Body size, body composition, and behavior of juvenile Belding ground squirrels

Juvenile Belding ground squirrels were studied in the Sierra Nevada. Females were more trappable, had smaller home ranges, and tended to enter hibernation earlier than males. The primary sex ratio was 1:1. Individuals first emerged from the natal burrow at three to four weeks of age and a body weight of 35 g. Body weight and linear dimensions increased thereafter until hibernation began. Maximum prehibernatory weight of 200 to 260 g was attained at about 12 weeks of age. Prehibernatory fattening began at about six weeks of age. Maximum lipid stores attained weighed about 80 percent of the lean, dry body compartment. Seasonal changes occurred in weight of white and brown fat depots, adrenal glands, spleen, heart, kidneys, liver, and testes. Annual variations in snowpack and emergence schedule caused the reproductive period, and thus phenology of juveniles, to vary by as much as three weeks. The last animals to immerge were unusually small, being from late litters. Nonetheless, they may have had lipid stores sufficient for surviving hibernation.     

Body fat, body water, and total caloric value of Uinta ground squirrels

The weight of body water and fat-free dry weight of Uinta ground squirrels ( Spermophilus armatus ) is given as a function of body weight. Body fat is presented as a function of body weight and body length. An equation for calculating the total caloric content of Uinta ground squirrels is given. Fat index (weight of fat/fat-free dry weight) values of juveniles increased from 0.11 to 0.22 from 5 June to 28 July. In male yearlings and adults the fat index increased about 8 to 9 times in the latter half of June and early July.         

Time budgets of Wyoming ground squirrels, Spermophilus elegans

Time budget of free-living adult Spermophilus elegans differed significantly from that of juveniles in the Front Range of the Rockies during 1974–1975. No differences were found between males and females. Hour of day, day since emergence, air temperature, cloud cover, and presence of predators all correlated with the frequency of various components of the time budget.     

Correlates of burrow location in Beechey ground squirrels

Partial correlation analysis indicates that Beechey ground squirrels show a strong preference for digging burrows under and around large objects, may show a weaker tendency to locate their burrows under the cover of tree canopies, and avoid digging burrows in areas with both treecanopy and ground cover (stones, logs). These relationships hold for large but not small burrow systems. The need for unobstructed visual surveillance and an autumn food supply are proposed to be determinants of these preferences.     

Populations and habitat relationships of Piute ground squirrels in southwestern Idaho

Piute ground squirrels ( Spermophilus mollis idahoensis ) are normally above ground from late January until late June or early July in the Snake River Birds of Prey National Conservation Area in southwestern Idaho. In 2002 they were rarely seen above ground after early May. Because of the ecological importance of ground squirrels for nesting raptors and other species, we sought to determine the reasons for their early disappearance. We sampled 12 sites from January 2003 through March 2003 to determine if a population crash had occurred in 2002. Tests indicated that Piute ground squirrels had not been exposed to plague within the past year. The presence of yearlings in the population indicated that squirrels reproduced in 2002 and that at least some yearlings survived the winter. Both yearling and adult squirrels appeared to be reproducing at or above normal rates in 2003. The most plausible explanation for the early disappearance of Piute ground squirrels in 2002 is that squirrels entered seasonal torpor early in response to a late spring drought. In addition, the breeding chronology of squirrels may have shifted during the past 2 decades in response to climate change and/or habitat alteration. Shrub habitats provide a more favorable and stable environment for squirrels than grass habitats. Squirrel abundance was higher on live-trapping grids with sagebrush than on grids dominated by grass, and squirrel masses were higher at sites dominated by shrubs and Sandberg bluegrass ( Poa secunda ). Densities in big sagebrush ( Artemisia tridentata ) were within the ranges reported for earlier years, but densities in grass were lower than previously reported. Low densities at grassland sites in 2003 support other findings that drought affects squirrels in altered grass communities more than those in native shrub habitats. Long-term shifts in ground squirrel breeding chronology may have implications for raptors that depend on them for food.     

Reproductive cycle of the Belding ground squirrel ( Spermophilus beldingi beldingi ): seasonal and age differences

The reproductive cycle in Belding ground squirrels was studied in the Sierra Nevada Mountains at two locations, one at 2,100 m elevation, the other at 3,000 m. Adults emerged from hibernation completely prepared physiologically for reproduction. Males tended to emerge slightly ahead of females and yearlings tended to emerge later than adults. Yearling females were fertile but produced smaller litters than adults, 4.48 vs. 6.31. Yearling males were infertile. They exhibited a slight seasonal cycle in testicular growth but did not reach sexual maturity. Testicular growth and spermatogenesis were incipient in many adults and in yearlings prior to hibernation.       

Seasonal activity pattern of Columbian ground squirrels in the Idaho primitive area

Data were gathered concerning the seasonal activity pattern of a population of Columbian ground squirrels ( Spermophilus columbianus ) in the Idaho Primitive Area. Adult females were significantly more active in June of all years than were adult males. A relationship between ground squirrel activity and temperature is postulated in which the squirrels alter their activity so as to avoid high temperatures and possible heat stress.     

Postemergence development and interyear residence of juvenile Columbian ground squirrels in the Idaho Primitive Area

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Eimeria sp. (Apicomplexa: Eimeriidae) from Wyoming ground squirrels Spermophilus elegans , and white-tailed prairie dogs, Cynomys leucurus , in Wyoming

Six species of the coccidian genus Eimeria ( E. larimerensis [prevalence = 17%], E. bilamellata [12%] E. beecheyi [34%], E. morainensis [43%], E. callospermophili [21%], and E. spermophili [5%]) were recovered from Wyoming ground squirrels ( Spermophilus elegans elegans ) collected during 1983, 1984, 1985, and 1986. Infected ground squirrels were found to harbor from one to five species simultaneously. The 1007 hosts examined were collected from two different habitats: (1) a xeric desert shrub-steppe and (2) an irrigated alfalfa-brome field. All species of Eimeria occurred at each study site during all years, although the prevalence of each species varied between years. This is the first report of these congeries of species infecting this host. In a second study of sympatric populations of Wyoming ground squirrels and white-tailed prairie dogs ( Cynomys leucurus ), found three species of Eimeria present in both host populations ( E. beecheyi [white-tailed prairie dog prevalence = 83%, Wyoming ground squirrel = 52%], E. morainensis [22%, 52%], and E. bilamellata [17%, 10%]). This is the first report of these three species infecting white-tailed prairie dogs. Eimeria larimerensis was found in Wyoming ground squirrels but not in prairie dogs.     

Interactions among squirrels, mycorrhizal fungi, and coniferous forests in Oregon

We examined the mycophagy (ingestion of fungi) of squirrels of five genera and eight species in the coniferous forests of Oregon. Data from 644 dietary samples demonstrated that squirrels of all eight species are mycophagous and eat the belowground fruiting bodies of at least 26 genera of mycorrhizal fungi. Four species are primarily arboreal and active throughout the year; the other four are primarily terrestrial and hibernate during winter. Of the squirrels examined, only the northern flying squirrel ( Glaucomys sabrinus [Shaw]) is nocturnal and almost exclusively a fungivore. The flying squirrel is used to illustrate the dynamics of all the squirrels in association with hypogeous mycorrhizal fungi, nitrogen-fixing bacteria, yeast, and coniferous trees in Oregon forests because we have studied it the most. Squirrels may prove to be vital links among different processes within temperate coniferous forests.     

Sex ratios of the white-tailed antelope ground squirrel (Ammospermophilus leucurus), Indian Wells Valley, San Bernardino County, California

We studied the white-tailed antelope ground squirrel during spring and summer 2006 to determine young-of-the-year and adult sex ratios in the Indian Wells Valley, San Bernardino County, California. We calculated a young-of-the-year sex ratio of 1.45:1 (female to male), whereas the adult sex ratio was approximately 1:1. Our young-ofthe-year sex ratio was greater than the 1.1:1 (female to male) natal sex ratio previously reported. Differences between young-of-the-year and adult sex ratios may represent low female young-of-the-year survivorship in the Indian Wells Valley.     

Tanypodine midges of the genus Ablabesmyia Johannsen (Diptera: Chironomidae) from West Bengal with a note on their seasonal incidence and sex ratios

Summary

A key to the species of the subgenus Ablabesmyia occurring in India is provided. Four new species of Ablabesmyia, alba, ensiceps, maculitibialis and transversus are described. Systematic positions of paivai (Kieffer) and photophilus (Kieffer) in the genus are confirmed and is placed in the subgenus Karelia Roback previously unrecognised in the Oriental region. Seasonal incidence and sex ratio of some species are given.     

Qualitative relations of egg size,egg production and colony size in some ponerine ants (Hymenoptera: Formicidae)

The sizes of eggs and reproductives of 13 species of ponerine ant were measured, and information about the mature colony sizes, ovarial anatomy and individual fecundities of a selection of ponerine species was assembled. Inter-specific variation in the size of colonies was found to be poorly related to aspects of individual fecundity, and although the few cases of polygyny were associated with larger colony sizes, monogynous species often attained even larger sizes. Within the subfamily individual fecundity may be increased primarily by a decrease in the maternal investment in individual eggs, and perhaps to a lesser extent by an increase in the number of ovarioles in each ovary or an increase in the length of each ovariole. The diet of a species and the longevity of adult worker ants relative to the duration of their larval development are suggested as factors besides reproductive characteristics that might also contribute to differences in colony size.     

Estimation of the stock size of adult Nephrops norvegicus (L.) from larvae surveys in the western Irish Sea in 1982

This paper describes the results of Nephrops larvae surveys in the western Irish Sea from April to June 1982. Total production of Stage I zoea obtained from the seasonal production curve is used, together with an estimate of effective fecundity, to assess the number of mature females contributing to the season's hatch. Total production of Stage I zoea was also obtained from the intercept at zero time of the stage to stage mortality regression. Length and weight data from the fishery allow an estimate of the biomass of the mature female stock to be made.     

Diet and habitat of northern flying squirrels ( Glaucomys sabrinus ) in the Black Hills of South Dakota

During the summers of 2005 and 2006, northern flying squirrels ( Glaucomys sabrinus Shaw) were live-captured in the northern Black Hills of South Dakota from mixed deciduous/coniferous and coniferous habitats. Squirrel captures were significantly correlated with volume of downed wood and number of snags. Diets were examined from scat collections ( n = 40, deciduous/coniferous; n = 10, coniferous). Number of fungal spores in the scat was significantly correlated with number of snags. From each scat collection, the frequencies of plant, animal, fungal, and unidentified components were determined. Hypogeous fungi were a frequent component of the diet, being found in 98.3% and 78.8% of the scat observed in 2005 and 2006. In 2006, as the frequency of dietary fungi decreased, the frequency of plant material increased from <1.0% to 8.0% and frequency of unidentified material increased from 2.0% to 74.0%. Animal content in the scat was negligible (<1.0% to 1.0%). Rhizopogon was the most frequently occurring hypogeous fungus observed. Rhizopogon spores made up 97.9% of the spores counted in 2005 and 96.4% in 2006. Elaphomyces, Gautieria, Geopora, Hymenogaster, and Hysterangium were observed at much lower frequencies. Sporocarps were collected throughout the trapping periods. Fourteen were collected in 2005 and 12 in 2006. Of the 26 sporocarps collected, 11 were Rhizopogon, 4 Elaphomyces, 2 Gautieria, 1 Hymenogaster, 7 Hysterangium, and 1 Tuber. This study is the first to examine flying squirrel diets in the Black Hills and the first to report Elaphomyces, Gautieria, Hymenogaster, Hysterangium, Rhizopogon, and Tuber sporocarps from the South Dakota Black Hills.     

Vertical distribution of adult fish in Pyramid Lake, Nevada

Inshore and limnetic vertical distribution of adult fish in Pyramid Lake, Nevada was determined from late spring to early fall 1977. The benthic (23 m) inshore area exhibited a relatively diverse composition of five species, while the inshore surface and offshore limnetic zones were composed of over 98 percent tui chubs ( Gila bicolor ). Vertical fish distribution was associated with temperature and zooplankton distribution.     

Species composition and relative abundance of adult fish in Pyramid Lake, Nevada

Pyramid Lake fish populations were sampled with nets on a monthly basis from November 1975 through December 1977. Fish species were taken in the following order of numerical relative abundance: tui chub ( Gila bicolor ), Tahoe sucker ( Catostomus tahoensis ), Lahontan cutthroat trout ( Salmo clarki henshawi ) including cutthroat-rainbow hybrids, cui-ui ( Chasmistes cujus ), and Sacramento perch ( Archoplites interruptus ). Relative abundance estimates are discussed with respect to seasonal availability, spatial distribution of the fish, sampling bias of the fishing methods, and biomass of the fish. Recent temporal trends in the population structure of the lake are presented.     

Influence of substrate size, Cladophora , and caddisfly pupal cases on colonization of macroinvertebrates in Sagehen Creek, California

Colonization of stream macroinvertebrates onto artificial substrates was examined in Sagehen Creek, California, during 1993. Substrate size and presence or absence of pupal cases of the caddisfly Anagapetus (Glossosomatidae) were examined as possible influences on macroinvertebrate colonization. Macroinvertebrates were collected from substrates after 60 d of incubation and identified to the lowest feasible taxonomic unit. Dry weight of the filamentous green alga Cladophora also was determined for each substrate. A general linear model indicated a significant positive relationship between both substrate size and presence of pupal cases on richness ( P Anagapetus cases on Micrasema bactro , Epeorus , and Rhyacophila sp. 1, and of substrate size on Hydropsyche occidentalis and Epeorus . Neither cases nor substrate size had a significant effect on Cladophora density ( P > 0.05). There were significant negative correlations between Cladophora density and both Shannon H′ and J′ indices. There were significant positive relationships between Cladophora density with Baetis , Simulium , and Chironomidae density. Combined main effects of substrate size, Anagapetus pupal cases, and Cladophora have dynamic influences on this macroinvertebrate fauna. This study demonstrates the complex interplay of biotic and abiotic factors that determine macroinvertebrate distribution and abundance in this system.