Revisiting the insect mitochondrial molecular clock: the mid-Aegean trench calibration

Genetic diversity, population structure and ecological niche modeling of Thyrinteina arnobia (Lepidoptera: Geometridae), a native Eucalyptus pest in Brazil

Thyrinteina arnobia (Lepidoptera: Geometridae) is a native American species. Despite its historical importance as an insect pest in Eucalyptus plantations, more information is needed regarding the population diversity, demography, and climatic variables associated with its distribution in different regions of Brazil. We used a phylogeographic approach to infer the genetic diversity, genetic structure, and demographic parameters of T. arnobia. We also conducted an ecological niche modeling (ENM) to predict suitable areas for T. arnobia occurrence in Brazil and other countries worldwide. Although T. arnobia populations have low genetic diversity in Brazil, we identified mitochondrial haplogroups predominating in different Brazilian regions and high ФST and ФCT values in AMOVA, suggesting a low frequency of insect movement among these regions. These results indicate that outbreaks of T. arnobia in Eucalyptus areas in different regions of Brazil are associated with local or regional populations, with no significant contribution from long-distance dispersal from different regions or biomes, suggesting that pest management strategies would be implemented on a regional scale. In Brazil, the demographic and spatial expansion signals of T. arnobia seem to be associated with the history of geographical expansion of Eucalyptus plantations, a new sustainable host for this species. ENM indicated that isothermality and annual rainfall are critical climatic factors for the occurrence of T. arnobia in tropical and subtropical areas in the Americas. ENM also suggested that T. arnobia is a potential pest in Eucalyptus areas in all Brazilian territory and in regions from Africa, Asia, and Oceania.

The Fast Evolution of the Stenobothrini Grasshoppers (Orthoptera, Acrididae, and Gomphocerinae) Revealed by an Analysis of the Control Region of mtDNA, with an Emphasis on the Stenobothrus eurasius Group

The two cryptic grasshopper species of the genus Stenobothrus, S. eurasius and S. hyalosuperficies, demonstrate different acoustic behavior despite a strong similarity in morphology. A hybridization between these species is possible in the contact zone; however, there are little molecular data about the relationships of these species. The analysis of the mtDNA control region (CR) reveals that haplotypes of S. hyalosuperficies have more in common with the more distant Stenobothrus species than with the closely related S. eurasius. In the contact zone, S. eurasius has mt-haplotypes shared with S. hyalosuperficies, which might indicate an introgression of mtDNA from S. hyalosuperficies to the S. eurasius gene pool. We also analyze the structure and evolutionary rate of the mtDNA CR for the Stenobothrus genus and estimate the time of divergence of the species within the genus. The phylogenetic tree of the tribe Stenobothrini reconstructed with either the CR or COI gave the same four groups. The phylogenetic tree of the Stenobothrus genus has a star-like topology with each mtDNA haplotype found in any analyzed species, except S. eurasius, which forms a separate branch. The maximum degree of incomplete lineage sorting can demonstrate either ancestral polymorphism or introgression.

Cryptic diversity and phylogeographic patterns of Mediodactylus species in the Eastern Mediterranean region

Cryptic diversity poses a great obstacle in our attempts to assess the current biodiversity crisis and may hamper conservation efforts. The gekkonid genus Mediodactylus, a well-known case of hidden species and genetic diversity, has been taxonomically reclassified several times during the last decade. Focusing on the Mediterranean populations, a recent study within the M. kotschyi species complex using classic mtDNA/nuDNA markers suggested the existence of five distinct species, some being endemic and some possibly threatened, yet their relationships have not been fully resolved. Here, we generated genome-wide SNPs (using ddRADseq) and applied molecular species delimitation approaches and population genomic analyses to further disentangle these relationships. Τhe most extensive nuclear dataset, so far, encompassing 2,360 loci and ∼ 699,000 bp from across the genome of Mediodactylus gecko, enabled us to resolve previously obscure phylogenetic relationships among the five, recently elevated, Mediodactylus species and to support the hypothesis that the taxon includes several new, undescribed species. Population genomic analyses within each of the proposed species showed strong genetic structure and high levels of genetic differentiation among populations.

Evolution of secondary metabolites, morphological structures and associated gene expression patterns in galls induced by four closely related aphid species on a host plant species

Gall-forming insects induce various types of galls on their host plants by altering gene expression in host plant organs, and recent studies have been conducted for gene expression in galls. However, the evolutionary trajectories of gene expression patterns and the resulting phenotypes have not yet been studied using multiple related species. We investigated the speciation and the diversification process of galls induced by four closely related aphid species (Hormaphidini) on a host plant species (Hamamelis japonica) by examining the phylogenetic congruence between the geographical divergences of aphids and the host plant, and by comparing their gene expression patterns and resulting phenotypes. Phylogenetic analysis of aphids and the host plant showed that geographical isolation among host plant populations has interrupted gene flow in aphids and accelerated the speciation process. The concentration of phenolics and the complexity of the internal structure of galls were correlated with the expression levels of genes for the biosynthesis of phenolics and morphogenesis respectively. These results suggest that the expression levels of genes for the biosynthesis of phenolics and morphogenesis have evolutionarily increased in galls accelerated by the speciation process of aphids due to the distribution change of the host plant, leading to the related phenotypic evolution. Our study showed the evolutionary process of phenotypic traits in galls in the wild from both gene expression and actual phenotype levels.

Demographic inference from the mt-DNA COI gene and wing geometry of Culex gelidus (Diptera: Culicidae), an important vector of Japanese encephalitis in Thailand

Culex gelidus (Diptera: Culicidae), an important vector of the Japanese encephalitis virus (JEV), contributes to human viral encephalitis in many Asian countries, including Thailand. This study represents the first investigation of the demographic patterns of Cx. gelidus populations in Thailand using cytochrome c oxidase subunit I (COI) gene analysis and wing geometric morphometrics (GM). Mosquitoes were collected from 10 provinces across six regions of Thailand in 2022. Analysis of the COI sequences (n = 182) indicated high haplotype diversity (0.882) and low nucleotide diversity (0.006), with 72 haplotypes identified. The haplotype network demonstrated no profound splits among the geographic populations. Neutral tests, including Tajima's D and Fu's Fs, displayed negative values, with a significant result observed for Fu's Fs (-33.048, p < 0.05). The mismatch distribution analysis indicated that the population does not statistically deviate from a model of sudden population expansion (SSD = 0.010, p > 0.05; Rg = 0.022, p > 0.05). The estimations suggest that the Cx. gelidus population in Thailand began its expansion approximately between 459,243 and 707,011 years ago. The Mantel test showed no significant relationship between genetic and geographic distances (r = 0.048, p > 0.05). Significant phenotypic differences (based on wing shape) were observed among most populations. Additionally, in this study, we found no significant relationships between phenotypic and genetic distances (r = 0.250, p > 0.05). Understanding the genetic and morphological dynamics of Cx. gelidus is vital for developing targeted surveillance and vector control measures. This knowledge will also help to predict how future environmental changes might affect these populations, thereby informing long-term vector management strategies.

Phylogeography of Parnassius citrinarius Based on Mitochondrial DNA Reveals Large Differences in Genetic Structure between the Eastern and Western Japan

The Japanese Archipelago hosts a rich butterfly fauna, and elucidating the genetic structures of multiple species is necessary to clarify their formation processes. This study aimed to reveal the genetic structure and distribution formation process of Parnassius citrinarius, which is widely distributed across the Japanese Archipelago from Hokkaido to Shikoku, through phylogeographic analysis based on the mitochondrial cytochrome c oxidase subunit I (COI) gene sequence. Thirty haplotypes were revealed from 311 individuals from 47 sites, indicating significant differences in the genetic structures between the eastern and western parts of the Japanese Archipelago. In Eastern Japan, multiple genetic clusters were found, with some sites harboring two clusters. The divergence times among populations in Eastern Japan were relatively recent, and no genetic differentiation was observed between regions, including between Hokkaido and Honshu, which are separated by a narrow strait. In contrast, in Western Japan, including Shikoku, unique genetic clusters were observed in each region. The phylogenetic relationships among populations were regionally clustered, and the divergence times were relatively ancient. The distribution and genetic structure of P. citrinarius in the Japanese Archipelago have been significantly influenced by temperature fluctuations and the presence of geographical barriers during the Pleistocene glacial-interglacial cycles, including the potential formation of refugia in Western Japan.

Integrating wing morphometrics and mitochondrial DNA analysis to assess the filaria vector Mansonia uniformis (Diptera: Culicidae) populations in Thailand

Mansonia uniformis (Diptera: Culicidae) is recognized as a vector of Brugia malayi and has been reported to transmit Wuchereria bancrofti, both causing lymphatic filariasis in humans. This study employed geometric morphometrics (GM) to investigate wing shape variation and analyzed genetic diversity through cytochrome c oxidase subunit 1 (COI) gene analyses in Ma. uniformis populations across Thailand. Wing GM analyses indicated significant differences in wing shape based on Mahalanobis distances among nearly all population pairs (p < 0.05), with no significant correlation between wing shape and geographic distance (r = 0.210, p > 0.05). Genetic analyses identified 63 haplotypes and 49 polymorphic sites, with the overall population exhibiting a nucleotide diversity of 0.006 (± 0.001) and a haplotype diversity of 0.912 (± 0.017). Deviations from neutrality, as indicated by Tajima's D and Fu's FS tests for the overall Ma. uniformis populations in Thailand, were statistically significant and negative, suggesting population expansion (both p < 0.05). Analysis of molecular variance revealed no significant genetic structure when all populations were categorized based on collection sites and geographic regions. However, significant differences in FST values were observed between some populations. These findings enhance our understanding of the geographical and genetic factors influencing Ma. uniformis populations, which are crucial for developing effective control strategies in Thailand.

Stronger interspecific sexual differences may be favored when females search for mates in the presence of congeners

Why are some species sexually dimorphic while other closely related species are not? While all females in genus Strauzia share a multiply-banded wing pattern typical of many other true fruit flies, males of four species have noticeably elongated wings with banding patterns "coalesced" into a continuous dark streak across much of the wing. We take an integrative phylogenetic approach to explore the evolution of this dimorphism and develop general hypotheses underlying the evolution of wing dimorphism in flies. We find that the origin of coalesced and other darkened male wing patterns correlate with the inferred origin of host plant sharing in Strauzia. While wing shape among non-host-sharing species tended to be conserved across the phylogeny, shapes of male wings for Strauzia species sharing the same host plant were more different from one another than expected under Brownian models of evolution and overall rates of wing shape change differed between non-host-sharing species and host-sharing species. A survey of North American Tephritidae finds just three other genera with specialist species that share host plants. Host-sharing species in these genera also have wing patterns unusual for each genus. Only genus Eutreta is like Strauzia in having the unusual wing patterns only in males, and of genera that have multiple species sharing hosts, only in Eutreta and Strauzia do males hold territories while females search for mates. We hypothesize that in species that share host plants, those where females actively search for males in the presence of congeners may be more likely to evolve sexually dimorphic wing patterns.

How dispersal rates depend on the prey capture strategy: A case study of Georgia's spiders

Large-scale barcoding projects help to aggregate information on genetic variability of multiple species throughout their ranges. Comparing DNA sequences of both non-conspecific and conspecific individuals from distant parts of their ranges helps to compare level of genetic isolation-by-distance patterns in different species and adaptive types. We compared mitochondrial CO1 gene sequences of 223 spiders from Georgia (Caucasus), representing 124 species and eight families, with 3097 homological sequences from spiders mostly from Europe, but also from other parts of the World. In most families, a significant isolation-by distance pattern was observed on family level. On species level, a significant isolation-by-distance was observed in 40 species, although this low proportion is most likely related to a lack of data. Simultaneously, remarkable differences in spatial structure were shown for different species. Although the majority of the studied species have a broad western Palearctic range, web-building spiders from families Araneidae, Theridiidae, and Linyphiidae are less isolated spatially than flower spiders (Thomisidae), jumping spiders (Salticidae), wolf spiders (Lycosidae), sac spiders (Clubionidae), and ground spiders (Gnaphosidae). This pattern is related with more common ballooning in web building than in actively hunting spiders, which commonly remain isolated since preglacial time. Ground spiders build the most isolated populations in the Caucasus.

Phylogeographic Pattern of the Assassin Bug Sycanus bifidus Inferred from Mitochondrial Genomes and Nuclear Genes

The assassin bug Sycanus bifidus has a wide distribution across southern China. This study explored its distribution and evolution by analyzing mitochondrial and nuclear ribosomal RNA genes, revealing how Pleistocene climate and geological changes shaped its phylogeography. We identified two main clades, A and B, that diverged in the Middle Pleistocene. Hainan Island's populations form a unique group within Clade A, suggesting that the Qiongzhou Strait served as a dispersal corridor during glaciation. Rising sea levels likely separated the Hainan population afterward. Ecological niche modeling showed that both populations have been viable since the last interglacial period, with demographic analyses indicating possible expansions during the Middle and Late Pleistocene, driven by favorable climates. This study highlights the significant effects of Pleistocene sea-level and climatic changes on the distribution and evolution of S. bifidus in China.

The effect of missing data on evolutionary analysis of sequence capture bycatch, with application to an agricultural pest

Sequence capture is a genomic technique that selectively enriches target sequences before high throughput next-generation sequencing, to generate specific sequences of interest. Off-target or 'bycatch' data are often discarded from capture experiments, but can be leveraged to address evolutionary questions under some circumstances. Here, we investigated the effects of missing data on a variety of evolutionary analyses using bycatch from an exon capture experiment on the global pest moth, Helicoverpa armigera. We added > 200 new samples from across Australia in the form of mitogenomes obtained as bycatch from targeted sequence capture, and combined these into an additional larger dataset to total > 1000 mitochondrial cytochrome c oxidase subunit I (COI) sequences across the species' global distribution. Using discriminant analysis of principal components and Bayesian coalescent analyses, we showed that mitogenomes assembled from bycatch with up to 75% missing data were able to return evolutionary inferences consistent with higher coverage datasets and the broader literature surrounding H. armigera. For example, low-coverage sequences broadly supported the delineation of two H. armigera subspecies and also provided new insights into the potential for geographic turnover among these subspecies. However, we also identified key effects of dataset coverage and composition on our results. Thus, low-coverage bycatch data can offer valuable information for population genetic and phylodynamic analyses, but caution is required to ensure the reduced information does not introduce confounding factors, such as sampling biases, that drive inference. We encourage more researchers to consider maximizing the potential of the targeted sequence approach by examining evolutionary questions with their off-target bycatch where possible-especially in cases where no previous mitochondrial data exists-but recommend stratifying data at different genome coverage thresholds to separate sampling effects from genuine genomic signals, and to understand their implications for evolutionary research.

At a crossroads: Genetic lineages and dispersal routes of Morimusasper (Sulzer, 1776) s.l. (Coleoptera, Cerambycidae) in Bulgaria

The present study fills a knowledge gap in the distribution and genetic variation of Morimus populations in the Balkans, by studiyng the representatives of the genus in Bulgaria - M.asperfunereus Mulsant, 1862, M.verecundusbulgaricus Danilevsky, 2016 and M.orientalis Reitter, 1894. Additional information is provided for Albania and northern Greece. The mitochondrial cytochrome C oxidase subunit I (COI) marker and the nuclear internal transcribed spacer 2 (ITS2) were used for the genetic analyses. Three of the previously-defined mitochondrial lineages (Lb/HgA, L2 and L3) were detected in Bulgaria, as well as a new lineage (Str) from the Strandzha Mountains (south-eastern Bulgaria). A total of 24 distinct haplotypes, 20 of them in Bulgaria, were found. Bulgarian populations of Morimus demonstrated relatively high nucleotide diversity. The L3 COI lineage was confirmed as the most diverse and frequent in the Balkans. The L3 lineage is dominant in most of Bulgaria, but was not identified in the easternmost parts near the Black Sea coast, where the L2 and Str lineages were found. New data highlighted two dispersal routes of the L2 mitochondrial lineage on the Balkan Peninsula: 1) northwards along the Black Sea coast and 2) westwards, across the Balkans where only disjunct populations remain. North-western Bulgaria seems to be the eastern limit of the basal lineage Lb/HgA distribution. Our results show high levels of genetic exchange between most of the mitochondrially defined lineages, yet some of the easternmost populations probably remained isolated for comparatively longer periods.

Co-occurrence of dual lineages within Simulium (Gomphostilbia) atratum De Meijere in the Indonesian Archipelago along Wallace's Line

Mitochondrial cytochrome c oxidase subunit I (COI) sequences were utilized to infer the population genetic structure of Simulium (Gomphostilbia) atratum De Meijere, an endemic simulid species to Indonesia. Both median-joining haplotype network and maximum-likelihood tree revealed two genetic lineages (A and B) within the species, with an overlap distribution in Lombok, which is situated along Wallace's line. Genetic differentiation and gene flow with varying frequencies (FST = 0.02-0.967; Nm = 0.01-10.58) were observed between populations of S. (G.) atratum, of which population pairs of different lineages showed high genetic differentiation. Notably, the high genetic distance of up to 5.92 % observed within S. (G.) atratum in Lombok was attributed to the existence of two genetically distinct lineages. The co-occurrence of distinct lineages in Lombok indicated that Wallace's line did not act as faunistic border for S. (G.) atratum in the present study. Moreover, both lineages also exhibited unimodal distributions and negative values of neutrality tests, suggesting a pattern of population expansion. The expansion and divergence time estimation suggested that the two lineages of S. (G.) atratum diverged and expanded during the Pleistocene era in Indonesia.

Biology, ecology, and biogeography of eremic praying mantis Blepharopsis mendica (Insecta: Mantodea)

Background

Blepharopsis mendica (Fabricius, 1775) is a large mantid species found from the Canary Islands across North Africa, the Middle East, and Pakistan. Research on this species has been limited, especially in Iran, despite the country's potential significance for studying its biology and distribution. Adults of this species are easily recognizable by their marble-white pattern and rhomboidal leaf-like pronotum. They are sit-and-wait predators that inhabit various open environments.

Methods

Field observations were conducted across various regions of the Egyptian Flower mantis (Blepharopsis mendica) global distribution, with a focus on Morocco, Tunisia, and Iran. Distribution data for B. mendicawere gathered from fieldwork, museum collections, online biodiversity databases, and publications, totaling 593 occurrence points. Ecological niche modeling was performed using environmental data, and various models were evaluated for suitability. Phylogeographic analyses involved DNA sequencing and construction of a haplotype network to examine genetic relationships between populations. Divergence time estimation and biogeographical range expansion models were applied to explore historical distribution shifts of the species across different regions. The study provided comprehensive insights into the biology, distribution, and genetic history of B. mendica.

Results

We provide information on the life cycle, ootheca, defense behavior, habitat, and biogeography of the Egyptian Flower mantis Blepharopsis mendica. This mantid is an overwintering univoltine species with nymphs emerging in summer and becoming adults in spring. In the wild, females start oviposition in April and can lay their first ootheca within a week after mating. The species is distributed from the Canary Islands to Pakistan in the dry belt. Thus, its distribution is associated with xeric areas or desert and semi-desert habitats. Phylogeographic analyses revealed three major genetic lineages, (i) in the Maghreb, (ii) from Egypt via Arabia to Iran (with internal substructures), and (iii) likely in Pakistan; the estimated onset of differentiation into these lineages is of Pleistocene age. Defense behavior involves flying away or extending wings broadly and lifting forelegs. Performing laboratory breeding, we documented life cycle and color changes from first instar to adulthood. Due to overwintering, the last larval instar needs considerably longer than the others. At 25 °C (±2), average adult life span was 118 days (±6 SD) for females (range: 100-124) and 46 days (±5 SD) for males (range: 39-55), with a significant difference among sexes. On average, oothecae contained 32.3 eggs (±10.1 SD) and the mean incubation period was 36.8 days (±2.9 SD). We did not find evidence of parthenogenesis. In general, the biology of B. mendica shows a variety of adaptations to its often extreme and little predictable type of habitat.

The presence of Ixodes pavlovskyi and I. pavlovskyi-borne microorganisms in Rishiri Island: an ecological survey

IMPORTANCE

Understanding the ecology of ticks and tick-borne microorganisms is important to assess the risk of emerging tick-borne diseases. Despite the fact that the Ixodes pavlovskyi tick bites humans, we lack information including population genetics and the reason for the inadequate distribution in Japan. A 5-year survey revealed that Rishiri Island, the main stopover in the East Asian Flyway of wild birds in the northern Sea of Japan, was a refuge of I. pavlovskyi. The I. pavlovskyi included two haplogroups, which were supposed to diverge a long time before the island separated from the continent and Hokkaido mainland. The detection of microorganisms from wildlife revealed that wild birds and rodents play a role in diffusion and settlement, respectively, of not only I. pavlovskyi but also I. pavlovskyi-borne microorganisms including Candidatus Ehrlichia khabarensis and Babesia microti US lineage. Various island-specific factors control I. pavlovskyi dominance and tick-borne pathogen maintenance. The results may enable us to explain how tick-borne infectious microorganisms are transported.

Reconstructing the post-glacial spread of the sand fly Phlebotomus mascittii Grassi, 1908 (Diptera: Psychodidae) in Europe

Phlebotomine sand flies (Diptera: Phlebotominae) are the principal vectors of Leishmania spp. (Kinetoplastida: Trypanosomatidae). In Central Europe, Phlebotomus mascittii is the predominant species, but largely understudied. To better understand factors driving its current distribution, we infer patterns of genetic diversity by testing for signals of population expansion based on two mitochondrial genes and model current and past climate and habitat suitability for seven post-glacial maximum periods, taking 19 climatic variables into account. Consequently, we elucidate their connections by environmental-geographical network analysis. Most analyzed populations share a main haplotype tracing back to a single glacial maximum refuge area on the Mediterranean coasts of South France, which is supported by network analysis. The rapid range expansion of Ph. mascittii likely started in the early mid-Holocene epoch until today and its spread possibly followed two routes. The first one was through northern France to Germany and then Belgium, and the second across the Ligurian coast through present-day Slovenia to Austria, toward the northern Balkans. Here we present a combined approach to reveal glacial refugia and post-glacial spread of Ph. mascittii and observed discrepancies between the modelled and the current known distribution might reveal yet overlooked populations and potential further spread.

Geologically calibrated mammalian tree and its correlation with global events, including the emergence of humans

A robust timetree for Mammalia was constructed using the time calibration function of BEAST v1.10.4 and MEGA 11. The analysis involved the application of times of the most recent common ancestors, including a total of 19 mammalian fossil calibration ages following Benton et al. (Palaeontologia Electronica, 2015, 1-106) for their minimum ages. Additionally, fossil calibration ages for Gorilla, Pan, and a geologic event calibration age for otters were incorporated. Using these calibration ages, I constructed a geologically calibrated tree that estimates the age of the Homo and Pan splitting to be 5.69 Ma. The tree carries several significant implications. First, after the initial rifting at 120 Ma, the Atlantic Ocean expanded by over 500 km around Chron 34 (84 Ma), and vicariant speciation between Afrotheria (Africa) and Xenarthra (South America) appears to have commenced around 70 Ma. Additionally, ordinal level differentiations began immediately following the K-Pg boundary (66.0 Ma), supporting previous hypothesis that mammalian radiation rapidly filled ecological niches left vacant by non-avian dinosaurs. I constructed a diagram depicting the relationship between base substitution rate and age using an additional function in BEAST v1.10.4. The diagram reveals an exponential increase in the base substitution rate approaching recent times. This increased base substitution rate during the Neogene period may have contributed to the expansion of biodiversity, including the extensive adaptive radiation that led to the evolution of Homo sapiens. One significant driving factor behind this radiation could be attributed to the emergence and proliferation of C4 grasses since 20 Ma. These grasses have played a role in increasing carbon fixation, reducing atmospheric CO2 concentration, inducing global cooling, and initiating Quaternary glacial-interglacial cycles, thereby causing significant climatic changes.

The Genetic Diversity of White-Backed Planthoppers (Sogatella furcifera) between Myanmar and Yunnan Province of China

In order to clarify the migration route and the source of white-backed planthopper (WBPH) (Sogatella furcifera) between Myanmar and Yunnan Province, China, we collected six populations throughout Myanmar and five populations around the border areas in Yunnan Province, China. A total of 790 base pairs in the mtDNA COI genes from 416 individuals were obtained. A total of 43 haplotypes were identified, among which 37 were unique haplotypes, and the remaining 6 were shared among different populations. Two common shared haplotypes (H_1 and H_2) had a widespread distribution in all populations and accounted for 88.8% of the total haplotype frequency, suggesting a high-level gene flow among the Myanmar and Yunnan populations. Bayesian skyline plot (BSP) analysis results indicated that the effective population size of WBPH expanded between about 10,000 and 7000 years ago, and S. furcifera might follow the post-LGM (Last Glacial Maximum) expansion pattern. Based on the total migrant (Nem) value, it can be deduced that north and northeast Myanmar were the primary migration sources for WBPH populations in the southwest and south Yunnan regions. This study aims to contribute to the sustainable regional management of this important rice pest and provide new insights into the genetic diversity of WBPH in Southeast Asia.

Limited congruence in phylogeographic patterns observed for riverine predacious beetles sharing distribution along the mountain rivers

Riverine predacious beetles (RPB) (Carabidae, Staphylinidae) are highly diverse and numerous elements of riverine ecosystems. Their historical and contemporary distribution and diversity are highly dependent on natural flow regimes and topography of watercourses. Despite broad knowledge of their ecology, data on population genetic diversity and connectivity are lacking. This study aimed to fill this gap in order to solve two principal hypotheses assuming (i) congruence of phylogeographic patterns observed for RPB indicating that they share a common history and the ecological adaptations to the dynamic environment, (ii) genetic structuration of populations according to river basins. The Carpathian populations of four ground beetles and three rove beetles were examined using cytochrome oxidase and arginine kinase sequencing. There are substantial differences in RPB demographic history and current genetic diversity. Star-like phylogeny of Bembidion and complex haplotype networks of Paederus/Paederidus, with some haplotypes being drainage-specific and others found in distant populations, indicate a general lack of isolation by distance. Signs of recent demographic expansion were detected for most RPB with the latest population collapse for some rove beetles. To some extent, migration of examined species has to be limited by watersheds. Observed phylogeographic patterns are essential for correctly understanding RPB meta-population functioning.

History of the terrestrial isopod genus Ligidium in Japan based on phylogeographic analysis

BACKGROUND

Phylogeographical approaches explain the genetic diversity of local organisms in the context of their geological and geographic environments. Thus, genetic diversity can be a proxy for geological history. Here we propose a genus of woodland isopod, Ligidium, as a marker of geological history in relation to orogeny and the Quaternary glacial cycle.

RESULTS

Mitochondrial analysis of 721 individuals from 97 sites across Japan revealed phylogenetic divergence between the northeastern and southwestern Japan arcs. It also showed repeated population expansions in northeastern Japan in response to Quaternary glacial and interglacial cycles. Genome-wide analysis of 83 selected individuals revealed multiple genetic nuclear clusters. The genomic groupings were consistent with the local geographic distribution, indicating that the Ligidium phylogeny reflects its regional history.

CONCLUSION

Ligidium DNA sequence analysis can provide insight into the geological, geographical, and paleoenvironmental history of the studied region.

Species delimitation, biogeography, and natural history of dwarf funnel web spiders (Mygalomorphae, Hexurellidae, Hexurella) from the United States / Mexico borderlands

The rarely encountered spider genus Hexurella Gertsch & Platnick, 1979 includes some of the smallest mygalomorph spiders in the world, with four poorly known taxa from central and southeastern montane Arizona, southern California, and northern Baja California Norte. At time of description the genus was known from fewer than 20 individuals, with sparse natural history information suggesting a vagrant, web-building, litter-dwelling natural history. Here the first published taxonomic and natural history information for this taxon is provided in more than 50 years, working from extensive new geographic sampling, consideration of male and female morphology, and sequence capture-based nuclear phylogenomics and mitogenomics. Several new species are easily diagnosed based on distinctive male morphologies, while a complex of populations from central and northern Arizona required an integrative combination of genomic algorithmic species delimitation analyses and morphological study. Four new species are described, including H.ephedrasp. nov., H.uwiiltilsp. nov., H.xericasp. nov., and H.zassp. nov. Females of H.encina Gertsch & Platnick, 1979 are also described for the first time. It is predicted that additional new species will ultimately be found in the mountains of central and northwestern Arizona, northern mainland Mexico, and the Mojave Desert of California.

Northern Richness, Southern Dead End-Origin and Dispersal Events of Pseudolycoriella (Sciaridae, Diptera) between New Zealand's Main Islands

Sciaridae (Diptera) is a widespread insect family of which some species can reach high abundances in arboreal habitats. This trait, together with their (passive) mobility, enables them to quickly colonise suitable habitats. To reveal the biogeographic history of the New Zealand members of the sciarid genus Pseudolycoriella, we analysed three molecular markers of selected species and populations in a Bayesian approach. At the intra- and interspecific levels, we detected a pattern of northern richness vs. southern purity, which has probably developed as a result of Pleistocene glacial cycles. Since the late Miocene, we identified 13 dispersal events across the sea strait separating New Zealand's main islands. As nine of these dispersal events were south-directed, North Island can be considered the centre of radiation for this genus. An unequivocal re-colonisation of North Island was only observed once. Based on the inclusion of three undescribed species from Tasmania and on previously published data, three colonisations of New Zealand are likely, all of them assumed to be of Australian origin. One of these most probably took place during the late Miocene, and the other two during the late Pliocene or at the Pliocene-Pleistocene boundary.

Multiple mitogenomes indicate Things Fall Apart with Out of Africa or Asia hypotheses for the phylogeographic evolution of Honey Bees (Apis mellifera)

Previous morpho-molecular studies of evolutionary relationships within the economically important genus of honey bees (Apis), including the Western Honey Bee (A. mellifera L.), have suggested Out of Africa or Asia origins and subsequent spread to Europe. I test these hypotheses by a meta-analysis of complete mitochondrial DNA coding regions (11.0 kbp) from 22 nominal subspecies represented by 78 individual sequences in A. mellifera. Parsimony, distance, and likelihood analyses identify six nested clades: Things Fall Apart with Out of Africa or Asia hypotheses. Molecular clock-calibrated phylogeographic analysis shows instead a basal origin of A. m. mellifera in Europe ~ 780 Kya, and expansion to Southeast Europe and Asia Minor ~ 720 Kya. Eurasian bees spread southward via a Levantine/Nilotic/Arabian corridor into Africa ~ 540 Kya. An African clade re-established in Iberia ~ 100 Kya spread thereafter to westerly Mediterranean islands and back into North Africa. Nominal subspecies within the Asia Minor and Mediterranean clades are less differentiated than are individuals within other subspecies. Names matter: paraphyletic anomalies are artefacts of mis-referral in GenBank of sequences to the wrong subspecies, or use of faulty sequences, which are clarified by inclusion of multiple sequences from available subspecies.

Geological events and climate change drive diversification and speciation of mute cicadas in eastern continental Asia

The poor mobility of nymphs living underground, usually for many years and the weak flying ability of adults make cicadas unique for evolutionary biology and bio-geographical study. Cicadas of the genus Karenia are unusual in Cicadidae in lacking the timbals that produce sound. Population differentiation, genetic structure, dispersal and evolutionary history of the eastern Asian mute cicada Karenia caelatata were investigated based on morphological, acoustic and molecular data. The results reveal a high level of genetic differentiation in this species. Six independent clades with nearly unique sets of haplotypes corresponding to geographically isolated populations are recognized. Genetic and geographic distances are significantly correlated among lineages. The phenotypic differentiation is generally consistent with the high levels of genetic divergence across populations. Results of ecological niche modeling suggest that the potential distribution range of this mountain-habitat specialist during the Last Glacial Maximum was broader than its current range, indicating this species had benefited from the climate change during the early Pleistocene in southern China. Geological events such as orogeny in Southwest China and Pleistocene climate oscillations have driven the differentiation and divergence of this species, and basins, plains and rivers function as natural "barriers" to block the gene flow. Besides significant genetic divergence being found among clades, the populations occurring in the Wuyi Mountains and the Hengduan Mountains are significantly different in the calling song structure from other populations. This may have resulted from significant population differentiation and subsequent adaptation of related populations. We conclude that ecological differences in habitats, coupled with geographical isolation, have driven population divergence and allopatric speciation. This study provides a plausible example of incipient speciation in Cicadidae and improves understanding of population differentiation, acoustic signal diversification and phylogeographic relationships of this unusual cicada species. It informs future studies on population differentiation, speciation and phylogeography of other mountain-habitat insects in the East Asian continent.

New Insights into the Variation and Admixture of the Cave-Dwelling Spider Trogloneta yunnanensis in South China Karst

Subterranean karst caves can contain unexpected biodiversity, but few studies related to spider population genetics have been conducted in the karst area of Southern China. In this study, we investigated the population genetic structure of Trogloneta yunnanensis (Song & Zhu, 1994) based on 73 spider samples from six underground populations in South China Karst. Population genetic structure analysis showed a clear divergence (FST > 0.9 and Nm < 0.05) among populations according to mitochondrial genes. The phylogenetic gene tree constructed by BI and ML methods recovered six geographic clades. Divergence time estimation indicated that the divergence of these six populations can be traced back to the late Pleistocene. We supposed that the geographic isolation led to the extreme population structure. According to this study and previous studies about troglobites living in this region, the subterranean habitats of the Yunnan-Guizhou Plateau may contain many organisms with similar genetic structures. The subterranean biodiversity in the karst area of Southern China needs to be re-evaluated and protected.

Climatic oscillation promoted diversification of spinous assassin bugs during Pleistocene glaciation

Insect speciation is among the most fascinating topics in evolutionary biology; however, its underlying mechanisms remain unclear. Allopatric speciation represents one of the major types of speciation and is believed to have frequently occurred during glaciation periods, when climatic oscillation may have caused suitable habitats to be fragmented repeatedly, creating geographical isolation among populations. However, supporting evidence for allopatric speciation of insects in East Asia during the Pleistocene glaciation remains lacking. We aim to investigate the effect of climatic oscillation during the Pleistocene glaciation on the diversification pattern and evolutionary history of hemipteran insects and to test the hypothesis of Pleistocene species stability using spinous assassin bugs Sclomina (Hemiptera: Reduviidae), a small genus widely distributed in southern China but was later found to have cryptic species diversity. Here, using the whole mitochondrial genome (mitogenome) and nuclear ribosomal RNA genes, we investigated both interspecific and intraspecific diversification patterns of spinous assassin bugs. Approximate Bayesian computation, ecological niche modeling, and demographic history analyses were also applied to understand the diversification process and driven factors. Our data suggest that the five species of Sclomina are highly diverged, despite three of them currently being cryptic. Speciation occurred during the Pleistocene when suitable distribution areas were possibly fragmented. Six phylogeographic groups in the type species S. erinacea were identified, among which two groups underwent expansion during the early Last Glacial Period and after Last Glacier Maximum. Our analyses suggest that this genus may have experienced climate-driven habitat fragmentation and postglacial expansion in the Pleistocene, promoting allopatric speciation and intraspecific diversification. Our results reveal underestimated species diversity in a small insect group and illustrate a remarkable example of allopatric speciation of insects in East Asia promoted by Pleistocene climatic oscillations. These findings provide important insights into the speciation processes and aid the conservation of insect species diversity.

Genetic analysis reveals the putative native range and widespread double-clonal reproduction in the invasive longhorn crazy ant

Clonal reproduction can provide an advantage for invasive species to establish as it can circumvent inbreeding depression which often plagues introduced populations. The world's most widespread invasive ant, Paratrechina longicornis, was previously found to display a double-clonal reproduction system, whereby both males and queens are produced clonally, resulting in separate male and queen lineages, while workers are produced sexually. Under this unusual reproduction mode, inbreeding is avoided in workers as they carry hybrid interlineage genomes. Despite the ubiquitous distribution of P. longicornis, the significance of this reproductive system for the ant's remarkable success remains unclear, as its prevalence is still unknown. Further investigation into the controversial native origin of P. longicornis is also required to reconstruct the evolutionary histories of double-clonal lineages. Here, we examine genetic variation and characterize the reproduction mode of P. longicornis populations sampled worldwide using microsatellites and mitochondrial DNA sequences to infer the ant's putative native range and the distribution of the double-clonal reproductive system. Analyses of global genetic variations indicate that the Indian subcontinent is a genetic diversity hotspot of this species, suggesting that P. longicornis probably originates from this geographical area. Our analyses revealed that both the inferred native and introduced populations exhibit double-clonal reproduction, with queens and males around the globe belonging to two separate, nonrecombining clonal lineages. By contrast, workers are highly heterozygous because they are first-generation interlineage hybrids. Overall, these data indicate a worldwide prevalence of double clonality in P. longicornis and support the prediction that the unusual genetic system may have pre-adapted this ant for global colonization by maintaining heterozygosity in the worker force and alleviating genetic bottlenecks.

A molecular phylogeny of the European nesticid spiders (Nesticidae, Araneae): Implications for their systematics and biogeography

Nesticidae is a small family of spiders with a worldwide distribution that includes 15 genera and 272 described species. Seven genera and 56 species are known from Europe, distributed from the Iberian Peninsula to the Caucasus and the Ural Mountains. Most of these European species are cave dwellers and many of them are troglobites. In this study we present the first molecular phylogeny of the family Nesticidae in Europe with a wide geographical sampling across the continent. In our analysis the European nesticid fauna is well represented, including six genera and 40 of the 56 currently accepted species including the type species of all sampled genera. We have included in the analysis representatives of the North American and Asian fauna to test the monophyly of the European species and the phylogenetic relationships of European lineages. Phylogenetic relationships were reconstructed using maximum likelihood and Bayesian inference. As part of our Bayesian analyses, we also dated the phylogeny using two approaches, one based only on fossil calibrations and one that included an additional biogeographical constraint. Our results show paraphyly of the European nesticids with respect to the Asian and North American taxa. We recover four main lineages within Europe. These four European lineages and all European genera have 100% bootstrap support and high posterior probability support in the BEAST2 analysis. The Typhlonesticus lineage is the earliest branching clade present in Europe and includes seven species, the five currently accepted species plus T. parvus from Bosnia and Herzegovina and T. silvestrii from western North America. The Eastern lineage includes the genus Aituaria and is the sister group of the Asian genera Nesticella and Wraios. The Domitius lineage is likely the sister group of the Central European lineage and spreads over the Iberian and Italian peninsulas. Finally, the Central European lineage includes three genera: Kryptonesticus, distributed from the karstic massifs of the Balkan Peninsula to Turkey, Nesticus with a single synanthropic species N. cellulanus and Carpathonesticus, exclusive to the Carpathian Mountains. With the exception of the genus Typhlonesticus, all European genera show an allopatric distribution (except for the two European synanthropic species). The results obtained in this study together with the revision of the original descriptions, redescriptions, and illustrations, lead us to propose 11 nomenclatural changes (new combinations) concerning the genera Typhlonesticus, Nesticus and Carpathonesticus.

Molecular phylogeny and historical biogeography of Cyclommatus stag beetles (Coleoptera: Lucanidae): Insights into their evolution and diversification in tropical and subtropical Asia

Cyclommatus stag beetles (Coleoptera, Lucanidae) are very interesting insects, because of their striking allometry (mandibles can be longer that the whole body in large males of some species) and sexual dimorphism. They mainly inhabit tropical and subtropical forests in Asia. To date, there has been no molecular phylogenetic research on how these stag beetles evolved and diversified. In this study, we constructed the first phylogenetic relationship for Cyclommatus using multi-locus datasets. Analyses showed that Cyclommatus is monophyletic, being subdivided into two well-supported clades (A and B). The clade A includes the island species from Southeast Asia, and the clade B is formed by the continental species. The divergent time estimates showed these beetles split from the outgroup around 43.10 million years ago (Mya) in the late Eocene, divided during the late Oligocene (around 24.90 Mya) and diversified further during the early and middle Miocene (around 18.19 Mya, around 15.17 Mya). RASP analysis suggested that these beetles likely originated in the Philippine archipelago, then dispersed to the other Southeast Asian archipelagoes, Indochina Peninsula, Southeast Himalayas, and Southern China. Moreover, relatively large genetic distance and stable morphological variations signified that the two clades reach the level of inter-generic differences, i.e., the current Cyclommatus should be separated in two genera: Cyclommatus Parry, 1863 including the clade A species, and Cyclommatinus Didier, 1927 covering the clade B species. In addition, the evidence we generated indicated these beetles’ diversification was promoted probably by both long-distance dispersal and colonization, supporting an “Upstream” colonization hypothesis. Our study provides insights into the classification, genetics and evolution of stag beetles in the Oriental region.

New Dielis species and structural dichotomy of the mitochondrial cox2 gene in Scoliidae wasps

Some mitochondrial protein-coding genes of protists and land plants have split over the course of evolution into complementary genes whose products can form heteromeric complexes that likely substitute for the undivided proteins. One of these genes, cox2, has also been found to have split in animals, specifically in Scoliidae wasps (Hymenoptera: Apocrita) of the genus Dielis (Campsomerini), while maintaining the conventional structure in related Scolia (Scoliini). Here, a hitherto unrecognized Nearctic species of Dielis, D. tejensis, is described based on its phenotype and mtDNA. The mitogenome of D. tejensis sp. nov. differs from that of the sympatric sibling species Dielis plumipes fossulana by the reduced size of the cox2-dividing insert, which, however, still constitutes the fifth part of the mtDNA; an enlarged nad2-trnW intergenic region; the presence of two trnK^ttt paralogues; and other features. Both species of Dielis have a unique insertion of a threonine in COXIIA, predicted to be involved in COXIIA-COXIIB docking, and substitutions of two hydrophobic residues with redox-active cysteines around the Cu_A centre in COXIIB. Importantly, the analysis of mtDNA from another Campsomerini genus, Megacampsomeris, shows that its cox2 gene is also split. The presented data highlight evolutionary processes taking place in hymenopteran mitogenomes that do not fall within the mainstream of animal mitochondrion evolution.

Genetic diversity of tick (Acari: Ixodidae) populations and molecular detection of Anaplasma and Ehrlichia infesting beef cattle from upper-northeastern Thailand

Genetic diversity, genetic structure and demographic history of the ticks infesting beef cattle in Thailand were examined based on mitochondrial cytochrome c oxidase I (cox1) sequences. Tick samples were collected in 12 provinces in upper-northeastern Thailand. Three species were found; Rhipicephalus microplus, R. sanguineus, and Haemaphysalis bispinosa. Of these, R. microplus was by far the most abundant species in beef cattle and was widely distributed throughout the area. No cox1 sequence variation was found in the R. sanguineus or H. bispinosa specimens collected. Low nucleotide diversity but high haplotype diversity was observed in R. microplus. All collected R. microplus specimens belonged to lineage A. Mismatch-distribution analysis, as well as Tajima's D and Fu's Fs tests, provided evidence of recent demographic expansion. A subsample of tick specimens was investigated for presence of Anaplasma and Ehrlichia using a fragment of the 16S rRNA gene. Three species of Anaplasma were detected from R. microplus; Anaplasma marginale (19.08%), Anaplasma platys (1.97%) and unidentified Anaplasma strain (0.66%). The infection rate of Ehrlichia was 7.24% (two ticks were infected with E. minasensis (1.97%) and eight with an unidentified Ehrlichia strain (5.26%). No infections were found in R. sanguineus or H. bispinosa. This is the first report of A. platys and E. minasensis in cattle ticks in Thailand, providing information for future epidemiological surveys and control strategies in this region.

The Quality of Sequence Data Affects Biodiversity and Conservation Perspectives in the Neotropical Damselfly Megaloprepus caerulatus

Ideally, the footprint of the evolutionary history of a species is drawn from integrative studies including quantitative and qualitative taxonomy, biogeography, ecology, and molecular genetics. In today’s research, species delimitations and identification of conservation units is often accompanied by a set of—at minimum—two sequence markers appropriate for the systematic level under investigation. Two such studies re-evaluated the species status in the world’s largest Odonata, the Neotropical damselfly Megaloprepus caerulatus. The species status of the genus Megaloprepus has long been debated. Despite applying a highly similar set of sequence markers, the two studies reached different conclusions concerning species status and population genetic relationships. In this study, we took the unique opportunity to compare the two datasets and analyzed the reasons for those incongruences. The two DNA sequence markers used (16S rDNA and CO1) were re-aligned using a strict conservative approach and the analyses used in both studies were repeated. Going step by step back to the first line of data handling, we show that a high number of unresolved characters in the sequence alignments as well as internal gaps are responsible for the different outcomes in terms of species delimitations and population genetic relationships. Overall, this study shows that high quality raw sequence data are an indispensable requirement, not only in odonate research.

Multilocus evidence provides insight into the demographic history and asymmetrical gene flow between Ostrinia furnacalis and Ostrinia nubilalis (Lepidoptera: Crambidae) in the Yili area, Xinjiang, China

Tianshan Mountains provide a model for studying biological evolution and speciation. Here we assess the evolutionary history of Ostrinia furnacalis (ACB) and Ostrinia nubilalis (ECB), which are sympatric in the Yili River Valley in Xinjiang, China.Our study is based on the historical gene flow analyses of two species by using three mitochondrial DNA (mtDNA, COI, COII, Cytb) and four nuclear DNA (nuDNA, EF-1α, Wingless, RPS5, CAD) markers obtained from representatives of HC (Huocheng), YN (Yining), XY (Xinyuan), and MNS (Manasi).Our results reveal that there is an asymmetrical gene flow pattern between the four populations. The population migratory pathways between these different populations show inflow into HC and YN, outflow from XY, and that MNS maintained a flow balance. Bayesian divergence time dating based on the COI gene suggests that the genetic divergence between the two species in this area may have occurred in Holocene at 0.008 Mya. Neutrality tests (Tajima's D, Fu's F s), and mismatch distribution test results suggest that population expansion events may not have occurred in the recent past. The demographic history and gene flow pattern between ACB and ECB may follow the "mountain isolation" hypothesis. The ML and BI trees of the mtDNA haplotype dataset show that ECB haplotypes are grouped together in a distinct clade and are clearly separate from ACB haplotypes. However, the geographical pattern of haplotype distribution is less clear for both ACB and ECB, supporting that there has been frequent gene flow among the geographic populations in the Tianshan Mountains.These findings indicate that the Tianshan Mountains are less likely a barrier to gene flow of the two species.

Specific and Intraspecific Diversity of Symphypleona and Neelipleona (Hexapoda: Collembola) in Southern High Appalachia (USA)

Collembola, commonly known as springtails, are important detritivores, abundant in leaf litter and soil globally. Springtails are wingless hexapods with many North American species having wide distributions ranging from as far as Alaska to Mexico. Here, we analyze the occurrence and intraspecific diversity of springtails with a globular body shape (Symphypleona and Neelipleona), in southern high Appalachia, a significant biodiversity hotspot. The peaks of high Appalachia represent ‘sky islands’ due to their physical isolation, and they host numerous endemic species in other taxa. We surveyed globular Collembola through COI metabarcoding, assessing geographic and genetic diversity across localities and species. Intraspecific diversity in globular Collembola was extremely high, suggesting that considerable cryptic speciation has occurred. While we were able to associate morphospecies with described species in most of the major families in the region (Dicyrtomidae, Katiannidae, Sminthuridae, and Sminthurididae), other families (Neelidae, and Arrhopalitidae) are in more pressing need of taxonomic revision before species identities can be confirmed. Due to poor representation in databases, and high intraspecific variability, no identifications were accomplished through comparison with available DNA barcodes.

Complete mitochondrial genomes from museum specimens clarify millipede evolution in the Eastern Arc Mountains

The Eastern Arc Mountains in Tanzania represent a hotspot for biological diversity of global importance. The level of endemism is high, and Eastern Arc biodiversity has been studied extensively in vertebrates and invertebrates, including millipedes. However, millipede evolution is vastly understudied at the molecular level. Therefore, we used next-generation ‘shotgun’ sequencing to obtain mitochondrial genome sequences of 26 museum specimens, representing six genera and 12 millipede species found across the Eastern Arc Mountains. Bayesian and maximum likelihood methods yielded consistent topologies with high node support, confirming a high level of congruence between molecular and morphological analyses. The only exception was a Tropostreptus sigmatospinus individual from Zanzibar, which was placed outside an otherwise monophyletic group consisting of mainland individuals of the same assumed species. For two species with a distribution across several mountain blocks (Tropostreptus sigmatospinus and Tropostreptus hamatus), each mountain population represents a distinct monophyletic lineage. In contrast, we also observe that distinct species exist sympatrically in the same montane forests, indicative of older speciation events that are not defined by current forest distribution. Our results are important for understanding speciation mechanisms in montane rain forests and highlight that ethanol-preserved invertebrates exhibit a tremendous potential for genomic analyses.

Population Genetic Structure and Population History of the Biting Midge Culicoides mahasarakhamense (Diptera: Ceratopogonidae)

Biting midges of the genus Culicoides Latreille are significant pests and vectors of disease agents transmitted to humans and other animals. Understanding the genetic structure and diversity of these insects is crucial for effective control programs. This study examined the genetic diversity, genetic structure, and demographic history of Culicoides mahasarakhamense, a possible vector of avian haemosporidian parasites and Leishmania martiniquensis, in Thailand. The star-like shape of the median joining haplotype network, a unimodal mismatch distribution, and significant negative values for Tajima's D and Fu's F_S tests indicated that populations had undergone recent expansion. Population expansion time was estimated to be 2000-22,000 years ago. Population expansion may have been triggered by climatic amelioration from cold/dry to warm/humid conditions at the end of the last glaciations, resulting in the increased availability of host blood sources. Population pairwise F_ST revealed that most (87%) comparisons were not genetically different, most likely due to a shared recent history. The exception to the generally low level of genetic structuring is a population from the northern region that is genetically highly different from others. Population isolation in the past and the limitation of ongoing gene flows due to large geographic distance separation are possible explanations for genetic differentiation.

Psectrascelis senex sp. nov. (Coleoptera: Tenebrionidae), a new species from the southern Atacama Desert, Chile

Psectrascelis Solier, 1836 is the most specious South American genus of Nycteliini, which inhabit arid and semiarid regions. Recent expeditions to the southern part of the Atacama Desert collected specimens of Psectrascelis which do not fit with any other described species belonging to this genus. These specimens are morphologically close to P. penai Kulzer, 1955 but the presence of carinae on the elytra easily differentiates this taxon from this mentioned above. Here, we analyzed external morphology, both male and female genitalia, and sequences from a fragment of the mitochondrial cytochrome c oxidase subunit I (COI) gene with that of morphologically close species. Our study supports the description of Psectrascelis senex sp. nov. and suggests that P. senex sp. nov. is the sister species of P. penai.  

Vast Gene Flow among the Spanish Populations of the Pest Bactrocera oleae (Diptera, Tephritidae), Phylogeography of a Metapopulation to Be Controlled and Its Mediterranean Genetic Context

Simple Summary

The output of olive industry at the Mediterranean Basin, headed by Spain, is huge worldwide. The olive fruit fly Bactrocera oleae is the major pest of olive orchards. The damages it causes become in considerable economic losses as well as a decrease in oil quantity and quality. A key question for the success of pest control strategies is the further knowledge about the species, and genetic data becomes essential for this purpose. The present work analyses more than 250 fruit flies from six different Mediterranean countries, showing relevant data about the genetic structure and gene flow of this damaging pest. These findings are helpful to improve the integrated pest management strategies according to the current European Guidelines.

Abstract

Spain is the leading producer of olives and olive oil. Ninety-five percent of world production originate from Spain and other regions of the Mediterranean Basin. However, these olive-growing countries face a major problem, the harmful fly Bactrocera oleae, the main pest of olive crops. To improve its control, one of the challenges is the further knowledge of the species and populations dynamics in this area. A phylogeographic work is necessary to further characterise the levels and distribution patterns of genetic diversity of the Spanish populations and their genetic relationships with other Mediterranean populations. A 1151 bp fragment of the mitochondrial cytochrome oxidase subunit I (COI) gene has been analysed in over 250 specimens of the six main Mediterranean countries via sequencing. Genetic diversity parameters were high; 51 new haplotypes have been identified showing a geographical pattern across the Mediterranean area. The data revealed that olive fruit fly populations have been long time established in the Mediterranean Basin with two genetic groups. Gene flow seems to be the main process in shaping this genetic structure as well as fly’s colonisation routes that have paralleled those of the olive tree.

Dispersal ability and its consequences for population genetic differentiation and diversification

Dispersal ability is known to influence geographical structuring of genetic variation within species, with a direct relationship between low vagility and population genetic structure, which can potentially give rise to allopatric speciation. However, our general understanding of the relationship between dispersal ability, population differentiation and lineage diversification is limited. To address this issue, we sampled mitochondrial DNA variation within lineages of beetles and spiders across the Canary Islands to explore the relationships between dispersal ability, differentiation within lineages and diversification. We found positive relationships between population genetic structure and diversification for both beetles and spiders. Comparisons between dispersive and non-dispersive lineages revealed significant differences for both lineage differentiation and diversification. For both taxa, non-dispersive lineages had stronger population genetic structure. Genus-level endemic species richness and proxies for diversification rate within genera were higher in non-dispersive taxa for both beetles and spiders. Comparisons of average and maximum node divergences within genera suggest that species turnover may be higher in non-dispersive genera. Our results reveal a model where dispersal limitation may shape the diversity of lineages across evolutionary timescales by positively influencing intraspecific and species diversity, moderated by higher extinction rates compared to more dispersive lineages.

Revision of Taiwanese and Ryukyuan species of Pristepyris Kieffer, 1905, with description of a new species (Hymenoptera, Bethylidae)

The pristocerine genus Pristepyris comprises 38 valid species recorded worldwide, except in the Australian Region. Of them, three species, namely P.mieae (Terayama, 1995), P.tainanensis (Terayama, 1995) and P.takasago (Terayama, 1996), have been recorded from Taiwan and three species, i.e. P.ishigakiensis (Yasumatsu, 1955), P.minutus (Yasumatsu, 1955) and P.ryukyuensis (Terayama, 1999), from the Ryukyus in Japan. In the present study, the species-level classification of both Taiwanese and Ryukyuan species of Pristepyris was revised using newly-collected specimens by the external and male genital morphological as well as molecular phylogenetic analysis. Overall, six species of Pristepyris were recorded from Taiwan and the Ryukyus. Among these, five were previously recorded for the region and were revised here: P.ishigakiensis, P.mieae, P.ryukyuensis, P.tainanensis and P.zhejiangensis. Additionally, a new species, P.seqalu sp. nov., is herein described and illustrated. Furthermore, the species P.minutus is transferred to Eleganesia and P.takasago is synonymized under P.minutus. Due to the new combination of Pristepyrisminutus, a key to Taiwanese and Ryukyuan species of the genus Eleganesia, based on male morphology, is provided in Appendix 1. We confirmed for the first time the correspondence between the male and female species of P.zhejiangensis by molecular data. High compatibility in species delimitation patterns, suggested by the morphological and molecular phylogenetic approaches, highlighted the significance of the former approach for accurately classifying aged voucher specimens of Pristocerinae in public collections.

Intraspecific evolution of sexually dimorphic characters in a female diving beetle can be promoted by demographic history and temperature

Previous studies have predicted that antagonistic intraspecific evolution of sexually dimorphic characters causing rapid speciation can be driven by demographic history and environmental variations. However, researchers have rarely examined this issue in the wild. Here, we examined intraspecific evolution of sexually dimorphic characters and its driving force by using a diving beetle, Acilius japonicus, which has very marked sexually dimorphic characters. Males with wider big suction cups could copulate with females with a higher success rate, whereas the mating durations of females with more hairs on their pronota were shorter. Females in a region with greater interpopulation genetic differentiation had more pronotal hairs. Considering that a previous study showed that less continuity among populations leads to a higher female cost of mating, this result suggests a greater female cost of mating in this region. Females at warmer sites also had more pronotal hairs. In light of the increase in O₂ consumption in warmer water, our result suggests that more pronotal hairs in females at warmer sites have been maintained to prevent prolonged underwater mating at higher O₂ demand. These findings suggest that demographic history and temperature can direct the evolution of sexually dimorphic characters related to sexual conflict in females.

Local ecological divergence of two closely related stag beetles based on genetic, morphological, and environmental analyses

The process of phenotypic adaptation to the environments is widely recognized. However, comprehensive studies integrating phylogenetic, phenotypic, and ecological approaches to assess this process are scarce. Our study aims to assess whether local adaptation may explain intraspecific differentiation by quantifying multidimensional differences among populations in closely related lucanid species, Platycerus delicatulus and Platycerus kawadai, which are endemic saproxylic beetles in Japan. First, we determined intraspecific analysis units based on nuclear and mitochondrial gene analyses of Platycerus delicatulus and Platycerus kawadai under sympatric and allopatric conditions. Then, we compared differences in morphology and environmental niche between populations (analysis units) within species. We examined the relationship between morphology and environmental niche via geographic distance. P. kawadai was subdivided into the “No introgression” and “Introgression” populations based on mitochondrial COI gene – nuclear ITS region discordance. P. delicatulus was subdivided into “Allopatric” and “Sympatric” populations. Body length differed significantly among the populations of each species. For P. delicatulus, character displacement was suggested. For P. kawadai, the morphological difference was likely caused by geographic distance or genetic divergence rather than environmental differences. The finding showed that the observed mitochondrial–nuclear discordance is likely due to historical mitochondrial introgression following a range of expansion. Our results show that morphological variation among populations of P. delicatulus and P. kawadai reflects an ecological adaptation process based on interspecific interactions, geographic distance, or genetic divergence. Our results will deepen understanding of ecological specialization processes across the distribution and adaptation of species in natural systems.

Pronounced mito-nuclear discordance and various Wolbachia infections in the water ringlet Erebia pronoe have resulted in a complex phylogeographic structure

Several morphological and mitochondrial lineages of the alpine ringlet butterfly species Erebia pronoe have been described, indicating a complex phylogenetic structure. However, the existing data were insufficient and allow neither a reconstruction of the biogeographic history, nor an assessment of the genetic lineages. Therefore, we analysed mitochondrial (COI, NDI) and nuclear (EF1α, RPS5) gene sequences and compared them with sequences from the sister species Erebia melas. Additionally, we combined this information with morphometric data of the male genitalia and the infection patterns with Wolbachia strains, based on a WSP analysis. We obtained a distinct phylogeographic structure within the E. pronoe-melas complex with eight well-distinguishable geographic groups, but also a remarkable mito-nuclear discordance. The mito-nuclear discordance in E. melas and E. pronoe glottis can be explained by different ages of Wolbachia infections with different Wolbachia strains, associated selective sweeps, and hybridisation inhibition. Additionally, we found indications for incipient speciation of E. pronoe glottis in the Pyrenees and a pronounced range dynamic within and among the other high mountain systems of Europe. Our results emphasize the importance of combined approaches in reconstructing biogeographic patterns and evaluating phylogeographic splits.

Evolution and Diversity of Inherited Viruses in the Nearctic Phantom Midge, Chaoborus americanus

Inherited mutualists, parasites, and commensals occupy one of the most intimate ecological niches available to invertebrate-associated microbes. How this transmission environment influences microbial evolution is increasingly understood for inherited bacterial symbionts, but in viruses, research on the prevalence of vertical transmission and its effects on viral lineages is still maturing. The evolutionary stability of this strategy remains difficult to assess, although phylogenetic evidence of frequent host shifts and selective sweeps have been interpreted as strategies favoring parasite persistence. In this study, we describe and investigate a natural insect system in which species-wide sweeps have been restricted by the isolation of host populations. Previous work identified evidence of pronounced mitochondrial genetic structure among North American populations of the phantom midge, Chaoborus americanus. Here we take advantage of the geographical isolation in this species to investigate the diversity and persistence of its inherited virome. We identify eight novel RNA viruses from six families and use small RNA sequencing in reproductive tissues to provide evidence of vertical transmission. We report region-specific virus strains that mirror the continental phylogeography of the host, demonstrating that members of the inherited virome have independently persisted in parallel host lineages since they last shared a common ancestor in the Mid Pleistocene. We find that the small interfering RNA pathway, a frontline of antiviral defense in insects, targets members of this inherited virome. Finally, our results suggest that the Piwi-mediated RNA silencing pathway is unlikely to function as a general antiviral defense in Chaoborus, in contrast to its role in some mosquitoes. However, we also report that the PIWI-interacting RNA pathway generates abundant piRNAs from endogenous viral elements closely related to actively infecting inherited viruses, potentially helping to explain idiosyncratic patterns of virus-specific Piwi targeting in this insect.