High Intraspecific Variability Research Articles

Bumble bee diet breadth increases with local abundance and phenophase duration, not intraspecific variation in body size.

Patterns of abundance across space and time, and intraspecific variation in body size, are two species attributes known to influence diet breadth and the structure of interaction networks. Yet, the relative influence of these attributes on diet breadth is often assumed to be equal among taxonomic groups, and the relationship between intraspecific variation in body size on interaction patterns is frequently neglected. We observed bee-flower interactions in multiple locations across Montana, USA, for two growing seasons and measured spatial and temporal patterns of abundance, along with interspecific and intraspecific variation in body size for prevalent species. We predicted that the association between spatial and temporal patterns of abundance and intraspecific variation in body size, and diet breadth, would be stronger for bumble bee compared to non-bumble bee species, because species with flexible diets and long activity periods can interact with more food items. Bumble bees had higher local abundance, occurred in many local communities, more intraspecific variation in body size, and longer phenophases compared to non-bumble bee species, but only local abundance and phenophase duration had a stronger positive association with the diet breadth of bumble bee compared to non-bumble bee species. Communities with a higher proportion of bumble bees also had higher intraspecific variation in body size at the network-level, and network-level intraspecific variation in body size was positively correlated with diet generalization. Our findings highlight that the association between species attributes and diet breadth changes depending on the taxonomic group, with implications for the structure of interaction networks.

Living at depth: ecophysiological condition of Boreomysis arctica in autumn and winter in the St. Lawrence estuary and gulf

Abstract Mysids, besides krill, play a significant role in energy transfer and carbon sequestration. The ecology of coastal species is better understood than that of deep dwelling species such as Boreomysis arctica. The objectives of this study were to quantify spatiotemporal variations in body condition and the trophic level of B. arctica in autumn and winter, under sea-ice conditions in the St. Lawrence system, using a multimarker approach. We sampled along a 1000 km transect. Mean abundances in winter were higher in the estuary compared to the Gulf of St. Lawrence. Body condition, measured as total lipid content, was higher in winter than in autumn. Lipids of B. arctica were mainly composed of wax esters, thereby B. arctica is richer in energetic lipids compared to the three dominant krill species. We also observed seasonal differences in the trophic level of B. arctica, revealing carnivorous behavior in autumn compared to omnivory in winter. High intra-specific variability in both energetic strategy and feeding behavior was found that is potentially due to opportunistic feeding. Energy rich reserves suggest that B. arctica could act as a valuable prey for both benthic and pelagic consumers and thus playing a key role in bentho-pelagic energy transfer.

New records of Micromegistus bakeri, Trägårdh 1948 (Acari: Mesostigmata: Parantennulidae), a mite symbiotic on carabid beetles, and notes on the species’ distribution and host specificity

Micromegistus bakeri is a purported commensal mite that spends most of its life on the ground beetle Scarites subterraneus. It is thought to sustain itself by feeding on the beetle’s dermal fluids and opportunistically scavenging on nearby organic debris, although the nature of this relationship, and whether it’s beneficial, detrimental or neutral to the host, is unclear. This species has previously been recorded in Mississippi, Texas, and Kansas. This study reports the first record of M. bakeri in Pennsylvania based on our collecting, as well as the first records for Ohio, Michigan, Missouri, Arizona, and Canada, based on previously unpublished museum records. The literature and our own survey of carabid beetles indicate that M. bakeri has a strong preference for S. subterraneus as a host and is not common on other carabids. Our own data shows a prevalence of 27% of S. subterraneus (10 out of 37) carrying M. bakeri, with an average of 3.1 (range 1–8) mites per infested beetle; none of the other 31 carabid species collected during this study carried M. bakeri. This study represents the first publicly available COI barcode sequence for this taxon. We also provide photographs of live mites and summarize suspected sightings from additional locations across North America obtained via the citizen science websites BugGuide and iNaturalist. These records indicate that M. bakeri is present throughout the known distribution of its beetle host. Suspected M. bakeri were observed on other Scarites species in North America, but their presence on these hosts needs to be confirmed via examination of physical specimens. It should be noted that the westernmost record for the species is in Arizona, based on a male specimen that exhibits 6.6% divergence in COI barcode sequence with specimens from Pennsylvania. The specimen is otherwise essentially morphologically identical to males of eastern USA, and it is therefore uncertain whether it represents a cryptic species or merely high intraspecific genetic divergence over a large geographic distance.

Intraspecific variation in antibiotic resistance potential within E. coli.

Intraspecific genomic diversity brings the potential for an unreported and diverse reservoir of cryptic antibiotic resistance genes in pathogens, as cryptic resistance can occur without major mutations and horizontal transmission. Here, we predicted the differences in the types of antibiotics and genes that induce cryptic and latent resistance between micro-diverse Escherichia coli strains. For example, we hypothesize that known resistance genes will be the culprit of latent resistance within clinical strains. We used a modified functional metagenomics method to induce expression in eight E. coli strains. We found a total of 66 individual genes conferring phenotypic resistance to 11 out of 16 antibiotics. A total of 14 known antibiotic resistance genes comprised 21% of total identified genes, whereas the majority (52 genes) were unclassified cryptic resistance genes. Between the eight strains, 1.2% of core orthologous genes were positive (conferred resistance in at least one strain). Sixty-four percent of positive orthologous genes conferred resistance to only one strain, demonstrating high intraspecific variability of latent resistance genes. Cryptic resistance genes comprised most resistance genes among laboratory and clinical strains as well as natural, semisynthetic, and synthetic antibiotics. Known antibiotic resistance genes primarily conferred resistance to multiple antibiotics from varying origins and within multiple strains. Hence, it is uncommon for E. coli to develop cross-cryptic resistance to antibiotics from multiple origins or within multiple strains. We have uncovered prospective and previously unknown resistance genes as well as antibiotics that have the potential to trigger latent antibiotic resistance in E. coli strains from varying origins.IMPORTANCEIntraspecific genomic diversity may be a driving force in the emergence of adaptive antibiotic resistance. Adaptive antibiotic resistance enables sensitive bacterial cells to acquire temporary antibiotic resistance, creating an optimal window for the development of permanent mutational resistance. In this study, we investigate cryptic resistance, an adaptive resistance mechanism, and unveil novel (cryptic) antibiotic resistance genes that confer resistance when amplified within eight E. coli strains derived from clinical and laboratory origins. We identify the potential of cryptic resistance genes to confer cross-resistance to antibiotics from varying origins and within multiple strains. We discern antibiotic characteristics that promote latent resistance in multiple strains, considering intraspecific diversity. This study may help detect novel resistance genes and functional genes that could become responsible for cryptic resistance among diverse strains and antibiotics, thus also identifying potential novel antibiotic targets and mechanisms.

High risk, high gain? Trade-offs between growth and resistance to extreme events differ in northern red oak (Quercus rubra L.).

Information about the resistance and adaptive potential of tree species and provenances is needed to select suitable planting material in times of rapidly changing climate conditions. In this study, we evaluate growth responses to climatic fluctuations and extreme events for 12 provenances of northern red oak (Quercus rubra L.) that were tested across three trial sites with distinct environmental conditions in Germany. Six provenances each were sourced from the natural distribution in North America and from introduced stands in Germany. We collected increment cores of 16 trees per provenance and site. Dendroecological methods were used to compare provenance performance and establish climate-growth relationships to identify the main growth limiting factors. To evaluate the provenance response to extreme drought and frost events, three site-specific drought years were selected according to the Standardized Precipitation Evapotranspiration Index (SPEI) and 2010 as a year with an extreme late frost event. Resistance indices for these years were calculated and assessed in relation to overall growth performance. We observed a high variation in growth and in the climate sensitivity between sites depending on the prevailing climatic conditions, as well as a high intra-specific variation. Overall, summer drought and low temperatures in the early growing season appear to constrain the growth of red oak. The resistance of provenances within sites and extreme years showed considerable rank changes and interaction effects. We did not find a trade-off between growth and resistance to late frost, namely, fast growing provenances had a high frost hardiness. Further, there was no evidence for a trade-off between growth and drought hardiness. Still, responses to drought or late frost differ between provenances, pointing to dissimilar adaptive strategies. Provenances from introduced (i.e. German) stands represent suitable seed sources, as they combine a higher growth and frost hardiness compared to their North American counterparts. Drought hardiness was slightly higher in the slow-growing provenances. The results provide a better understanding of the variable adaptive strategies between provenances and help to select suitable planting material for adaptive forest management.

A revision of the genus Arenopontia Kunz, 1937 (Copepoda, Harpacticoida, Arenopontiidae), including the description of five new species

A revision of the genus Arenopontia Kunz, 1937 (Harpacticoida, Arenopontiidae) is presented based on morphological examination of a wide range of material. The genus, as redefined herein, encompasses A. subterranea Kunz, 1937 (type species by monotypy), A. problematica Masry, 1970, A. nesaie Cottarelli, 1975 and A. riedli Lindgren, 1976, in addition to five new species from European waters: A. adriatica sp. nov., A. anatolica sp. nov., A. basibuyuki sp. nov., A. gunduzi sp. nov. and A. syltensis sp. nov. Arenopontia pontica Apostolov, 1969 is considered unidentifiable and confirmed as a species inquirenda. The widely accepted notion that A. subterranea represents a cosmopolitan species displaying high intraspecific variability is rejected. Previous illustrated records attributed to the type species are critically reassessed and indicate that future examination of additional material from sandy beaches in the Northern Hemisphere will lead to further splintering of “A. subterranea” into a complex of cryptic lineages. Arenopontia subterranea and A. syltensis sp. nov. occur sympatrically on the Isle of Sylt while extensive sampling in the Black Sea revealed a similar overlap in distribution between A. anatolica sp. nov. and A. basibuyuki sp. nov. This study provides yet another example of how rigorous morphology-based analysis of pseudocosmopolitan taxa allows resolution of previously unrecognized cryptic status into multiple named species without recourse to molecular sequence data. A key to the nine valid species of Arenopontia is presented and distribution data for each species are collated.

Detailed DNA barcoding of mayflies in a small European country proved how far we are from having comprehensive barcode reference libraries.

Mayflies (Ephemeroptera) are among the crucial water and habitat quality bioindicators. However, despite their intensive long-term use in various studies, more reliable mayfly DNA barcode data have been produced in a negligible number of countries, and only ~40% of European species had been barcoded with less than 50% of families covered. Despite being carried out in a small area, our study presents the second-most species-rich DNA reference library of mayflies from Europe and the first comprehensive view from an important biodiversity hotspot such as the Western Carpathians. Within 1153 sequences, 76 morphologically determined species were recorded and added to the Barcode of Life Data System (BOLD) database. All obtained sequences were assigned to 97 BINs, 11 of which were unique and three represented species never barcoded before. Sequences of 16 species with high intraspecific variability were divided into 40 BINs, confirming the presence of cryptic lineages. Due to the low interspecific divergence and the non-existing barcoding gap, sequences of six species were assigned to three shared BINs. Delimitation analyses resulted in 79 and 107 putative species respectively. Bayesian and maximum-likelihood phylogenies confirmed the monophyly of almost all species and complexes of cryptic taxa and proved that DNA barcoding distinguishes almost all studied mayfly species. We have shown that it is still sufficient to thoroughly investigate the fauna of a small but geographically important area to enrich global databases greatly. In particular, the insights gained here transcend the local context and may have broader implications for advancing barcoding efforts.

CyanoStrainChip: A Novel DNA Microarray Tool for High-Throughput Detection of Environmental Cyanobacteria at the Strain Level.

Detecting cyanobacteria in environments is an important concern due to their crucial roles in ecosystems, and they can form blooms with the potential to harm humans and nonhuman entities. However, the most widely used methods for high-throughput detection of environmental cyanobacteria, such as 16S rRNA sequencing, typically provide above-species-level resolution, thereby disregarding intraspecific variation. To address this, we developed a novel DNA microarray tool, termed the CyanoStrainChip, that enables strain-level comprehensive profiling of environmental cyanobacteria. The CyanoStrainChip was designed to target 1277 strains; nearly all major groups of cyanobacteria are included by implementing 43,666 genome-wide, strain-specific probes. It demonstrated strong specificity by in vitro mock community experiments. The high correlation (Pearson's R > 0.97) between probe fluorescence intensities and the corresponding DNA amounts (ranging from 1-100 ng) indicated excellent quantitative capability. Consistent cyanobacterial profiles of field samples were observed by both the CyanoStrainChip and next-generation sequencing methods. Furthermore, CyanoStrainChip analysis of surface water samples in Lake Chaohu uncovered a high intraspecific variation of abundance change within the genus Microcystis between different severity levels of cyanobacterial blooms, highlighting two toxic Microcystis strains that are of critical concern for Lake Chaohu harmful blooms suppression. Overall, these results suggest a potential for CyanoStrainChip as a valuable tool for cyanobacterial ecological research and harmful bloom monitoring to supplement existing techniques.

High genetic load without purging in caribou, a diverse species at risk

High intra-specific genetic diversity is associated with adaptive potential, which is key for resilience to global change. However, high variation may also support deleterious alleles through genetic load, thereby increasing the risk of inbreeding depression if population sizes decrease. Purging of deleterious variation has been demonstrated in some threatened species. However, less is known about the costs of declines and inbreeding in species with large population sizes and high genetic diversity even though this encompasses many species globally that are expected to undergo population declines. Caribou is a species of ecological and cultural significance in North America with a wide distribution supporting extensive phenotypic variation but with some populations undergoing significant declines resulting in their at-risk status in Canada. We assessed intra-specific genetic variation, adaptive divergence, inbreeding, and genetic load across populations with different demographic histories using an annotated chromosome-scale reference genome and 66 whole-genome sequences. We found high genetic diversity and nine phylogenomic lineages across the continent with adaptive diversification of genes, but also high genetic load among lineages. We found highly divergent levels of inbreeding across individuals, including the loss of alleles by drift but not increased purging in inbred individuals, which had more homozygous deleterious alleles. We also found comparable frequencies of homozygous deleterious alleles between lineages regardless of nucleotide diversity. Thus, further inbreeding may need to be mitigated through conservation efforts. Our results highlight the "double-edged sword" of genetic diversity that may be representative of other species atrisk affected by anthropogenic activities.

High intraspecific variability and previous experience affect polyphenol metabolism in polyphagous Lymantria mathura caterpillars.

Polyphagous insect herbivores feed on multiple host-plant species and face a highly variable chemical landscape. Comparative studies of polyphagous herbivore metabolism across a range of plants is an ideal approach for exploring how intra- and interspecific chemical variation shapes species interactions. We used polyphagous caterpillars of Lymantria mathura (Erebidae, Lepidoptera) to explore mechanisms that may contribute to its ability to feed on various hosts. We focused on intraspecific variation in polyphenol metabolism, the fates of individual polyphenols, and the role of previous feeding experience on polyphenol metabolism and leaf consumption. We collected the caterpillars from Acer amoenum (Sapindaceae), Carpinus cordata (Betulaceae), and Quercus crispula (Fagaceae). We first fed the larvae with the leaves of their original host and characterized the polyphenol profiles in leaves and frass. We then transferred a subset of larvae to a different host species and quantified how host shifting affected their leaf consumption and polyphenol metabolism. There was high intraspecific variation in frass composition, even among caterpillars fed with one host. While polyphenols had various fates when ingested by the caterpillars, most of them were passively excreted. When we transferred the caterpillars to a new host, their previous experience influenced how they metabolized polyphenols. The one-host larvae metabolized a larger quantity of ingested polyphenols than two-host caterpillars. Some of these metabolites could have been sequestered, others were probably activated in the gut. One-host caterpillars retained more of the ingested leaf biomass than transferred caterpillars. The pronounced intraspecific variation in polyphenol metabolism, an ability to excrete ingested metabolites and potential dietary habituation are factors that may contribute to the ability of L. mathura to feed across multiple hosts. Further comparative studies can help identify if these mechanisms are related to differential host-choice and response to host-plant traits in specialist and generalist insect herbivores.

Effects of microhabitat features on the intraspecific variability of the distribution and functional traits in a highest elevational distributed lizard.

Exploring the microhabitat determinants of organisms distribution and functional traits differences can help us better understand the importance of intraspecific variations in ecological niches. Investigations on animals functional niche primarily focused on differences among species and tended to neglect the potential variability within species, despite the fact that the ecological and evolutionary importance of intraspecific variations was widely recognized. In this study, we examined the influence of microhabitat features on the intraspecific variability of the distribution and functional traits of a highest elevational distributed lizard species Phrynocephalus erythrurus. To do so, field work was conducted between July and August, 2020 and August and September, 2021 in Namtso watershed in central Xizang, China. Specifically, 11 transects were sampled for P. erythrurus individuals, which were measured for a set of 10 morphological traits. Moreover, 11 microhabitat variables that potentially affect the distribution of lizards were also measured for each transect. Our results indicated that juveniles, males, and females exhibited different functional traits, allowing them to occupy distinct functional space. The distribution of juveniles, males, and females was determined by different microhabitat variables such as illuminance and air temperature. More importantly, these variables also determined the intraspecific functional traits variability in this lizard species. All of these results supported previous claims that intraspecific traits variation should be incorporated into functional ecological studies, and diverse microhabitat features should be conserved to maintain high intraspecific diversity. Future studies can focus on the food analysis to explore the linkage between functional traits and resources utilization within animal populations.

Selection of photosynthetic traits by turbulent mixing governs formation of cyanobacterial blooms in shallow eutrophic lakes.

Abstract Prediction of the complex cyanobacteria-environment interactions is vital for understanding harmful bloom formation. Most previous studies on these interactions considered specific properties of cyanobacterial cells as representative for the entire population (e.g. growth rate, mortality, and photosynthetic capacity (Pmax)), and assumed that they remained spatiotemporally unchanged. Although, at the population level, the alteration of such traits can be driven by intraspecific competition, little is known about how traits and their plasticity change in response to environmental conditions and affect the bloom formation. Here we test the hypothesis that intraspecific variations in Pmax of cyanobacteria (Microcystis spp.) play an important role in its population dynamics. We coupled a one-dimensional hydrodynamic model with a trait-based phytoplankton model to simulate the effects of physical drivers (turbulence and turbidity) on the Pmax of Microcystis populations for a range of dynamic conditions typical for shallow eutrophic lakes. Our results revealed that turbulence acts as a directional selective driver for changes in Pmax. Depending on the intensity of daily-periodic turbulence, representing wind-driven mixing, a shift in population-averaged phenotypes occurred toward either low Pmax, allowing the population to capture additional light in the upper layers, or high Pmax, enhancing the efficiency of light utilization. Moreover, we observed that a high intraspecific diversity in Pmax accelerated the formation of surface scum by up to more than four times compared to a lower diversity. This study offers insights into mechanisms by which cyanobacteria populations respond to turbulence and underscores the significance of intraspecific variations in cyanobacterial bloom formation. Highlights

Diverse eggs, diverse species? Production of two egg morphotypes in Paramacrobiotus bifrons, a new eutardigrade species within the areolatus group

Species within the eutardigrade superfamily Macrobiotoidea are usually differentiated through their eggshell morphology. However, this trait can show very high intraspecific variability and, as consequence, species delimitation is challenging without molecular support. Although eggshell variability usually consists of small details, cases of species with very different egg morphotypes are known. Paramacrobiotus bifrons sp. nov. here described with an integrative approach, represents one of the species with extreme variability in eggshell morphology and it belongs to the areolatus group. The production by this gonochoric species of both areolatus-type and csotiensis-type eggs, the latter being rare in the group but most abundant in this species, was assessed by DNA barcoding, culturing, and inter-morphotype crosses. The reason underlying the production of two different eggshells resulted not related to tested culturing conditions, seasonality, or male’s influence. Confocal (with and without staining), Light, and Scanning Electron Microscopies analyses of the two egg morphotypes laid by P. bifrons sp. nov. allowed to redescribe the csotiensis-type egg, shed light on its composition (excluding chitin as a component), and to find shared details supporting the belonging of the two egg morphotypes to the same species. http://www.zoobank.org/urn:lsid:zoobank.org:pub:E9519638-2CE9-414D-B96B-0F403845D4CA http://www.zoobank.org/urn:lsid:zoobank.org:act:82DDACA5-F539-4A80-8418-8AF4A370B631

Effect of temperature on growth and yessotoxin production of Protoceratium reticulatum and Lingulodinium polyedra (Dinophyceae) isolates from the Portuguese coast (NE Atlantic)

The dinoflagellates Protoceratium reticulatum and Lingulodinium polyedra are potential yessotoxin (YTX) producers, which have been associated with blooms responsible for economic, social, and ecological impacts around the world. They occur in Iberian waters, but in this region, little is known of their ecophysiology and toxin profiles. This study investigated the growth and toxin production of two strains of each species, from the Portuguese coast, at 15 °C, 19 °C, and 23 °C. Growth curves showed higher growth rates at 19 °C, for both species. YTX and three analogs (homo YTX; 45-OH YTX; 45-OH homo YTX) were investigated by Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS), and the presence of other analogs was investigated by Liquid Chromatography-High-Resolution Mass Spectrometry (LC-HRMS). No evidence of toxin production was found in L. polyedra. By contrast, YTX and 45,55-diOH-YTX were detected in both strains of P. reticulatum. These results confirm P. reticulatum as a source of yessotoxins along the Portuguese coast and add to the observed high intraspecific variability on YTX production of both species, at a global scale.

Untangling the taxonomic ambiguities of the spotted seerfish Scomberomorus guttatus with the description of a new species from India.

Scomberomorus guttatus has been subjected to a series of synonym assignations over the years. Its taxonomy has been mired with ambiguities due to the greater-than-average morphological variations observed in samples from different regions. An integrated taxonomic revision with molecular support indicated that the species that was thought to be a single entity, in reality, is a complex of three distinct species. They are morphologically distinct with respect to the body depth and elongation, cephalic morphometry, and meristic characteristics. Otolith morphometry and phylogenetic evidence further established the taxonomic divergence within the spotted seerfish complex. The phylogenetic characteristic as indicated by the mitochondrial Cytochrome c Oxidase subunit I (COI) sequence unveiled that S. guttatus had a high intraspecific divergence of 11.1% from its two identical congeners and a divergence of 2.34% between the congeners, indicating scope for categorizing them as separate species. Based on the morphological and molecular evidence, S. guttatus is redescribed; the senior synonym Scomberomorus leopardus is resurrected as a valid species; and a new species Scomberomorus avirostrus n. sp. is described with keys for species distinction.

Molecular Discrimination and Phylogenetic Relationships of Physalis Species Based on ITS2 and rbcL DNA Barcode Sequence

Plants of the genus Physalis are of economic interest because of their fleshy edible fruits with high nutritional value. Some species have high medicinal value with a long history of ethno-medicinal use to treat diverse diseases. There is therefore a need to correctly discriminate the different species of Physalis for proper utilization. Although most Physalis species have unique morphologies, their vegetative stages are identical, making it difficult to accurately identify them based on morphological characteristics. DNA barcoding has the potential to discriminate species accurately. In this study, ribulose bisphosphate carboxylase large (rbcL) and internal transcribed spacer 2 (ITS2) regions were used to discriminate Physalis species and to reveal their phylogenetic relationships and genetic diversity. Physalis plant samples were collected from seven counties in Kenya based on the availability of the germplasm. The voucher specimens were identified using the botanical taxonomy method and were deposited in the University of Nairobi herbarium. Genomic DNA was isolated from leaf samples of 64 Physalis accessions and used for PCR amplification and the sequencing of rbcL and ITS2 barcode regions. The discriminatory ability of the barcodes was based on BLASTn comparison, phylogenetic reconstruction and cluster analysis, and the determination of inter- and intra-specific distances. The nucleotide polymorphism, genetic diversity and distance of the identified Physalis species were determined using DnaSP and MEGA 11.0 software. Species discrimination was more robust using ITS2 sequences. The species identified and discriminated by ITS2 sequences were Physalis purpurea, Physalis peruviana and Physalis cordata. The rbcL sequences were only able to identify Physalis to the genus level. There was high interspecific and low intraspecific divergence within the identified Physalis species based on ITS2 sequences. The ITS2 barcode is an ideal DNA barcode for use in the discrimination of species, as well as in genetic diversity studies of Physalis accessions in Kenya.

Biogeographic patterns of micro-eukaryotic generalists and specialists and their effects on regional α-diversity at inter-oceanic scale

Inter-oceanic scale studies allow us to understand the global spread of micro-organisms in marine ecosystems. In this study, micro-eukaryotic communities in marine surface sediment were collected from tropical to Arctic sites. We found that micro-eukaryotic generalists had much higher intraspecific variation than specialists which allow them to distribute more widely through higher spatiotemporal asynchrony and complementary niche preferences among conspecific taxa. Moreover, comparing to the host-associated protozoa and small metazoa, the algae and free-living protozoa with higher intraspecific variation allow them to have wider distribution ranges. Species abundance also played an important role in driving the distribution ranges of generalists and specialists. The generalists had important effects on regional α-diversity even at an inter-oceanic scale which led to the micro-eukaryotic species richness in polar sites to be mainly influenced by the regional generalists but not the local specialists. In particular, more than 97% of algal species in polar sites were shared with the tropical and subtropical sites (including toxic dinoflagellate). Overall, our study suggests that the effects of global change and human activities on the vulnerable high latitude habitats may lead to biotic homogenization for the whole microbial community (not only the dispersal of some harmful algae) through the potential long-distance spread of generalists.

First record of Colpodidium caudatum (Ciliophora, Colpodidiidae) in Europe

The present study documents the discovery of the first European population of Colpodidium caudatum (Ciliophora, Colpodidiidae) in a water drain in a school playground in Manzanares (Ciudad Real, Spain). This species has been documented on every continent except Antarctica and Europe, until now. The ciliate was isolated from wet run-off soil collected from the water drain and was grown in semi-permanent cultures in the laboratory. The infraciliature of the ciliate was revealed using silver carbonate impregnation and cell measurements were taken from living and silver-impregnated specimens. A comparative analysis of published data from various populations of C. caudatum across the globe showed high intraspecific morphological variability in this species. To differentiate between species within the Colpodidium genus, a dichotomous key is presented. This investigation shows that C. caudatum is a ciliate that is found all over the world and is particularly associated with terrestrial habitats that are periodically flooded.

Molecular Characterization of Ciborinia camelliae Kohn Shows Intraspecific Variability and Suggests Transcontinental Movement of the Pathogen.

Ciborinia camelliae Kohn is the causal agent of camellia flower blight. The fungus infects only the flowers of camellias. C. camelliae isolates obtained from symptomatic samples, collected in 13 different localities worldwide, were characterized by Multi-Locus Sequence Typing (MLST) using the following: (i) a nuclear ribosomal DNA internal transcribed spacer; (ii) subunit 2 of β-tubulin (β-TUB II), (iii) elongation factor 1-α (EF1α); and (iv) glycerol-3-phosphate dehydrogenase (GPDH). The variability of the strains was assessed using a universally primed-polymerase chain reaction (UP-PCR) with six universal primers. Gene sequence comparison showed high similarity among all the European strains and highlighted the diversity of the New Zealand and Chinese representative strains. The profiles obtained by UP-PCR confirmed the significant diversity of extra-European strains and identified subgroups within the European population. The presence of shared genetic profiles obtained from strains isolated in different countries (New Zealand and France) suggests the movement of strains from one location to another, which is probably due to the exchange of infected plant material. Moreover, our study shows the overall high intraspecific variability of C. camelliae, which is likely due to the sexual reproduction of the fungus, suggesting the risk of emergence of new pathotypes adapting to novel camellia varieties.

Molecular phylogeny, biogeography, and species delimitation of segmented spider genus Liphistius (Araneae: Liphistiidae) in Thailand

Abstract Mesothelae, or primitively segmented trapdoor spiders, form the most basal clade among living spiders. In Southeast Asia, Liphistius is the only genus recognized in the extant family Liphistiidae. Liphistius taxonomy and species identification are based largely on characters of the genitalia; however, the female genitalia show high intraspecific variation, males are rarely collected, and the phylogenetic relationships among the 69 described Liphistius species are unresolved. Here, we focused on the Liphistius of Thailand, including 37 described and numerous undescribed species in four species groups. We generated sequences from five loci (COI, 16S, H3, 28S, and ITS2) for 162 specimens from 52 sites in Thailand and Myanmar to reconstruct phylogenetic relationships, infer historical biogeography, and delimit species. The five-locus data set resolved nearly all species and species group relationships and was mostly congruent with morphology-based classifications. Ancestral area reconstruction suggested that Liphistius originated in Sibumasu (Siam–Burma–Malaysia–Sumatra) and diversified into several species groups, four (birmanicus, bristowei, linang, and trang) of which are found in Thailand. Speciation within Liphistius occurred in the area corresponding to their current distribution. All delimitation methods tested (ASAP, GMYC, PTP, STACEY and BFD) delimited specimens from discrete locations as separate species; variation in the number of species proposed (ranging from 53 to 72) stemmed from variation in delimitation of sympatric cryptic species.