Description of Sarcocystis campestris sp. n. (Protozoa: Sarcocystidae): a parasite of the badger Taxidea taxus with experimental transmission to the Richardson's ground squirrel, Spermophilus richardsonii

1983 ◽  
Vol 61 (2) ◽  
pp. 370-377 ◽  
Author(s):  
Richard J. Cawthorn ◽  
Gary A. Wobeser ◽  
Alvin A. Gajadhar
Keyword(s):  
Ground Squirrel ◽  
Prepatent Period ◽  
Ground Squirrels ◽  
Intermediate Hosts ◽  
Patent Period ◽  
Sporocyst Residuum ◽  
Experimental Transmission ◽  
Taxidea Taxus ◽  
Spermophilus Richardsonii ◽  
Large Round

Sarcocystis campestris sp. n. (Protozoa: Sarcocystidae) is an heteroxenous coccidium with badgers (Taxidea taxus) as natural and experimental definitive hosts and Richardson's ground squirrels (Spermophilus richardsonii) as experimental intermediate hosts. Free sporocysts (10.2 × 8.0 μm with a large, round sporocyst residuum consisting of a single refractile granule), obtained from intestinal scrapings of badgers (carcasses frozen 2 years at −20 °C), were orally administered to juvenile Richardson's ground squirrels. Acute fatal sarcocystosis developed in some squirrels at 11–13 days postinoculation (p.i.). Meronts (second generation) were present 9–12 days p.i. in the vascular endothelium of many tissues (especially the lungs). Cysts developed in skeletal muscle, contained metrocytes (7 × 5 μm) 30 days p.i., and beginning 46 days p.i., bradyzoites (12.0 × 3.5 μm) were present. Cysts were macroscopic as early as 258 days p.i. Squirrel carcasses containing cysts (76 days p.i.) of S. campestris sp. n. were fed to Sarcocystis-free badgers. The prepatent period was 9 days and the patent period at least 13 days. Both badgers were ill early in the patent period and passed unformed feces during the patent period. Free sporocysts were 10.2 × 8.0 μm and each had an elongate sporocyst residuum containing numerous small refractile granules.

Killing technique of North American badgers preying on Richardson's ground squirrels

2001 ◽  
Vol 79 (11) ◽  
pp. 2109-2113 ◽  
Author(s):  
Gail R Michener ◽  
Andrew N Iwaniuk
Keyword(s):  
North American ◽  
Prey Size ◽  
Ground Squirrels ◽  
Thoracic Cavity ◽  
Internal Organs ◽  
Small Prey ◽  
Taxidea Taxus ◽  
Spermophilus Richardsonii ◽  
Southern Alberta

Carcasses of 13 Richardson's ground squirrels (Spermophilus richardsonii) cached during autumn by North American badgers (Taxidea taxus) in southern Alberta, Canada, were inspected to determine the capture and killing technique. Regardless of prey size (251–651 g) or torpor status (normothermic or torpid), badgers killed ground squirrels with a single grasping bite directed dorsally or laterally to the thorax. The canines and third upper incisors of badgers generally bruised the skin without puncturing it, but caused extensive hematomas on the thoracic musculature and penetrated between the ribs, with associated breakage of ribs and hemorrhaging in the thoracic cavity. Internal organs and bones other than ribs were usually not damaged. Thoracic bites, rather than nape or throat bites, are used by several mustelids, including North American badgers, when capturing small prey (<10% of the predator's mass).

scholarly journals The adaptive utility of Richardson’s ground squirrel (Spermophilus richardsonii) short-range ultrasonic alarm signals

2006 ◽  
Vol 84 (9) ◽  
pp. 1322-1330 ◽  
Author(s):  
David R. Wilson ◽  
James F. Hare
Keyword(s):  
Ground Squirrel ◽  
Ground Squirrels ◽  
Alarm Calls ◽  
Older Individuals ◽  
Alarm Signals ◽  
Active Space ◽  
Spermophilus Richardsonii ◽  
Ultrasonic Calls ◽  
Audible Alarm ◽  
Signal Type

Richardson’s ground squirrels ( Spermophilus richardsonii (Sabine, 1822)) produce audible (ca. 8 kHz) and (or) ultrasonic (ca. 48 kHz) alarm vocalizations that warn conspecifics of impending danger. Audible calls have a larger active space than ultrasonic calls because they travel farther, are louder, and contain frequencies to which conspecific and allospecific recipients are more sensitive. In our first experiment, we presented an alarming stimulus to 103 squirrels to examine the effect of threat proximity on signal type. The ratio of ultrasonic to audible alarm calls increased with increasing distance from the stimulus. We conclude that the size of the active space influences signalling strategy and that squirrels emitting ultrasonic calls can signal conspecifics to the exclusion of distant predators. As recipients of ultrasonic calls must be close to the signaler, one context in which ultrasonic calling may be most adaptive is during natal emergence when juveniles are particularly abundant, highly vulnerable to predation, and clustered in space. In our second experiment, we broadcast ultrasonic alarm signals to emerging juveniles and found that they, like older individuals, responded to calls by increasing vigilance. We discuss the adaptive utility of multiple signalling strategies in light of our findings.

FLEAS (SIPHONAPTERA) ASSOCIATED WITH GROUND SQUIRRELS (SPERMOPHILUS SPP.) IN MANITOBA, CANADA

1990 ◽  
Vol 122 (3) ◽  
pp. 449-458 ◽  
Author(s):  
Terry D. Galloway ◽  
John E. Christie
Keyword(s):  
Ground Squirrel ◽  
Ground Squirrels ◽  
Spermophilus Richardsonii ◽  
Eastern Chipmunk ◽  
First Time

AbstractTwenty-one species of fleas, seven of which are considered true ground squirrel fleas, were collected by various means from Spermophilus richardsonii (Sabine), S. tridecemlineatus (Mitchell), and S. franklinii (Sabine) in Manitoba. Opisocrostis tuberculatus tuberculatus (Baker), O. labis (Jordan and Rothschild), Neopsylla inopina Rothschild, and Rhadinopsylla fraterna (Baker) are ground squirrel fleas reported from Manitoba for the first time. These, in addition to Oropsylla rupestris (Jordan) and Thrassis bacchi bacchi (Rothschild), were restricted to the southwestern region of the province, but Opisocrostis bruneri (Baker) was collected throughout the range of the ground squirrels, irrespective of location. Fourteen species collected were considered accidental on ground squirrels, one of which, Tamiophila grandis (Rothschild) (an eastern chipmunk parasite), was recorded for the first time in the province.

Populations of ferruginous and Swainson's hawks increase in synchrony with ground squirrels

1989 ◽  
Vol 67 (10) ◽  
pp. 2596-2601 ◽  
Author(s):  
Josef K. Schmutz ◽  
Daniel J. Hungle
Keyword(s):  
Ground Squirrel ◽  
Prey Density ◽  
Prey Species ◽  
Ground Squirrels ◽  
Crop Damage ◽  
Agricultural Fields ◽  
Fledging Success ◽  
Spermophilus Richardsonii ◽  
Buteo Regalis ◽  
Buteo Swainsoni

We compared changes in the densities of breeding ferruginous (Buteo regalis) and Swainson's hawks (Buteo swainsoni) over a period of 9 years with the abundance of a major prey species, Richardson's ground squirrel (Spermophilus richardsonii). We used the amount of poison distributed by landowners annually in their attempts to reduce crop damage by ground squirrels as an index of ground squirrel abundance. Though ground squirrel abundance was positively correlated with hawk density overall, the hawks differed in their responses to changing prey density. Breeding density and fledging success of the ferruginous hawk, a food specialist, were consistently correlated with squirrel abundance. The density of Swainson's hawks increased only where grassland was interspersed with agricultural fields. Fledging success of Swainson's hawks was not correlated with ground squirrel abundance. We suggest that the availability of small prey in spring affected breeding dispersion and reproductive success of Swainson's hawks.

scholarly journals Observations of Nocturnal Hunting Behaviour of American Badgers, Taxidea taxus, in Southwestern Saskatchewan

2013 ◽  
Vol 126 (3) ◽  
pp. 226
Author(s):  
Gilbert Proulx ◽  
Neil MacKenzie
Keyword(s):  
Ground Squirrel ◽  
Ground Squirrels ◽  
Taxidea Taxus ◽  
Hunting Behaviour ◽  
Urocitellus Richardsonii

This study describes the nocturnal hunting behaviour of American Badgers (Taxidea taxus) in areas inhabited by Richardson’s Ground Squirrels (Urocitellus richardsonii) in southwestern Saskatchewan. Adult American Badgers searched for prey by zigzagging through clusters of Richardson’s Ground Squirrel burrows or by going back and forth between one enlarged Richardson’s Ground Squirrel burrow and other adjacent burrows. American Badgers’ movements were not random and they were oriented to encounter prey.

Description of Sarcocystis rauschorum sp. n. (Protozoa: Sarcocystidae) with experimental cyclic transmission between varying lemmings (Dicrostonyx richardsoni) and snowy owls (Nyctea scandiaca)

1984 ◽  
Vol 62 (2) ◽  
pp. 217-225 ◽  
Author(s):  
Richard J. Cawthorn ◽  
Alvin A. Gajadhar ◽  
Ronald J. Brooks
Keyword(s):  
Small Intestine ◽  
Mus Musculus ◽  
Rattus Norvegicus ◽  
Striated Muscle ◽  
Prepatent Period ◽  
House Mice ◽  
Post Inoculation ◽  
Intermediate Hosts ◽  
Patent Period ◽  
Snowy Owl

Sarcocystis rauschorum sp. n. (Protozoa: Sarcocystidae) is heteroxenous, with varying lemmings (Dicrostonyx richardsoni) as expermental intermediate hosts and snowy owls (Nyctea scandiaca) as natural and experimental definitive hosts. Free sporocysts of a Sarcocystis-like organism (11.6 × 9.2 μm with a diffuse residuum of numerous small refractile granules) from intestinal scrapings of a naturally infected snowy owl were orally administered to laboratory-reared varying lemmings. Meronts were present 7 days post inoculation (DPI) in hepatocytes. Cysts of S. rauschorum sp. n. developed in striated muscle and contained metrocytes (4.6 × 3.8 μm) 14 DPI; bradyzoites (6 × 2 μm) were present at least as early as 28 DPI. Cysts at 84 DPI were not macroscopic (greatest diameter 80.9 μm, least diameter 70.9 μm) with walls 0.35–0.70 μm thick. Laboratory-reared rats (Rattus norvegicus), house mice (Mus musculus), white-footed mice (Peromyscus leucopus), red-backed voles (Clethrionomys gapped), and brown lemmings (Lemmus sibiricus) were not suitable intermediate hosts. Carcasses of varying lemmings containing cysts (57 and 84 DPI) of S. rauschorum sp. n. were fed to three Sarcocystis-free snowy owls. The prepatent period was 7 days and the patent period 12 – 19 days. Sporogony occurred in the lamina propria throughout the length of the small intestine. Free sporocysts (10.4 × 8.2 μm with a compact residuum of numerous small refractile granules) from experimentally infected owls were infective for varying lemmings.

Factors associated with nest- and roost-burrow selection by burrowing owls (Athene cunicularia) on the Canadian prairies

2005 ◽  
Vol 83 (10) ◽  
pp. 1373-1380 ◽  
Author(s):  
Ray G Poulin ◽  
L Danielle Todd ◽  
Kimberly M Dohms ◽  
R Mark Brigham ◽  
Troy I Wellicome
Keyword(s):  
Ground Squirrels ◽  
Athene Cunicularia ◽  
Canadian Prairies ◽  
Burrowing Owls ◽  
Burrowing Owl ◽  
Factors Associated ◽  
Crop Fields ◽  
Taxidea Taxus ◽  
Spermophilus Richardsonii ◽  
Selection Of

We examined nest- and roost-burrow characteristics from a declining population of burrowing owls (Athene cunicularia (Molina, 1782)) in Saskatchewan. Between 1992 and 2003, 84% of the 584 nests we found were in grassland pastures, even though these pastures constituted only 7% of the potentially available nesting area within our study area. In contrast, less than 3% of nests were in crop fields, despite these fields comprising 90% of the potentially available area. Within grassland pastures, owls selected nest burrows in areas with a higher density of burrows within 75 m (11.1 burrows/ha) compared with non-nest burrows of similar dimensions (5.6 burrows/ha). Richardson's ground squirrels (Spermophilus richardsonii (Sabine, 1822)) and badgers (Taxidea taxus (Schreber, 1777)) are the primary excavators of suitable nesting burrows in prairie Canada. In our study area, burrowing owls chose to nest and roost in badger-sized burrows, selecting those with taller tunnel entrances and soil mounds relative to unused burrows. We suggest that management for burrowing owl nesting habitat in Canada should consider the owls' avoidance of crop fields and their preference for grassland pastures. Managers should also consider the owls' apparent preference for nesting in areas of high burrow densities and their selection of badger-sized burrows for nesting and roosting.

Repetitive calls of juvenile Richardson's ground squirrels (Spermophilus richardsonii) communicate response urgency

2001 ◽  
Vol 79 (4) ◽  
pp. 569-573 ◽  
Author(s):  
Kurtis J Warkentin ◽  
Annika TH Keeley ◽  
James F Hare
Keyword(s):  
Ground Squirrel ◽  
Ground Squirrels ◽  
Call Rate ◽  
Spermophilus Richardsonii ◽  
Predator Model ◽  
Antipredator Calls

Richardson's ground squirrels, Spermophilus richardsonii, produce both repetitive and non-repetitive antipredator calls. While many hypotheses have been advanced to explain non-repetitive calls, the function of repetitive calling has received relatively little attention. We presented juvenile Richardson's ground squirrels with a predator model at distances ranging from 1 to 8 m and recorded the subsequent repetitive calls on digital audiotape. The rate of calling was inversely correlated with the distance between the model and the caller, with distance explaining almost 24% of the variation in call rate. To determine whether call recipients use that information, we manipulated the intersyllable latency of a single repetitive call exemplar to form 3 test stimuli varying only in call rate. Across 16 Richardson's ground squirrel colonies to which these calls were broadcast, the proportion of squirrels assuming the highly vigilant, alert posture increased with the rate of the repetitive call presented. Hence, juvenile Richardson's ground squirrels appear to communicate the proximity and presumably the degree of threat posed by potential predators.

Reproduction of Richardson's ground squirrel (Spermophilus richardsonii) in southern Saskatchewan

1972 ◽  
Vol 50 (12) ◽  
pp. 1577-1581 ◽  
Author(s):  
D. H. Sheppard
Keyword(s):  
Sex Ratio ◽  
Litter Size ◽  
Ground Squirrel ◽  
Ground Squirrels ◽  
Spermophilus Richardsonii ◽  
Live Trapping ◽  
Native Grassland ◽  
Adult Sex Ratio ◽  
The Mean ◽  
Sexually Mature

Adult Richardson's ground squirrels (n = 238) were collected near Regina, Saskatchewan in April and May of 1969 and 1970. The adult sex ratio (males: females) of collected animals was 1:3.3 compared with a juvenile sex ratio of 1:1 obtained by live trapping in 1967and 1968. The breeding season extended from 3 to 28 April but 77.8% of all conceptions occurred between 7 and 16 April. All yearlings seemed to be sexually mature and the mean litter size for all females baaed on living embryos was 6.93 ± 0.18. Mortality of embryos was 6.83%. Yearlings were smaller than adults but mean litter sizes of yearlings and adults did not differ. Ground squirrels collected from cropland had a significantly larger mean litter size, were somewhat heavier, and had significantly longer humeri than those from native grassland.

Temperature and the Regulation of Enzyme Activity in the Hibernator. Isoenzymes of Liver Pyruvate Kinase from the Hibernating and Non-hibernating Arctic Ground Squirrel

1974 ◽  
Vol 52 (10) ◽  
pp. 894-902 ◽  
Author(s):  
Hans W. Behrisch
Keyword(s):  
Molecular Weight ◽  
Pyruvate Kinase ◽  
Wide Temperature Range ◽  
Ground Squirrel ◽  
Energy Charge ◽  
High Energy ◽  
Ground Squirrels ◽  
The Arctic ◽  
Arctic Ground Squirrel ◽  
Temperature Range

Liver of the hibernating (H) Arctic ground squirrel (Citellus undulatus) contains a single species of pyruvate kinase (PyK) that is distinct from the single isoenzyme of pyK observed in the non-hibernating (NH) ground squirrel, which has been previously described (Behrisch &Johnson (1974) Can. J. Biochem. 52, 547–559). The H-PyK has a pI value of 5.7 and a molecular weight of 241 000 – 243 000. Affinity of the H-PyK for the substrates phosphoenolpyruvate (PEP) and ADP is not affected by changing temperature. It is argued that this stability of the apparent Km's for substrate over a wide temperature range permits the hibernator to take advantage of the Q10 effect in maintaining a low rate of the PyK reaction. Similarly, affinity of H-PyK for the allosteric activator fructose-1,6-phosphate (FDP) and the inhibitor ATP is also conspicuously independent of temperature, suggesting a fine stoichiometry in the relative concentrations of the regulatory ligands in control of H-PyK over a wide temperature range. Further, affinity of H-PyK for the inhibitor ATP is about three- to fourfold lower than that of the NH-PyK, a condition that would favor the maintenance of a high energy charge in the hibernating liver cell. ATP apparently inhibits PyK by causing a dissociation of the enzyme molecule into two "halves" of about 110 000 molecular weight each. This dissociation is offset and reversed by FDP. Removal of the ATP by dialysis does not of itself result in a reassociation of the PyK "halves"; FDP and/or the substrates are required for the two subunits of PyK to reassociate. As the apparent Ki of H-PyK for ATP is higher than that of NH-PyK, substantially higher concentrations of ATP are required to effect the dissociation of H-PyK. Similarly, elevated concentrations of FDP are required to offset the ATP-caused dissociation of the H-PyK.Hibernating Arctic ground squirrels that are preparing to emerge finally from the hibernating state already possess substantial activities of the NH-PyK isoenzyme. This suggests that the animal "anticipates" its transition from one metabolic state from another. On the basis of these data a formal mechanism is proposed for the regulation of liver PyK in the Arctic ground squirrel in both the non-hibernating and hibernating states.

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