Inclusion of juvenile stages improves diversity assessment and adds to our understanding of mite ecology – A case study from mires in Norway

Arachnid orders, Mesostigmata, Trombidiformes, and Sarcoptiformes, commonly known as ‘mites’, are abundant in mires, both as adults and as juveniles. However, due to the challenges of identification, the juvenile forms are often excluded from analyses. This is the first study in mires that included all three mite orders identified to the species level, including juvenile instars. We aimed to compare how diversity and the response to ecological variables differed if only the adults (ad) vs. the total number of specimens (ad+juv) are considered. Samples of 20 Sphagnum species (five subgenera) were collected and mites were extracted using Berlese funnels. Overall, nearly 60,000 mites were analyzed; of these Mesostigmata made up 1.87% of the total, Trombidiformes −0.27%, and Sarcoptiformes −97.86%. The study revealed 154 species (33 Mesostigmata, 24 Trombidiformes, and 97 Sarcoptiformes), the highest diversity of mites ever reported from mires. The inclusion of juveniles increased observed species richness by 6%, with 10 species (one Mesostigmata, six Trombidiformes, and three Sarcoptiformes) represented only by juvenile forms. Seventeen species are new to Norway (four Mesostigmata, one Sarcoptiformes, and 12 Trombidiformes, including five undescribed species of Stigmaeidae and Cunaxidae). Four of these were represented in the samples only by juveniles. Including the juveniles explained a greater amount of the variability of Trombidiformes (explanatory variables account for 23.60% for ad, and 73.74% for ad+juv) and Mesostigmata (29.23% − ad, 52.91% − ad+juv), but had less of an impact for Sarcoptiformes (38.48% − ad, 39.26% − ad+juv). Locality, Sphagnum subgenus and species, wetness, and trophic state significantly affected the mite communities and should be taken into consideration when studying mires. Since juvenile stages contribute significantly to mite diversity in mires, they should also be included in mite studies in other habitats.publishedVersio

Diversity and Distribution of Mites (Acari: Ixodida, Mesostigmata, Trombidiformes, Sarcoptiformes) in the Svalbard Archipelago

Svalbard is a singular region to study biodiversity. Located at a high latitude and geographically isolated, the archipelago possesses widely varying environmental conditions and unique flora and fauna communities. It is also here where particularly rapid environmental changes are occurring, having amongst the fastest increases in mean air temperature in the Arctic. One of the most common and species-rich invertebrate groups in Svalbard is the mites (Acari). We here describe the characteristics of the Svalbard acarofauna, and, as a baseline, an updated inventory of 178 species (one Ixodida, 36 Mesostigmata, 43 Trombidiformes, and 98 Sarcoptiformes) along with their occurrences. In contrast to the Trombidiformes and Sarcoptiformes, which are dominated in Svalbard by species with wide geographical distributions, the Mesostigmata include many Arctic species (39%); it would thus be an interesting future study to determine if mesostigmatid communities are more affected by global warming then other mite groups. A large number of new species (42 spp.) have been described from Svalbard, including 15 that have so far been found exclusively there. It is yet uncertain if any of these latter species are endemic: six are recent findings, the others are old records and, in most cases, impossible to verify. That the Arctic is still insufficiently sampled also limits conclusions concerning endemicity.publishedVersio

New records of mites (Acari) and harvestmen (Opiliones) from Malta with a preliminary checklist of Maltese Arachnida

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Potential for Chemical Repellents Against the Mite Tyrophagus putrescentiae to Prevent Infestation of Country Hams

Tyrophagus putrescentiae (Shrank), commonly known as the ham mite, is a cosmopolitan pest found of various stored food commodities, including aged hams and cheeses (Amoah et al. 2017; Campbell et al. 2017). Recent research suggested methods to deter T. putrescentiae from infestation of country hams using different types of food-safe chemicals (Abbar et al. 2016). In this experiment, four chemicals were tested to ascertain their effectiveness in deterring T. putrescentiae from ham infestation. Repellency tests used a piece of ham and a group of mites placed on opposite sides of a Petri dish with a black construction paper floor. A test barrier of a test compound or solvent control was deposited on a white filter paper strip bisecting the dish at its center. The chemicals Nootkatone, Propylene Glycol, Glycerol and a fatty acid blend called “C8910” prevented more mites from contacting the ham compared to strips with solvent. These results suggest the potential for using one or more of these food-safe compounds to prevent ham mites form infesting hams in aging rooms

Origin and higher-level diversification of acariform mites – evidence from nuclear ribosomal genes, extensive taxon sampling, and secondary structure alignment

Abstract Background Acariformes is the most species-rich and morphologically diverse radiation of chelicerate arthropods, known from the oldest terrestrial ecosystems. It is also a key lineage in understanding the evolution of this group, with the most vexing question whether mites, or Acari (Parasitiformes and Acariformes) is monophyletic. Previous molecular studies recovered Acari either as monophyletic or non-monophyletic, albeit with a limited taxon sampling. Similarly, relationships between basal acariform groups (include little-known, deep-soil 'endeostigmatan' mites) and major lineages of Acariformes (Sarcoptiformes, Prostigmata) are virtually unknown. We infer phylogeny of chelicerate arthropods, using a large and representative dataset, comprising all main in- and outgroups (228 taxa). Basal diversity of Acariformes is particularly well sampled. With this dataset, we conduct a series of phylogenetically explicit tests of chelicerate and acariform relationships and present a phylogenetic framework for internal relationships of acariform mites. Results Our molecular data strongly support a diphyletic Acari, with Acariformes as the sister group to Solifugae (PP =1.0; BP = 100), the so called Poecilophysidea. Among Acariformes, some representatives of the basal group Endeostigmata (mainly deep-soil mites) were recovered as sister-groups to the remaining Acariformes (i. e., Trombidiformes + and most of Sarcoptiformes). Desmonomatan oribatid mites (soil and litter mites) were recovered as the monophyletic sister group of Astigmata (e. g., stored product mites, house dust mites, mange mites, feather and fur mites). Trombidiformes (Sphaerolichida + Prostigmata) is strongly supported (PP =1.0; BP = 98–100). Labidostommatina was inferred as the basal lineage of Prostigmata. Eleutherengona (e. g., spider mites) and Parasitengona (e. g., chiggers, fresh water mites) were recovered as monophyletic. By contrast, Eupodina (e. g., snout mites and relatives) was not. Marine mites (Halacaridae) were traditionally regarded as the sister-group to Bdelloidea (Eupodina), but our analyses show their close relationships to Parasitengona. Conclusions Non-trivial relationships recovered by our analyses with high support (i.e., basal arrangement of endeostigmatid lineages, the position of marine mites, polyphyly of Eupodina) had been  proposed by previous underappreciated morphological studies. Thus, we update currently the accepted taxonomic classification to reflect these results: the superfamily Halacaroidea Murray, 1877 is moved from the infraorder Eupodina Krantz, 1978 to Anystina van der Hammen, 1972; and the subfamily Erythracarinae Oudemans, 1936 (formerly in Anystidae Oudemans, 1902) is elevated to family rank, Erythracaridae stat. ressur., leaving Anystidae only with the nominal subfamily. Our study also shows that a clade comprising early derivative Endeostigmata (Alycidae, Nanorchestidae, Nematalycidae, and maybe Alicorhagiidae) should be treated as a taxon with the same rank as Sarcoptiformes and Trombidiformes, and the scope of the superfamily Bdelloidea should  be changed. Before turning those findings into nomenclatural changes, however, we consider that our study calls for (i) finding shared apomorphies of the early derivative Endeostigmata clade and the clade including the remaining Acariformes; (ii) a well-supported hypothesis  for Alicorhagiidae placement; (iii) sampling the families Proterorhagiidae, Proteonematalycidae and Grandjeanicidae not yet included in molecular analyses; (iv) undertake a denser sampling of clades traditionally placed in Eupodina, Anystina (Trombidiformes) and Palaeosomata (Sarcoptiformes), since consensus networks and Internode certainty (IC) and IC All (ICA) indices indicate high levels of conflict in these tree regions. Our study shows that regions of ambiguous alignment may provide useful phylogenetic signal when secondary structure information is used to guide the alignment procedure and provides an R implementation to the Bayesian Relative Rates test.http://deepblue.lib.umich.edu/bitstream/2027.42/113097/1/12862_2015_Article_458.pd

On the diversification of highly host-specific symbionts: the case of feather mites.

One of the most relevant and poorly understood topics in Evolutionary Ecology is symbiont evolutionary diversification. Since Fahrenholz's rule (1913), the idea of symbionts speciating following hosts speciation (i.e., cospeciating) has been pervasive. Recent studies, however, have shown that host-shift speciation (speciation after switching to a new host) is almost as relevant as cospeciation in explaining symbiont diversification. Also, these studies have revealed that methodological biases have favored cospeciation. Nonetheless, most symbiont groups, especially those highly host-specific and specialized in which cospeciation is expected to be the rule, such as the feather mites of birds, were yet to be studied. Symbionts are the most abundant and diverse organisms on Earth, and thus essential components of ecosystems. However, symbionts have attracted historically less attention than other organisms and their study entails numerous methodological challenges, so surprisingly little is understood about the basic biology and ecology of many symbiont groups, especially the non-parasitic. By studying vane-dwelling feather mites living permanently on the surface of flight feathers of birds (Acariformes: Astigmata: Analgoidea and Pterolichoidea), this thesis is a contribution to fill this gap. This thesis is divided into three parts: 1) First, resources and molecular tools enabling large-scale studies of feather mites are developed. 2) Then, these and other tools are used to investigate eco-evolutionary aspects relevant to understand feather mite diversification, such as their mode of transmission and the type of interaction they have with their hosts. 3) Finally, feather mites diversification at a macro- and microevolutionary scale is investigated. The first part compiles a global database of bird-feather mites associations. Also, it evaluates and adjusts DNA barcoding and metabarcoding to be suitable methodologies for studying feather mites. The second part reveals feather mites as highly specialist and hostspecific symbionts whose main mode of transmission is vertical. Analyses of feather mites diet reveal them as trophic generalists which maintain a commensalistic-mutualistic relationship with birds. Finally, the last part of the thesis shows host-shift speciation as the primary process driving the diversification of feather mites. Also, it highlights that majorhost switching, despite being an infrequent process, is highly relevant for the diversification of this group. Lastly, analyses of straggling reveal a high rate of preferential straggling governed by ecological filters. Overall, despite feather mites are revealed as highly specialized and host-specific symbionts, the coevolutionary scenario is highly dynamic. Straggling and host-switching are prevalent processes which allow colonizing new hosts in highly specialized and hostspecific symbionts. Accordingly, coevolution and codiversification do not operate in isolated host-symbiont interactions but more likely in a manner compatible with the geographic mosaic of coevolution. Finally, ecological fitting and interspecific competition are most likely the main factors governing the (co)eco-evolutionary dynamics.La diversificación evolutiva de los simbiontes es uno de los aspectos más relevantes, pero menos entendidos en Ecología Evolutiva. Desde la regla de Fahrenholz (1913), la idea de que los simbiontes especian a la par que sus hospedadores (i.e. coespecian) ha sido extremadamente popular. Sin embargo, estudios recientes han encontrado que la especiación por salto de hospedador (el proceso de especiación que ocurre cuando los simbiontes especian a consecuencia de un cambio de hospedador) es casi tan relevante como la coespeciación. Estos estudios, además, han encontrado que problemas metodológicos favorecían que se encontraran evidencias de coespeciación donde no las había. En cualquier caso, los procesos de diversificación evolutiva de la mayoría de los grupos de simbiontes nunca han sido investigados. Especialmente de aquellos altamente especializados y específicos en términos de hospedador, que son aquellos donde el proceso de coespeciación se espera que sea más relevante, como los ácaros de las plumas de las aves. Los organismos simbiontes son el grupo más abundante y diverso de la tierra, por ende, son componentes esenciales de los ecosistemas. Sin embargo, históricamente los simbiontes han atraído menos la atención de los investigadores, en parte debido a que su estudio conlleva numerosos retos metódologicos. De hecho, debido a esto, actualmente se desconoce una gran parte de aspectos sobre su biología básica y ecología, especialmente de aquellos simbiontes no parásitos. Ésta tésis pretende completar este vacío de conocimiento mediante el estudio de los ácaros de las plumas de las aves. La tésis está dividida en tres partes: 1) En la primera parte se han generado recursos y herramientas moleculares para estudios a gran escala en este grupo de simbiontes. 2) Despues, éstas y otras herramientas se han usado para investigar aspectos eco-evolutivos relavantes para entender el proceso de diversificación evolutiva, tales como, el modo de transmisión y el tipo de interacción que mantienen con sus hospedadores. 3) Finalmente, se ha estudiado el proceso de diversificación evolutiva a escala macro y icroevolutiva. La primera parte de la tesis presenta una base de datos global de relaciones ácaroave resultado de una extensa compilación de datos ya presentes en la literatura. También evalua y ajusta metodologías de “DNA barcoding” y “metabarcoding” para el estudio de los ácaros de las plumas. La segunda parte, revela a los ácaros de las plumas como simbiontes altamente especialistas en términos de hospedador cuyo modo de transmisión principal es el vertical. Por otro lado, el análisis de la dieta de los ácaros los sitúa como simbiontes comensales-mutualistas de las aves. Finalmente, la ultima parte de la tesis demuestra que la especiación por salto de hospedador es el proceso principal de diversificación de este grupo de simbiontes. Asimismo, también demuestra que los saltos de hospedador a larga distancia, a pesar de ser muy raros son muy relevantes para la diversificación de este grupo. Por último, los análisis de simbiontes encontrados en hospedadores inesperados (“stragglers”) revelan que este proceso es más prevalente de lo que se pensaba, y que sigue un patrón compatible con que está modulado por filtros ecológicos. A pesar de que los ácaros de las plumas se revelan como altamente especializados y específicos en términos de hospedador, su escenario coevolutivo es muy dinámico. El proceso de “straggling” y de cambio de hospedador son procesos prevalentes que permiten colonizar nuevos hospedadores. De acuerdo con esto, los procesos de coevolución y codiversificación en estos organismos no operan de manera aislada para cada pareja de hospedador y simbionte, si no de una manera similar a un mosaico geográfico de coevolución. Finalmente, el encaje ecológico y la competencia intraspecífica se identifican como los factores potencialmente más relevantes en las dinámicas (co)ecoevolutivas

Anatomie des Verdauungstraktes der Rhagidiidae (Acari, Trombidiformes)

Die Rhagidien ernähren sich von kleinen weichhäutigen Arthropoden. Der Verdauungstrakt besteht aus folgenden Abschnitten: Oesophagus, Pharynx, Ventrikel mit Caecen, Colon, Postcolon und Rectum. Der Ventrikel ist nicht blind geschlossen sondern mit dem Colon verbunden. Nach der Resorption im Ventrikel sammeln sich die mit Zellfaeces beladenen ExkretzeIlen sowie unverdauliche Nahrungsreste aus dem Beutetier und dessen Exkrete zu einem Pfropf, der in den »Exkretionsdarm« übertritt. Dieser ist durch einen Sphinkter in ein Colon und Postcolon unterteilt, wodurch am lebenden Tier 2 hintereinanderliegende »Kotballen« zu sehen sind. Nur im Postcolon findet die Bildung von Exkreten statt. An den Exkretionsdarm schließt das ektodermale Rectum an. Der als ursprünglich anzusehende Verdauungstrakt der Rhagidien läßt sich mit dem der Sarcoptiformes homologisieren. Es wird der Versuch unternommen, eine Entwicklungsreihe des Verdauungstraktes für die Prostigmata aufzustellen. Anhand unterschiedlicher Ausgestaltung des Exkretionsdarmes bei verschiedenen trombidiformen Milben wird eine Hypothese aufgestellt, wie es morphologisch zu der möglicherweise vorhandenen Abtrennung des »Exkretlonsorqans« bei einigen Milben gekommen sein könnte. Der blind geschlossene Mitteldarm kann nicht mehr uneingeschränkt als kennzeichnendes Merkmal der Trombidiformes angesehen werden.TheRhagidiid mites prey upon soft skinned small-arthropods. The alimentary canal consists of oesophagus, pharynx, ventriculus with caecen, colon and postcolon. The ventriculus does not end blindly but is connected with the colon. After resorption in the ventriculus the cellfaeces and the food-rests clump together into a bolus which then enters the excretory gut. This part of the alimentary canal is devided into a colon and postcolon by a sphincter. This is why in living mites often 2 excrement-balls can be seen, The excretory gut leeds into the ectodermal rectum. The alimentary canal of the Rhagidiid mites can be considered primeval and is to be homologized with that of the Sarcoptiformes. The aim of the study is to construate a developmental sequence of the alimentary canal by the Prostigmata. According to the different forms of the excretory gut of the Prostigmata a hypothesis can be formed about how the detached excretory organ may have developed. The blind-ending ventriculus can no longer be regarded as typical of the Trombidiformes

Ectoparasites and Other Arthropod Associates of the Hairy-tailed Mole, \u3ci\u3eParascalops Breweri\u3c/i\u3e

A total of 33 taxa of ectoparasites and other associates was taken on seven individuals of the Hairy-tailed Mole, Parascalops breweri, from New York and New England. The most abundant form was the glycyphagid mite, Labidophorus nearcticus

Developing a predictive model of the autecology of the spruce-fir moss spider, Microhexura montivaga Crosby and Bishop 1925 (Araneae: Dipluridae)

The spruce-fir moss spider (Microhexura montivaga) is a federally endangered species of spider found only in the high-elevation Southern Appalachian spruce-fir forests on North-facing slopes underneath moss mats. Despite this fact, little is known about some of the basic ecology of the spider, more specifically the characteristics of the habitat found underneath the moss mats. The goals of this project was to determine the temperature and humidity parameters of the microhabitat conditions around known spider locations, catalogue what other species live there, and use predictive mathematical models created in the Maxent software to estimate past and current locations of potential habitats and identify the key environmental factors that drive such a model. iButton temperature and humidity data loggers placed at Mt. Lyn-Lowry, Browning Knob, Whitetop Mountain and Mt. Rogers (a range that encompasses all metapopulations). Lyn-Lowry and Browning Knob are located in the Plott Balsam range in North Carolina. Whitetop Mountain and Mt. Rogers are located in the Mt. Rogers National Recreation Area in Virginia. No statistically significant differences in daily maximum or minimum temperature between positive and negative presence sites, among metapopulations, or individual sites. A potential set of temperature conversion factors were calculated using percent change for temperature by comparing the collected data, a local weather station, and a U.S. Fish and Wildlife Service deployed HOBO data logger mounted in a tree. Soil samples collected from Blackrock Mountain in the Plott Balsams yielded 2039 individuals comprising 11 orders, with Collembola and Acari being by far the most abundant; this is important as these orders have been hypothesized to be the primary prey items of M. montivaga. Maxent models show the current potential range as well as historical models of the last interglacial period and glacial maximum. Maxent models use presence only data and environmental factors to estimate potential habitat. Range during the last glacial maximum was greater than present range while the range during the last interglacial period was less than present range according to the models. They also include potential range expansion and retraction patterns. All models were heavily driven by temperature environmental layers, in particular those dealing with temperature maximums. This research provides a number of potential applications for the conservation and management of M. montivaga, such as using collected data to determine conversion factors for temperature data between microhabitat measurements and larger scale measuring methods, such as weather stations. For example, HOBO data loggers mounted in trees measure maximum daily temperature higher by 83.5% compared to microhabitat measurements. This allows for large scale monitoring can be done without having to actually measure the temperatures underneath the moss mats. It is hoped that this research, along with the continuing work of U.S. Fish and Wildlife Service, will contribute to a much more positive outlook for this endangered species