89 research outputs found

    Host-parasite cophylogeny and rates of evolution in two rodent-louse assemblages

    Get PDF
    Studies of cophylogeny greatly increase understanding of associations between hosts and their parasites. This study uses molecular data to test the hypothesis that members of two rodent families (Geomyidae and Heteromyidae) and their associated lice (Geomydoecus and Fahrenholzia, respectively) show a statistically significant pattern of cophylogeny. Both host groups are generally solitary organisms and both louse groups are obligate ectoparasites, often exhibiting extreme degrees of host specificity. This intimate and potentially long-term association likely has resulted in coevolutionary adaptations and counter adaptations on the part of both symbiotic partners. Phylogenetic analysis of chewing lice (Geomydoecus) reveals two major clades corresponding to the G. coronadoi and G. mexicanus species complexes. These louse complexes are reciprocally monophyletic, and each clade within each complex parasitizes a different species of pocket gopher. Both louse species complexes exhibit a significant pattern of cophylogeny when compared to their hosts. The mitochondrial COI gene of lice of the G. coronadoi complex is evolving approximately 2 -3 times faster than the COI gene of their hosts, whereas the COI gene of lice of the G. mexicanus complex is evolving at roughly the same rate as the same gene of their hosts. Future analyses are necessary to determine why evolutionary rates in these two parasite lineages differ. The phylogenetic analysis of sucking lice (Fahrenholzia) resolves relationships among 11 of the 12 currently recognized species and identifies several possible cryptic species. Although there is conflict among the basal nodes of the host and parasite phylogenies, cophylogenetic analysis reveals significant topological congruence between these lice and their heteromyid hosts. The mitochondrial COI gene of Fahrenholzia lice is evolving roughly 1.6 times faster than the COI gene of their hosts, but additional comparisons of molecular rates are necessary to determine if this rate difference is shared by other groups of sucking lice and their hosts. Results of this study indicate that a combination of tree-based, distance-based, and data-based methods should be used in cophylogeny analyses. The final chapter of this dissertation presents a compilation of mammal-louse associations reveals and offers a preliminary assessment of sucking louse prevalence and abundance on heteromyid rodents

    Bridging Opportunities in Human Health Services

    Get PDF
    The Campus to Community project aims to develop facilitated, in-depth site visits for VCU faculty and staff interested in exploring human health services opportunities in the Richmond community. The site visit experience will provide exposure to various community organizations specializing in human health, essentially creating a “bridge” between VCU’s campus and these facilities. This initiative is intended to motivate employees to action within the Richmond community by enabling them to observe first-hand the services that these organizations provide, learn more about the organizations’ missions, and engage in meaningful interactions with representatives on site. Likewise, it will allow Richmond community organizations to discuss unique needs and opportunities for partnerships with VCU

    Evolutionary history of mammalian sucking lice (Phthiraptera: Anoplura)

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Sucking lice (Phthiraptera: Anoplura) are obligate, permanent ectoparasites of eutherian mammals, parasitizing members of 12 of the 29 recognized mammalian orders and approximately 20% of all mammalian species. These host specific, blood-sucking insects are morphologically adapted for life on mammals: they are wingless, dorso-ventrally flattened, possess tibio-tarsal claws for clinging to host hair, and have piercing mouthparts for feeding. Although there are more than 540 described species of Anoplura and despite the potential economical and medical implications of sucking louse infestations, this study represents the first attempt to examine higher-level anopluran relationships using molecular data. In this study, we use molecular data to reconstruct the evolutionary history of 65 sucking louse taxa with phylogenetic analyses and compare the results to findings based on morphological data. We also estimate divergence times among anopluran taxa and compare our results to host (mammal) relationships.</p> <p>Results</p> <p>This study represents the first phylogenetic hypothesis of sucking louse relationships using molecular data and we find significant conflict between phylogenies constructed using molecular and morphological data. We also find that multiple families and genera of sucking lice are not monophyletic and that extensive taxonomic revision will be necessary for this group. Based on our divergence dating analyses, sucking lice diversified in the late Cretaceous, approximately 77 Ma, and soon after the Cretaceous-Paleogene boundary (ca. 65 Ma) these lice proliferated rapidly to parasitize multiple mammalian orders and families.</p> <p>Conclusions</p> <p>The diversification time of sucking lice approximately 77 Ma is in agreement with mammalian evolutionary history: all modern mammal orders are hypothesized to have diverged by 75 Ma thus providing suitable habitat for the colonization and radiation of sucking lice. Despite the concordant timing of diversification events early in the association between anoplurans and mammals, there is substantial conflict between the host and parasite phylogenies. This conflict is likely the result of a complex history of host switching and extinction events that occurred throughout the evolutionary association between sucking lice and their mammalian hosts. It is unlikely that there are any ectoparasite groups (including lice) that tracked the early and rapid radiation of eutherian mammals.</p

    Temporal and spatial dynamics of competitive parapatry in chewing lice

    Get PDF
    We synthesize observations from 1979 to 2016 of a contact zone involving two subspecies of pocket gophers (Thomomys bottae connectens and T. b. opulentus) and their respective chewing lice (Geomydoecus aurei and G. centralis) along the Rio Grande Valley in New Mexico, U.S.A., to test predictions about the dynamics of the zone. Historically, the natural flood cycle of the Rio Grande prevented contact between the two subspecies of pocket gophers. Flood control measures completed in the 1930s permitted contact, thus establishing the hybrid zone between the pocket gophers and the contact zone between their lice (without hybridization). Since that time, the pocket gopher hybrid zone has stabilized, whereas the northern chewing louse species has replaced the southern louse species at a consistent rate of similar to 150 m/year. The 0.2-0.8 width of the replacement zone has remained constant, reflecting the constant rate of chewing louse species turnover on a single gopher and within a local pocket gopher population. In contrast, the full width of the replacement zone (northernmost G. centralis to southernmost G. aurei) has increased annually. By employing a variety of metrics of the species replacement zone, we are better able to understand the dynamics of interactions between and among the chewing lice and their pocket gopher hosts. This research provides an opportunity to observe active species replacement and resulting distributional shifts in a parasitic organism in its natural setting

    Review of endemic Sulawesi squirrels.

    Get PDF
    260 p. : ill. (some col.), maps ; 26 cm. "Issued June 11, 2010." Includes bibliographical references (p. 246-255).Analyses of fur color patterns, morphometric data derived from external, cranial, and dental dimensions, and distributions of collection sites for voucher specimens form the basis for a taxonomic revision of Sulawesi’s endemic squirrel fauna. Eight species of tree squirrels in Rubrisciurus and Prosciurillus and two species of ground squirrels in Hyosciurus are recognized. All are diurnal and inhabit primary forest formations. Diet consists of fruit, nuts, seeds, and arthropods. Rubrisciurus rubriventer, the largest in body size, forages on the ground and in the lower canopy layer, is found throughout Sulawesi where primary forest persists, and occurs through an altitudinal range embracing tropical lowland evergreen and lower montane rain forests; it is absent from upper montane rain forest. Five species of arboreal squirrels comprise the Prosciurillus leucomus group, a cluster of species occupying the upper forest canopy: P. leucomus, known only from lowland and montane habitats in the northern peninsula and one offshore island; P. alstoni, recorded from lowland tropical evergreen rain forest in the eastern section of Sulawesi’s central core, the east-central and southeastern arms, and two southeastern islands; P. weberi, represented by a few specimens from the coastal lowlands of the southern core of Sulawesi; P. topapuensis, endemic to the western mountain block in Sulawesi’s central core and occurring along an altitudinal gradient from lowland evergreen rain forest to upper montane rain forest; and P. rosenbergii, the only species of squirrel collected on islands in the Sangihe Archipelago north of the northeastern tip of the northern peninsula. The Prosciurillus murinus group contains two species of small body size: P. murinus, found throughout Sulawesi and in all forest formations, from the coastal lowlands to mountaintops, and a forager in the lower canopy layers; and P. abstrusus, known only from montane forest habitats on Pegunungan Mekongga in the southeastern peninsula. Of two species of ground squirrels, Hyosciurus heinrichi occupies montane forest habitats in the western mountain block of Sulawesi’s central core. It is altitudinally parapatric to H. ileile, which inhabits lowland evergreen and lower montane rain forests in the western mountain block and northeastern lowlands of central Sulawesi, and montane forest on the northern peninsula. A slightly revised classification of Sciuridae is provided in which a new tribe, Exilisciurini, is proposed for the Bornean and Philippine Exilisciurus. Previously published results of morphological and molecular analyses point to Rubrisciurus, Prosciurillus, and Hyosciurus as a monophyletic cluster, the Hyosciurina, nested within a larger clade, the Nannosciurini, which along with Exilisciurini n. tribe and Funambulini, comprise the Nannosciurinae, one of the three subfamilies constituting Sciuridae, and one that contains most of the Indomalayan genera. The present diversity of species endemic to Sulawesi was derived from an ancient lineage that crossed a sea barrier from the Sunda Shelf to Sulawesi during the late Miocene. Eight new species of hoplopleurid sucking lice â€Ș(‬Insecta, Anopluraâ€Ș)‬ are described as parasitizing 8 of the 10 species of squirrels endemic to Sulawesi: Hoplopleura rubrisciuri from Rubrisciurus rubriventer, Hoplopleura leucomus from Prosciurillus leucomus, Hoplopleura alstoni from Prosciurillus alstoni, Hoplopleura topapuensis from Prosciurillus topapuensis, Hoplopleura murinus from Prosciurillus murinus, Hoplopleura abstrusus from Prosciurillus abstrusus, Hoplopleura heinrichi from Hyosciurus heinrichi, and Hoplopleura ileile from Hyosciurus ileile. Examples of Prosciurillus weberi and P. rosenbergii were surveyed but no lice were recovered. A phylogenetic analysis based on cladistic principles for six species of Sulawesian squirrel lice for which both sexes were available is presented and the results discussed with respect to host relationships. These new data are incorporated into a discussion covering zoogeography of global sciurid-sucking louse associations, emphasizing the Indomalayan squirrel fauna. Globally, members of 11 genera of Anoplura parasitize sciurids, a figure far exceeding the number of anopluran genera associated with any other mammalian family. Nine of these â€Ș(‬the enderleinellids, Atopophthirus, Enderleinellus, Microphthirus, Phthirunculus, and Werneckia; the hoplopleurid, Paradoxophthirus; and the polyplacids, Johnsonpthirus, Linognathoides, and Neohaematopinusâ€Ș)‬ are primary parasites of sciurids. The remaining two â€Ș(‬the hoplopleurid Hoplopleura, and the polyplacid Polyplaxâ€Ș)‬ include representatives that are acquired â€Ș(‬secondaryâ€Ș)‬ parasites of sciurids--the majority of species in these two louse genera parasitize other groups of mammals but a small number of species have transferred to squirrel hosts. Sciurid hosts and geographic distributions of these 11 anopluran genera are discussed. Historically, representatives of Hoplopleura colonized different sciurid hosts on several separate occasions with one known species on a North American tree squirrel â€Ș(‬Sciurusâ€Ș)‬, two described species on North American flying squirrels â€Ș(‬Glaucomysâ€Ș)‬, two species parasitizing North American species of chipmunks â€Ș(‬Tamias and Eutamiasâ€Ș)‬, 14 described species from Indomalayan nannosciurine squirrels â€Ș(‬Callosciurus, Tamiops, Rubrisciurus, Prosciurillus, Hyosciurus, and Funambulusâ€Ș)‬, and one species parasitizing a Chinese xerine ground squirrel â€Ș(‬Sciurotamiasâ€Ș)‬. The zoogeography of the seven sciurid-infesting louse genera known from Southeast Asia is discussed using data from nine different countries or regions â€Ș(‬China, Taiwan, Thailand, peninsular Malaysia, Sumatra, Java, Borneo, the Philippines, and Sulawesiâ€Ș)‬. A reduction in the number of sciuirid-infesting anopluran genera and species is apparent from mainland northern/western regions to insular southern/eastern regions with members of seven genera and 23 species described from China but only one genus and eight species from Sulawesi. The absence of known species of Hoplopleura from Bornean and Javanese squirrels suggests that such a fauna may await discovery on one or both of these islands. Six of the eight species of Hoplopleura found parasitizing species of endemic Sulawesi squirrels were recovered as a monophyletic clade from a phylogenetic analysis employing anatomical structures associated with male and female lice. â€Ș(‬Two species of Sulawesi Hoplopleura are based on females and nymphs only and were not incorporated into the analysis.â€Ș)‬ The monophyletic cluster formed by the Sulawesian squirrel lice joined with the monophyletic assemblage containing the three Sulawesi squirrel genera--Rubrisciurus, Prosciurillus, and Hyosciurus--suggest that the ancestral squirrel lineage that arrived in Sulawesi during the late Miocene may have been carrying its unique Hoplopleura parasite

    A meta-analytic review of stand-alone interventions to improve body image

    Get PDF
    Objective Numerous stand-alone interventions to improve body image have been developed. The present review used meta-analysis to estimate the effectiveness of such interventions, and to identify the specific change techniques that lead to improvement in body image. Methods The inclusion criteria were that (a) the intervention was stand-alone (i.e., solely focused on improving body image), (b) a control group was used, (c) participants were randomly assigned to conditions, and (d) at least one pretest and one posttest measure of body image was taken. Effect sizes were meta-analysed and moderator analyses were conducted. A taxonomy of 48 change techniques used in interventions targeted at body image was developed; all interventions were coded using this taxonomy. Results The literature search identified 62 tests of interventions (N = 3,846). Interventions produced a small-to-medium improvement in body image (d+ = 0.38), a small-to-medium reduction in beauty ideal internalisation (d+ = -0.37), and a large reduction in social comparison tendencies (d+ = -0.72). However, the effect size for body image was inflated by bias both within and across studies, and was reliable but of small magnitude once corrections for bias were applied. Effect sizes for the other outcomes were no longer reliable once corrections for bias were applied. Several features of the sample, intervention, and methodology moderated intervention effects. Twelve change techniques were associated with improvements in body image, and three techniques were contra-indicated. Conclusions The findings show that interventions engender only small improvements in body image, and underline the need for large-scale, high-quality trials in this area. The review identifies effective techniques that could be deployed in future interventions

    Palaeoclimatic events, dispersal and migratory losses along the Afro-European axis as drivers of biogeographic distribution in Sylvia warblers

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>The Old World warbler genus <it>Sylvia </it>has been used extensively as a model system in a variety of ecological, genetic, and morphological studies. The genus is comprised of about 25 species, and 70% of these species have distributions at or near the Mediterranean Sea. This distribution pattern suggests a possible role for the Messinian Salinity Crisis (from 5.96-5.33 Ma) as a driving force in lineage diversification. Other species distributions suggest that Late Miocene to Pliocene Afro-tropical forest dynamics have also been important in the evolution of <it>Sylvia </it>lineages. Using a molecular phylogenetic hypothesis and other methods, we seek to develop a biogeographic hypothesis for <it>Sylvia </it>and to explicitly assess the roles of these climate-driven events.</p> <p>Results</p> <p>We present the first strongly supported molecular phylogeny for <it>Sylvia</it>. With one exception, species fall into one of three strongly supported clades: one small clade of species distributed mainly in Africa and Europe, one large clade of species distributed mainly in Africa and Asia, and another large clade with primarily a circum-Mediterranean distribution. Asia is reconstructed as the ancestral area for <it>Sylvia</it>. Long-distance migration is reconstructed as the ancestral character state for the genus, and sedentary behavior subsequently evolved seven times.</p> <p>Conclusion</p> <p>Molecular clock calibration suggests that <it>Sylvia </it>arose in the early Miocene and diverged into three main clades by 12.6 Ma. Divergence estimates indicate that the Messinian Salinity Crisis had a minor impact on <it>Sylvia</it>. Instead, over-water dispersals, repeated loss of long-distance migration, and palaeo-climatic events in Africa played primary roles in <it>Sylvia </it>divergence and distribution.</p

    Accelerating Medicines PartnershipÂź Schizophrenia (AMPÂź SCZ): Rationale and Study Design of the Largest Global Prospective Cohort Study of Clinical High Risk for Psychosis

    Get PDF
    This article describes the rationale, aims, and methodology of the Accelerating Medicines PartnershipÂź Schizophrenia (AMPÂź SCZ). This is the largest international collaboration to date that will develop algorithms to predict trajectories and outcomes of individuals at clinical high risk (CHR) for psychosis and to advance the development and use of novel pharmacological interventions for CHR individuals. We present a description of the participating research networks and the data processing analysis and coordination center, their processes for data harmonization across 43 sites from 13 participating countries (recruitment across North America, Australia, Europe, Asia, and South America), data flow and quality assessment processes, data analyses, and the transfer of data to the National Institute of Mental Health (NIMH) Data Archive (NDA) for use by the research community. In an expected sample of approximately 2000 CHR individuals and 640 matched healthy controls, AMP SCZ will collect clinical, environmental, and cognitive data along with multimodal biomarkers, including neuroimaging, electrophysiology, fluid biospecimens, speech and facial expression samples, novel measures derived from digital health technologies including smartphone-based daily surveys, and passive sensing as well as actigraphy. The study will investigate a range of clinical outcomes over a 2-year period, including transition to psychosis, remission or persistence of CHR status, attenuated positive symptoms, persistent negative symptoms, mood and anxiety symptoms, and psychosocial functioning. The global reach of AMP SCZ and its harmonized innovative methods promise to catalyze the development of new treatments to address critical unmet clinical and public health needs in CHR individuals
    • 

    corecore