Phylogeny of Meloini blister beetles (Coleoptera, Meloidae) and patterns of island colonization in the Western Palaearctic

Molecular diversity of Pseudoscorpiones in southern High Appalachian leaf litter

The Pseudoscorpiones fauna of North America is diverse, but in regions like the southern Appalachian Mountains, they are still poorly documented with respect to their species diversity, distributions and ecology. Several families have been reported from these mountains and neighbouring areas. Here we analyse barcoding data of 136 specimens collected in leaf litter, most of them from high-elevation coniferous forest. We used ASAP as a species delimitation method to obtain an estimation of the number of species present in the region. For this and based on interspecific genetic distance values previously reported in Pseudoscorpions, we considered three different genetic Kimura two-parameter distance thresholds (3%/5%/8%), to produce more or less conservative estimates. These distance thresholds resulted in 64/47/27 distinct potential species representing the families Chthoniidae (33/22/12 species) and Neobisiidae (31/25/15) and at least six different genera within them. The diversity pattern seems to be affected by the Asheville Depression, a major biogeographic barrier in this area, with a higher diversity to the west of this geographic feature, particularly within the family Neobisiidae. The absence of representatives from other families amongst our studied samples may be explained by differences in their ecological requirements and occupation of different microhabitats.

The complete mitochondrial genome of Meloeproscarabaeus (Coleoptera, Meloidae): genome descriptions and phylogenetic inferences

Oil beetles are meloids, which are characterised for their cleptoparasitic habits in bee nests and oily fluid of cantharidin that causes blistering and swelling of the skin. The complete mitochondrial genome of Meloeproscarabaeus is determined using the next-generation sequencing technology and its genomic characteristics are described. The 15,653-bp long genome is a circular molecule consisting of 13 protein-coding genes (PCG), 22 transport RNA, two ribosomal RNA, and a control region. The A + T bias of the mitochondrial genome is manifested in the complete sequence and the codon usage of protein-coding genes. The genetic distance within and between genera is calculated to confirm the taxonomic status of M.proscarabaeus. The phylogenetic relationships among 15 available meloid taxa are inferred by the maximum likelihood (ML) method based on 13 mitochondrial PCGs. The ML trees resulting from nucleotide and amino acid datasets recover both the monophyly of Meloe and Epicauta and the polyphyly comprising Hycleus and Mylabris. This study provides the first description of a mitochondrial genome belonging to the genus Meloe. The mitochondrial genome sequence and its characteristics are expected to be conducive to future studies on taxonomy, systematics, and molecular phylogenetics of the family Meloidae.

A new systematic arrangement for the blister beetle genus Eurymeloe (Meloini, Meloidae, Coleoptera) with the description of a new species from Spain

The taxonomic status and subgeneric arrangement of the genus Eurymeloe have been debated for decades. In this work, the internal taxonomy of Eurymeloe is redefined by recognising three subgenera: Eurymeloe for the former Eurymeloebrevicollis species group, Coelomeloe for Eurymeloetuccia, and Bolognaia Ruiz, García-París, Sánchez-Vialas & Recuero, subgen. nov., to accommodate the species of the formerly recognised Eurymeloerugosus species group. Additionally, a new species of the newly described subgenus Bolognaia is described from the Iberian Peninsula based on molecular and morphological traits. The new species, Eurymeloe (Bolognaia) orobatessp. nov., can be distinguished from all other species of Eurymeloe by the following combination of morphological traits: dispersed brownish setae over the body that are arranged in small tufts on the abdominal terga; a small, very transverse pronotum that presents a unique macrosculpture; a deeply and densely punctured integument of the head and pronotum; and the very rugose elytra. The characters displayed by E.orobates suggest that the species groups that were previously defined and recognised for Eurymeloe, and that are now integrated within the newly erected subgenus Bolognaia, are non-monophyletic.

Mitogenomics and hidden-trait models reveal the role of phoresy and host shifts in the diversification of parasitoid blister beetles (Coleoptera: Meloidae)

Changes in life history traits are often considered speciation triggers and can have dramatic effects on the evolutionary history of a lineage. Here, we examine the consequences of changes in two life history traits, host‐type and phoresy, in the hypermetamorphic blister beetles, Meloidae. Subfamilies Nemognathinae and Meloinae exhibit a complex life cycle involving multiple metamorphoses and parasitoidism. Most genera and tribes are bee‐parasitoids, and include phoretic or nonphoretic species, while two tribes feed on grasshopper eggs. These different life strategies are coupled with striking differences in species richness among clades. We generated a mitogenomic phylogeny for Nemognathinae and Meloinae, confirming the monophyly of these two clades, and used the dated phylogeny to explore the association between diversification rates and changes in host specificity and phoresy, using state‐dependent speciation and extinction (SSE) models that include the effect of hidden traits. To account for the low taxon sampling, we implemented a phylogenetic‐taxonomic approach based on birth‐death simulations, and used a Bayesian framework to integrate parameter and phylogenetic uncertainty. Results show that the ancestral hypermetamorphic Meloidae was a nonphoretic bee‐parasitoid, and that transitions towards a phoretic bee‐parasitoid and grasshopper parasitoidism occurred multiple times. Nonphoretic bee‐parasitoid lineages exhibit significantly higher relative extinction and lower diversification rates than phoretic bee‐and grasshopper‐parasitoids, but no significant differences were found between the latter two strategies. This suggests that Orthopteran host shifts and phoresy contributed jointly to the evolutionary success of the parasitoid meloidae. We also demonstrate that SSE models can be used to identify hidden traits coevolving with the focal trait in driving a lineage's diversification dynamics.

The Strait of Gibraltar is an ineffective palaeogeographic barrier for some flightless darkling beetles (Coleoptera: Tenebrionidae: Pimelia)

The geographic distribution of a species is shaped by its biology and by environmental and palaeogeographic factors that interact at different spatial-temporal scales, which leads to distributions and diversification patterns observed between and within lineages. The darkling beetle genus Pimelia has been diversifying for more than 31.2 Mya showing different colonization patterns after the opening of the Gibraltar Strait 5 Mya. Three of the 14 subgenera of Pimelia have populations on both sides of the Strait. Through extensive sampling and the analysis of three molecular markers, we determine levels of intra- and interspecific genetic variation, identify evolutionary lineages in subgenera, estimate their temporal origin and distribution ranges and discuss the historical basis for the geographic and diversification patterns of Pimelia around the Strait. This single geographical feature acted both as a barrier and as a dispersal route for different Pimelia species. The Strait has represented a strong barrier for the subgenus Magrebmelia since the Middle Miocene. However, the subgenera Amblyptera and Amblypteraca share repetitive signatures of post-Messinian colonization across the Strait, possibly driven by stochastic or ‘catastrophic’ events such as tsunamis. Our demographic analyses support Wallace’s hypothesis on insect dispersal stochasticity. Some taxonomic changes, including the designation of a lectotype for Pimelia maura, are also proposed.

Morphological revision of the Palaearctic species of the nominate subgenus Meloe Linnaeus, 1758 (Coleoptera, Meloidae), with description of ten new species

A morphological revision of the Meloe (Meloe) species from the Palaearctic Region, including the Transitional Chinese area is published. Groups and subgroups of species from the Palaearctic Region are defined for the first time and relationships with Afrotropical and Nearctic groups of species are discussed. Twenty-five species are considered, mostly after the examination of the types, with brief descriptions and figures of diagnostic characters. Ten species, from China and the Himalayan region, are described: Meloe chinensis n. sp., M. distincticornis n. sp., M. himalayensis n. sp., M. kashmirensis n. sp., M. kaszabi n. sp., M. lateantennatus n. sp., M. orientalis n. sp., M. poggii n. sp., M. shapovalovi n. sp., and M. xuhaoi n. sp. Both Meloe aegyptius and M. rathjensi are referred to M. proscarabaeus as subspecies. Four new synonymies are pointed out: M. sapporensis Kno, 1936 and M. tenuipes Jakowlew, 1897 = M. proscarabaeus exaratus Faldermann, 1832; M. medogensis Tan, 1981 = M. arunachalae Saha, 1979; M. patellicornis Fairmaire, 1887 = M. lobatus Gebler, 1832. Lectotype of M. subcordicollis is designated. M. formosensis is tentatively maintained as distinct species, with the suggestion that it could be a subspecies of M. gracilior. Meloe menoko is tentatively included in the intraspecific variability of M. auriculatus, a formal synonymy will be made by other authors. Meloe poteli is not considered in this revision, being the type is unavailable; other species (M. modestus, M. longipennis, M. elegantulus), previously considered in the nominate subgenus are excluded. A key to both sexes of the species is carried out and a catalogue of localities is recorded as Appendix 1. Ecological information about phenology, elevation range, host plants, is summarized in a table, and some biogeographical remarks are proposed.

Proctodeal extrusion as a defensive behavioral response in blister beetles (Coleoptera: Meloidae)

Defensive mechanisms in blister beetles (Coleoptera: Meloidae) include a wide variety of behavioral responses, chemical defense, and conspicuous external colorations. Although some of these mechanisms have been previously described, proctodeal extrusion, a defensive behavior involving the extrusion of inner abdominal membranes from the proctodeal region which appear intensely red or orange colored when the hemolymph is seen through them, has not been reported to date. Here, we tested the ability to display proctodeal extrusion in response to threat stimuli in wild populations of three blister beetle species inhabiting Central Spain: Berberomeloe majalis (Linnaeus, 1758), Berberomeloe comunero Sánchez-Vialas, García-París, Ruiz & Recuero, 2020, and Physomeloe corallifer (Germar, 1818). In addition, we observed and recorded various other defensive behaviors such as immobility, antennal threat display, autohemorrhage (reflex bleeding), defecation, and thanatosis (death feigning). The frequency at which proctodeal extrusion was observed differed among species, as did the stress intensity needed for extrusion and the probability of proctodeal extrusion in response to a particular threatening stimulus. Our findings indicate that, although proctodeal extrusion might be a widespread potential defensive mechanism in Meloidae, the ability to elicit it is not generalized across lineages. Physomeloe and Berberomeloe are endemic to the semi-arid Mediterranean region, and species adapted to such a climate would have developed strategies that limit hydric stress such as proctodeal extrusion, which mirrors the effect of autohemorrhage but without the fluid loss.