina sp. nov. has two strongly allopatric populations: a compact alpine population above 1000m and a dispersed east coastal one at sealevel. However, mitochondrial Control Region D-loop molecular analysis suggests a single species identity for these disparate populations. Detailed internal and external morphological descriptions and photographs of living and preserved type material are presented. We also speculate on some hypotheses which could account for the unusual distribution of this charismatic insect.

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Eminespina burma gen. et sp. nov., is described and illustrated based on a female embedded in Cretaceous Burmese amber of Cenomanian age. Autapomorphic are three unique spines distributed anterior quarter of pronotum from longer posterior part. The new evidence of Batesian mimicry in the insect fossil record is briefly discussed.

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Termites are intimately tied to the microbial world, as they utilize their gut microbiome for the conversion of plant cellulose into necessary nutrients. Subterranean termites must also protect themselves from the vast diversity of harmful microbes found in soil. However, not all soil microbes are harmful, such as Streptomyces and methanotrophic bacteria that some species of termites harbor in complex nest structures made of fecal material. The eastern subterranean termite, Reticulitermes flavipes, has a simple nest structure consisting of fecal lined galleries. We tested the hypothesis that R. flavipes maintains a select microbial community in its nests to limit the penetration of harmful soilborne pathogens and favor the growth of beneficial microbes. Using Illumina sequencing, we characterized the bacterial and fungal communities in the surrounding soil, in the nest galleries, and on the cuticle of workers. We found that the galleries provide a more beneficial microbial community than the surrounding soil. Bacterial and fungal diversity was highest in the soil, lower in the galleries, and least on the cuticle. Bacterial communities clustered together according to the substrate from which they were sampled, but this clustering was less clear in fungal communities. Most of the identified bacterial and fungal taxa were unique to one substrate, but the soil and gallery communities had very similar phylum-level taxonomic profiles. Notably, the galleries of R. flavipes also harbored both the potentially beneficial Streptomyces and the methanotrophic Methylacidiphilales, indicating that these microbial associations in fecal material pre-date the emergence of complex fecal nest structures. Surprisingly, several pathogenic groups were relatively abundant in the galleries and on the cuticle, suggesting that pathogens may accumulate within termite nests over time while putatively remaining at enzootic level during the lifetime of the colony.

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Cockroaches have existed for 300 million years and more than 4600 extant species have been described. Throughout their evolution, cockroaches have been associated with bacteria, and today Blattabacterium species flourish within specialized bacteriocytes, recycling nitrogen from host waste products. Cockroaches can disseminate potentially pathogenic bacteria via feces and other deposits, particularly members of the family Enterobacteriaceae, but also Staphylococcus and Mycobacterium species, and thus, they should be cleared from sites where hygiene is essential, such as hospitals and kitchens. On the other hand, cockroaches also carry bacteria that may produce metabolites or proteins with potential industrial applications. For example, an antibiotic-producing Streptomyces strain was isolated from the gut of the American cockroach Periplaneta americana. Other cockroach-associated bacteria, including but not limited to Bacillus, Enterococcus, and Pseudomonas species, can also produce bioactive metabolites that may be suitable for development as pharmaceuticals or plant protection products. Enzymes that degrade industrially relevant substrates, or that convert biomasses into useful chemical precursors, are also expressed in cockroach-derived bacteria and could be deployed for use in the food/feed, paper, oil, or cosmetics industries. The analysis of cockroach gut microbiomes has revealed a number of lesser-studied bacteria that may form the basis of novel taxonomic groups. Bacteria associated with cockroaches can therefore be dangerous or useful, and this review explores the bacterial clades that may provide opportunities for biotechnological exploitation. KEY POINTS: • Members of the Enterobacteriaceae are the most frequently cultivated bacteria from cockroaches. • Cultivation-independent studies have revealed a diverse community, led by the phyla Bacteroidetes and Firmicutes. • Although cockroaches may carry pathogenic bacteria, most strains are innocuous and may be useful for biotechnological applications. Graphical abstract.

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Neuropeptides are among the structurally most diverse signaling molecules and participate in intercellular information transfer from neurotransmission to intrinsic or extrinsic neuromodulation. Many of the peptidergic systems have a very ancient origin that can be traced back to the early evolution of the Metazoa. In recent years, new insights into the evolution of these peptidergic systems resulted from the increasing availability of genome and transcriptome data which facilitated the investigation of the complete neuropeptide precursor sequences. Here we used a comprehensive transcriptome dataset of about 200 species from the 1KITE initiative to study the evolution of single-copy neuropeptide precursors in Polyneoptera. This group comprises well-known orders such as cockroaches, termites, locusts, and stick insects. Due to their phylogenetic position within the insects and the large number of old lineages, these insects are ideal candidates for studying the evolution of insect neuropeptides and their precursors. Our analyses include the orthologs of 21 single-copy neuropeptide precursors, namely ACP, allatotropin, AST-CC, AST-CCC, CCAP, CCHamide-1 and 2, CNMamide, corazonin, CRF-DH, CT-DH, elevenin, HanSolin, NPF-1 and 2, MS, proctolin, RFLamide, SIFamide, sNPF, and trissin. Based on the sequences obtained, the degree of sequence conservation between and within the different polyneopteran lineages is discussed. Furthermore, the data are used to postulate the individual neuropeptide sequences that were present at the time of the insect emergence more than 400 million years ago. The data confirm that the extent of sequence conservation across Polyneoptera is remarkably different between the different neuropeptides. Furthermore, the average evolutionary distance for the single-copy neuropeptides differs significantly between the polyneopteran orders. Nonetheless, the single-copy neuropeptide precursors of the Polyneoptera show a relatively high degree of sequence conservation. Basic features of these precursors in this very heterogeneous insect group are explained here in detail for the first time.

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