Effect of Seasonal Swings and Age Specific Variations on Body Weight of Indian Gerbille (Tatera indica) (original) (raw)
2021
Present study observed growth index and morphological characters of male and female Indian gerbil, Tatera indica (N = 64) live trapped from crop fields in Punjab, India as an attempt to record intraspecific variations. Growth index determined on the basis of increase in body weight and length of body parts recorded at weekly intervals upto nine weeks revealed a positive correlation between the two. No significant difference was found between growth index of male and female gerbils (body weight ≤150g and >150g). Tail length was slightly shorter (in ≤150g) or more (in >150g) than head+body length in females while, it was shorter than head+body length in males. Length of hind limbs was more in males, ears were oblong with fine hair on inner margin and the soles of hind paws were granulated. The study clearly depicted some differences in morphological and morphometric characteristics of T. indica suggesting further comprehensive studies to establish intra-specific variations.
Seasonal Body Weight Variation in Five Species of Woodpeckers
The Condor, 2005
We investigated patterns of seasonal variation in body weight in six populations of five resident species of temperate-zone woodpeckers: Acorn Woodpecker (Melanerpes formicivorus), Red-bellied Woodpecker (M. carolinus), Red-cockaded Woodpecker (Picoides borealis), Downy Woodpecker (P. pubescens), and Great Spotted Woodpecker (Dendrocopos major). After controlling for time of day and overall body size, annual variation in body weight was small and generally not statistically significant. However, analysis revealed evidence of significant ''winter fattening,'' comparable in magnitude to other temperate-zone resident species, in three of the species. The degree of winter fattening did not correlate with either the size of the acorn crop (for the Acorn Woodpecker) or latitude, two variables potentially related to predictability of food resources. However, the smaller species exhibited significantly greater winter fattening than the larger species, as predicted by the hypothesis that energy storage should be more important for small-bodied species. Furthermore, the food-storing Acorn Woodpecker exhibited considerably less winter fattening than the nonfood-storing species, supporting the hypothesis that food storage provides an ecological alternative to winter fattening.
Seasonal variation in the length – weight relationships
Length-weight relationship (LWR) and Condition factor (K) of Gymnarchus niloticus from Lekki Lagoon were studied for 24 months to provide useful information for the sustainable development of Gymnarchus niloticus in Lekki lagoon. Samples of G. niloticus caught from the lagoon were obtained from fishers on a bimonthly basis for 24 months. Length – weight data were analyzed and Length – weight relationship graphs were plotted for the dry and wet seasons of the sampling years. The b values in the LWR (W=aLb) varied between 2.56 – 2.60 for the dry seasons and 2.51 – 2.62 for the wet seasons revealing that the somatic growth of G. niloticusat Lekki lagoon had negative allometry. The average condition factor (K) were found to be 0.7113 ± 0.3485 for dry seasons and 0.7047 ± 0.5069 for wet seasons of the sampling period. There was a strong positive correlation (r = 0.99) between the length and weight of fish specimen examined while the Coefficient of determination (R2) varied between 0.9822 – 0.9976 and 0.9951 – 0.9970 for both dry and wet seasons respectively. It was concluded that the data generated will form a baseline tool for effective fisheries management and sustainable exploitation of G. niloticus in Lekki lagoon.
Functional Ecology, 2010
1. In a seasonal environment, subcutaneous energy reserves of resident animals often increase in winter and decline again in summer reflecting gradual seasonal changes in their fattening strategies. We studied changes in body reserves of wintering great tits in relation to their dominance status under two contrasting temperature regimes to see whether individuals are capable of optimizing their body mass even under extreme environmental conditions.2. We predicted that dominant individuals will carry a lesser amount of body reserves than subordinate great tits under mild conditions and that the body reserves of the same dominant individuals will increase and exceed the amount of reserves of subordinates under conditions of extremely low ambient temperatures, when ambient temperature dropped down to −37 °C.3. The results confirmed the predictions showing that dominant great tits responded to the rising risk of starvation under low temperatures by increasing their body reserves and this was done at the expense of their safety.4. Removal experiments revealed that lower body reserves of subordinate flock members are due to the increased intraspecific competition for food under low ambient temperatures.5. Our results also showed that fattening strategies of great tits may change much quicker than previously considered, reflecting an adaptive role of winter fattening which is sensitive to changes in ambient temperatures.
Seasonality in daily body mass variation in a hoarding boreal passerine
Oecologia, 2003
We studied the body mass variation from autumn to winter, in a free-living population of willow tits (Parus montanus), a food-hoarding passerine living year-round in boreal forests. Our aim was to find out whether this population exhibits 'winter fattening' as part of the annual body mass cycle. 'True winter fattening' is considered to be a strategic response to winter conditions. The strategy includes an increase in both the morning mass and the daily mass increase, as winter approaches. A multivariate approach was used to find which predictors (year, date, age, sex, body size, temperature and snow depth) explained the mass variation in birds measured twice per day. Morning mass variation was explained by sex, age, wing length and snow depth. Independently, date explained morning mass variation only in adult males. None of the predictors explained the variation observed in daily mass increase in any age or sex class. Therefore, we failed to detect winter fattening in our study population of willow tits. Response to increasing night length is not due to higher absolute intake, but to higher energy acquisition rate and decreased night-time energy consumption. The results suggest that willow tits at high latitudes manage increasing energy demands on a short-term basis and respond flexibly to changing conditions by adjusting foraging efficiency and especially night-time energy expenditure.
Effect of supplemental feeding on winter diet and body mass of northern bob
Supplemental feeding by spreading grain is a common management practice on private lands managed for northern bobwhites (Colinus viginianus), but its effect on diet of bobwhites is not well documented. We examined crop contents from 160 northern bobwhites collected in January and February of 2002 and 2003 from Tall Timbers Research Station, Tallahassee, FL, and Pebble Hill Plantation, Thomasville, GA. Sorghum seed (Sorghum vulgare) was spread biweekly on approximately half of each study area along a dedicated feed trail through the cover. Dry mass of crop contents from harvested bobwhites averaged 2.51g (SE = 0.171) and was composed primarily of seeds (χ = 2.44 g; SE = 0.171), with minor invertebrate (χ = 0.052g; SE = 0.021) and vegetation (χ = 0.016g; SE = 0.004) matter. Dry mass of crop contents for bobwhites averaged 2.94 g (SE = 0.280) for birds from fed sites and 2.09g (SE = 0.187) from reference sites. On fed sites 67.5% of bobwhites had used sorghum and sorghum accounted 71% of food items by weight. Diet varied annually, primarily with changing use of acorn, (Quercus spp.) pine (Pinus spp.) mast, and partridge pea (Cassia spp.). Adult bobwhites captured in January averaged 169.9g (SE = 0.970; n = 181) on reference sites and 174.8g (SE = 0.896; n = 237) on fed sites. Supplemental feeding by spreading sorghum was an effective method of providing seeds with high metabolizable energy to bobwhites.
Indian Journal of Animal Research
Average duration of pro-estrous, estrous, met-estrous and di-estrous stages in one oestrous cycle of female Indian gerbil, Tatera indica was found 0.61, 0.38, 0.62 and 1.37 days, respectively with total average duration of one cycle to be 2.99 days. Pairing of cyclic female gerbils with mature males resulted in 88% breeding success within gestation period of 21-24 days. Post-partum estrous was observed immediately after parturition in females not separated from males. Observations on onset of sexual maturity in female pups of seven different age groups (30, 45, 60, 75, 90, 105 and 120 days old) revealed significant increase in body weight and weights of ovary and uterus, plasma level of estradiol and activity of 3â-HSD in ovarian tissue with increasing age. Sexual maturity in female T. indica was attained at age of 3-4 months. It is therefore suggested to apply control measures before they reproduce and cause damage to crops.
The Influence of Ambient Temperature on Diet in the Great Tit
Journal of Avian Biology, 1994
In winter, Great Tits Parus major have a mixed diet of insect food and seeds. Field data suggest a dietary shift towards seeds with declining ambient temperatures. We hypothesised that Great Tits increase their preference for seeds with decreasing temperatures to raise their fat intake over time. An experiment was carried out to test whether this dietary shift with temperature exists. Six Great Tit females, held in captivity and acclimatized to winter conditions, had free access to two food types that differed in fat content. The ambient temperature was manipulated during the night, and for both food types the consumption and digestibility were estimated. During the night the energy expenditure was estimated using indirect calorimetry. Neither the digestibility of fat, nor the energy metabolization was related to ambient temperature. Evening weight, nocturnal energy expenditure, net food consumption and metabolizable energy intake were higher at lower temperatures. The proportion of fat in the diet was independent of the night temperature. There is no evidence that the preference for a fat-rich diet in Great Tits is affected by ambient temperatures.