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1

Oocyst production in multispecific eimerian infections in the Wyoming ground squirrel, Spermophilus elegans elegans

100%
Thomas D. M., Seville R. S., Stantom N. L.
Acta Parasitologica
|
1992
|
tom 37
|
nr 3
We have investigated a stable assemblage of 6 species of Eimeria in the intestine of the Wyoming ground squirrel consisting of three abundant species (E. beecheyi, E. callospermophili and E. morainensis) and three rare species E. larimerensis, E. bilamellata and E. spermophili). To test the hypothesis that no interactions occur among these parasite species, five squirrels were inoculated with 12,500 oocysts consisting of 1 E. larimerensis, 10 E. bilamellata, 22 E. beecheyi and 67 % E. callospermophili. The proportion of each species in the output was quite different: 41 E. larimerensis, 5 E. beecheyi, 0 E. bilamellata and 54% E. callospermophili. When the same squirrels were reinoculated with 10,000 oocysts of 85 E. larimerensis, 7 E. beecheyi and 8% E. callospermophili, the output was 9 E. larimerensis, 13 E. beecheyi and 78% E. callospermophili. In the initial infections, the intrinsic rate of increase (r) for E. larimerensis was considerably higher than that of E. beecheyi or E. callospermophili. During the reinfections, (r) for E. larimerensis was significantly lower and for E. beecheyi and E. callospermophili significantly higher than initial values. Although E. larimerensis appears to have initially compromised the reproductive potential of its congenerics, acquired host immunity may have caused its reduced reproductive potential in the second trial.
2

Chromosomal differentiation of spotted ground squirrel Spermophilus suslicus Guld.1770

100%
Korablev V.
Polish Ecological Studies
|
1994
|
tom 20
|
nr 3-4
3

Patch occupancy by squirrels in fragmented deciduous forest: effects of behavior

86%
Walpole A. A., Bowman J.
Acta Theriologica
|
2011
|
tom 56
|
nr 1
We tested whether species-specific behavioral traits could explain patterns of habitat patch occupancy by five different squirrel species in Ontario, Canada: the northern and southern flying squirrel (Glaucomys sabrinus and Glaucomys volans), the North American red squirrel (Tamiasciurus hudsonicus), the eastern chipmunk (Tamias striatus), and the eastern gray squirrel (Sciurus carolinensis). Flying squirrel species exhibit group nesting in winter, which may put them at risk of extirpation in small patches with few individuals to contribute to group nests. Flying squirrels are also volant, potentially making non-treed matrix a barrier. Our surveys revealed that G. sabrinus was most likely to occur in large patches that were embedded in landscapes with low connectivity, and least likely to occur in small patches in highly connected landscapes. Conversely, G. volans was most likely to occur in large, well-connected patches and least likely to occur in small, unconnected patches. Patch occupancy by the cursorial squirrels was not strongly influenced by patch area or isolation. These findings reinforce previous studies suggesting that an understanding of species-specific traits such as behavior is an important consideration when interpreting habitat fragmentation effects.
4

Estimating the relatedness in a population of grey squirrels Sciurus carolinensis, using DNA fingerprinting

86%
David-Gray Z. K., Gurnell J., Hunt D. M.
Acta Theriologica
|
1999
|
tom 44
|
nr 3
Studies on the behaviour of grey squirrels Sciurus carolinensis Gmelin, 1788 and other species belonging to the same genus, suggest they exhibit dominance hierarchies among both males and females, and their mating strategy is promiscuous or polygynous, However, there is little information available on how dominance translates into repro­ductive success or on the levels of genetic variation or genetic substructuring within a population. To address these questions, we used multilocus DNA fingerprinting to quantify genetic diversity and estimate relatedness amongst individuals in a free­-ranging population of grey squirrels. Background band-sharing values revealed a high degree of genetic diversity existed. The frequency distribution of band-sharing values between known first order relatives and presumed unrelated animals was significantly different. Estimates of relatedness between individuals were therefore based on threshold levels of genetic similarity and used as a tool to infer close kinship. Possible kinship groups were identified using the spatial distribution of the home ranges of adults and juveniles. Levels of relatedness between neighbouring adults was low with five family units identified comprised of putative parents and their offspring. Several juveniles from the single cohort revealed levels of relatedness intermediate between first order relatives and unrelated animals, suggesting possible second order relationships (eg half siblings) existed. The implications of these relationships are discussed.
5

Feeding and hoarding behaviour of the Eurasian red squirrel Sciurus vulgaris during autumn in Hokkaido, Japan

72%
Lee T. H.
Acta Theriologica
|
2002
|
tom 47
|
nr 4
The feeding habits and hoarding behaviour of the Eurasian red squirrel Sciurus vulgaris Linnaeus, 1758 were examined during autumn in Nopporo Forest Park (43°20'N, 141°30'E), in western Hokkaido, Japan. The diet consisted of 32 plant species. Twelve species were both eaten and hoarded (the two most common of which were Abies sachalinensis and Pinus koraiensis), and 20 species were eaten but not hoarded. The distance from where a food item was found to the hoarding spot averaged 50 m and differed significantly according to food type. Walnuts Juglans regia were transported farthest, and chestnuts Castanea crenata to the second farthest from the site of origin. Most food was hoarded beneath the ground surface (95%), but some were hoarded in forks of trees and in small tree holes. Squirrels selected food items of high energy content for hoarding, in preparation for winter and the breeding season.
6

Species-specific and shared features in vocal repertoires of three Eurasian ground squirrels (genus Spermophilus)

58%
Matrosova V. A., Schneiderova I., Volodin I. A., Volodina E. V.
Acta Theriologica
|
2012
|
tom 57
|
nr 1
Along to alarm calls, Eurasian ground squirrels of the genus Spermophilus also produce other call types toward potential predators and rival conspecifics. Individually identified 50 speckled (Spermophilus suslicus), 18 European (S. citellus) and 59 yellow (S. fulvus) ground squirrels were examined for interspecies differences in their vocal repertoires. A separate sample of 116 (90 adult and 26 juvenile) S. suslicus was examined for presence of ultrasound in their alarm calls. In addition, all tonal calls in all the three species were checked for presence of nonlinear phenomena. Calls were elicited by approaching animals in live-traps or near burrows; some types of vocalizations were also recorded during handling. Eight call types, three tonal and five wideband ones, were described. Vocal repertoires were remarkably similar between species, excluding the alarm calls, which were species-specific. Alarm calls with ultrasonic components were found in two individuals of S. suslicus. Concerning nonlinear phenomena, biphonation in alarm calls of S. suslicus, frequency jumps and sidebands in screams of S. citellus, frequency jumps and subharmonics in screams of S. fulvus were found. Results are discussed with literature evidence on audible and ultrasonic vocalizations in ground squirrels.
7

Topographic distribution and daily activity of the European ground squirrel population in Bugacpuszta, Hungary

58%
Katona K., Vaczi O., Altbacker V.
Acta Theriologica
|
2002
|
tom 47
|
nr 1
Factors affecting the population density and daily pattern of activity of the European ground squirrel Spermophilus citellus (Linnaeus, 1766) were studied in two habitats of the Kiskunsag National Park, Hungary. One habitat was dominated by sandy and the other by salty grassland. Population densities were estimated by counting ground squirrel burrow entrances in sample areas with different microhabitat characteristics. Three categories (elevated, level and depressed) were used to describe the spatial distribution of burrows according to microtopography. Daily activity was evaluated by counting the ground squirrels visible on the surface and registering their alarm calls. The highest proportion of ground squirrel holes was found on elevations in the two habitats. Ground squirrels showed a similar daily activity pattern in different areas and in the same season in consecutive years. The daily activity consisted in a morning peak, a midday pause and a less regular afternoon activity period. Human activity had no direct effect on the daily activity pattern. Emission of alarm calls peaked in June, when litters emerge from the maternal burrows.
8

Wolinski National Park

44%
Jakuczun B.
Polish Food
|
1999
|
nr 1
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