110 research outputs found
Morphology, Evolution, and Host Associations of Bee-Associated Mites of the Family Chaetodactylidae (Acari: Astigmata) with a monographic revision of North American taxa
http://deepblue.lib.umich.edu/bitstream/2027.42/110995/1/Bee Mites.pdfDescription of Bee Mites.pdf : Main Pape
Improved tRNA prediction in the American house dust mite reveals widespread occurrence of extremely short minimal tRNAs in acariform mites
<p>Abstract</p> <p>Background</p> <p>Atypical tRNAs are functional minimal tRNAs, lacking either the D- or T-arm. They are significantly shorter than typical cloverleaf tRNAs. Widespread occurrence of atypical tRNAs was first demonstrated for secernentean nematodes and later in various arachnids. Evidence started to accumulate that tRNAs of certain acariform mites are even shorter than the minimal tRNAs of nematodes, raising the possibility that tRNAs lacking both D- and T-arms might exist in these organisms. The presence of cloverleaf tRNAs in acariform mites, particularly in the house dust mite genus <it>Dermatophagoides</it>, is still disputed.</p> <p>Results</p> <p>Mitochondrial tRNAs of <it>Dermatophagoides farinae </it>are minimal, atypical tRNAs lacking either the T- or D-arm. The size (49-62, 54.4 ± 2.86 nt) is significantly (p = 0.019) smaller than in <it>Caenorhabditis elegans </it>(53-63, 56.3 ± 2.30 nt), a model minimal tRNA taxon. The shortest tRNA (49 nt) in <it>Dermatophagoides </it>is approaching the length of the shortest known tRNAs (45-49 nt) described in other acariform mites. The D-arm is absent in these tRNAs, and the inferred T-stem is small (2-3 bp) and thermodynamically unstable, suggesting that it may not exist in reality. The discriminator nucleotide is probably not encoded and is added postranscriptionally in many <it>Dermatophagoides </it>tRNAs.</p> <p>Conclusions</p> <p>Mitochondrial tRNAs of acariform mites are largely atypical, non-cloverleaf tRNAs. Among them, the shortest known tRNAs with no D-arm and a short and unstable T-arm can be inferred. While our study confirmed seven tRNAs in <it>Dermatophagoides </it>by limited EST data, further experimental evidence is needed to demonstrate extremely small and unusual tRNAs in acariform mites.</p
Cox1 barcoding versus multilocus species delimitation: validation of two mite species with contrasting effective population sizes
Abstract
Background
The cox1-barcoding approach is currently extensively used for high-throughput species delimitation and discovery. However, this method has several limitations, particularly when organisms have large effective population sizes. Paradoxically, most common, abundant, and widely distributed species may be misclassified by this technique.
Results
We conducted species delimitation analyses for two host-specific lineages of scab mites of the genus Caparinia, having small population sizes. Cox1 divergence between these lineages was high (7.4–7.8%) while that of nuclear genes was low (0.06–0.53%). This system was contrasted with the medically important American house dust mite, Dermatophagoides farinae, a globally distributed species with very large population size. This species has two distinct, sympatric cox1 lineages with 4.2% divergence. We tested several species delimitation algorithms PTP, GMYC, ABGD, BPP, STACEY and PHRAPL, which inferred different species boundaries for these entities. Notably, STACEY recovered the Caparinia lineages as two species and D. farinae as a single species. BPP agreed with these results when the prior on ancestral effective population sizes was set to expected values, although delimitation of Caparinia was still equivocal. No other cox1 species delimitation algorithms inferred D. farinae as a single species, despite the fact that the nuclear CPW2 gene shows some evidence for introgression between the cox1 groups. This indicates that the cox1-barcoding approach may result in excessive species splitting.
Conclusions
Our research highlights the importance of using nuclear genes and demographic characteristics to infer species boundaries rather than relying on a single-gene barcoding approach, particularly for putative species having large effective population sizes.https://deepblue.lib.umich.edu/bitstream/2027.42/146770/1/13071_2018_Article_3242.pd
Host specificity and multivariate diagnostics of cryptic species in predacious cheyletid mites of the genus Cheletophyes (Acari: Cheyletidae) associated with large carpenter bees
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72537/1/j.1095-8312.2006.00554.x.pd
MUSEUM SPECIMENS AND PHYLOGENIES ELUCIDATE ECOLOGY'S ROLE IN COEVOLUTIONARY ASSOCIATIONS BETWEEN MITES AND THEIR BEE HOSTS
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74970/1/j.1558-5646.2007.00119.x.pd
A review of mites and ticks parasitizing rock lizards (Lacertidae: Darevskia)
Rock lizards of the genus Darevskia are interesting research models due to their asexual reproduction. Ectoparasitic mites and ticks of these lizards are poorly known, despite some of these chelicerates being vector pathogens of humans and wildlife. Here we document and curate previously known data on ectoparasitic Acari of rock lizards and, based on our extensive survey, provide an annotated list of these ectoparasitic arthropods (six tick species, one macronyssid species, and seven chigger species). We also provide new host records (Ixodes ricinus on Darevskia caucasica, D. dryada, D. mixta, and D. szczerbaki; Haemaphysalis sulcata on D. rudis; Odontacarus saxicolis on D. brauneri); and new geographical records (O. saxicolis in Russia and Georgia)
Faunistic and taxonomic additions to the oribatid mites (Acari, Oribatida) of Cuba
The present study is based on oribatid mite materials collected from leaf litter in two forest locations in Cuba. A list of 64 species, belonging to 47 genera and 31 families, is presented. Of these, one genus and two species are recorded for the first time from the Neotropical region; 17 species, one subgenus, six genera, and two families are recorded for the first time from Cuba. Two new species of the superfamily Oripodoidea—Lagenobates fossatus Ermilov and Kontschán n. sp. (Haplozetidae) and Muliercula curvilineata Ermilov and Kontschán n. sp. (Scheloribatidae)—are described
A transitional fossil mite (Astigmata: Levantoglyphidae fam. n.) from the early Cretaceous suggests gradual evolution of phoresy-related metamorphosis
Abstract Metamorphosis is a key innovation allowing the same species to inhabit different environments and accomplish different functions, leading to evolutionary success in many animal groups. Astigmata is a megadiverse lineage of mites that expanded into a great number of habitats via associations with invertebrate and vertebrate hosts (human associates include stored food mites, house dust mites, and scabies). The evolutionary success of Astigmata is linked to phoresy-related metamorphosis, namely the origin of the heteromorphic deutonymph, which is highly specialized for phoresy (dispersal on hosts). The origin of this instar is enigmatic since it is morphologically divergent and no intermediate forms are known. Here we describe the heteromorphic deutonymph of Levantoglyphus sidorchukae n. gen. and sp. (Levantoglyphidae fam. n.) from early Cretaceous amber of Lebanon (129 Ma), which displays a transitional morphology. It is similar to extant phoretic deutonymphs in its modifications for phoresy but has the masticatory system and other parts of the gnathosoma well-developed. These aspects point to a gradual evolution of the astigmatid heteromorphic morphology and metamorphosis. The presence of well-developed presumably host-seeking sensory elements on the gnathosoma suggests that the deutonymph was not feeding either during phoretic or pre- or postphoretic periods
Recommended from our members
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 an increased demand for genome analysis of ancient human remains. Destructive sampling is increasingly difficult for ethical reasons, and previous methods of breaking the skull to access the petrous bone are often forbidden for curatorial reasons, together with teeth which may be missing or too precious to sample. 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 eggs (nits) to the hair of ancient Argentinian mummies, 1,500–2,000 years old. The cement also preserves ancient environmental DNA of the skin, including the earliest recorded case of Merkel Cell Polyomavirus. We also show that human DNA obtained from nit cement can equal human genome assessment from tooth DNA, can increase assessment from petrous bone by two-fold, and by four-fold DNA over bloodmeal of adult lice a millennium younger. Genome-wide analyses from nit cement DNA also enables identification of the population genetic affinities of ancient humans. In metric studies of the sheaths, the length of the cement tube negatively correlated with the age of the specimens, while hair linear distance between nit and scalp informed about environmental conditions at the time before death. Ectoparasitic lice sheaths on hair, feathers, skins, or mummified remains can offer an alternative, non-destructive source of high-quality ancient DNA from a variety of host taxa and reveal details of their historical environment
- …