Sexual Differences in Body Weight Patterns of Richardson's Ground Squirrels during the Breeding Season

1984 ◽  
Vol 65 (1) ◽  
pp. 59-66 ◽  
Author(s):  
G. R. Michener
Keyword(s):  
Body Weight ◽  
Breeding Season ◽  
Ground Squirrels ◽  
Sexual Differences

Sexual differences in behaviour during the breeding season in the soldier crab (Mictyris brevidactylus)

2005 ◽  
Vol 266 (2) ◽  
pp. 197-204 ◽  
Author(s):  
Satoshi Takeda
Keyword(s):  
Breeding Season ◽  
Sexual Differences

Physical and behavioral postnatal development of woodchucks (Marmota monax)

1991 ◽  
Vol 69 (4) ◽  
pp. 1040-1047 ◽  
Author(s):  
J. Ferron ◽  
J.-P. Ouellet
Keyword(s):  
Growth Rate ◽  
Body Weight ◽  
Social Behavior ◽  
Postnatal Development ◽  
Tail Length ◽  
Postnatal Growth ◽  
Behavioral Development ◽  
Ground Squirrels ◽  
Behavioral Repertoire ◽  
Marmota Monax

The physical and behavioral postnatal development of woodchucks (Marmota monax) was analyzed from birth to 42 days of age, the age at which weaning begins. Postnatal growth was evaluated by means of daily measurements of body weight, body length, tail length, and length of hind foot. Data on length of ear pinnae, vibrissae, and fur, and on the timing of appearance of some events of physical development are also presented. We considered postnatal development of locomotion, alertness, exploratory behavior, feeding, and comfort and social behavior. Our results indicate no sexual dimorphism in body size in young woodchucks, despite its occurrence in adults. Intraspecific comparisons reveal that woodchucks from different populations show marked variation in growth rate. The high level of intraspecific variation in developmental rates of sciurid rodents provides a warning to those performing interspecific comparisons. The data also suggest that the ratio of growth rate to adult body weight is not related to environmental severity. Behavioral development in M. monax is similar to that of ground squirrels but faster than that of tree squirrels and flying squirrels. There is also no direct relationship between size and timing of behavioral development in sciurid rodents. The behavioral repertoire of young woodchucks is simpler than that of young Spermophilus lateralis, another asocial species. It is possible that specific differences in rates of development of social interactions led to such differentiation in the repertoire of social behavior.

Sexual Differences in the Behavior of Adult Great Black-Backed Gulls (Larus marinus) during the Pre-and Post-Hatch Periods

The Auk ◽  
1983 ◽  
Vol 100 (1) ◽  
pp. 63-75 ◽  
Author(s):  
Ronald G. Butler ◽  
Saskia Janes-Butler
Keyword(s):  
Breeding Season ◽  
Parental Investment ◽  
Agonistic Behavior ◽  
Sexual Differences ◽  
Larus Marinus ◽  
Hatch Period ◽  
Long Calls

Abstract Sexual differences in the behavior of adult Great Black-backed Gulls (Larus marinus) were examined during the pre- and post-hatch periods of the 1980 breeding season. Following clutch completion, females invested more time than males in both territorial attendance and incubation, but there were no sexual differences in egg-shifting or grass-collection. In contrast, males engaged in more agonistic behavior and long-called and yelped in all contexts more than females before chick hatching. Males also displayed more mate-oriented mews and chokes than did females at this time. During the post-hatch period, there were no sexual differences in territorial attendance, brooding, or frequency of chick feedings, but males continued to exhibit higher frequencies of agonistic acts than did females, as well as higher levels of long-calls and yelps. After chick hatching, both sexes demonstrated increased levels of agonistic acts, long-calls, yelps, mews, and yeows, while males exhibited decreased frequencies of chokes and head-tosses. The results of this study strongly suggest that parental investment by male L. marinus may equal that of females.

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.

Can fruit pulp meet the calcium needs of tropical frugivorous passerines during reproduction?

2013 ◽  
Vol 30 (1) ◽  
pp. 79-88 ◽  
Author(s):  
Mercedes S. Foster
Keyword(s):  
Body Weight ◽  
Breeding Season ◽  
Dry Weight ◽  
Floodplain Forest ◽  
Fruit Pulp ◽  
Natural Mineral ◽  
South Eastern ◽  
Mineral Licks ◽  
Calcium Sources ◽  
The Way

Abstract:Calcium is an important nutrient for birds, especially for eggshell production and the mineralization of the skeleton of developing young. In temperate regions insects and seeds that form the bulk of the diet of breeding passerines do not contain sufficient calcium to meet the needs of breeding females and young; these birds obtain their calcium by eating snails, woodlice and millipedes. Little is known about the way tropical frugivorous passerines meet their calcium needs. The calcium contents of fruits of 34 species eaten by birds during the breeding season in mature floodplain forest in south-eastern Peru were determined. The suitability of these fruits as calcium sources for hypothetical 10-g and 25-g birds and for 26 species of frugivore that breed at the study site was evaluated based on bird body weight and on the rictal width of the bill, which influences feeding. Fruits of five species in the study area appear to be suitable sources of calcium for birds ≤25 g, although those of Ficus killipii (Moraceae) are likely optimal. The latter contain a lot of calcium (2.48% dry weight of pulp or c. 4.15 mg per pulp per fruit) and are small enough (mean diam. = 9 mm) for most birds to swallow whole, and trees produce large crops. Snails, woodlice and millipedes are common in the area and also contain sufficient calcium to meet birds’ needs. In addition, birds could likely meet their calcium needs through geophagy at natural mineral licks.

Sexual differences in over-winter torpor patterns of Richardson's ground squirrels in natural hibernacula

Oecologia ◽  
1992 ◽  
Vol 89 (3) ◽  
pp. 397-406 ◽  
Author(s):  
Gail R. Michener
Keyword(s):  
Ground Squirrels ◽  
Sexual Differences

scholarly journals Seasonal expressions of androgen receptor, estrogen receptors and cytochrome P450 aromatase in the uteri of the wild Daurian ground squirrels (Spermophilus dauricus)

2018 ◽  
Author(s):  
Yu Wang ◽  
Ziyi Wang ◽  
Wenyang Yu ◽  
Xia Sheng ◽  
Haolin Zhang ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Androgen Receptor ◽  
Breeding Season ◽  
Stromal Cells ◽  
Seasonal Changes ◽  
Ground Squirrels ◽  
Sex Steroid ◽  
Expression Levels ◽  
Cytochrome P450 Aromatase ◽  
Glandular Cells

The reproductive tissues including the uterus undergo dramatic changes in seasonal breeders from the breeding to non-breeding seasons. Classically, sex steroid hormones play important roles in the uterine morphology and functions. To clarify the relationship between sex steroid hormones and seasonal changes in the uterine morphology and functions, the wild Daurian ground squirrels (Spermophilus dauricus) were used as seasonal breeder model. And the immunolocalizations and expression levels of androgen receptor (AR), estrogen receptors α and β (ERα and ERβ) and cytochrome P450 aromatase (P450arom) were investigated in the uteri of the wild Daurian ground squirrels in the breeding (April) and the non-breeding (June) seasons via immunohistochemistry, Western blot and RT-PCR. Histologically, the uterine weight, the thickness of endometrium and the glandular density were significantly higher in the uteri of the breeding season than those of the non-breeding season. In both seasons, the immunostaining of AR was only presented in stromal cells of the uteri; the positive staining of ERα and ERβ were localized in stromal cells and glandular cells; P450arom was merely immunolocalized in glandular cells. The protein and mRNA expression levels of ERα, ERβ and P450arom were higher in the uteri of the breeding season than those of the non-breeding season; conversely, the expressions of AR were higher in the uteri of the non-breeding season comparing with those of the breeding season in both protein and mRNA levels. The AR: ER ratio in the uteri of the non-breeding season exceeded the AR: ER ratio in the uteri of the breeding season in the wild Daurian ground squirrels. These results suggested that seasonal changes in the expression levels of AR, ERs and P450arom might be correlated with the uterine morphology and histology changes, and estrogen may play an important autocrine/paracrine role in regulating the uterine functions of the wild Daurian ground squirrels.

Effect of body weight on the attainment of puberty and reproductive performance of Galway and Fingalway female lambs

1979 ◽  
Vol 28 (3) ◽  
pp. 297-307 ◽  
Author(s):  
J. F. Quirke
Keyword(s):  
Body Weight ◽  
Breeding Season ◽  
Litter Size ◽  
Conception Rate ◽  
Restricted Feeding ◽  
Ewe Lambs ◽  
Younger Age ◽  
Body Weights ◽  
The Mean ◽  
Ad Libitum

ABSTRACTGroups of spring-born Galway (G) and Fingalway (F) ewe lambs were fed a concentrate diet either ad libitum (H) or at a restricted level (L) during the period 25 July to 16 October 1974 in order to induce differences in body weight at the start of the breeding season. The mean live weights of the GL, GH, FL and FH groups on 16 October 1974 were 37·8 ± 1·3, 44·6 ± 1·3, 35·1 ± 1·1 and 41·9 ± 1·2 kg respectively. More than 95% of the lambs in all four groups attained puberty before 28 February 1975. Galway ewe lambs reached puberty later in the breeding season and were older and heavier at puberty than Fingalways. Animals fed ad libitum were heavier at puberty and attained puberty earlier in the season and at a younger age than those on the restricted feeding regime.Both conception rate and litter size were lower in Galways than Fingalways. There was no evidence of any effect of the nutritional treatments on conception rate or litter size. The mean body weights at puberty for ewes which lambed and those which were barren were 41·9 ± 0·49 and 41·5 ± 0·78 kg respectively. The birth weight and growth rate of the progeny of the ewe lambs was similar for the two breeds and was not influenced by the previous nutritional treatment of the dams. The total lamb mortality between birth and weaning was 40·3%, and 72% of all deaths occurred within 48 h of birth. Losses among twins (48%) were particularly heavy.

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