Differential parasitism of Peromyscus maniculatus and Peromyscus truei by Cuterebra larvae

During a 2 - month field study of sympatric Peromyscus maniculatus (Deer Mouse) and Peromyscus truei (pinyon mouse), 12/152 (7.9 percent) P. maniculatus and 1/45 (2.2 percent) P. truei were parasitized by Cuterebra larvae. Both parasitized P. maniculatus and P. truei and nonparasitized P. maniculatus selected different habitats in the community. Differential parasitism of P. maniculatus and P. truei was possibly caused by host specificity of Cuterebra, whereas differential parasitism of P. maniculatus may have been due to habitat selection.     

Deer mouse, Peromyscus maniculatus, and associated rodent fleas (Siphonaptera) in the arctic-alpine life zone of Rocky Mountain National Park, Colorado

Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Peromyscus maniculatus and related small rodents have been examined for ectoparasites in the tundra region of the Rocky Mountain National Park 1974–1979. One hundred and ninety-four P. maniculatus were examined from two tundra sites. Flea infestation rates were 1.9 fleas per mouse examined and 4.1 fleas per infested mouse. Species taken in significant numbers were Monopsyllus thambus (51 percent), Peromyscopsylla hesperomys (34 percent), Malaraeus euphorbi (9 percent), and Catallagia calisheri (4 percent). Peromyscus maniculatus host/flea relationships in the tundra are compared with those in other life zones in the park.       

Summer food habits of coyotes in central Wyoming

Summer food habits of coyotes ( Canis latrans ) were investigated on a 3100-km 2 area in central Wyoming, divided into one deer-use area and five non-deer areas. Analysis of 404 scats (fecal samples) revealed an overall average of 63 percent occurrence of native ungulates, 63 percent leporids, 46 percent rodents, 14 percent livestock, and 11 percent birds. Pronghorn ( Antilocapra Americana ) was the ungulate most frequently consumed, occurring in about 87 percent of the scats. Mule deer ( Odocoileus hemionus ) occurred in only 8 percent, and in 5 percent the native ungulate remains were not identifiable beyond order. This large percentage of big game in the diet is apparently unusual, because big game has been of minor importance in most coyote food-habit studies. The high incidence of leporids is consistent with other studies performed in arid intermountain areas. Although cricetines, especially deer mice ( Peromyscus maniculatus ), were trapped consistently in all habitats, months, and trapping areas, they were found in scats at a lower frequency than microtines and sciurids. This suggests a coyote hunting strategy that selected for the latter two groups.     

An ecological and taxonomic investigation of Peromyscus maniculatus serratus in Idaho

Twenty - two sites in central Idaho were sampled to determine the geographic range of Peromyscus maniculatus serratus. Isolating mechanisms which exist between the P. maniculatus subspecies of region require further investigation.     

Influence of yellow starthistle ( Centaurea solstitialis ) on small mammals in central California

Yellow starthistle ( Centaurea solstitialis ) is native to Europe and Asia and has quickly invaded disturbed grasslands and rangelands in the western United States. The purpose of our study was to determine the effects of starthistle on rodents at Beale Air Force Base, Yuba County, California, by examining rodent species diversity, species abundance, age structure, and reproductive condition among locations with low, medium, and high percent cover and height of starthistle. Listed in decreasing order of abundance, the rodents were house mouse ( Mus musculus ), California vole ( Microtus californicus ), deer mouse ( Peromyscus maniculatus ), western harvest mouse ( Reithrodontomys megalotis ), and roof rat ( Rattus rattus ). Indices of diversity did not differ among starthistle cover categories. Regression analyses showed that Reithrodontomys megalotis was more abundant in high-cover starthistle plots, with 90.5% of captures occurring in at least 40% starthistle cover. Significant differences were found in capture rates, reproduction, and age between season only. To manage for all rodent species, an area with medium percent cover and height of starthistle will likely provide adequate protective cover.     

Rodent populations, biomass, and community relationships in Artemisia tridentata, Rush Valley, Utah

Three desert Artemisia tridentata communities in Rush Valley, Utah, were trapped for small rodents during the summer of 1970, and population densities were estimated for each population category using Lincoln's index. Animals were weighed and rodent biomass calculated by species throughout the summer. Population, biomass, and other data were then analyzed to gain an understanding of the community relationships of the three study areas to each other as well as to the A. tridentata community types of the Great Basin. Peromyscus maniculatus, Eutamias minimus, and Reithrodontomys megalotis were common to area 1, whereas P. maniculatus, E. minimus, and Perognathus parvus were common to areas 2 and 3. The peak estimated standing crops were 182.8 (74.0). 143.1 (57.9), and 129.7 g/acre (52.5 g/ha) for areas 2, 1, and 3 respectively. The population and biomass of area 2 peaked in midsummer, area 1 early summer, and area 3 late summer.     

Short-term effects of logging on red-backed voles and deer mice

Clearcutting and selective logging effects on red-backed voles ( Clethrionomys gapperi ) and deer mice ( Peromyscus maniculatus ) were studied (September–November, 1975; June–October, 1976) in Bridger-Teton National Forest, Wyoming. Five selective cuts (total 137 ha) removed 57 percent (range 34–74 percent) of the trees. One clearcut (9.6 ha) eliminate 84 percent of the trees. Soils remained mesic in selective cuts, but became xeric in the clearcut. Snap-trapping indicated that voles were most abundant on the unlogged and selectively cut mesic sites (76 percent of 408 captures), whereas deer mice were more common on the xeric clearcut (80 percent of 60 captures). Species composition remained unchanged on selective cuts following logging (77 percent voles of 256 captures), but changed from predominantly voles to mostly deer mice (80 percent of 60 captures) in the clearcut. Intraspecific age and sex ratios, litter sizes, and morphological measurements were compared between logged and unlogged areas.     

Habitat use by small mammals in southeastern Utah, with reference to Mexican Spotted Owl management

We determined temporal and spatial differences in abundance and habitat use by small mammals in southeastern Utah as part of an effort to enhance management of the Mexican Spotted Owl ( Strix occidentalis lucida ), listed by the federal government as threatened. Woodrats ( Neotoma spp.) were captured only in canyons and most frequently in the pinyon-juniper ( Pinus edulis-Juniperus osteosperma ) vegetation type. White-footed mice ( Peromyscus spp.) were found in a variety of vegetation types in both canyons and mesas. The deer mouse ( P. maniculatus ) was generally the most frequently captured species among vegetation types. We found seasonal and yearly differences in relative abundance of each small mammal species. Our data suggest that the pinyon-juniper vegetation type within canyons is an important component of Mexican Spotted Owl habitat.     

Vegetative and edaphic factors affecting abundance and distribution of small mammals in southeast Oregon

The relationships between vegetative and edaphic habitat factors and the local distribution and abundance of small mammals on Malheur National Wildlife Refuge, Harney County, Oregon, were examined between July 1973 and June 1975. Of 16 species of small mammals captured, deer mice ( Peromyscus maniculatus ), montane voles ( Microtus montanus ), Great Basin pocket mice ( Perognathus parvus ), and least chipmunks ( Eutamias minimus ) comprised 90.1 percent of the individuals. The physiognomy of the vegetation was a factor in the distribution of rodent species other than deer mice. Pocket mice and chipmunks were restricted to the communities dominated by sagebrush ( Artemisia tridentata ) or greasewood ( Sarcobatus vermiculatus ). Population densities of pocket mice and chipmunks were significantly related to edaphic factors such as soil depth, texture, and strength, which may have affected the construction and stability of burrows. Montane voles occurred only in marsh or grassland communities. Population densities of voles were directly correlated with the amount of cover and inversely correlated with its patchiness. Deer mice were the most common species encountered and occurred in all but the grassland communities. The density of this species was related to vegetative or edaphic factors only seasonally or in certain habitats, and few generalizations could be made.     

Factors influencing the frequency of nest parasitism by Brown-headed Cowbirds in the northern Sierra Nevada

Nest parasitism by Brown-headed Cowbirds ( Molothrus ater ) can negatively affect host populations. Landscape-scale factors, such as proximity to residential areas, equestrian riding stables, and grazing allotments, can affect the risk of nest parasitism as well as the abundance of Brown-headed Cowbirds. Recent increases in residential and recreational development along with a reduction in grazing allotments in the northern Sierra Nevada provide an opportunity to reevaluate factors that influence frequency of nest parasitism by Brown-headed Cowbirds. Frequency of nest parasitism increased as the distance to the nearest residential center and distance to the nearest equestrian riding stable decreased. Similarly, Brown-headed Cowbird abundance was negatively correlated with distance to the nearest residential center and distance to the nearest equestrian stable. To reduce the risk of nest parasitism, efforts should be devoted to (1) reducing further residential development at the wildland–urban interface and (2) educating landowners about bird feeders, which frequently attract Brown-headed Cowbirds.     

Genetic variation of woodrats ( Neotoma cinerea ) and deer mice ( Peromyscus maniculatus ) on montane habitat islands in the Great Basin

Seventeen loci were examined for polymorphism in four populations of Neotoma cinerea and Peromyscus maniculatus on isolated mountain ranges in the Great Basin, one population of each in the Sierra Nevada, and one of each in the Rocky Mountains. All Peromyscus populations had higher levels of heterozygosity than syntopic Neotoma populations.     

Hip glands in a natural population of montane voles ( Microtus montanus )

Average linear movement by populations of Dipodomys ordii, Microtus montanus, Perognathus parvus, and Peromyscus maniculatus   was investigated over a 15-month period by live trapping on a low-level, radioactive waste disposal area in Idaho. No significant differences in movement among habitats were observed seasonally, excepting M. montanus in spring. Average linear movements within habitats ranged from 20 to 70 m for all species, but some patterns varied seasonally and among age classes for individual species. Although predation on contaminated small mammals from the disposal area is a vector of radionuclide transport, local movements by these rodents do not appear to be of sufficient magnitude to contribute significantly to redistribution of radioactive particles.     

A new genus and new species (Orthoptera: Acrididae: Gomphocerinae) from south-east Xizang,China

In 2007, a 3-year survey was started in northeastern Italy to assess the influence of agricultural management on parasitoid composition and parasitism rates of parasitoids attacking larvae and pupae of Syrphidae (Diptera). Two types of management were considered – intensive (including wheat and maize monoculture with very low or null vegetation diversity) and extensive (with different types of habitats, characterized by a higher vegetation complexity). In habitats simplified by intensive agriculture, and particularly in maize fields, parasitism rates of syrphid larvae were higher than recorded in more diversified habitats. A substantial difference in the composition of the parasitoid complex was also found. In extensive and wheat sites, Diplazontinae (Braconidae), highly specialized to Syrphidae, were the dominant parasitoids, whereas in maize fields Pachyneuron (Pteromalidae) species, known as generalists, accounted for more than 80% of total parasitoids. In the habitats where Pachyneuron spp. were dominant, parasitism rates were very high. Conversely, in habitats where Diplazontinae were more abundant, the parasitism rates were very low. The higher rate of parasitism of syrphid larvae and pupae recorded in intensive monocultures could have a large impact on the development and control of aphid populations in such crops.     

Altitudinal patterns of abundances and parasitism in frugivorous drosophilids in west Java,Indonesia

Abundances and parasitism rates of frugivorous drosophilid flies were studied in three localities at altitudes of 250–1350 m in and near Bogor, Indonesia. The drosophilid and parasitoid species were classified into four groups: low-altitude species, high-altitude species, species abundant at a mid-altitude location and species occurring rather evenly from low to high locations. The ananassae and immigrans species groups were major drosophilids collected. All species of the ananassae species group were more abundant at lower altitudes, and the parasitism rate in this species group decreased with increasing altitude. Thus, the host abundance seems to affect the parasitism rate. On the other hand, the rate of parasitism in the immigrans species group showed no apparent relation with altitude or density, possibly due to the fact that species of this species group varied in altitudinal distribution. It is also suggested that the diversity of drosophilid species affects the composition of parasitoid species.     

Terrestrial vertebrates of the Mono Lake islands, California

We compared vertebrate populations between the two major islands (paoha and Negit) in Mono Lake, California and the adjacent mainland to further elucidate the mechanisms underlying island colonization. Deer mice ( Peromyscus maniculatus ) and montane voles ( Microtus montanus ) were captured on Paoha, but only deer mice were captured on Negit. In contrast, eight species of rodents were captured on the mainland. Overall rodent abundance on Paoha and the mainland was similar, but on Negit it was about three times greater than on Paoha or the mainland. Adult deer mice from Paoha were significantly ( P Canis latrans ) and one or two species of lagomorphs were observed on the islands and the mainland. No amphibians or reptiles were found on the islands; both occurred in low numbers on the mainland. Rafting and human transport are probable means of colonization for mice and voles. The occurrence of coyotes on the islands may have modified historic predator-prey relationships, and thus the population of rodents and lagomorphs.     

Habitat affinities of rodents in northeastern Nevada rangeland communities

From May 1978 through September 1980, baseline data for rodent populations were collected by livetrapping in the Saval Ranch area of northeastern Nevada. The objectives of this study were to determine species composition and relative abundance of rodents for the various range sites. The 3 most abundant and uniformly distributed species were deer mice ( Peromyscus maniculatus ), Great Basin pocket mice ( Perognathus parvus ), and least chipmunks ( Neotamias minimus ). Relative abundance indices and densities reported for most species were similar to those reported in other multiyear studies at similar sites. The composition and relative abundance / density of rodent species was variable among habitats and over time. Diverse rodent species within the sagebrush ecosystem have commensurately diverse habitat requirements that should be considered when vegetation management is planned. Annual population fluctuations and differences among similar habitats should be considered when researchers propose to test rodent population responses to livestock grazing or other habitat treatments.     

Cheek pouch capacities and loading rates of deer mice ( Peromyscus maniculatus )

Eight deer mice ( Peromyscus maniculatus were attracted to bait stations in the field and filled their cheek pouches with seeds. Pouch capacity of the deer mice, which have small, internal cheek pouches, was 0.45 ± 0.11 mL, about 12-27% of that carried by similar-sized heteromyid rodents. Cheek pouches of deer mice, although small, give them the capacity to carry 3-5 times more food than unspecialized mice. This presumably increases efficiency of deer mice in exploiting small, particulate food items that are patchily distributed.     

Role of three rodents in forest nitrogen fixation in western Oregon: another aspect of mammal-mycorrhizal fungus-tree mutualism

To determine the role of the California red-backed vole ( Clethrionomys califonicus ), the northern flying squirrel ( Glaucomys sabrinus ), and the deer mouse ( Peromyscus maniculatus ) in the nitrogen cycle of forest stands in western Oregon, bacterial colonies were isolated and purified from feces, and their nitrogen-fixing ability measured by acetylene-reduction assay. The ability of the bacterial species Azospirillum   sp. to withstand freezing was also tested. Fecal extracts were used to test whether fecal pellets can provide the nutrients necessary for growth of the bacteria. All the feces tested contained viable nitrogen-fixing bacteria, and both species can survive drying and one can survive freezing. Azospirillum colonies grew well on liquid medium but required yeast extract for growth and nitrogenase activity. Fecal extracts from flying squirrels and chickarees ( Tamiasciurus douglasi ) were as effective as the yeast. The results suggest another link in the chain of mutualism that unites small mammals, mycorrhizal fungi, and forest trees.     

Observations of sagebrush gall morphology and emergence of Rhopalomyia pomum (Diptera: Cecidomyiidae) and its parasitoids

Galls induced by insects are specialized plant tissues thought to provide a suitable microclimate and high-quality food for insect development. Galls are also hypothesized to provide protection from predators, and particularly from parasitoids, because larger galls may be too deep for parasitoid oviposition (enemies hypothesis). However, galls may actually increase the risk of parasitism by making the location of gallformers more apparent (apparency hypothesis). Rhopalomyia pomum (Diptera: Cecidomyiidae) forms soft, lobed galls on big sagebrush ( Artemisia tridentata : Asteraceae). The volume of the largest galls can be 600X that of the smallest. Here I explore the relationships of the number of lobes per gall and gall volume with the emergence of R. pomum and its parasitoids. I collected 159 galls from 4 locations in southern Utah in spring 2002, measured them, and monitored emergence from each. Lobing was not related to midge emergence ( F 1,150 = 2.35, P = 0.13) but was positively associated with parasitoid emergence ( F 1,150 = 15.27, P F 1,150 =22.0, P F 1,150 = 0.3, P = 0.6), providing no support for either the enemies or apparency hypothesis.     

Movements by small mammals on a radioactive waste disposal area in southeastern Idaho

Average linear movement by populations of Dipodomys ordii, Microtus montanus, Perognathus parvus, and Peromyscus maniculatus   was investigated over a 15-month period by live trapping on a low-level, radioactive waste disposal area in Idaho. No significant differences in movement among habitats were observed seasonally, excepting M. montanus in spring. Average linear movements within habitats ranged from 20 to 70 m for all species, but some patterns varied seasonally and among age classes for individual species. Although predation on contaminated small mammals from the disposal area is a vector of radionuclide transport, local movements by these rodents do not appear to be of sufficient magnitude to contribute significantly to redistribution of radioactive particles.