A second fossil species of the enigmatic rove beetle genus Charhyphus in Eocene Baltic amber, with implications on the morphology of the female genitalia (Coleoptera: Staphylinidae: Phloeocharinae)

ABSTRACT Phloeocharinae is a small and likely non-monophyletic subfamily of rove beetles. The enigmatic genus Charhyphus Sharp, 1887 has long been placed in Phloeocharinae, whereas recent studies have found it to be phylogenetically very distant from the core members of this subfamily, suggesting the possibility that it actually deserves its own separate subfamily status. So far, the sole definitive fossil record for Charhyphus is known based on a single male from Eocene Baltic amber as represented by †Charhyphus balticus Shavrin, 2020. Here, we describe and illustrate another new Charhyphus species, †Charhyphus serratus sp. nov. Yamamoto & Shavrin, from Baltic amber based on a well-preserved female fossil. Considering the general proportions of the body and the head, this new species is most similar to †C. balticus. The new species differs from all known species by the development of strong serration of the lateral edges of the pronotum and features of the shape of the apical margin of the mesoventrite. By using X-ray micro-computed tomography, we succeeded in visualising not only the general habitus but also each individual body part, recovering a previously undocumented sclerite on the female internal genital segments in the genus. Morphological features of extinct and extant species of Charhyphus are briefly discussed. Figures of all extant Charhyphus species and a key for the genus are also provided. Our study is important for considering possible higher palaeodiversity, more common occurrence, and palaeobiogeography of Charhyphus.

Structure of an ant-myrmecophile-microbe community

Superorganismal ant colonies play host to a menagerie of symbiotic arthropods, termed myrmecophiles, which exhibit varying degrees of social integration into colony life. Such systems permit examination of how animal community interactions influence microbial assemblages. Here, we present an ecologically and phylogenetically comprehensive characterization of an ant-myrmecophile-microbe community in Southern California. Using 16S rRNA profiling, we find that microbiotas of the velvety tree ant (Liometopum occidentale) and its cohort of myrmecophiles are distinguished by species-specific characteristics but nevertheless bear signatures of their behavioral interactions. We found that the host ant microbiome was diverse at all taxonomic levels; that of a myrmecophilous cricket was moderately diverse, while microbiotas of three myrmecophilous rove beetles (Staphylinidae), which have convergently evolved symbiosis with Liometopum, were dominated by intracellular endosymbionts. Yet, despite these compositional differences, similarities between ant and myrmecophile microbiotas correlated with the nature and intimacy of their behavioral relationships. Physical interactions such as grooming and trophallaxis likely facilitate cross-species extracellular microbial sharing. Further, phylogenetic comparisons of microbiotas from myrmecophile rove beetles and outgroups revealed a lack of co-cladogenesis of beetles and intracellular endosymbionts, and limited evidence for convergence among the myrmecophiles' intracellular microbiotas. Comparative genomic analyses of the dominant Rickettsia endosymbiont of the most highly socially integrated myrmecophile imply possible functions unrelated to nutrient-provisioning in the host beetle's specialized lifestyle. Our findings indicate that myrmecophile microbiotas evolve largely independently of the constraints of deep evolutionary history, and that the transition to life inside colonies, including social interactions with hosts, plays a significant role in structuring bacterial assemblages of these symbiotic insects.

Tachinus Laticollis Grav. (Coleoptera, Staphylinidae, Tachyporinae) – a new representative of Tachiporins in the fauna of the Republic of Moldova

The paper presents the approach of researches on the species Tachinus laticollis Gravenhorst, 1802 (Coleoptera, Staphylinidae, Tachyporinae) identified as a new species for the fauna of the Republic of Moldova. The tachiporin specimen was collected at 05.03.2016 in the cattle manure in the pasture from Cocieri village, Dubasari District. The principal method of collecting was extraction by applying the flotation method. In the context of this study, the paper refers in more detail to the species in the collection of Staphylinidae within the Museum of Entomology of the Institute of Zoology, during the applied research (2015-2017). Also, to the analysis of rove beetles material extracted from samples accumulated during study, data on the systematic classification of the species, geographical distribution, bioecology, morphology, illustrative presentation.

Further evidence of Cretaceous termitophily: Description of new termite hosts of the trichopseniine Cretotrichopsenius (Coleoptera: Staphylinidae), with emendations to the classification of lower termites (Isoptera)

Termites (Isoptera) are among the most ecologically ubiquitous of terrestrial eusocial insects and provide an attractive environment for symbionts, which have evolved numerous times independently, and in lineages as diverse as millipedes and beetles. Previous studies reported the discovery of unequivocal termitophily in mid-Cretaceous amber from northern Myanmar, providing evidence that pushed the origin of termitophily back into the Mesozoic. Here we report the discovery of two more pieces of Cretaceous amber containing individuals of the trichopseniine rove beetle Cretotrichopsenius burmiticus Cai et al., 2017 (Staphylinidae: Aleocharinae: Trichopseniini) preserved together with their potential host termites, providing further evidence regarding the association between these two insect lineages. Two new termite species and genera are described as putative hosts for C. burmiticus: Arceotermes hospitis Engel & Jiang, gen. et sp. nov. and Tanytermitalis philetaerus Engel & Cai, gen. et sp. nov. Each is included in a new family, Arceotermitidae Engel, fam. nov. (type genus: Arceotermes Engel & Jiang, gen. nov.), and Tanytermitidae Engel, fam. nov. (type genus: Tanytermes Engel et al., 2007). In order to better characterize these two families the classification of lower Isoptera and clade Xylophagodea (= Cryptocercidae + Isoptera) is emended with the following new taxa: Idanotermitinae Engel, subfam. nov.; Melqartitermitidae Engel, fam. nov.; Mylacrotermitidae Engel, fam. nov.; Krishnatermitidae Engel, fam. nov.; Cosmotermitinae Engel, subfam. nov.; Hodotermopsinae Engel, subfam. nov.; Artisoptera Engel, minord. nov.; Cryptocercaptera Engel, infraord. nov. Lower termites were remarkably diverse during the mid-Cretaceous but declined in diversity considerably by the Palaeogene. The fossil rove beetle Cretotrichopsenius Cai et al., 2017 currently provides the earliest definitive evidence of termitophily and the complex association between rove beetles and termites.

Cave-adapted beetles from continental Portugal

The cave biodiversity of continental Portugal faces tremendous conservation challenges, mostly linked to their direct destruction and contamination infiltrating from the surface. Beetles are the most diverse insects and one of the most diverse arthropod groups in caves of Portugal. We present the IUCN Red List profiles for the cave-adapted beetles from continental Portugal, all endemic to their respective geological units and massifs. Ground beetles (Carabidae) are the most diverse family of cave-adapted beetles in continental Portugal, followed by rove beetles (Staphylinidae). Beetles in caves of Portugal are mostly terrestrial and only one species is known to have evolved to live in groundwater. Trechus is the most diverse genus with four species, followed by Domene with three species and by Speonemadus and Iberoporus, both with one cave-adapted species. The aim of this contribution is to assess all endemic cave-adapted species of beetles from continental Portugal and to support their specific protection, to promote adequate management of surface habitats and the establishment of priority areas for conservation. The main biodiversity erosion drivers that are impacting the conservation of the studied species are pollution infiltrating from the surface, urbaniation, modifications of the natural habitat for touristic purposes and mining, quarrying and energy production infrastructures. This document can be used in spatial planning and territory management in karst, based on the current scientific knowledge.

Rove beetles of Belarus: the genus Oligota Mannerheim, 1830 (Coleoptera: Staphylinidae: Aleocharinae)

An annotated list of eight species of the genus Oligota collected in Belarus in 1982–2020 is given. Three species, O. inexspectata Williams, 1994, O. pseudoparva Williams, 1972 and O. ruficornis Sharp, 1870, are new for the Belarusian fauna. The data on distri¬bution and ecology of these rove beetles is also given.

Silica nanoparticles as pesticide against insects of different feeding types and their non-target attraction of predators

The agricultural use of silica (SiO2) nanoparticles (NPs) has the potential to control insect pests while the safety and tritrophic effects on plants and beneficial natural enemies remains unknown. Here, we evaluate the effects of silica NPs on insect pests with different feeding niches, natural enemies, and a plant. Silica NPs were applied at different concentrations (75–425 mg/L) on field-cultivated faba bean and soybean for two growing seasons. The faba bean pests, the cowpea aphid Aphis craccivora and the American serpentine leafminer Liriomyza trifolii, and the soybean pest, the cotton leafworm Spodoptera littoralis, were monitored along with their associated predators. Additional laboratory experiments were performed to test the effects of silica NPs on the growth of faba bean seedlings and to determine whether the rove beetle Paederus fuscipes is attracted to cotton leafworm-infested soybean treated with silica NPs. In the field experiments, silica NPs reduced the populations of all three insect pests and their associated predators, including rove beetles, as the concentration of silica NPs increased. In soybean fields, however, the total number of predators initially increased after applying the lowest concentration. An olfactometer-based choice test found that rove beetles were more likely to move towards an herbivore-infested plant treated with silica NPs than to a water-treated control, suggesting that silica NPs enhance the attraction of natural enemies via herbivore-induced plant volatiles. In the laboratory, while silica NPs inhibited the development of faba bean roots at 400 mg/L, they did not affect germination percentage, germination time, shoot length, or vigor index compared to the control.

Spatial and temporal variation of epigaeic beetle assemblages (Coleoptera, Carabidae, Staphylinidae) in aspen-dominated mixedwood forests across north-central Alberta

Epigaeic beetle assemblages were surveyed using continuous pitfall trapping during the summers of 1992 and 1993 in six widely geographically distributed locations in Alberta’s aspen-mixedwood forests prior to initial forest harvest. Species composition and turnover (β-diversity) were evaluated on several spatial scales ranging from Natural Regions (distance between samples 120–420 km) to pitfall traps (40–60 m). A total of 19,885 ground beetles (Carabidae) representing 40 species and 12,669 rove beetles (non-AleocharinaeStaphylinidae) representing 78 species was collected. Beetle catch, species richness, and diversity differed significantly among the six locations, as did the identity of dominant species. Beetle species composition differed significantly between the Boreal Forest and Foothills Natural Regions for both taxa. Staphylinidae β-diversity differed significantly between Natural Regions, whereas Carabidae β-diversity differed among locations. Climate variables such as number of frost-free days, dry periods, and mean summer temperatures were identified as significant factors influencing beetle assemblages at coarse spatial scales, whereas over- and understory vegetation cover, litter depth, shade, slope, and stand age influenced beetle assemblages at finer spatial scales. Significant interannual variation in assemblage structure was noted for both taxa. Because composition of epigaeic beetle assemblages differed across spatial scales, forest management strategies based only on generalized understanding of a single location will be ineffective as conservation measures. In addition, site history and geographic variation significantly affect species distributions of these two beetle families across the landscape. Thus, we underscore Terry Erwin’s suggestion that biodiversity assessments focused on species assemblages at different spatial scales provide a sound approach for understanding biodiversity change and enhancing conservation of arthropod biodiversity.

DNA-barcode and endophallus morphology delimit congruent species in a systematic revision of the oxyporine rove beetles of Russia (Coleoptera: Staphylinidae: Oxyporinae)

Rigorous species delimitation is a challenge in biology and systematics in particular. In insects, male genitalia traditionally, and the barcoding region of the CO1 gene recently, are the main markers to identify species, even though a standalone use of CO1 for that is often criticized. In our systematic revision of the mycophagous and in other ways peculiar oxyporine rove beetles of Russia, the legacy alpha-taxonomy could not be improved by traditional investigation of genitalia as they are unusually character-poor in this group. Using phylogenetic inference and ancestral state reconstruction, we demonstrate that CO1 and endophallus are useful markers for species delimitation in Oxyporus. We also show that many morphological traits previously used for species delimitation in Oxyporus are in fact highly variable and thus inconsistent. We hypothesize that in Oxyporus diversification of the endophallic structures is driven by intense intra- and inter-species interactions of multiple individuals co-occurring in narrow spaces inside fungal bodies during mating. Our results encourage broader use of both markers, especially easy-to-generate dna barcodes, for the desired alpha-taxonomical work in Oxyporinae globally. The revision revealed 10 species of Oxyporus in the fauna of the Russian Federation; eliminated erroneous species records; established two new synonyms, Oxyporus (Oxyporus) basicornis Cameron, 1930 = O. (O.) aequicollis Bernhauer, 1935, syn.nov. = O. (O.) parvus Lee et al., 2020, syn. nov.; and raised the hypothesis that O. (O.) aokii Dvořák, 1956, O. (O.) basiventris Jarrige, 1948 and O. (O.) kobayashii Hayashi, 2015 are conspecific with O. (O.) maxillosus Fabricius, 1793. Lectotypes are designated for O. (O.) basicornis Cameron, 1930, O. (O.) germanus Sharp, 1889, O. (O.) niger Sharp, 1889, and O. (O.) triangulus Sharp, 1889. Comprehensive taxonomic treatment and an identification key are provided for all species.