Mixta mediterraneensis as a novel and abundant gut symbiont of the allergen-producing domestic mite Blomia tropicalis.

Blomia tropicalis is an allergen-producing mite in the human environment in tropical regions. The microbiome of B. tropicalis was described using the barcode sequencing region of V4 16S rDNA and genome assemblage. Mixta mediterraneensis, previously isolated from human skin swabs, was identified as a B. tropicalis gut symbiont based on genome assembly. The microbiome contains two bacteria, Staphylococcus and M. mediterraneensis. The number of M. mediterraneensis 16S DNA copies was 106 per mite and 109 per feces in the rearing chamber based on qPCR quantification. The profile of this bacterium reached 50% of reads in the mite gut and feces. Genomic analyses revealed that the bacterium has several metabolic pathways that suggest metabolic cooperation with the mite host in vitamin and amino acid synthesis, nitrogen recycling, and antimicrobial defense. Lysozyme is present in the symbiotic bacterium but absent in the mite. The B. tropicalis microbiome contained Staphylococcus, which accelerates mite population growth. Mites can digest Staphylococcus by using specific enzymes with hydrolytic functions against bacterial cell walls (chitinases and cathepsin D), leading to endocytosis of bacteria and their degradation in lysosomes and phagosomes. Gene expression analysis of B. tropicalis indicated that phagocytosis was mediated by the PI3-kinase/Akt pathway interacting with the invasins produced by M. mediterraneensis. Moreover, the symbiont had metabolic pathways that allowed it to recycle the mite metabolic waste product guanine, known as a mite attractant. The mite host symbiont enhances mite aggregation in the feces, and the fecal-oral transmission route is excepted.

Ancient Human Genomes and Environmental DNA from the Cement Attaching 2,000-Year-Old Head Lice Nits.

Over the past few decades, there has been a growing demand for genome analysis of ancient human remains. Destructive sampling is increasingly difficult to obtain for ethical reasons, and standard methods of breaking the skull to access the petrous bone or sampling remaining teeth are often forbidden for curatorial reasons. However, most ancient humans carried head lice and their eggs abound in historical hair specimens. Here we show that host DNA is protected by the cement that glues head lice nits to the hair of ancient Argentinian mummies, 1,500-2,000 years old. The genetic affinities deciphered from genome-wide analyses of this DNA inform that this population migrated from north-west Amazonia to the Andes of central-west Argentina; a result confirmed using the mitochondria of the host lice. The cement preserves ancient environmental DNA of the skin, including the earliest recorded case of Merkel cell polyomavirus. We found that the percentage of human DNA obtained from nit cement equals human DNA obtained from the tooth, yield 2-fold compared with a petrous bone, and 4-fold to a bloodmeal of adult lice a millennium younger. In metric studies of sheaths, the length of the cement negatively correlates with the age of the specimens, whereas hair linear distance between nit and scalp informs about the environmental conditions at the time before death. Ectoparasitic lice sheaths can offer an alternative, nondestructive source of high-quality ancient DNA from a variety of host taxa where bones and teeth are not available and reveal complementary details of their history.

Population growth and respiration in the dust mite Dermatophagoides farinae under different temperature and humidity regimes.

Dermatophagoides farinae is an important house dust mite species that causes allergies in humans worldwide. In houses, these mites are commonly found in actively used mattresses and pillows, which provide food (i.e. sloughed skin and microorganisms), moisture, and increased temperature for faster mite development. In mattresses, feeding mites prefer the upper sector, as close as possible to the resting human (temperature 32-36 °C, humidity between 55 and 59%). However, mites that are not actively feeding prefer staying at deeper zones of the mattress. Here, we analyzed mite responses to different temperatures (15-35 °C) and relative humidity (62-94% RH) in terms of their population size growth and respiration (CO2 production) using lab mite cultures. The intrinsic rate of population increase had a single maximum at approximately 28 °C and 85% RH. At 30 °C, there were two respiration peaks at RH 90% (smaller peak) and 65% (larger peak). Therefore, there is a mismatch between the optimal temperature/humidity for the population size increase vs. respiration. We propose preliminary hypotheses explaining the two respiration peaks and suggest that future research should be done to elucidate the nature of these peaks.

One-way ticket to the blue: A large-scale, dated phylogeny revealed asymmetric land-to-water transitions in acariform mites (Acari: Acariformes).

Acariform mites are an ancient and megadiverse lineage that may have experienced a complex pattern of invasions into terrestrial and aquatic habitats. These among-realm transitions may relate to periods of turmoil in Earth's history or be simply results of uneven biodiversity patterns across habitats. Here, we inferred a dated, representative acariform phylogeny (five genes, 9,200 bp aligned, 367 terminals belonging to 150 ingroup plus 15 outgroup families, 23 fossil calibration points) which was used to infer transitions between marine/freshwater/terrestrial habitats. We detected four unambiguous transitions from terrestrial to freshwater habitats (Hydrozetes, Naiadacarus, Fusohericia, Afronothrus, Homocaligus); one from freshwater to marine (Pontarachnidae), and four from marine to brackish or freshwater transitions (all among Halacaridae: Acarothrix; Halacarellus petiti; Copidognathus sp.; clade Limnohalacarus + Soldanellonyx + Porohalacarus + Porolohmannella). One transition to the sea was inferred ambiguously with respect to the ancestor being either terrestrial or freshwater (Hyadesiidae), and another must be most carefully examined by adding potential related taxa (Selenoribatidae + Fortuyniidae). Finally, we inferred a single, remarkable transition from aquatic to terrestrial habitats involving early evolution of the large and ecologically diverse lineage: the ancestor of the Halacaridae + Parasitengona clade was probably freshwater given our dataset, thus making terrestrial Parasitengona secondarily terrestrial. Overall, our results suggested a strong asymmetry in environmental transitions: the majority occurred from terrestrial to aquatic habitats. This asymmetry is probably linked to mites' biological properties and uneven biodiversity patterns across habitats rather than Earth's geological history. Since the land holds more acariform diversity than water habitats, a shift from the former is more likely than from the latter. We inferred the following relationships: alicid endeostigmatid + eriophyoid (Alycidae, (Nanorchestidae, (Nematalycidae, Eriophyoidea))) being sister group to the remaining Acariformes: (proteonematalycid Endeostigmata, alicorhagiid Endeostigmata, Trombidiformes, Oribatida (including Astigmata)). Trombidiform relationships had several novel rearrangements: (i) traditional Eupodina lacked support for the inclusion of Bdelloidea; (ii) Teneriffidae, traditionally placed among Anystina, was consistently recovered in a clade including Heterostigmata in Eleutherengona; (iii) several lineages, such as Adamystidae, Paratydeidae, Caeculidae and Erythracaridae, were recovered in a large clade along other Anystina and Eleutherengona, suggesting single origins of several fundamental character states, such as the reduction of the cheliceral fixed digit and development of the palpal thumb-claw complex.

Microbial Communities of Stored Product Mites: Variation by Species and Population.

Arthropod-associated microorganisms are important because they affect host fitness, protect hosts from pathogens, and influence the host's ability to vector pathogens. Stored product mites (Astigmata) often establish large populations in various types of food items, damaging the food by direct feeding and introducing contaminants, including their own bodies, allergen-containing feces, and associated microorganisms. Here we access the microbial structure and abundance in rearing diets, eggs, feces fraction, and mite bodies of 16 mite populations belonging to three species (Carpoglyphus lactis, Acarus siro, and Tyrophagus putrescentiae) using quantitative PCR and 16S ribosomal RNA (rRNA) gene amplicon sequencing. The mite microbiomes had a complex structure dominated by the following bacterial taxa (OTUs): (a) intracellular symbionts of the genera Cardinium and Wolbachia in the mite bodies and eggs; (b) putative gut symbionts of the genera Solitalea, Bartonella, and Sodalis abundant in mite bodies and also present in mite feces; (c) feces-associated or environmental bacteria of the genera Bacillus, Staphylococcus, and Kocuria in the diet, mite bodies, and feces. Interestingly and counterintuitively, the differences between microbial communities in various conspecific mite populations were higher than those between different mite species. To explain some of these differences, we hypothesize that the intracellular bacterial symbionts can affect microbiome composition in mite bodies, causing differences between microbial profiles. Microbial profiles differed between various sample types, such as mite eggs, bodies, and the environment (spent growth medium-SPGM). Low bacterial abundances in eggs may result in stochastic effects in parent-offspring microbial transmission, except for the intracellular symbionts. Bacteria in the rearing diet had little effect on the microbial community structure in SPGM and mite bodies. Mite fitness was positively correlated with bacterial abundance in SPGM and negatively correlated with bacterial abundances in mite bodies. Our study demonstrates critical host-microbe interactions, affecting all stages of mite growth and leading to alteration of the environmental microbiome. Correlational evidence based on absolute quantitation of bacterial 16S rRNA gene copies suggests that mite-associated microorganisms are critical for modulating important pest properties of mites by altering population growth.

Rewired RNAi-mediated genome surveillance in house dust mites.

House dust mites are common pests with an unusual evolutionary history, being descendants of a parasitic ancestor. Transition to parasitism is frequently accompanied by genome rearrangements, possibly to accommodate the genetic change needed to access new ecology. Transposable element (TE) activity is a source of genomic instability that can trigger large-scale genomic alterations. Eukaryotes have multiple transposon control mechanisms, one of which is RNA interference (RNAi). Investigation of the dust mite genome failed to identify a major RNAi pathway: the Piwi-associated RNA (piRNA) pathway, which has been replaced by a novel small-interfering RNA (siRNA)-like pathway. Co-opting of piRNA function by dust mite siRNAs is extensive, including establishment of TE control master loci that produce siRNAs. Interestingly, other members of the Acari have piRNAs indicating loss of this mechanism in dust mites is a recent event. Flux of RNAi-mediated control of TEs highlights the unusual arc of dust mite evolution.

Sharing a bed with mites: preferences of the house dust mite Dermatophagoides farinae in a temperature gradient.

House dust mites inhabit bed mattresses contaminating them with allergens. A strong temperature/moisture gradient exists in mattresses when it is used by humans daily. Here, we studied migration patterns of the mite Dermatophagoides farinae in continuous and time-discontinuous temperature gradients consisting of five sectors with 19-23, 23-28, 28-32, 32-36 and 36-41 °C, containing dye-labeled diets as an indicator of mite presence and feeding. The mites migrated through the sectors and fed on the labeled diets or stayed unfed. The numbers of mites with the same coloration in their guts and the numbers of unfed mites in the sectors were recorded. Unfed mites provided information on short-term temperature preferences. Apart from a control trial, two experiments were performed: (i) a constant 19-41 °C gradient for 24 h, and (ii) alternating cycles of the same temperature gradient (19-41 °C, 8 h) and room temperature (16 h) for 5 days to model the typical daily occupancy of bed by humans. In both experiments, fed mites preferred a sector with 32-36 °C, suggesting that in mattresses, house dust mites prefer to stay as close as possible to the resting human, thus maximizing allergen exposure. However, the number of unfed mites decreased with increased temperatures in the gradient. Experiment (ii) showed that the fed mites remained at the same optimal distance from the heat source, suggesting that they stay at the upper surface of the regularly used mattress, even when human was temporarily absent during the day. Unfed mites apparently hide deeper in mattresses as suggested by their avoidance of increased temperatures.

Molecular phylogeny of the phytoparasitic mite family Phytoptidae (Acariformes: Eriophyoidea) identified the female genitalic anatomy as a major macroevolutionary factor and revealed multiple origins of gall induction.

Phytoptidae s.str. is a lineage of eriophyoid mites associated with angiosperms. Based on representative taxon sampling and four gene markers (COI, HSP70, 18S, and 28S), we inferred the molecular phylogeny of this group and performed comparative analyses of cuticle-lined female internal genitalia. Although basal relationships were unclear, several well supported clades were recovered. These clades were supported by geography, host associations, and female genital anatomy, but contradicted the current morphology-based systematics. The monophyly of each of five conventional supraspecific groupings (Fragariocoptes, Phytoptus, Phytoptinae, Sierraphytoptinae, and Sierraphytoptini) is rejected based on a series of statistical tests. Additionally, four morphological characters (the absence of tibial solenidion φ and opisthosomal seta c1, presence of telosomal pseudotagma, and 'morphotype') were found to be homoplasies that cannot be used to confidently delimit supraspecific lineages of phytoptids. However, our molecular topology was highly congruent with female genital characters. Eight molecular clades were unambiguously supported by the shapes and topography of the spermathecal apparatus and genital apodemes. This suggests that the female genital anatomy could be an important factor affecting cladogenesis in Phytoptidae, a conclusion contrasting with the general expectation that host characteristics should be a major macroevolutionary force influencing the evolution of host-specific symbionts. Indeed, despite the high host-specificity, there were no apparent cophylogenetic patterns. Furthermore, we show that gall-inducing ability evolved multiple times in phytoptids. Because gall formation creates nearly instantaneous niche partitioning and the potential loss or reduction of gene flow, we hypothesize that it could be an important evolutionary factor affecting speciation within different host-associated clades of phytoptid mites.

Whole genomic sequencing and sex-dependent abundance estimation of Cardinium sp., a common and hyperabundant bacterial endosymbiont of the American house dust mite, Dermatophagoides farinae.

The two common species of house dust mites (HDMs), Dermatophagoides farinae and D. pteronyssinus, are major sources of allergens in human dwellings worldwide. Many allergens from HDMs have been described, but their extracts vary in immunogens. Mite strains may differ in their microbiomes, which affect mite allergen expression and contents of bacterial endotoxins. Some bacteria, such as the intracellular symbiont Cardinium, can affect both the sex ratio and biochemical pathways of mites, resulting in abundance variations of mite allergens/immunogens. Here, we investigated the bacterial microbiomes of D. farinae and D. pteronyssinus males and females using barcode 16S rDNA sequencing, qPCR, and genomic data analysis. We found a single species of Cardinium associated with D. farinae strains from the USA, China and Europe. Cardinium had high abundance relative to other bacterial taxa and represented 99% of all bacterial DNA reads from female mites from the USA. Cardinium was also abundant with respect to the number of host cells-we estimated 10.4-11.8 cells of Cardinium per single female mite cell. In a European D. farinae strain, Cardinium was more prevalent in females than in males (representing 92 and 67% of all bacterial taxa in females and males, respectively). In contrast, D. pteronyssinus lacked any Cardinium species, and the microbiomes of male and female mites were similar. We produced a Cardinium genome assembly (1.48 Mb; GenBank: PRJNA555788, GCA_007559345.1) associated with D. farinae. The ascertained ubiquity and abundance of Cardinium strongly suggest that this intracellular bacterium plays an important biological role in D. farinae.

Molecular phylogenetic analyses reveal a deep dichotomy in the conifer-inhabiting genus Trisetacus (Eriophyoidea: Nalepellidae), with the two lineages differing in their female genital morphology and host associations.

We analyzed the phylogenetic relationships of the genus Trisetacus using two genes [cytochrome c oxidase subunit I (COI) and D1-D2 region of 28S rDNA (D1-D2 28S)], a representive taxon sampling (nearly 40% of known diversity), and a large set of close and distant outgroups. Our analyses suggest the presence of a dichotomy between Trisetacus associated with Cupressaceae and Pinaceae. The following smaller molecular clades were found: Pin-1 (bud mites, twig sheath mites, bark gall mites, and endoparasitic mites from pinaceans), Pin-2 (needle sheath mites from pines), Pin-2a (putative Nearctic group of needle sheath mites), Pin-2b (putative Palearctic group of needle sheath mites), Cup-1 and 2 (bud, cone, seed mites and mites living under bark scales from cupressaceans). The monophyly of the recently proposed subgenus Brevithecus nested within clade Cup-2 was confirmed. Ancestral character reconstruction analyses recovered: (1) Pinaceae as the ancestral hosts of Nalepellidae and Trisetacus, (2) repetitive reductions of the spermathecal tube independently occurred in two lineages of Trisetacus from Cupressaceae, and (3) several mite habitats on host (galls, cones, twig sheaths, seeds, inside leaves, and under scales) are evolutionarily derived states, whereas living in buds or needle sheaths are ancestral states for Trisetacus clades Cup and Pin. Using confocal microscopy, we identified six basic types of the female internal genitalia of Trisetacus based on shapes of the spermatheca and spermathecal tube. These genitalic types are strongly correlated with lineages recovered by molecular phylogenetic analyses, suggesting that the female genital morphology is both evolutionarily conserved and is a factor influencing macroevolutionary patterns in this group of mites.

Population and Culture Age Influence the Microbiome Profiles of House Dust Mites.

Interactions with microorganisms might enable house dust mites (HDMs) to derive nutrients from difficult-to-digest structural proteins and to flourish in human houses. We tested this hypothesis by investigating the effects of changes in the mite culture growth and population of two HDM species on HDM microbiome composition and fitness. Growing cultures of laboratory and industrial allergen-producing populations of Dermatophagoides farinae (DFL and DFT, respectively) and Dermatophagoides pteronyssinus (DPL and DPT, respectively) were sampled at four time points. The symbiotic microorganisms of the mites were characterized by DNA barcode sequencing and quantified by qPCR using universal/specific primers. The population growth of mites and nutrient contents of mite bodies were measured and correlated with the changes in bacteria in the HDM microbiome. The results showed that both the population and culture age significantly influenced the microbiome profiles. Cardinium formed 93% and 32% of the total sequences of the DFL and DFT bacterial microbiomes, respectively, but this bacterial species was less abundant in the DPL and DPT microbiomes. Staphylococcus abundance was positively correlated with increased glycogen contents in the bodies of mites, and increased abundances of Aspergillus, Candida, and Kocuria were correlated with increased lipid contents in the bodies of mites. The xerophilic fungus Wallemia accounted for 39% of the fungal sequences in the DPL microbiome, but its abundance was low in the DPT, DFL, and DFT microbiomes. With respect to the mite culture age, we made three important observations: the mite population growth from young cultures was 5-8-fold higher than that from old cultures; specimens from old cultures had greater abundances of fungi and bacteria in their bodies; and yeasts predominated in the gut contents of specimens from young cultures, whereas filamentous mycelium prevailed in specimens from old cultures. Our results are consistent with the hypothesis that mites derive nutrients through associations with microorganisms.

Molecular phylogeny of marine mites (Acariformes: Halacaridae), the oldest radiation of extant secondarily marine animals.

The family Halacaridae comprises more than one thousand mostly marine or rarely freshwater species. Many are predacious, but among marine mites, some genera evolved the ability to feed on macroalgae. We inferred a time-calibrated phylogeny based on 18S rDNA, 28S rDNA, and Cytochrome oxidase I (5,143 nt aligned) and all non-monotypic halacarid subfamilies plus a representative outgroup set (72 taxa). The family Halacaridae was rendered as the sister-group of Parasitengona, diverging 321.5, 264.0-381.3 Ma and radiating 271.3, 221.7-324.2 Ma (median, HPD). Thus, marine mites represent the oldest known extant animal lineage that secondarily invaded the sea, with the marine turtles being the second oldest such lineage (crown group 212.3, 194.9-231.4 Ma). Two freshwater mite lineages, represented by Limnohalacarus (219.2, 165.9-274.6) and Porohalacarus (175.3, 118.5-233.1), were inferred mutually non-monophyletic, suggesting two independent invasions to freshwater. The conventional subfamily Rhombognathinae (macroalgae feeders) was not recovered as monophyletic, with Metarhombognathus-Rhombognathides, restricted to the Northern Hemisphere, originating 177.5, 134.8-223.3 Ma and diversifying 88.3, 32.7-152.3 Ma. This is congruent to a previous hypothesis of their northern origin prior to the opening of the Norwegian Sea (58 Ma). Our phylogeny indicates the need for reclassification of the traditional subfamilies and suggests that previous molecular results (e.g., Rhombognathus deeply nested in Copidognathinae) is an analytical artifact due to a chimeric sequence.

Comprehensive phylogeny of acariform mites (Acariformes) provides insights on the origin of the four-legged mites (Eriophyoidea), a long branch.

Eriophyoid, or four-legged mites, represent a large and ancient radiation of exclusively phytophagous organisms known from the Triassic (230 Mya). Hypothesizing phylogenetic relatedness of Eriophyoidea among mites is a major challenge due to the absence of unambiguous morphological synapomorphies, resulting in ten published hypotheses placing eriophyoids in various places in the acariform tree of life. Here we test the evolutionary relationships of eriophyoids using six genes and a representative taxonomic sampling of acariform mites. The total evidence analysis places eriophyoids as the sister group of the deep soil-dwelling, vermiform family Nematalycidae (Endeostigmata). This arrangement was supported by the rDNA and CO1 partitions. In contrast, the nuclear protein partition (genes EF1-α, SRP54, HSP70) suggests that Eriophyoidea is sister to a lineage including Tydeidae, Ereynetidae, and Eupodidae (Eupodina: Trombidiformes). On both of these alternative topologies, eriophyoids appear as a long branch, probably involving the loss of basal diversity in early evolution. We analyze this result by using phylogenetically explicit hypothesis testing, investigating the phylogenetic signal from individual genes and rDNA stem and loop regions, and removing long branches and rogue taxa. Regardless of the two alternative placements, (i) the cheliceral morphology of eriophyoids, one of the traits deemed phylogenetically important, was likely derived directly from the plesiomorphic acariform chelicerae rather than from the modified chelicerae of some trombidiform lineages with a reduced fixed digit; and (ii) two potential synapomorphies of Eriophyoidea+Raphignathina (Trombidiformes) related to the reduction of genital papillae and to the terminal position of PS segment can be dismissed as result of convergent evolution. Our analyses substantially narrow the remaining available hypotheses on eriophyoid relationships and provide insights on the early evolution of acariform mites.

Investigating species boundaries using DNA and morphology in the mite Tyrophagus curvipenis (Acari: Acaridae), an emerging invasive pest, with a molecular phylogeny of the genus Tyrophagus.

Mites of the genus Tyrophagus (Acari: Acaridae) are among the most widespread and common mites, inhabiting diverse natural and anthropogenic habitats. Some species are pests of agricultural products and stored food and/or live in house dust, causing allergies to humans. We sequenced 1.2 kb of the mitochondrial COI gene for 38 individuals belonging to seven species of Tyrophagus, including T. curvipenis, T. putrescentiae, T. fanetzhangorum, T. longior, T. perniciosus, and T. cf. similis. Molecular phylogenetic analyses (1) recovered two major clades corresponding to the presence or absence of eyespots, and (2) separated all included morphological species. Tyrophagus curvipenis and T. putrescentiae had the lowest between-species genetic distances (range, mean ± SD): 14.20-16.30, 15.17 ± 0.40 (K2P). The highest within-species variation was found in T. putrescentiae 0.00-4.33, 1.78 ± 1.44 (K2P). In this species, we recovered two distinct groups; however, no geographical or ecological dissimilarities were observed between them. Based on our analyses, we document important morphological differences between T. curvipenis and T. putrescentiae. For the first time, we record the occurrence of T. curvipenis in the New World and suggest that it may be an emerging pest as it is currently spreading in agricultural produce.

Convergent and unidirectional evolution of extremely long aedeagi in the largest feather mite genus, Proctophyllodes (Acari: Proctophyllodidae): Evidence from comparative molecular and morphological phylogenetics.

Proctophyllodid feather mites (400+ species) are permanent (full-time) symbionts commonly occurring on passerine birds. Phenotypic evolution of these mites appears to be greatly influenced by characters related to reproduction (>87.5% of a total of 32 taxonomically important discrete characters) and male genitalic characters (21.9%). Because sexual selection could the major evolutionary driver in this system, we test the theoretical expectation that genitalic or sexually dimorphic characters should evolve more rapidly and divergently then other characters. We inferred a time-calibrated molecular phylogeny (6 genes, 8571 nt aligned, no missing data) for 133 taxa of proctophyllodid mites and 40 outgroups. Comparisons of the average number of character state changes inferred on 10,696 Bayesian stationary trees indicate that male genitalic or sexually dimorphic characters do not evolve significantly faster than other characters (p=0.537 and p=0.819, respectively). However, among the male genitalic characters, a trait related to the relative length of the aedeagus experienced extremely fast rates of evolution and was detected as a statistical outlier. In this character, the transitions between short, long, and several intermediate states occurred in both directions. In contrast, the evolution of extremely long aedeagi (nearly as long as the body) occurred unidirectionally and irreversibly. This surprising result may be due to constraints imposed by the female spermathecal canal, which, in species where males have extremely long aedeagi, is also very long and may impede pumping sperm by short aedeagi. In proctophyllodid mites, extremely long aedeagi evolved independently five times in five different monophyletic lineages. Several of these lineages were lumped together by taxonomists to form easy-to-distinguish but apparently artificial species-groups. Male genitalic characters, thus, can introduce false synapomorphies that could affect morphology-based phylogenetic inference. For the most species-rich genus, Proctophyllodes, we develop a predictive classification of species-groups that reconciles molecular and morphological data.

Phylogenetic position of the house dust mite subfamily Guatemalichinae (Acariformes: Pyroglyphidae) based on integrated molecular and morphological analyses and different measures of support.

Based on multilocus phylogenetic analyses (18S, 28S, EF1-α, SRP54, HSP70, CO1, 10 860 nt aligned), we show that the house dust mite subfamily Guatemalichinae is nested within non-onychalgine pyroglyphid mites and forms the sister group to the genus Sturnophagoides (bootstrap support 100, posterior probability 1.0). Because high bootstrap support values may be misleading in the presence of incongruence, we evaluate robustness of the Guatemalichinae+Sturnophagoides clade using: (1) internode certainty indices to estimate the frequency of conflicting bipartitions in maximum-likelihood bootstrap trees, (ii) consensus networks to investigate conflict among different loci; and (iii) statistical hypothesis testing based on information theory, both multi-scale and regular bootstrap. Results suggest that this grouping is very well supported given the data. The molecular analyses were integrated with detailed morphological study using scanning electron and light microscopy. We suggest that the subfamilial status of Guatemalichinae should be reconsidered, and this lineage should be placed within the subfamily Dermatophagoidinae. The latter subfamily is currently accepted in the literature as a monophyletic group but was here inferred as paraphyletic and was not supported by any morphological synapomorphy. The paraphyly involved the most species-rich and medically important genus, Dermatophagoides. Our findings suggest the need for a comprehensive revision of the higher-level relationships of pyroglyphid house dust mites using both DNA sequences and morphology coupled with a broad taxonomic sampling.

Global phylogenetic structure of the hyperdiverse ant genus Pheidole reveals the repeated evolution of macroecological patterns.

Adaptive radiations are of particular interest owing to what they reveal about the ecological and evolutionary regulation of biodiversity. This applies to localized island radiations such as Darwin's finches, and also to rapid radiations occurring on a global scale. Here we analyse the macroevolution and macroecology of Pheidole, a famously hyperdiverse and ecologically dominant ant genus. We generate and analyse four novel datasets: (i) a robust global phylogeny including 285 Pheidole species, (ii) a global database on regional Pheidole richness in 365 political areas summarizing over 97 000 individual records from more than 6500 studies, (iii) a global database of Pheidole richness from 3796 local communities and (iv) a database of Pheidole body sizes across species. Analysis of the potential climate drivers of richness revealed that the patterns are statistically very similar across different biogeographic regions, with both regional and local richness associated with the same coefficients of temperature and precipitation. This similarity occurs even though phylogenetic analysis shows that Pheidole reached dominance in communities through serial localized radiations into different biomes within different continents and islands. Pheidole body size distributions have likewise converged across geographical regions. We propose these cases of convergence indicate that the global radiation of Pheidole is structured by deterministic factors regulating diversification and diversity.

Review and resolution of some nomenclatural issues regarding the genus Psoroptes (Acari: Psoroptidae), scab-mites of domestic and wild mammals.

Some classifications recognize a number of species in the scab-mite genus, Psoroptes, mites that are of considerable importance in livestock production and veterinary medicine. However, modern studies suggest that populations from some host species are not morphologically or genetically distinct, creating taxonomic confusion with older names, which treated mites from different hosts as separate species. We review the taxonomy and nomenclature of the genus and the two oldest binomens, most recently known as Psoroptes ovis and Psoroptes equi. Prior authors have attributed these names to various authorities, with most attributing both names to Hering (Nova Acta Phys-Med Acad Caesar Leopold-Carol Nat Curios 18(2):573-624, 1838). In particular, the priority between these names was recently a point of contention, with P. ovis being treated as junior synonym of P. equi. A review of all relevant nineteenth and twentieth century publications indicates, however, that these binomens should be cited as P. ovis (Viborg in Veterinair-Selskabets Skrifter 2:139-152, 1813) and P. equi (Raspail in Bull gener Theraput Med Chir 7:169-184, 1834), with the former having priority over the latter assuming their conspecificity. We also clarify attribution of the authorship and the type species of the genus Psoroptes.