Parthenogenetic Populations Research Articles

Intraspecific diversity of Myrmecophilus acervorum (Orthoptera: Myrmecophilidae) indicating an ongoing cryptic speciation

Myrmecophilus acervorum, previously considered a parthenogenetic species widely-distributed in Europe, has been observed to have both sexes in populations inhabiting the central part of the distribution range. Specimens from those heterosexual populations have been found being infected with Wolbachia. New mitochondrial data (COI and 16S markers) revealed the well-supported differentiation of M. acervorum populations inhabiting western Polesie (Poland) and southern Europe. In turn, analyses of EF1α marker support the hypothesis on the unfinished lineage sorting at the nuclear DNA level. Interestingly, we found that parthenogenetic populations inhabiting western Polesie are infected with Wolbachia belonging to supergroup A, while endosymbionts occurring in sexual populations of M. acervorum observed in Romania belong to supergroup B. Furthermore, new and potentially diagnostic characteristics in the external structures of the eyes of M. acervorum were identified. The surface of ommatidia in specimens occurring in southern Europe was smooth. In contrast, the ommatidia surface of individuals collected in Poland was visibly sculptured. To sum up, the significant genetic variability found in the present case, and the differentiating morphological character, are almost certainly effects of cryptic species being present within M. acervorum. This is indicative of ongoing speciation within the populations of this insect, and of simultaneous unfinished lineage sorting at the nuclear DNA level.

The number of artemia bottom cysts (Artemia Leach, 1819) in different hyperhaline lakes of the Altai territory

Artemia cysts are economically significant. One of the components of the reserve is the biomass of artemia cysts submerged to the bottom. 22 hyperhaline lakes of the Altai Territory were studied in 2018–2021. It was found that artemia lived in all the studied lakes, including bisexual populations in 4 lakes, and parthenogenetic populations in 18. The lakes were conditionally divided into 5 groups. 1192 soil samples were selected and processed. The types of sediments were conditionally divided into 6 groups depending on the dominant particles. The dependence of the concentration of bottom artemia cysts on the type of sediments was revealed (r = 0.289, p = 0.001, n = 732). It is determined that the concentration of cysts does not depend on the salinity of the water in the lake, with the same salinity, the density of cysts varies from 0 to several million depending on the type of sediments. The dependence of the concentration of bottom cysts in the summer period on the selected group of lakes was established (r = 0.817, p = 0.1, n = 5). In brine lakes the minimum concentration was observed in spring, in Deep-water and Medium-deep lakes the maximum was observed in summer, in Shallow brine lakes — in autumn. In group of lakes “Shallow, salt precipitates“ and “Drying up in summer” lakes a decrease in the concentration of cysts at the bottom was noted from spring to autumn. The influence of the depth of occurrence on the density of artemia cysts in silt sediments has been studied: in Maloe Yarovoye Lake 63% is in the upper layer, in Kulundinskoye Lake the highest density is in a layer of 5–10 cm, in Bolshoe Yarovoye Lake cysts are evenly distributed in viscous silt at a depth of 5 to 20 cm. The change in the concentration of bottom cysts in autumn and subsequent spring was analyzed to identify the proportion of cysts that have risen from the bottom. Up to 98% of cysts float in Shallow lakes, 4–62% in Deep and Medium-deep lakes.

Tiny but mighty mayfly - probing Prosopistoma pennigerum (Müller 1785) as the Flagship species for the Vjosa Wild River National Park

The recently created Vjosa Wild River National Park sets precedence at the European scale to protect a rare river ecosystem and, at the same time, the last refuge of the almost extinct mayfly Prosopistoma pennigerum (Müller 1785, Fig. 1). We extensively searched for the species in the Vjosa and five abiotically similar but fragmented surrounding rivers. To characterize the genetic diversity of the Vjosa population and assess its potential as a source population, we analysed partial mtCOI data. Besides high abundances in the Vjosa River, we observed only a few specimens in the free-flowing section of the Osumi River, but in no other investigated river although suitable habitat appears to be widely available at site-scale. Molecular analysis of 174 specimens revealed largely homogeneous sequences across all sampling sites and an almost 100% infection rate with Wolbachia sp. that suggests parthenogenetic reproduction, possibly as a strategy to increase resilience to high natural disturbance dynamics. We argue that P. pennigerum should serve as a flagship species for the Vjosa Wild River National Park. The species is exceptionally aesthetic, and its most viable, but apparently parthenogenetic populations are restricted to the Vjosa River where the species is widespread. The restricted regional distribution indicates only weak (or no) potential to recolonize and/or re-establish in other rivers, and the absence from fragmented rivers suggests dependence on high ecological integrity. Implications for conservation: Our findings thus sanction our nomination of P. pennigerum as the flagship species for the Vjosa Wild River National Park.

Does ecology shape geographical parthenogenesis? Evidence from the facultatively parthenogenetic stick insect Megacrania batesii.

Closely related sexual and parthenogenetic species often show distinct distribution patterns, known as geographical parthenogenesis. Similar patterns, characterized by the existence of separate sexual and parthenogenetic populations across their natural range, can also be found in facultative parthenogens - species in which every female is capable of both sexual and parthenogenetic reproduction. The underlying mechanisms driving this phenomenon in nature remain unclear. Features of the habitat, such as differences in host-plant phenotypes or niche breadth, could favour sexual or asexual reproductive modes and thus help to explain geographical parthenogenesis in natural insect populations. Megacrania batesii is a facultatively parthenogenetic stick insect that displays geographical parthenogenesis in the wild. We aimed to explore whether sexual and parthenogenetic populations of M. batesii displayed niche differentiation or variations in niche breadth that could explain the separation of the two population types. To do this, we sampled host plants from across the range of M. batesii and quantified phenotypic traits that might affect palatability or accessibility for M. batesii, including leaf thickness, toughness, spike size and density, plant height, and chemical composition. We also quantified host-plant density, which could affect M. batesii dispersal. We found little evidence of phenotypic differences between host plants supporting sexual versus asexual M. batesii populations, and no difference in host-plant density or niche breadth between the two population types. Our results suggest that habitat parameters do not play a substantial role in shaping patterns of geographical parthenogenesis in wild populations of M. batesii. Instead, population sex ratio variation could result from interactions between the sexes or dispersal dynamics.

Comparative Analysis of Bisexual and Parthenogenetic Populations in Haemaphysalis Longicornis.

Haemaphysalis longicornis, a three-host tick with a wide host range, is widely distributed in different countries and regions. It stands out among ticks due to its unique feature of having both parthenogenetic and bisexual populations. Despite their morphological resemblance, the characteristics of the parthenogenetic population have been overlooked. In this comprehensive study, we systematically compared the similarities and differences between these two populations. Our investigation revealed that the parthenogenetic H. longicornis, widely distributed in China, was found in ten provinces, surpassing the previously reported distribution. Notably, individuals from the parthenogenetic population exhibited a prolonged blood-feeding duration during the larval and nymph stages compared to their bisexual counterparts. Additionally, the life cycle of the parthenogenetic population was observed to be longer. A flow cytometry analysis indicated a DNA content ratio of approximately 2:3 between the bisexual and parthenogenetic populations. A phylogenetic analysis using whole mitochondrial genome sequences resulted in the separation of the phylogenetic tree into two distinct branches. A molecular analysis unveiled a consistent single T-base deletion at nucleotide 8497 in the parthenogenetic population compared to the bisexual population. Both populations displayed high viral infection capability and significant resistance to ivermectin. Intriguingly, despite these differences, the parthenogenetic population exhibited a similar life cycle to the bisexual population, retaining the ability to transmit pathogens such as Severe fever with thrombocytopenia syndrome virus (SFTSV) and Heartland Virus (HRTV). These findings contribute to a deeper understanding of the distinct characteristics and similarities between different populations of H. longicornis, laying the foundation for future research in this field.

The species problem in Artemia Leach, 1819 (Crustacea: Anostraca), a genus with sexual species and obligate parthenogenetic lineages

Abstract Parthenogenesis is an asexual reproduction mode characterized by the development of a female oocyte without fertilization. From an evolutionary perspective, parthenogenesis seems less successful than the predominant sexual mode, though there are groups in which both reproductive types exist, an example of which is the genus Artemia Leach, 1819. This salt-tolerant crustacean inhabiting hypersaline environments contains regionally endemic sexual species and obligate parthenogenetic groups with different ploidy levels, collectively referred to as Artemia parthenogenetica. Here, we discuss the difficulties of using a common species concept in Artemia Leach, 1819. While sexual species are widespread and fit the Biological Species Concept (BSC), which emphasizes reproductive isolation to maintain species genetic integrity or cohesiveness, it does not apply to uniparental organisms originating from sexual species with major meiotic changes. We show that different ploidy levels of parthenogenetic Artemia groups with uniform nuclear gene pools are maternally independent genetic entities (or cohesive), collectively and wrongly referred to as Artemia parthenogenetica. Thus, we conclude that ‘Artemia parthenogenetica’ is an invalid nominal specific name. Additionally, parthenogenetic Artemia groups cannot be considered a form of Artemia species (A. urmiana and/or A. sinica). In conclusion, we recommend using the term ‘parthenogenetic lineage(s)’ instead of ‘parthenogenetic population(s)’ to describe asexual Artemia group(s), because in modern population genetics and systematics, the term ‘population’ refers to interbreeding individuals with sexual reproduction. Furthermore, it clarifies that parthenogenetic lineages of Artemia are native to Mediterranean biodiversity.

Wolbachia springs eternal: symbiosis in Collembola is associated with host ecology.

Wolbachia are endosymbiotic alpha-proteobacteria infecting a wide range of arthropods and nematode hosts with diverse interactions, from reproductive parasites to obligate mutualists. Their taxonomy is defined by lineages called supergroups (labelled by letters of the alphabet), while their evolutionary history is complex, with multiple horizontal transfers and secondary losses. One of the least recently derived, supergroup E, infects springtails (Collembola), widely distributed hexapods, with sexual and/or parthenogenetic populations depending on species. To better characterize the diversity of Wolbachia infecting springtails, the presence of Wolbachia was screened in 58 species. Eleven (20%) species were found to be positive, with three Wolbachia genotypes identified for the first time in supergroup A. The novel genotypes infect springtails ecologically and biologically different from those infected by supergroup E. To root the Wolbachia phylogeny, rather than distant other Rickettsiales, supergroup L infecting plant-parasitic nematodes was used here. We hypothesize that the ancestor of Wolbachia was consumed by soil-dwelling nematodes, and was transferred horizontally via plants into aphids, which then infected edaphic arthropods (e.g. springtails and oribatid mites) before expanding into most clades of terrestrial arthropods and filarial nematodes.

Taxonomic study of Scytosiphon (Phaeophyceae) from temperate coasts of Argentina.

Scytosiphon is a common intertidal genus widely distributed on temperate coasts worldwide. Recently, eight species have been delimited with molecular tools. Although S. lomentaria is the only species that predominates in the macroalgal literature of the Southwestern Atlantic Ocean (SwAO), unpublished molecular data obtained for a population study of S. lomentaria revealed hidden species diversity of Scytosiphon among the individuals collected from four localities at the SwAO. The aim of this study was to revise the identity and phylogenetic relationships of Scytosiphon from temperate coasts of the SwAO using DNA data. Thalli were collected from the Argentinean coast between 39° S and 43° S, from which cox1 and rbcL gene sequences were obtained. Phylogenies and haplotype networks were inferred and morphology of gametophytes was studied. Four species were recognized, S. lomentaria, S. promiscuus, S. shibazakiorum, and one species that belongs to a complex of species known as "Scytosiphon Atlantic complex." This complex was known to occur only in the North Atlantic, however, the results found in this study revealed that it has an extended distribution range that includes the southern hemisphere, where its populations have high genetic diversity and unique haplotypes. The morphological differences among the four species were subtle; denoting that previous Scytosiphon records from the SwAO attributed to the renowned S. lomentaria could represent different species. In addition, sex ratio and genome-wide single nucleotide polymorphisms (SNPs) analyses were done for populations of S. promiscuus presumably introduced to the SwAO, and the results indicated that they included female-dominant parthenogenetic populations, which were probably introduced from Japan.

Morphology and biometry of two Chinese diploid parthenogenetic Artemia populations with a special emphasis on the gonopods and frontal knobs of rare males

Morphological and biometric characters of rare males and females of two diploid parthenogenetic populations from Gahai Lake (GH) and Chengkou Saltern (CK-par) (China) were surveyed. The characters were compared with those of six bisexual species. The gonopod of rare males consists of a basal portion and a distal portion. The distal portion of the gonopod ends in a fine digitiform apex and is ornamented with numerous spines (distal gonopod spines). The number and height of spines on the posterior surface (posterior spines) are conspicuously larger than spines on the exo-lateral surface (exo-lateral spines). The morphology of distal gonopod spines of rare males is most closely related to Artemia urmiana, but posterior spines are apparently taller in the rare males than in A. urmiana. Frontal knobs of rare males are sub-spherical in lateral view, and sub-elliptic in frontal view. The large diameter against small diameter ratio of the frontal knob of GH is significantly larger than that of CK-par. The number of frontal knob spines in rare males is close to that of Artemia salina, Artemia franciscana and Artemia persimilis, but significantly smaller than that of Artemia sinica, Artemia tibetiana and A. urmiana. The number of solitary spines of GH is significantly smaller than that of CK-par. Discriminant analyses using 13 parameters in females and 24 parameters in males show that GH and CK-par are close to each other but divergent from bisexual species. The analytical result based on male genital parameters is likely to be more coincident with the molecular phylogeny than that based on the non-sex-related parameters.

Microhabitat modeling of the invasive Asian longhorned tick (Haemaphysalis longicornis) in New Jersey, USA

The Asian longhorned tick (Haemaphysalis longicornis) is a vector of multiple arboviral and bacterial pathogens in its native East Asia and expanded distribution in Australasia. This species has both bisexual and parthenogenetic populations that can reach high population densities under favorable conditions. Established populations of parthenogenetic H. longicornis were detected in the eastern United States in 2017 and the possible range of this species at the continental level (North America) based on climatic conditions has been modeled. However, little is known about factors influencing the distribution of H. longicornis at geographic scales relevant to local surveillance and control. To examine the importance of local physiogeographic conditions such as geology, soil characteristics, and land cover on the distribution of H. longicornis we employed ecological niche modeling using three machine learning algorithms - Maxent, Random Forest (RF), and Generalized Boosting Method (GBM) to estimate probability of finding H. longicornis in a particular location in New Jersey (USA), based on environmental predictors. The presence of H. longicornis in New Jersey was positively associated with Piedmont physiogeographic province and two soil types - Alfisols and Inceptisols. Soil hydraulic conductivity was the most important predictor explaining H. longicornis habitat suitability, with more permeable sandy soils with higher hydraulic conductivity being less suitable than clay or loam soils. The models were projected over the state of New Jersey creating a probabilistic map of H. longicornis habitat suitability at a high spatial resolution of 90×90 meters. The model's sensitivity was 87% for locations sampled in 2017-2019 adding to the growing evidence of the importance of soil characteristics to the survival of ticks. For the 2020-2022 dataset the model fit was 57%, suggestive of spillover to less optimal habitats or, alternatively, heterogeneity in soil characteristics at the edges of broad physiographic zones. Further modeling should incorporate abundance and life-stage information as well as detailed characterization of the soil at collection sites. Once critical parameters that drive the survival and abundance of H. longicornis are identified they can be used to guide surveillance and control strategies for this invasive species.

First record of Ulva californica in the mainland of China: a single alien parthenogenetic population in discontinuous distribution

First record of Ulva californica in the mainland of China: a single alien parthenogenetic population in discontinuous distribution

Validation of two novel primers for the promising amplification of the mitogenomic Cytochrome c Oxidase subunit I (COI) barcoding region in Artemia aff. sinica (Branchiopoda, Anostraca)

Abstract Due to the lack of a taxonomic key for the identification of Artemia species, molecular markers have been increasingly used for phylogenetic studies. The mtCOI marker is a regularly considered marker for the molecular systematics of Artemia populations. The proposed universal and specific primers have mostly failed to amplify the Artemia aff. sinica mtCOI marker, and on the whole, the successfully amplified products of the PCR were inefficient, primarily through the representation of poly-peak or incomplete sequences. We presumed that if a forward primer could be developed regarding the joint regions of the last part of the previous gene (tRNATyr) and the beginning of the target gene mtCOI, the sequence could be relevant to the target-sequence of mtCOI. Thus, here, we describe a new set of primers, which could be used to amplify the mtCOI barcoding region of Artemia aff. sinica Cai, 1989, with a high performance of sequencing. The new primer set worked well also for other Artemia bisexual species, as well as for parthenogenetic populations. It is recommended that joint regions between the previous/next gene(s) and the target marker, could be aimed at when designing specific primers for other markers and taxa.

Cyst size variability in invasive American Artemia franciscana Kellogg, 1906 (Branchiopoda, Anostraca) in Asia: a commercial approach

Abstract Artemia is the most common live food that is used in aquaculture worldwide. This study reports on biometrical variation in the cysts of the introduced, originally American Artemia franciscana from 24 non-native localities and two native habitats, in Asia and the U.S.A., respectively. The results show, that the largest diameter of untreated cysts, the largest diameter of decapsulated cysts, and a thicker chorion usually are found in invasive populations. Because of the small cysts, which have an effect on an increasing quantity per unit weight and thus could be the cause of increased hatching efficiency, commercial productions of A. franciscana cysts from native sources should potentially be considered higher quality than productions from non-indigenous environments. Principal Component Analysis revealed that all cyst batches from San Francisco Bay were classified in one group and most of the invasive populations could be arranged in another, separate group. Although the diameter of the decapsulated cyst and chorion thickness showed a negative and significant correlation among invasive populations, there was no significant relationship within native populations. These observations contrast with biometrical patterns of parthenogenetic populations.

Range of Occurrence of Bisexual and Parthenogenetic Populations of Labidostomma luteum (Acari: Prostigmata) in Europe

The current article describes an interesting case of geographic parthenogenesis among European mites from the Labidostommidae family (Acari: Prostigmata). In earlier publications on Labidostomma luteum Kramer, 1879, the authors pointed out that most of the populations of this species in Europe consisted of parthenogenetic females. Until now, populations of both sexes were known only in southwestern France. In the north–west areas, the number of males in the populations has gradually decreased, and in the populations found west of Paris there are no males at all. During the research project carried out in 2018, Błoszyk found the presence of populations which consisted of both sexes of the species in question near the town of Bény (60 km NE of Lion). This is the easternmost site of L. luteum in France where males have been found. All other known sites located east and north of the Bény–Paris line have only parthenogenetic females. Thus, this line can be considered as the boundary of L. luteum populations reproducing sexually. However, establishing the exact course of this range requires further research.

Sexually but not parthenogenetically produced females benefit from mating in a stick insect

Abstract In facultatively parthenogenetic populations, the prevalence of sexual reproduction depends on whether females mate and therefore produce sons and daughters or avoid mating and produce daughters only. The relative advantage of mating in such species may depend on a female's own reproductive origin (i.e. development from a fertilised or unfertilised egg) if parthenogenesis reduces heterozygosity similar to sexual inbreeding, or if it inhibits mating, sperm storage or fertilisation. But effects of reproductive origin on development and performance are poorly understood. Using the facultatively parthenogenetic stick insect, Extatosoma tiaratum, we quantified morphology, mating probability, and reproductive success in mated versus unmated females of sexual versus automictic (parthenogenetic) origin. We found strong evidence that increased homozygosity negatively impacted some traits in parthenogenetically produced females: compared to sexually produced females, parthenogenetically produced females were smaller and more prone to deformities in vestigial wings, but not more prone to fluctuating asymmetry in their legs. Parthenogenetically produced females received fewer mating attempts and avoided mating more often than sexually produced females. Yet, contrary to the expectation that sex should rescue parthenogenetic lineages from the detrimental effects of increased homozygosity, parthenogenetically produced females gained no net reproductive benefit from mating, suggesting that physiological constraints limit fitness returns of sexual reproduction for these females. Our findings indicate that advantages of mating in this species depend on female reproductive origin. These results could help to explain spatial distributions of sex in facultatively parthenogenetic animals and evolutionary transitions to obligate asexuality. Read the free Plain Language Summary for this article on the Journal blog.

Population genetic dynamics during colonisation and establishment of an obligate parthenogenetic Daphnia pulex population in a small lake of a continental archipelago

Abstract Population genetic diversity and structure are known to influence successful colonisation and establishment of a population in a novel habitat. However, our understanding of actual population genetic changes in the early stage of colonisation and detailed time‐series of genetic changes during the establishment of a new population is still limited due to the difficulty of making long‐term direct observations of a colonising population. Using a paleolimnological approach, we revealed the long‐term genetic dynamics of an obligate parthenogenetic panarctic Daphnia pulex population during the early stage of colonisation and subsequent establishment in Lake Fukami‐ike of Nagano, Japan. We collected diapausing eggs in ephippia of D. pulex from layers of sediment core samples (c. 370 cm long; dated 1662–2017) and then the mitochondrial DNA was sequenced using the markers designed for the NADH dehydrogenase 5 (ND5) gene and the control region. Daphnia pulex colonised and established a population in the early 2000s. Population genetic analysis showed that one colonising haplotype predominated in the population throughout the study period. Genetic diversity was consistently limited and there was no recovery of genetic diversity after colonisation. Clearly limited genetic diversity did not hamper population growth, possibly because phenotypic plasticity was used to cope with changes in predation pressure. Analysis using multivariate auto‐regressive models showed that responses to environmental and ecological factors varied depending on the haplotype, which may have contributed to successful colonisation of the lake by the different haplotypes. The present results suggest that an obligate parthenogenetic population can establish in a new habitat and be maintained for generations even though it has limited genetic diversity. We found that two independent lineages (JPN1 and JPN2) successfully established and coexisted toward the end of the study period. Although limited genetic diversity did not impede colonisation success, how the later colonising JPN1 lineage has successfully invaded a population consisting solely of the early colonising JPN2 deserves future attention to understand the population genetic dynamics revealed in this study.

Brine shrimps adrift: historical species turnover in Western Mediterranean Artemia (Anostraca)

Brine shrimps (Artemia) have undergone geographic range and demographic expansions as a result of their interaction with humans since the beginning of salt harvesting. This interaction has favoured the expansion of some species but compromising the survival of others. Mediterranean native populations of Artemia salina from coastal salterns and lagoons are facing the presence and expansion of the introduced and invasive American species Artemia monica (= A. franciscana). However, this species could not be the only threat. Parthenogenetic populations of the Asian species A. urmiana and A. sinica are widespread along the Mediterranean and other areas of the world. In this work, with the use of large cox1 and mitogenomic datasets, phylogenetic and phylogeographic inferences, and a time calibrated tree, we confirmed the Asian origin and recent arrival of the current Western Mediterranean parthenogenetic populations of Artemia. In addition, the replacement of Iberian populations of A. salina by Asiatic parthenogenetic populations lead us to recognize parthenogens as invasive. Current salterns development and commercial importance of Artemia make human-mediated introduction probable. These results demonstrate again the impact that changing human interests have on population expansion or decline of species adapted to anthropogenic habitats. Artemia salina decline makes urgent the implementation of conservation measures such as its use in fish farming and salt production or its inoculation in inland salterns.

Rapid Spread of Severe Fever with Thrombocytopenia Syndrome Virus by Parthenogenetic Asian Longhorned Ticks.

Severe fever with thrombocytopenia syndrome virus (SFTSV) is spreading rapidly in Asia. This virus is transmitted by the Asian longhorned tick (Haemaphysalis longicornis), which has parthenogenetically and sexually reproducing populations. Parthenogenetic populations were found in ≥15 provinces in China and strongly correlated with the distribution of severe fever with thrombocytopenia syndrome cases. However, distribution of these cases was poorly correlated with the distribution of populations of bisexual ticks. Phylogeographic analysis suggested that the parthenogenetic population spread much faster than bisexual population because colonization is independent of sexual reproduction. A higher proportion of parthenogenetic ticks was collected from migratory birds captured at an SFTSV-endemic area, implicating the contribution to the long-range movement of these ticks in China. The SFTSV susceptibility of parthenogenetic females was similar to that of bisexual females under laboratory conditions. These results suggest that parthenogenetic Asian longhorned ticks, probably transported by migratory birds, play a major role in the rapid spread of SFTSV.

Ant crickets and their secrets:Myrmecophilus acervorumis not always parthenogenetic (Insecta: Orthoptera: Myrmecophilidae)

AbstractPreviously considered as a thelytokous parthenogenetic species, the widespread ant cricket Myrmecophilus acervorum actually turns out to have a mixed reproductive system: our recent surveys in the central part of its distribution area has revealed the presence of both sexes. Detailed morphological and morphometric descriptions of the previously unknown males are here provided. New data on species distribution in south-eastern Europe are presented, including the first records of M. balcanicus in Bulgaria and of M. nonveilleri in Bulgaria and Hungary. Phylogenetic and phylogeographic analyses have revealed several haplotypes of M. acervorum in Europe, with six of them forming a parthenogenetic clade in populations distributed west of the Carpathians. We tested our samples for bacterial infection by Wolbachia and, surprisingly, Wolbachia was identified only in populations with both sexes and no amplification was obtained from parthenogenetic populations. Phylogenetic analyses performed with sequences pertaining to five nominal species related to M. acervorum, yielded topological congruent trees with four well-supported groups: one group with M. acervorum samples, the second group with M. nonveilleri samples, the third group with M. fuscus and M. gallicus samples, and the fourth group with samples of M. balcanicus. We performed species delineation tests on our sequences, which delimited between four to seven putative species.

Illumina whole genome sequencing indicates ploidy level differences within the Valenzuela flavidus (Psocodea: Psocomorpha: Caeciliusidae) species complex

AbstractValenzuela flavidus is a species of bark louse which is known to have asexual parthenogenetic populations in Europe but is believed to have sexual and asexual populations in North America as well. Historically, Valenzuela aurantiacus was the species epithet recognized for North American members until reports of asexual reproduction surfaced in certain North American populations. Cytogenetic studies have demonstrated European all‐female populations are triploid. However, males are often reported in North America suggesting diploidy for sexual populations. With the use of Illumina whole genome sequencing, genetic diversity among North American and European populations was explored with phylogenomic methods. Ploidy level was estimated by examining allele frequencies of read‐mapped homologous gene regions. Results indicate divergent populations between Europe and North America. North American populations containing males are estimated to be diploid suggesting a different mechanism of genomic reproduction. These results suggest divergent population structure among European asexual and North American sexual members of V. flavidus providing insight for future studies to understand patterns of asexuality reported within the complex.