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The gut microbiome can play a fundamental role in several processes associated with an organism’s ecology, and research on the microbiota of wild animals has flourished in the last decades. Microbiome composition can vary across and within species according to taxonomy and environmental variability, including the availability of food resources. Species with a large distribution may exhibit spatial patterns acting at local/regional scales. We considered one of the most widespread and ecologically important predators in the world, i.e., the grey wolf Canis lupus, for which microbiome data is unduly limited. We studied four packs in different ecological conditions in Italy—two packs from a Mediterranean coastal area and two packs from an Alpine range—using an amplicon sequencing barcoding approach. Overall, our results are consistent with food habits entailing a diet largely based on wild prey and agree with findings obtained on other species of canids. If confirmed through a larger sample, they would support the hypothesis of an influence of the shared evolutionary history across canids on the composition of the gut microbiome. Some emerging differences were observed among packs in terms of species composition (Jaccard) and diversity, providing partial support to recent indications on pack identity as a significant determinant of microbiome composition. These results should be considered preliminary results of gut microbiome composition in our study areas.

Symphypleona (sensu stricto) are a group of Collembola (=springtails) that, despite displaying some variation in gene order, have been poorly investigated under the phylomitogenomic perspective. How families and subfamilies of this taxon are evolutionary related is still partially unknown. For this reason we sequenced, and herein described, the complete mitochondrial genome sequence of Allacma fusca (Sminthuridae). This sequence, alongside others from the literature, is here used to study the phylogenetic relationships among Symphypleona.

Complete mitochondrial genome data are frequently applied to address phylogenetic/phylogeographic issues at different taxonomic levels in ecology and evolution. While sample preparation/sequencing is becoming more and more straightforward thanks to dropping costs for next-generation sequencing (NGS), data preparation and visualization remains a manually intensive step that may lead to errors if improperly conducted. We have elaborated, and here introduce, EZmito, a simple and intuitive, freely accessible Web Server aimed at automating some of these tasks. EZmito is divided into three main tools: EZpipe that assembles DNA matrices for phylo-mitogenomic analyses; EZskew that calculates genome, strand, and codon nucleotide compositional skews and EZcodon which computes Relative Synonymous Codon Usage statistics as well as amino acid usage frequency over multiple mitogenomes. Output is produced in tabular format as well as publication-quality graphics.

Collembola are an ancient and early diverging lineage of basal hexapods that occur in virtually all terrestrial habitats on Earth. Phylogenetic relationships between the different orders of Collembola are fiercely debated. Despite a range of studies and the application of both morphological and genetic approaches (singly or in combination) to assess the evolutionary relationships of major lineages in the group, no consensus has been reached. Several mitogenome sequences have been published for key taxa of the class (and their number is increasing rapidly). Here, we describe two new Antarctic Collembola mitogenomes and compare all complete or semi-complete springtail mitogenome sequences available on GenBank in terms of both gene order and DNA sequence analyses in a genome evolution and molecular phylogenetic framework. With minor exceptions, we confirm the monophyly of Poduromorpha and Symphypleona sensu stricto (the latter placed at the most basal position in the springtail phylogenetic tree), whereas monophyly of Neelipleona and Entomobryomorpha is only supported when a handful of critical taxa in these two lineages are excluded. Finally, we review gene order models observed in the class, as well as the overall mitochondrial nucleotide composition.

The complete mitochondrial genome of the machilid Trigoniophthalmus alternatus (Silvestri 1904) is herein described and applied to phylogenetic analyses, inclusive of the most early-divergent lineages of hexapods. Both gene content and order generally conform with the organization of the arthropods’ mitochondrial genome. One gene translocation involving trnA is the autapomorphic character observed in this species. Another peculiar molecular feature is the long size of the A + T-rich region, due to the occurrence of repeat units. The phylogenetic analyses support the typical placement, along the hexapods’ tree, of Ectognatha, Monocondylia and Dicondylia, with Diplura as the adelphotaxon of all true insects.

Mitochondrial DNA (mtDNA) encodes for proteins mainly involved in the oxidative phosphorylation process, and due to its molecular features, it is one of the most used molecular markers for phylogenetic and taxonomic purposes. Since mitochondria are the primary source of energy for aerobic organisms, it has been suggested that modifications of the mitochondrial genome’s features could be linked with major adaptive processes to particular environmental conditions. In this respect, Antarctic Collembola (springtails) may be considered an interesting model to study whether positive selective pressure has occurred, inducing significant changes in the mtDNA characteristics that have eventually led to cold adaptation. In this study, we describe the molecular features of the mitochondrial genome of Cryptopygus terranovus, a springtail species endemic to Victoria Land. Molecular data are also employed to support the new taxonomic placement of C. terranovus, and to establish if the conspecific lineages of Friesea antarctica, that lives in separated biogeographical regions of the Antarctic Continent, are indeed distinct species. Finally, all the mitochondrial genomes of springtails, so far sequenced, were applied for calculating the ratio (ω) of nonsynonymous versus synonymous nucleotide substitutions. This approach allowed us to investigate if Antarctic collembolans could have experienced Darwinian selective pressures compared to the non-Antarctic springtail species. Indeed, our data does indicate positive selection (ω > 1), suggesting that survival at extreme environmental conditions could be also related to mtDNA modifications.

Symphypleona (sensu stricto) are a group of Collembola (=springtails) that, despite displaying some variation in gene order, have been poorly investigated under the phylomitogenomic perspective. How families and subfamilies of this taxon are evolutionary related is still partially unknown. For this reason we sequenced, and herein described, the complete mitochondrial genome sequence of Allacma fusca (Sminthuridae). This sequence, alongside others from the literature, is here used to study the phylogenetic relationships among Symphypleona.

The use of plastics burgeoned in the last decades to become an essential component of our society. An environment friendly method to dispose of plastic waste is not available yet, to the outcome that these accumulate in landfills or are scattered as microplastics. New researches reported that some coleopteran species are able to destroy plastics thanks to their chewing mouthparts and the metabolic activity of their gut microbiota. This study shows that the lesser mealworm Alphitobius diaperinus is capable of feeding on, and apparently degrading, polystyrene. The gut microbiota of polystyrene-fed larvae was characterized using an NGS metagenomic approach, targeting both bacteria and fungi. Several microbe taxa emerged as differentially abundant between treatment and control groups (Cronobacter, Kocuria and Pseudomonas as bacteria, Aspergillus, Hyphodermella, Trichoderma as fungi). Some of them have been found in association with plastic compounds and/or have been proposed to be capable of plastic degradation. This research supports the notion that, although synthetic molecules, unlike most natural compounds, do not generally enter the natural food chain to be degraded by the environmental microbiota, some microbial communities may be able to decompose plastics. We speculate that, once identified, such communities may open to the possibility of devising bioreactors for plastic degradation.

Background Clinical heterogeneity is a peculiarity of vestibular migraine, in contrast to other vestibular disorders that have a more stereotypical expression. Migraine presents a range of variability in symptoms depending on the age of the patient. Supposing that migraine headache and vestibular migraine share the same pathogenetic mechanisms, a multiparametric analysis was performed to verify the hypotheses of an age-related influence on the clinical features of vestibular migraine at the onset. Methods In this retrospective study, we analysed the clinical records of 72 consecutive patients affected by vestibular migraine from June 2012 to November 2018: 64 females and eight males; mean age 38.2 ± 9.6. We considered only patients that reported onset of vestibular symptoms within 12 months preceding inclusion into the study. Results Statistical analysis shows a significant increase in the diagnosis of probable vestibular migraine with increasing age and a decrease in vestibular migraine diagnosis ( p = 0.034). The incidence of spontaneous dizziness increases with age ( p = 0.012); by contrast, external spontaneous vertigo, and visually induced vertigo decrease after 40 years of age ( p = 0.018), clinically characterising the onset of juvenile forms. Spontaneous vertigo, head motion-induced vertigo/dizziness, and positional vertigo did not show significant variations with age. Conclusion Our data show that the type of vestibular symptoms in vestibular migraine varies according to the age of onset.

Proturans are small, wingless, soil-dwelling arthropods, generally associated with the early diversification of Hexapoda. Their bizarre morphology, together with conflicting results of molecular studies, has nevertheless made their classification ambiguous. Furthermore, their limited dispersal capability (due to the primarily absence of wings) and their euedaphic lifestyle have greatly complicated species-level identification. Mitochondrial and nuclear markers have been applied herein to investigate and summarize proturan systematics at different hierarchical levels. Two new mitochondrial genomes are described and included in a phylum-level phylogenetic analysis, but the position of Protura could not be resolved with confidence due to an accelerated rate of substitution and extensive gene rearrangements. Mitochondrial and nuclear loci were also applied in order to revise the intra-class systematics, recovering three proturan orders and most of the families/subfamilies included as monophyletic, with the exception of the subfamily Acerentominae. At the species level, most morphologically described species were confirmed using molecular markers, with some exceptions, and the advantages of including nuclear, as well as mitochondrial, markers and morphology are discussed. At all levels, an enlarged taxon sampling and the integration of data from different sources may be of significant help in solving open questions that still persist on the evolutionary history of Protura.

Previous work focused on allozymes and mitochondrial haplotypes has detected high levels of genetic variability betweenCryptopygus terranovuspopulations, a springtail species endemic to Antarctica, until recently namedGressittacantha terranova. This study expands these biogeographical surveys using additional analytical techniques, providing a denser haplotype dataset and a wider sampling of localities. Specimens were collected from 11 sites across Victoria Land and sequenced for the cytochromecoxidase subunit I mitochondrial gene (cox1). Haplotypes were used for population genetics, demographic, molecular clock and Bayesian phylogenetic analyses. Landscape distribution and clustering of haplotypes were also examined for the first time in this species. Only three (out of 67) haplotypes are shared among populations, suggesting high genetic structure and limited gene flow between sites. As in previous studies, the population of Apostrophe Island has a closer genetic similarity with those of the central sites, rather than with its neighbours. Molecular clock estimates point to early differentiation of haplotypes in the late/mid-Miocene, also supporting the view thatC. terranovusis a relict species that survived on the Antarctic continent during the Last Glacial Maximum. The present genetic composition of populations represents a mixture of ancient and more recent haplotypes, sometimes occurring in the same localities.

The complete mitochondrial genome of the springtail Bourletiella arvalis (Fitch, 1863) is herein described and applied to a Bayesian phylogenetic analysis, inclusive of all the Collembola mitochondrial DNAs sequenced so far. The gene content and order, as well as the nucleotide composition, conform with the well-known features of hexapods’ mitochondrial genomes. The phylogenetic analysis supports the monophyly of Collembola, Poduromorpha, Entomobryomorpha and Symphypleona. However, no mtDNA from Neelipleona is available to date, therefore limiting the application of mitochondrial genomes to further investigate springtail systematics.

The growing interest in Antarctic collembolan species has led us to re-evaluate both the morphological and molecular aspects of different species adapted to the extreme Antarctic environment. The genus Folsomotoma includes nine species mainly distributed in Antarctic and subantarctic areas and a few additionally from Australia and South America. We herein designate the neotype of Folsomotoma octooculata (Willem 1901) and redescribe its morphological characters with particular emphasis on the sensory and ordinary chaetotaxy. Furthermore, based on analyses of both our new and previously published morphological data for F. octooculata, we propose a systematic key of the species for the genus.

Stachorutes najtae n. sp. is described from the interstitial sand dunes of central Italy. It has 4 + 4 eyes with a postantennal organ composed of 7–9 simple vesicles and the furcal dens with six chaetae. Stachorutes najtae n. sp. appears closely related to S. gracilis Smolis & Shvejonkova, 2006 from which it can be separated by the different chaetotaxy of the dens and legs.

The ecological interactions that occur in and with soil are of consequence in many ecosystems on the planet. These interactions provide numerous essential ecosystem services, and the sustainable management of soils has attracted increasing scientific and public attention. Although soil ecology emerged as an independent field of research many decades ago, and we have gained important insights into the functioning of soils, there still are fundamental aspects that need to be better understood to ensure that the ecosystem services that soils provide are not lost and that soils can be used in a sustainable way. In this perspectives paper, we highlight some of the major knowledge gaps that should be prioritized in soil ecological research. These research priorities were compiled based on an online survey of 32 editors of Pedobiologia – Journal of Soil Ecology. These editors work at universities and research centers in Europe, North America, Asia, and Australia. The questions were categorized into four themes: (1) soil biodiversity and biogeography, (2) interactions and the functioning of ecosystems, (3) global change and soil management, and (4) new directions. The respondents identified priorities that may be achievable in the near future, as well as several that are currently achievable but remain open. While some of the identified barriers to progress were technological in nature, many respondents cited a need for substantial leadership and goodwill among members of the soil ecology research community, including the need for multi-institutional partnerships, and had substantial concerns regarding the loss of taxonomic expertise. nonPeerReviewed

Three sympatric springtail species, from the South Shetland Islands archipelago in the maritime Antarctic, are analysed here in a common biogeographic and evolutionary framework. This study was designed to compare their population genetic structure using the same molecular marker. Haplotype data for the mitochondrial cox1 gene have been obtained for seven populations of Folsomotoma octooculata and are compared with the data obtained, in previous studies and the current one, for the sympatric species Cryptopygus antarcticus antarcticus, and Friesea grisea. Molecular data obtained are consistent with the hypothesis that all species have been present in the archipelago since well before the last glacial maximum (around 20 000 ybp) and that their early diversifications appear to be linked with known interglacial periods in the region. These springtails may have survived the last glacial cycle in local refugia, from which they dispersed subsequently to ice-free ground re-exposed during the current interglacial period. The populations of the different species diversified at different times, although all of them are within the Pleistocene epoch. We propose that the earliest diversification of haplotypes in all three springtails in this archipelago occurred from local refugia in Livingston I., with subsequent spread of some haplotypes throughout the South Shetland Islands.

The darkling beetle Pimelia rugulosa rugulosa Germar, 1824 was selected to investigate the process of colonization in a volcanic archipelago and the role of volcanism in determining spatial patterns of genetic variability. Analyses were conducted in the Aeolian Islands, located in the central Mediterranean directly off the Sicilian coast. Genetic variability and geographic structure were studied in individuals from each island of the archipelago based on sequences of the cytochrome c oxidase subunit 2 mitochondrial gene; a network approach was employed to identify haplotype lineages. A strong genetic structure, with no haplotype sharing among islands, was observed. Six separate lineages were identified that independently colonized different islands of the archipelago from the mainland and differentiated locally to form small haplogroups. Variability of observed haplogroups is correlated with island age and a positive correlation between tenebrionid diversity and mitotype diversity is reported. Some, yet undescribed, catastrophic event is hypothesized to explain the depletion of a substantial part of the genetic, as well as biological diversity in the island of Filicudi. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 104, 29–37.

Mediterranean cetacean odontocetes are exposed to environmental stress, in particular to persistent organic pollutants, polycyclic aromatic hydrocarbons and trace elements. In the present study, the response of "gene-expression biomarkers" was evaluated in Mediterranean striped dolphin (Stenella coeruleoalba) skin biopsies collected in three sampling areas: Pelagos sanctuary (Ligurian sea), Ionian sea, and Strait of Gibraltar. The mRNA levels of five putative biomarker genes (aryl hydrocarbon receptor, E2F-1 transcription factor, cytochrome P450 1A, estrogen receptor 1, and heat shock protein 70) were measured for the first time by quantitative real-time PCR in cetacean skin biopsies. The different responses of most of the genes reflected contamination levels in the three sampling areas. Pelagos sanctuary dolphins appeared to be the most exposed to toxicological stress, having the highest up-regulation of CYP1A and AHR. Moreover, a cluster analysis distinguished the populations on the basis of the gene expression biomarker used in our study, showing different pattern between Mediterranean sea and Strait of Gibraltar. Our results suggest that this molecular approach applied to non-destructive biopsy material is a powerful diagnostic tool for evaluating ecotoxicological impact on cetacean populations.

The genus Pimelia is represented in Sicily by the two species P. grossa and P. rugulosa, the latter with the two subspecies P. r. rugulosa and P. r. sublaevigata. A third subspecies, P. r. apula, is present only in Puglia. The phylogeographic history of this genus in Sicily was reconstructed using sequences of the complete cox2 gene, applying phylogenetic and molecular dating methods. Phylogenetic analysis confirmed the monophyly of the two species, as well as the subdivision of P. rugulosa in the three morphological subspecies. One previously undetected and deeply divergent lineage was described that is geographically related to the Hyblean massif. It is therefore suggested that the deep divergence of the two major P. rugulosa clades in Sicily reflects an ancient separation between the Hyblean massif and the other land masses of Sicily. Dating analysis confirmed that the timing of P. rugulosa genetic divergence is compatible with the formation of the Hyblean massif. Furthermore, P. rugulosa populations of the Hyblean massif, whose taxonomy has been historically problematic, display levels of genetic divergence comparable to those observed at the species level. The possibility that this new lineage might deserve species rank is presented. Riassunto In Sicilia il genere Pimeliae rappresentato dalle due specie P. grossa e P. rugulosa, quest’ultima con le due sottospecie P. r. rugulosa e P. r. sublaevigata. Una terza sottospecie, P. r. apula, si trova soltanto in Puglia. Applicando metodi filogenetici e di datazione molecolare basati sull’analisi dell’intera sequenza del gene cox2e stata ricostruita la storia filogeografica di questo genere in Sicilia. L’analisi filogenetica ha confermato la monofilia delle due specie, cosi come la suddivisione di P. rugulosa nelle tre sottospecie morfologicamente riconosciute. E stata inoltre osservata una nuova linea evolutiva, sottolineata da una profonda divergenza genica, che riunisce le popolazioni di P. rugulosa provenienti dalla regione Iblea. Si ipotizza che questa suddivisione basale fra due linee di P. rugulosa possa riflettere l’antico isolamento del massiccio Ibleo dal resto della Sicilia. Le analisi di datazione molecolare hanno confermato che i tempi di divergenza di questa linea evolutiva di P. rugulosa potrebbero essere compatibili con la formazione del massiccio Ibleo. Queste popolazioni, che mostrano caratteri morfologici intermedi tra quelli delle tre sottospecie note, presentano livelli di distanza genica comparabili a quelli osservati tra specie distinte, facendo ipotizzare la loro appartenenza ad una specie inedita per la quale non e pero finora stato possibile individuare caratteri morfologici univoci.

Sperm ultrastructure and spermiogenesis of the dipluran Japygidae (Japyx solifugus, Metajapyx braueri and Occasjapyx japonicus) and Campodeidae (Campodea sp.) were studied with the aim of looking for potential characters for the reconstruction of the phylogenetic relationships of basal hexapods. Both Japygidae and Campodeidae share a common sperm axonemal model 9+9+2, provided with nine accessory microtubules. These microtubules, however, after their formation lose the usual position around the 9+2 and migrate between the two mitochondria. In Japygidae, four of these microtubules are very short and were observed beneath the nucleus after negative staining and serial sections. Accessory microtubules have 13 protofilaments in their tubular wall. Diplura have a sperm morphology which is very different from that of the remaining Entognatha (Protura+Collembola). On the basis of the present results, the presence of accessory microtubules suggests that Diplura are the sister-group of the Insecta s.s.. Moreover, Japygidae and Campodeidae differ with regards to the relative position of the sperm components, the former having the axoneme starting from beneath the nucleus (above which sits the short acrosome), while the latter having a long apical acrosome and a nucleus running parallel with the proximal part of the axoneme. The present study also allowed to redescribe the male genital system of Japyx.

Friesea grisea is the only springtail species currently described from both East (Victoria Land) and West Antarctica (Antarctic Peninsula), although levels of genetic divergence between the two regions suggest the possibility of cryptic species. Determining the genetic structure of populations in the two regions is necessary in order to compare the effects of the different environmental conditions in the two regions, the different evolutionary histories of their inhabitants, and for assessing any influence of latitude in each region on genetic diversity. We analysed sequences of the mitochondrial COX1 and ATP6 genes from a total of 111 individuals for 17 sites (nine on the Antarctic Peninsula and eight in Victoria Land), to assess levels of genetic diversity. Both regions have their own unique sets of haplotypes, differing by about 20% of their nucleotide sequences. A similar number of haplotypes was found in the two regions, and within each we found two groups of populations sharing no haplotypes. In the Antarctic Peninsula, two, presumably ancestral, haplotypes are dominant in frequency. In Victoria Land, the Cape Hallett population showed a distinct set of haplotypes, genetically different from the southernmost populations, suggesting differentiation on pre-Pleistocene timescales.

Collembola are one of the few hexapod groups adapted to live in the harsh environmental conditions of Antarctic terrestrial ecosystems. Diversity is limited to a few species that can be very abundant in coastal deglaciated sites. A remarkable lack of overlap in Collembola species composition is evident between Western and Eastern Antarctica, and Friesea grisea is currently the only species whose distribution is thought to span these two main regions of the continent. However, our analysis of the complete sequences of the mitochondrial genomes from specimens obtained from each of the two regions showed unexpected genetic divergence, well above the average levels observed between populations belonging to the same species, and so indicating that these are actually separate species, despite their lack of distinguishing morphology. Detailed analysis of the two genomes showed the presence of a non-coding region observed between trnS(uga) and nad1. Other features of these mitochondrial genomes, such as base compositional bias, secondary structure features of tRNAs and the presence of regulatory elements in the control region, are described and discussed from an evolutionary standpoint.

The North-Western Mediterranean basin is well known for its high number of relictual endemic taxa, and has been indicated as one of the world's major biodiversity hotspots at the species level. A possible contributing factor may be long-term persistence of populations and their prolonged stability. This study was designed to investigate the phylogeographic structure of three common species of the genus Lepidocyrtus (Hexapoda: Collembola), soil-dwelling arthropods characterized by limited dispersal capabilities and generally associated with forest habitats. We observed a remarkable geographic structure, with numerous deeply divergent genetic lineages occupying islands as well as mainland sites with no apparent gene flow among most sites, even across distances of only tens of kilometres. The reconstructed time frame for the evolution of these lineages suggests divergence between 5 and 15 Ma. This indicates a remarkably ancient origin and long-term persistence of individual lineages over a fine geographic scale despite the occurrence of abrupt sea level and climatic fluctuations in the area. This further suggests that currently recognized morphological species might be a serious underestimation of the true springtail biodiversity within this region.

We examined the genetic structure among populations and regions for the springtails Cryptopygus antarcticus antarcticus and Gomphiocephalus hodgsoni (Collembola) to identify potential historical refugia and subsequent colonization routes, and to examine population growth/expansion and relative ages of population divergence. Location Antarctic Peninsula for C. a. antarcticus; Antarctic continent (southern Victoria Land) for G. hodgsoni. Methods Samples were collected from 24 and 28 locations across the Antarctic Peninsula and southern Victoria Land regions for C. a. antarcticus and G. hodgsoni, respectively. We used population genetic, demographic and nested clade analyses based on mitochondrial DNA (cytochrome c oxidase subunit I and subunit II). Results Both species were found to have population structures compatible with the presence of historical glacial refugia on Pleistocene (2 Ma-present) time-scales, followed by post-glacial expansion generating contemporary geographically isolated populations. However, G. hodgsoni populations were characterized by a fragmented pattern with several 'phylogroups' (likely ancestral haplotypes present in high frequency) retaining strong ancestral linkages among present-day populations. Conversely, C. a. antarcticus had an excess of rare haplotypes with a much reduced volume of ancestral lineages, possibly indicating historical founder/bottleneck events and widespread expansion. Main conclusions We infer that these differences reflect distinct evolutionary histories in each locality despite the resident species having similar life-history characteristics. We suggest that this has predominantly been influenced by variation in the success of colonization events as a result of intrinsic historical glaciological differences between the Antarctic Peninsula and continental Antarctic environments.

Summary Collembola is a group of soil arthropods whose ecophysiological requirements tend to promote inter-population isolation and genetic differentiation. To test this, we analysed the genetic structure of 22 populations of two species of the genus Allacma (A. fusca and A. gallica), using allozyme electrophoresis. Several loci showed distinct differences between the two species, and high levels of genetic divergence (Nei's D=1.144±0.130) were found between them; in addition, the average genetic distance among populations was low in A. fusca (D=0.050±0.034), but considerably higher among those of A. gallica (D=0.435±0.342). The two species were significantly different in average heterozygosity with A. gallica (He=0.062) being more variable than A. fusca (He=0.028). Wright's FST statistics, based on polymorphic loci, indicate that the two species are subdivided into genetically heterogeneous populations, with A. gallica being more differentiated (FST=0.873) than A. fusca (FST=0.533). The observed divergence between and within the two species may result from the absence of gene flow and subsequent allopatric differentiation through genetic drift. In addition, ecological and geological factors may explain the origin of such a differentiation, while the peculiar mode of reproduction may influence the levels of intra-population genetic variability.

The present analyses employ the almost complete sequence of the 28S rRNA gene to investigate phylogenetic relationships among Pancrustacea, placing special emphasis on the position of basal hexapod lineages. This study utilizes a greater number of characters and taxa of Protura, Collembola and Diplura than previous analyses to focus on conflicts in the reconstruction of the early steps in hexapod evolution. Phylogenetic trees are mainly based on Bayesian approaches, but likewise include analyses with Maximum Likelihood and Maximum Parsimony. Different analyses, including the application of a mixed DNA/RNA substitution model, were performed to narrow possible misleading effects of non-stationarity of nucleotide frequencies, saturation and character independence down to a minimum. This is the first time that a mixed DNA/RNA model is applied to analyse 28S rRNA sequences of basal hexapods. All methods yielded strong support for the monophyly of Collembola, Diplura, Dicondylia and Insecta s.str., as well as for a cluster composed of Diplura and Protura (‘Nonoculata-hypothesis’). However, the last cluster may be an artifact caused by a shared GC bias of the 28S sequences between these orders, in combination with a long branch effect. The instability of the position of the ‘Nonoculata’ within Pancrustacea further bears out the misleading effect of non-stationarity of nucleotide frequencies. Protura and Diplura either form the sister-group to Collembola (Entognatha) or cluster with branchiopod crustaceans. Overall, the phylogenetic signal of the complete sequences of the 28S rRNA gene favours monophyly of Hexapoda over paraphyly. However, further corroboration from independent data is needed to rule out the competing hypothesis of mutually paraphyletic Crustacea and Hexapoda.

Acetylcholinesterase (AChE) is a key enzyme of thecholinergic nerve system. Of the two forms found ininsects, the predominant one is active in the synapsesand is the target of organophosphate and carbamateinsecticides, while the role of the second is currentlyunknown. Two acetylcholinesterase cDNAs from thebasal hexapod Orchesella villosa have been character-ized and compared with others reported form insects.One form conforms well to the typical structure, whilethe other is characterized by an unusual 3 ′′′ region. Noamino acid mutation could be directly associated withknown resistance mutations in other insect species orto a clear signal of selection in the distribution of alle-les, although the action of some population process issuggested.Keywords: Orchesella villosa , acetylcholinesterase, ace , AChE, insecticide resistance.Introduction Acetylcholinesterase (AChE; EC 3.1.1.7) in insects, as invertebrates, is a key enzyme involved in the transmission ofnerve impulses of the cholinergic system, and operates byinactivating the neurotransmitter acetylcholine (Toutant,1989). Additional functions have been proposed or inferredbased on evolutionary considerations (Weill

The sperm structure of two species of Embioptera, Embia savignyi Westwood 1837 and Aposthonia japonica (Okajima 1926), was studied. Spermatozoa of both species exhibit a monolayered acrosome and a layer of material surrounding the sperm cells for most of their length. The presence of a 9+9+2 axoneme provided with accessory microtubules with 16 protofilaments, two accessory bodies and two crystallized mitochondrial derivatives are characters shared with other polyneopteran taxa. The supposed close relationship between Embioptera and Phasmatodea is not supported by characters of the sperm ultrastructure.

We carried out a phylogeographic study using mtDNA (COII) for the endemic springtail Desoria klovstadi (formerly Isotoma klovstadi) from northern Victoria Land, Antarctica. Low levels of sequence divergence (≤ 1.6%) across 26 unique haplotypes (from 69 individuals) were distributed according to geographic location. Cape Hallett and Daniell Peninsula contained the highest nucleotide (both > 0.004) and haplotype (both > 0.9) diversity with 10 (of 16) and 8 (of 12) unique haplotypes, respectively. All other populations (Football Saddle, Crater Cirque, Cape Jones) had lower diversity with 2–4 unique haplotypes. Across the 69 individuals from five populations there was only a single haplotype shared between two populations (Daniell Peninsula and Football Saddle). Furthermore, nested clade analyses revealed that some of the Daniell Peninsula haplotypes were more closely related to Football Saddle haplotypes than to any other population. Such discrete haplotype groupings suggest historical (rare) dispersal across the Pleistocene (1.8 mya−11 kya) and Holocene (11 kya–present), coupled with repeated extinction, range contraction and expansion events, and/or incomplete sampling across the species range. The nested clade analyses reveal that a common pattern of climatic and geological history over long-term glacial habitat fragmentation has determined the geographic and haplotype distributions found for D. klovstadi.