Restudy of Spirura infundibuliformis McLeod, 1933 (Nematoda: Spiruroidea) from Spermophilus richardsonii, with observations on its development in insects

1993 ◽  
Vol 71 (9) ◽  
pp. 1869-1873 ◽  
Author(s):  
R. C. Anderson ◽  
E. T. Barnes ◽  
C. M. Bartlett
Keyword(s):  
Ground Squirrels ◽  
Infective Stage ◽  
Ambient Temperatures ◽  
Spermophilus Richardsonii ◽  
Southern Alberta

A redescription is provided of Spirura infundibuliformis from the stomach of ground squirrels, Spermophilus richardsonii, in southern Alberta, Canada; Spirura leucurusi Babero, 1973 is regarded as a synonym. Spirura infundibuliformis is distinguished from most members of Spirura by the presence of 9–13 pairs of preanal papillae; 20 other species described in the genus have only 4, rarely 5, pairs. Spirura infundibuliformis developed at ambient temperatures (20–30 °C) to the infective stage in 11–12 days in grasshoppers common on the prairies (Melanoplus infantilis, Aeropedellus clavatus, Aulocara elliotti, and Camnula pellucida), where the ground squirrels were collected, as well as in laboratory-reared crickets (Acheta pennsylvanicus).

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).

Effect of age and parity on weight gain and entry into hibernation in Richardson's ground squirrels

1978 ◽  
Vol 56 (12) ◽  
pp. 2573-2577 ◽  
Author(s):  
Gail R. Michener
Keyword(s):  
Weight Loss ◽  
Weight Gain ◽  
Survival Rate ◽  
Weight Maintenance ◽  
Ground Squirrels ◽  
Winter Survival ◽  
Delayed Entry ◽  
Spermophilus Richardsonii ◽  
Southern Alberta ◽  
Effect Of Age

Weight gain and time of entry into hibernation were recorded for nonparous yearling, parous yearling, and parous 3-year-old Spermophilus richardsonii in southern Alberta in 1977. Nonparous squirrels steadily gained weight over the 12-week period between emergence from hibernation and immergence into hibernation. The weight pattern of parous squirrels exhibited a sub-cycle of weight gain, weight loss, and weight maintenance associated with pregnancy, parturition, and lactation resulting in delayed attainment of prehibernation peak weights and delayed entry into hibernation. There was no difference in time of emergence of parous and nonparous females in the subsequent spring. Age affected rates of post lactation weight gain such that the oldest mothers remained active longest but attained the lowest prehibernation weights. Oldest mothers had the lowest over-winter survival rate.

Effect of climatic conditions on the annual activity and hibernation cycle of Richardson's ground squirrels and Columbian ground squirrels

1977 ◽  
Vol 55 (4) ◽  
pp. 693-703 ◽  
Author(s):  
Gail R. Michener
Keyword(s):  
Rocky Mountains ◽  
Climatic Conditions ◽  
Ground Squirrels ◽  
Active Season ◽  
Southern Alberta ◽  
Annual Activity ◽  
The Times ◽  
Columbian Ground Squirrels ◽  
Spring Emergence ◽  
Species Ecology

In 1975 and 1976 the times of spring emergence, breeding, and entry into hibernation were compared for Spermophilus richardsonii and S. columbianus in an area of sympatry in the foothills of the southern Alberta Rocky Mountains. Both species emerged earlier in 1976, which had a warmer than normal spring, than in 1975, which had a cooler than normal spring. In both years S. richardsonii emerged earlier than S. columbianus and remained active longer. Juvenile S. richardsonii entered hibernation when 17–20 weeks old whereas juvenile S. columbianus were 10–11 weeks old. Yearling S. richardsonii bred, whereas yearling S. columbianus did not. Breeding success affected the time of entry into hibernation but not the time of emergence from hibernation in the next spring. A possible relationship between the periodic arousals during hibernation and the emergence pattern of squirrels in spring is discussed. The significance of flexibility of spring emergence, length of the active season, and age at breeding to survival and species ecology is considered.

Effects of central injection of biogenic amines during arousal from hibernation

1979 ◽  
Vol 236 (3) ◽  
pp. R162-R167 ◽  
Author(s):  
J. D. Glass ◽  
L. C. Wang
Keyword(s):  
Ambient Temperature ◽  
Specific Heat ◽  
Biogenic Amines ◽  
Heat Production ◽  
Ground Squirrels ◽  
Spermophilus Richardsonii ◽  
Simultaneous Measurements ◽  
Apparent Specific Heat ◽  
Intracerebroventricular Injections ◽  
Made In

Simultaneous measurements of heat production (HP) and heat loss (HL) and brain and rectal temperatures were made in Richardon's ground squirrels (Spermophilus richardsonii) rewarming from hibernation at an ambient temperature of 6.0 +/- 0.5 degrees C. Calculations from HP and HL measurements from control animals showed that due to differential rewarming, there was a reduction of apparent specific heat of the animal to 0.59 cal/g. degrees C. This resulted in an energy saving of 30%. Three intracerebroventricular injections of 5-hydroxytryptamine (5-HT) of 56 microgram each at brain temperatures of 10, 20, and 30 degrees C caused initial suppression of HP and a greater overall HL, which resulted in a slower rate of arousal as compared to the controls. Injections of norepinephrine (NE) of 12.5 microgram each at similar brain temperatures caused a greater rate of HP, which resulted in a faster rate of arousal as compared to the controls. The respective actions of 5-HT and NE on thermoregulation during rewarming are similar to those in some euthermic hibernators and nonhibernating species. Our data indicated that these substances evoke thermoregulatory responses during arousal in much the same manner as during normothermia.

Parasympathetic influence on heart rate in euthermic and hibernating ground squirrels.

1995 ◽  
Vol 198 (4) ◽  
pp. 931-937 ◽  
Author(s):  
M B Harris ◽  
W K Milsom
Keyword(s):  
Heart Rate ◽  
Ambient Temperature ◽  
Parasympathetic Nervous System ◽  
Ground Squirrels ◽  
Relative Role ◽  
Body Temperatures ◽  
Inotropic Effects ◽  
Ambient Temperatures ◽  
Isolated Hearts ◽  
C 32

The relative role of the parasympathetic nervous system during deep hibernation is enigmatic. Conflicting hypotheses exist, and both sides draw support from investigations of vagal influence on the heart. Recent studies have shown cardiac chronotropic and inotropic effects of parasympathetic stimulation and inhibition in isolated hearts and anesthetized animals at hibernating body temperatures. No studies, however, have demonstrated such occurrences in undisturbed deeply hibernating animals. The present study documents respiratory-related alterations in heart rate during euthermia and hibernation at ambient temperatures of 15, 10 and 5 degrees C mediated by parasympathetic influence. During quiet wakefulness, euthermic squirrels breathed continuously and exhibited a 29% acceleration in heart rate during inspiration. During deep undisturbed hibernation, at 15, 10 and 5 degrees C ambient temperature, animals exhibited an episodic breathing pattern and body temperatures were slightly above ambient temperature. At each temperature, heart rate during the respiratory episode was greater than that during the apnea. The magnitude of this ventilatory tachycardia decreased with ambient temperature, being 108% at 15 degrees C, 32% at 10 degrees C and 11.5% at 5 degrees C. Animals exposed to 3% CO2 at 5 degrees C, which significantly increased ventilation, still exhibited an 11.7% increase in heart rate during breathing. Thus, the magnitude of the ventilation tachycardia was independent of the level of ventilation, at least over the range studied. Inhibition of vagus nerve conduction at 5 degrees C was achieved using localized nerve block. This led to an increase in apneic heart rate and abolished the ventilatory tachycardia.(ABSTRACT TRUNCATED AT 250 WORDS)

Accelerated circannual cycles in ground squirrels, Spermophilus richardsonii, kept in constant conditions

1983 ◽  
Vol 61 (8) ◽  
pp. 1765-1770 ◽  
Author(s):  
Roman B. Melnyk
Keyword(s):  
Body Weight ◽  
Weight Gain ◽  
Food Intake ◽  
Ground Squirrels ◽  
Food Utilization ◽  
Metabolic Processes ◽  
Reproductive Condition ◽  
Spermophilus Richardsonii ◽  
Upper Limit ◽  
Circannual Cycles

Six- to 8-month cycles of food intake, body weight, moult and reproductive condition in captive Richardson's ground squirrels (Spermophilus richardsonii) kept in 12 h light: 12 h dark and 23 ± 3 °C for over a year are described. A decrease in efficiency of food utilization towards the end of the weight gain period may be associated with metabolic processes which determine an upper limit for body weight. The advantages of this species as a model for the study of spontaneous obesity are discussed.

Increased heat loss affects hibernation in golden-mantled ground squirrels

2004 ◽  
Vol 287 (1) ◽  
pp. R167-R173 ◽  
Author(s):  
Alexander S. Kauffman ◽  
Matthew J. Paul ◽  
Irving Zucker
Keyword(s):  
Food Intake ◽  
Heat Loss ◽  
Body Mass ◽  
Complete Removal ◽  
Ground Squirrels ◽  
Control Procedure ◽  
Ambient Temperatures ◽  
Spermophilus Lateralis ◽  
Maintain Body Temperature ◽  
Body Heat

During hibernation at ambient temperatures (Ta) above 0°C, rodents typically maintain body temperature (Tb) ∼1°C above Ta, reduce metabolic rate, and suspend or substantially reduce many physiological functions. We tested the extent to which the presence of an insulative pelage affects hibernation. Tb was recorded telemetrically in golden-mantled ground squirrels ( Spermophilus lateralis) housed at a Ta of 5°C; food intake and body mass were measured at regular intervals throughout the hibernation season and after the terminal arousal. Animals were subjected to complete removal of the dorsal fur or a control procedure after they had been in hibernation for 3–4 wk. Shaved squirrels continued to hibernate with little or no change in minimum Tb, bout duration, duration of periodic normothermic bouts, and food intake during normothermia. Rates of rewarming from torpor were, however, significantly slower in shaved squirrels, and rates of body mass loss were significantly higher, indicating increased depletion of white adipose energy stores. An insulative pelage evidently conserves energy over the course of the hibernation season by decreasing body heat loss and reducing energy expenditure during periodic arousals from torpor and subsequent intervals of normothermia. This prolongs the hibernation season by several weeks, thereby eliminating the debilitating consequences associated with premature emergence from hibernation.

Sign in / Sign up

Export Citation Format

Share Document