Dusky Shrew Research Articles

Complex History of Codiversification and Host Switching of a Newfound Soricid-Borne Orthohantavirus in North America.

Orthohantaviruses are tightly linked to the ecology and evolutionary history of their mammalian hosts. We hypothesized that in regions with dramatic climate shifts throughout the Quaternary, orthohantavirus diversity and evolution are shaped by dynamic host responses to environmental change through processes such as host isolation, host switching, and reassortment. Jemez Springs virus (JMSV), an orthohantavirus harbored by the dusky shrew (Sorex monticola) and five close relatives distributed widely in western North America, was used to test this hypothesis. Total RNAs, extracted from liver or lung tissue from 164 shrews collected from western North America during 1983–2007, were analyzed for orthohantavirus RNA by reverse transcription polymerase chain reaction (RT-PCR). Phylogenies inferred from the L-, M-, and S-segment sequences of 30 JMSV strains were compared with host mitochondrial cytochrome b. Viral clades largely corresponded to host clades, which were primarily structured by geography and were consistent with hypothesized post-glacial expansion. Despite an overall congruence between host and viral gene phylogenies at deeper scales, phylogenetic signals were recovered that also suggested a complex pattern of host switching and at least one reassortment event in the evolutionary history of JMSV. A fundamental understanding of how orthohantaviruses respond to periods of host population expansion, contraction, and secondary host contact is the key to establishing a framework for both more comprehensive understanding of orthohantavirus evolutionary dynamics and broader insights into host–pathogen systems.

Parastrongyloides spp. nov. (Nematoda: Rhabditoidea: Strongyloididae) from the small intestine of a monotreme from Australia and a marsupial from the Republic of Colombia

ABSTRACTTwo new species of Parastrongyloides Morgan, 1928 (Nematoda: Rhabditoidea: Strongyloididae) are described, P. tachyglossi, from the small intestine of the short-beaked echidna, Tachyglossus aculeatus (Shaw, 1792) from southeastern New South Wales and northern Queensland and P. caenolesti from the small intestine of the common grey or dusky shrew opossum, Caenolestes fuliginosus (Tomes, 1863) from Parames du Puruce, the Republic of Colombia. The two new species are distinguished from each other by the position of the two pairs of caudal papillae of P. tachyglossi immediately pre- and post-cloacal in contrast to those in P. caenolesti which are distant from the cloacal aperture and by the generally smaller sizes of males and females of P. caenolesti and the presence of a minute terminal papilla or spine on the tail tip of male P. tachyglossi. They are distinguished from seven of the eight known species of Parastrongyloides by the absence of a single, median, dome-shaped papilla anterior to the cloacal opening in males and by the number and distribution of the other pre- and post-cloacal papillae in the male. The eighth species, Parastrongyloides skrjabini Petrov & Savinov, 1959 has no pre- or post-cloacal papillae. These represent the first species of Parastrongyloides to be described from a monotreme and from a South American marsupial.

Responses of small mammals to the scent of animals that previously encountered traps

Responses of the common shrew (Sorex araneus), masked shrew (S. caecutiens), pygmy shrew (S. minutus), dusky shrew (S. isodon), and bank vole (Clethrionomys glareolus) to the scent of other species were studied in nature (Tver oblast) taking into account their species, sex, and age. The research was performed by comparing (criterion χ2, exact confidence interval for binomial distribution) the number of recipient individuals captured by traps with the scent of animals that previously contacted them and the number of animals that could be expected under the random distribution of captures. All responses of the animals to the scent unintentionally left by other individuals were regarded as manifestations of mediated olfactory communications. Positive responses (“the observed number of captures is greater than that expected”) absolutely prevail in the intraspecific relations within all the species and sex–age groups. They also play an important role in the interspecific relations, which is particularly noticeable in the yearlings of red-toothed shrews. The responses of these animals to the odor of bank voles vary from neutral to negative. It was shown that S. minutus avoids the scent of other species. Seasonal changes in the responses to the odor of different species and sex–age groups were considered.

Description and Molecular Differentiation of a NewStaphylocystoides(Cyclophyllidea: Hymenolepididae) from the Dusky ShrewSorex monticolusin Southeast Alaska

Staphylocystoides gulyaevi n. sp. is described based on specimens obtained from the dusky shrew Sorex monticolus collected on Sukkwan Island, southeast Alaska. Staphylocystoides gulyaevi n. sp. is compared with other North American members of the genus having 10 rostellar hooks. The new species is morphologically similar to Staphylocystoides parvissima and Staphylocystoides asketus. The uterus in S. gulyaevi n. sp. develops much more rapidly, and a well-developed uterus appears abruptly after it is barely visible in a previous proglottid. In S. parvissima the uterus grows gradually, and its early development is seen in several proglottids. At the level of pre-gravid proglottids the uterus of S. gulyaevi n. sp. occupies only the middle field of the proglottid, while in S. parvissima it fills the whole proglottid including lateral fields. The rostellar hooks in the new species are significantly smaller in size than in S. asketus. Additionally, the new species has fewer proglottids than S. asketus, while having a similar strobila length. Molecular comparison, using 3 genes (28s rDNA, cox1, and nad1), between S. gulyaevi n. sp. and S. parvissima, further corroborates the status of S. gulyaevi n. sp. as a new species. The new species is the seventh species of Staphylocystoides found in North America and the first cestode or any helminth reported from shrews in southeast Alaska.

Changes within Small Mammal Communities since the 1988 Huckleberry Mountain Fire

This study is a continuation of investigations conducted at Huckleberry Mountain to determine the effect of the 1988 Greater Yellowstone fire on the small mammal community, and document changes in this community over the 22 years since this natural disturbance. Previous research was conducted in 1993, 1994, 1997, and 1998 and we sampled the same communities in 2009 and again in 2010 using the identical sampling methodology. During the summer of 2010 we live trapped 252 Southern Red-backed Vole (Myodes gapperi), 57 North American Deermouse (Peromyscus maniculatu), 22 Least Chipmunk (Tamias minimus), 12 Western Jumping Mouse (Zapus princeps), four Montane Vole (Microtus montanus), one Northern Pocket Gopher (Thomomys talpoides), four Cinereus Shrew (Sorex cinereus), and five Dusky Shrew (S. monticolus). These results are similar to our results from 2009 and corroborate findings from other investigations indicating early dominance of P. maniculatus in burned forests and M. gapperi in control unburned areas. M. gapperi and P. maniculatus accounted for the majority (87%) of captures. In addition more M. gapperi were found in control sites than P. maniculatus, and as the burned habitat recovers over time, the relative numbers of P. maniculatus are decreasing, and the number of M. gapperi are increasing, suggesting that the burned habitats are returning to a more natural pre-disturbance community structure. However, community diversity indices (which include all mammal species and their relative proportions) suggest that there are still considerable differences between burned and unburned sites. Despite the numbers of voles and deermice changing over time (as predicted), the burned and control small mammal communities are still quite different from one another even after 22 years.

Species of Coccidia (Apicomplexa: Eimeriidae) in Shrews From Alaska, U.S.A., and Northeastern Siberia, Russia, with Description of Two New Species

Fecal samples (n = 636) from 10 species of shrews collected in Alaska (n = 540) and northeastern Siberia (n = 96) were examined for the presence of coccidia (Apicomplexa: Eimeriidae). Five distinct oocyst morphotypes were observed. Three types were consistent with oocysts of previously recognized coccidia species from other shrew hosts. These were Eimeria inyoni, E. vagrantis, and Isospora brevicauda, originally described from the inyo shrew (Sorex tenellus), dusky shrew (S. monticolus), and northern short-tailed shrew (Blarina brevicauda), respectively. We found 5 new host records for E. inyoni, 3 for E. vagrantis, and 3 for I. brevicauda. The 2 additional oocyst morphotypes, both from the tundra shrew (Sorex tundrensis), are putative new species. Sporulated oocysts of Eimeria beringiacea n. sp. are subspheroidal, 17.7 x 15.6 microm (14-24 x 13-20 microm) with a length (L)/width (W) ratio of 1.1 (1.0-1.4); these lack a micropyle (M), an oocyst residuum (OR), and a polar granule (PG). Sporocysts are ellipsoidal, 10.3 x 6.1 microm (7-14 x 4-8 microm), with a L/W ratio of 1.7 (1.3-2.3) and have a Stieda body (SB), Substieda body (SSB), and sporocyst residuum (SR). Oocysts of Eimeria tundraensis n. sp. are spheroidal to subspheroidal, 24.8 x 23.5 microm (23-26 x 22-25 microm), with a L/W ratio of 1.1 (1.0-1.2); these lack a M and OR, but a single PG is present. Sporocysts are elongate ellipsoidal, 15.4 x 8.3 microm (13-17 x 7-9 microm), with a L/W ratio of 1.9 (1.4-2.1) and have a SB, SSB, and SR.

Phylogenetically Distinct Hantaviruses in the Masked Shrew (Sorex cinereus) and Dusky Shrew (Sorex monticolus) in the United States

A limited search for hantaviruses in lung and liver tissues of Sorex shrews (family Soricidae, subfamily Soricinae) revealed phylogenetically distinct hantaviruses in the masked shrew (Sorex cinereus) from Minnesota and in the dusky shrew (Sorex monticolus) from New Mexico and Colorado. The discovery of these shrew-borne hantaviruses, named Ash River virus and Jemez Springs virus, respectively, challenges the long-held dogma that rodents are the sole reservoir hosts and forces a re-examination of their co-evolutionary history. Also, studies now underway are aimed at clarifying the epizootiology and pathogenicity of these new members of the genus Hantavirus.

Small mammal response to group selection silvicultural systems in Engelmann spruce-subalpine fir forests

We measured small mammal response to several different group selection silvicultural systems that varied by opening size (0.03, 0.13, and 1.0 ha) but maintained a consistent 30% area removal. The southern redbacked vole (Clethrionomys gapperi), followed by the common shrew (Sorex cinereus) and dusky shrew (S. monticolus), were the most abundant species pre- and post-harvest. There was no evidence that the minimum number alive estimates for red-backed voles differed significantly (α = 0.05) among treatments pre-harvest (ρ = 0.67) or post-harvest (1993, ρ = 0.98; 1994, ρ = 0.84). However, red-backed voles used harvested openings less than the surrounding forest within each treatment. Common shrews showed some preference for the unlogged controls and the treatment units containing 1.0-ha openings. Dusky shrews showed no treatment preference. Overall, we conclude that the group selection silvicultural systems did not substantially change the relatively rich, abundant small mammal community present before harvesting.

Phylogeography of the dusky shrew, Sorex monticolus (Insectivora, Soricidae): insight into deep and shallow history in northwestern North America

Phylogenetic relationships among the dusky shrew (Sorexmonticolus) and eight related species (S. bairdi, S. bendirii, S. neomexicanus, S.ornatus, S. pacificus, S. palustris, S. sonomae and S.vagrans) were assessed using sequences from the mitochondrial cytochrome b gene (801 bp). Analyses using parsimony and maximum likelihood revealed significant molecular variation not reflected in previous morphological studies of these species. Conversely, three morphologically defined species (S.bairdi, S.neomexicanus and S.pacificus) were poorly differentiated. Sorexornatus and S.vagrans represented basal taxa for a more inclusive group that included: (i) a widespread Continental clade containing S.monticolus (Arizona to Alaska, including S. neomexicanus); (ii) a Coastal clade containing S.monticolus (Oregon to south-east Alaska, including S. bairdi and S. pacificus); (iii) the semiaquatic species (S. bendirii and S. palustris); and (iv) S.sonomae. Additional subdivision was observed within the Continental clade corresponding to populations from the northern and southern Rocky Mountains. Average uncorrected sequence divergence between the Coastal and Continental clades was 5.3% (range 4.5-6.2%), which exceeds many interspecific comparisons within this species complex and within the genus Sorex. Lack of resolution of internal nodes within topologies suggests a deep history of rapid diversification within this group. Late Pleistocene/Holocene glacial perturbations are reflected in the shallow phylogeographic structure within these clades in western North America. Our results suggest also that S. monticolus is not monophyletic under current taxonomic nomenclature. This perspective on phylogeographic history was developed within a growing comparative framework for other organisms in western North America.

FURTHER PERSPECTIVES ON THE HAIDA GWAII GLACIAL REFUGIUM.

Byun et al. (1997) reported molecular evidence supporting a purported, long-term Pleistocene glacial refugium for bears (Ursus americanus) located on or near the Haida Gwaii Archipelago (Queen Charlotte Islands), British Columbia. They examined sequence data from the mitochondrial cytochrome b gene and uncovered two lineages, which differed by an average of 3.6%. The lineages were characterized as (Washington to Haida Gwaii) and (Pennsylvania to central Alaska). The geographically restricted coastal lineage led them to conclude that black bear persisted in the Hecate refugium and during early stages of deglaciation recolonized Haida Gwaii, the coastal mainland, Vancouver Island, and eventually the Olympic Peninsula (Byun et al. 1997, p. 1651). In support of this hypothesis, they cited several lines of evidence for a coastal refugium (summarized in Scudder and Gessler 1989) and other recent molecular studies (Soltis et al. 1991; O'Reilly et al. 1993; Talbot and Shields 1996). Our commentary does not reject the possibility of a Haida Gwaii or Hecate refugium for U. arnericanus, but we argue that the conclusions reached by Byun et al. (1997) may be premature and an artifact of limited sampling of the coastal lineage. Wooding and Ward (1997) also reported two lineages (clade A = continental, lade B = coastal) of U. arnericanus based on sequence and restriction fragment length polymorphism analysis of the mitochondrial control region. When results from both studies are combined with earlier studies (Cronin et al. 1991; Paetkau and Strobeck 1996), widespread north-south distributions for the continental and coastal lineages of U. americanus are observed, including areas of potential secondary contact. We present sequence variation from the mitochondrial cytochrome b gene for the American pine marten (Martes americana) and dusky shrew (Sorex monticolus) that may support an alternative biogeographic hypothesis. These mammals, like U. arnericanus, have extensive distributions (Fig. 1) associated with forested habitats in North America. Our analysis uncovered two distinctive lineages in both species that overlap the coastal and continental lineages of U. arnericanus. In light of phylogeographic work on other codistributed mammals (e.g., Cronin 1992; Hogan et al. 1993; Carr and Hicks 1997; Arbogast 1999), amphibians (Good 1989; Green et al. 1996), birds (Zink 1996), and plants (Soltis et al. 1997),

A Survey of Small Mammals in Wood-Tikchik State Park, Alaska

Wood-Tikchik State Park in southwestern Alaska is the largest state park in the United States (7000 km2), however relatively little is known about the small mammal communities occurring in the area. Wood-Tikchik State Park is located approximately 30 km north of Dillingham in southwestern Alaska. Glaciation was the main influence in creating the Park's many features which include spire shaped granite peaks, rising from near sea level to 1525 m. From 1936 to 1938, Olaus Murie conducted a faunal survey of the Alaska Peninsula and Aleutian Islands. He reported that the masked shrew (Sorex cinereus), dusky shrew (S. monticolus), short-tailed weasel (Mustela erminea), and meadow jumping mouse (Zapus hudsonius) had been collected from the Dillingham area in the early 1900s, but apparently did no collecting himself in this area (Murie 1959. North American Fauna 61:1-406.). In 1972, Grumman Ecosystems Corporation conducted an inventory of the Park's resources, including incidental observations of small mammals (unpublished report on file at Alaska Department of Natural Resources, State Parks, Anchorage, AK 99503). Forty-two trap nights yielded only single specimens of the northern red-backed vole (Clethrionomys rutilus), deer mouse (Peromyscus maniculatus), tundra vole (Microtus oeconomus), Z. hudsonius and collared lemming Dicrostonyx groerlland icus). The methods used, including trap locations, trap types, habitats surveyed, and procedures for identifying specimens were not documented in the Grumman report. The meadow vole (M. pennsylvanicus) is also thought to occur in the Park, but no positive verification is available (P. Caswell, U.S. Fish and Wildlife Service; pers. comm.). To provide a current and more reliable inventory of small mammal species occurring in the Park we systematically trapped available habitats at 2 localities from June to September 1994. Our primary trapping site was along the Agulukpak River, which drains Lake Beverly into Lake Nerka in the Wood River Lakes. Mixed forest, meadow, wet tundra, and meadow/mixed forest edge are the dominant habitats near the river. Mixed forest consists of white spruce (Picea glauca), birch (Betula spp.), balsam poplar (Populus balsamifera), ferns (Athyrium, Mattiuccia, and Dryopteris spp.), and grasses (Poa spp.). Meadow habitat consists predominantly of grasses and fireweed (Epilobium angustifolium); whereas sedges (Carex spp.), cottongrass (Eriophorum spp.), crowberry (Empetrum nigrum), and sphagnum moss (Sphagnum spp.) predominate in the wet tundra habitat. The other location was Eagle Island, a 43.7-ha island in Lake Tikchik composed mainly of mixed forest, dry tundra and shrub edge habitats. Dry tundra is composed predominantly of E. nigrum, dwarf blueberry (Vaccinium caespitosum), and lichens (Cladina rangiferina and Cetraria islandica). Shrubs include dwarf willow (Salix spp.), and bog blueberry, (E uliginosum). We used 3 types of traps to collect specimens: small, homemade Sherman-style live traps, 1-gal can pitfall traps, and Museum Special snap traps. We used cheese, peanut butter, and sunflower seeds for bait in the live and snap traps. We placed traps in the dry tundra/shrub edge habitat on Eagle Island and in meadow, wet tundra, mixed forest, and meadow/ mixed forest edge habitats at the Agulukpak River. We used only snap traps in wet tundra, but used all 3 trap types in the remaining habitats. In each habitat type, we set 10 to 15 snap traps at 2.5-m intervals along a single transect. Five live traps and 8 pitfall traps were placed in no particular pattern within habitats. Traps in non-edge habitats were set at least 20 m from habitat edges. We recorded species, standard measurements, location, date, and habitat type for each animal captured. Voucher specimens for each species collected were identified by Dr. Johnson, Emeritus Professor of Zoology, University of Idaho, Moscow and deposited in the museum there. We collected 41 small mammals in habitats near the Agulukpak River: 30 shrews (S. monticolus, S. cirlereus, and pygmy shrew [S. hoyi], 3 C. rutilus, and 8 Z. hudsonius. One specimen of C. rutilus was collected on Eagle Island and 1 M. erminea was collected on the mainland adjacent to the island (Table 1). We observed a colony of arctic ground squirrels (Spermophilus parryii) in August on Lake Nuyakuk and saw red squirrels (Tamiasciurus hudsonicus) in several locations throughout the Park. A colony of little brown bats (Myotis lucifugus) lived in the Agulukpak cabin. The cabin is located at the head of the Agulukpak River and houses the Wood-Tikchik State Park volunteers. Pitfall traps were much more effective than snap traps in capturing shrews; of the 30 Sorex collected, 28 were caught in pitfall traps. Live traps were ineffective in capturing specimens for unknown reasons; none of the various baits placed inside the traps was ever disturbed. That only 1 C. rutilus was collected on Eagle Island in 255 trap nights suggests that species richness and abundance of small mammals on the island were low. This is the 1st record of

A new record in the distribution of the dusky shrew, Sorex isodon, in northern Norway

A new record in the distribution of the dusky shrew, <i>Sorex isodon</i>, in northern Norway

A Quantitative Study on the Activity of the Dusky Shrew (Sorex Vagrans Obscurus)

A Quantitative Study on the Activity of the Dusky Shrew (Sorex Vagrans Obscurus)

Helminths of Northwestern Mammals, Part V. Observations on Cestodes of Shrews with the Descriptions of New Species of Liga Weinland, 1857, and Hymenolepis Weinland, 1858

The cestodes recorded in this study represent a partial review of a large number of individuals recovered from thirteen specimens of three species of shrews, Palmer Marsh Shrew, Sorex bendirii palmeri Merriam (7 specimens); Cascade Dusky Shrew, S. obscurus permiliensis Jackson (2 specimens); and Vagrant Shrew, S. v. vagrans Baird (4 specimens). Neither of the former two shrews have been previously reported in the literature as harboring animal parasites, while only recently Locker and Rausch (1952) published a report on the helminths of the Vagrant Shrew. One of the specimens of S. bendirii palmeeri harbored along with its probable other intestinal fauna the following kinds of helminths: 7 species of cestodes, 5 species of trematodes, 2 species of nematodes, and an acanthocephalan. A conservative estimate of the total number of these fifteen species of helminths would probably exceed 1000. Even so the host weighed about 14 per cent more than the heaviest North American long-tailed shrew recorded by Jackson (1928) and from 43 to 76 per cent more than any of the other specimens of this species collected during the study. Gross examination of its viscera failed to reveal any evident pathology and it seems apparent that the host was able to maintain adequate nutrition even though burdened by its helminth dependents. Whole mounts were prepared from specimens stained in either Semichon's aceto-carmin or Kornhauser's hematin and where necessary, serial sections were prepared and stained with hematoxylin and eosin. Unless otherwise noted, all measurements are given in millimeters. Drawings were prepared with the aid of a camera lucida.

A new farm of dusky shrew from the prairie provinces of Canada

A new farm of dusky shrew from the prairie provinces of Canada

Nest and Young of the Olympic Dusky Shrew

Nest and Young of the Olympic Dusky Shrew

A Note on the Dusky Shrew in Captivity

A Note on the Dusky Shrew in Captivity