The Experts below are selected from a list of 309 Experts worldwide ranked by ideXlab platform
Peter Sowig - One of the best experts on this subject based on the ideXlab platform.
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habitat selection and offspring Survival rate in three paracoprid dung beetles the influence of soil type and soil moisture
Ecography, 1995Co-Authors: Peter SowigAbstract:Paracoprid dung beetles build brood chambers in the soil beneath a dung pat and provide them with dung. Onthophagus species lay one egg into each chamber. This paper deals with the influence of soil type and soil moisture on micro-habitat selection and Survival of offspring in three middle-European Onthophagus-species (O. coenobita, O. fracticornis and O. vacca). Discrimination between sandy soils with three different loam contents (0%, 20%, 40%) and four different water contents (4%, 8%, 12%, 16%) was tested in the laboratory. During the first 24 h of each replicate beetles which colonized one of the patches did not distinguish between different soil conditions. Emigration rates, measured as time when 50% of all individuals had left the patch, and numbers of brood chambers proved to be species specific and depended on soil moisture and soil type. Survival rates of the larvae in the brood chambers were influenced nearly exclusively by soil moisture. The results are discussed in relation to the ecology of the three species and in context with optimal foraging theories.
Tapio Mappes - One of the best experts on this subject based on the ideXlab platform.
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Determinants of reproductive success in voles: space use in relation to food and litter size manipulation
Evolutionary Ecology, 2002Co-Authors: Pernilla Jonsson, Tommi Hartikainen, Esa Koskela, Tapio MappesAbstract:Spacing behaviour of female mammals is suggested to depend on the distribution and abundance of food. In addition, food limitation has been found to constrain the reproductive success of females. However, whether females maximize their reproductive success by adjusting space use in relation to current food availability and reproductive effort (e.g. litter size) has not been experimentally studied. We examined these questions by manipulating simultaneously food resources (control vs. food supplementation) and litter sizes (control vs. plus two pups) of territorial female bank voles ( Clethrionomys glareolus ) in large outdoor enclosures. Females with supplementary food had smaller home ranges (foraging area) and home range overlaps than control females, whereas litter size manipulation had no effect on space use. In contrast, the size of territory (exclusive area) was not affected by food supplementation or litter size manipulation. As we have previously shown elsewhere, extra food increases the reproductive success of bank vole females in terms of size and proportion of weaned offspring. According to the present data, greater overlap of female home ranges had a negative effect on reproductive success of females, particularly on Survival of offspring. We conclude that higher food availability increases the reproductive success of bank vole females, and this effect may be mediated through lower vulnerability of offspring to direct killing and/or detrimental effects from other females in the population. Moreover, it seems that when density of conspecifics is controlled for, home range sizes of females, but not territoriality, is related to food resources in Clethrionomys voles.
Mary Bomberger Brown - One of the best experts on this subject based on the ideXlab platform.
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parent offspring resemblance in colony specific adult Survival of cliff swallows
Evolutionary Ecology, 2015Co-Authors: Charles R Brown, Erin A Roche, Mary Bomberger BrownAbstract:Survival is a key component of fitness. Species that occupy discrete breeding colonies with different characteristics are often exposed to varying costs and benefits associated with group size or environmental conditions, and Survival is an integrative net measure of these effects. We investigated the extent to which Survival probability of adult (≥1-year old) cliff swallows (Petrochelidon pyrrhonota) occupying different colonies resembled that of their parental cohort and thus whether the natal colony had long-term effects on individuals. Individuals were cross-fostered between colonies soon after hatching and their presence as breeders monitored at colonies in the western Nebraska study area for the subsequent decade. Colony-specific adult Survival probabilities of offspring born and reared in the same colony, and those cross-fostered away from their natal colony soon after birth, were positively and significantly related to subsequent adult Survival of the parental cohort from the natal colony. This result held when controlling for the effect of natal colony size and the age composition of the parental cohort. In contrast, colony-specific adult Survival of offspring cross-fostered to a site was unrelated to that of their foster parent cohort or to the cohort of non-fostered offspring with whom they were reared. Adult Survival at a colony varied inversely with fecundity, as measured by mean brood size, providing evidence for a Survival–fecundity trade-off in this species. The results suggest some heritable variation in adult Survival, likely maintained by negative correlations between fitness components. The study provides additional evidence that colonies represent non-random collections of individuals.
Le Yang - One of the best experts on this subject based on the ideXlab platform.
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does maternal stress influence winter Survival of offspring in root voles microtus oeconomus a field experiment
Oikos, 2011Co-Authors: Jianghui Bian, Yan Wu, Lowell L Getz, Fang Chen, Le YangAbstract:Maternal stress can have long-term adverse consequences on immunocompetence and disease risk of offspring, and winter Survival is a crucial demographic parameter in the life-history of an individual that can substantially affect northern rodent population dynamics. An understanding of the effects of maternal stress on winter Survival of offspring may help identify mechanisms driving population fluctuations of northern small mammals. Thus, we assessed the effects of maternal stress, resulting from high population densities, on winter Survival of first generation (F(1)) and second generation (F(2)) in root voles Microtus oeconomus. Replicate high- and low-density enclosed parental populations were established, from which we obtained F(1) generation that were used to establish new enclosed, equal-density populations. The adults of the high-density parental populations had higher corticosterone levels, an indication of physiological stress, than did those of the low-density parental populations. Over-winter Survival of the F(1) generation voles from the low-density parental populations was greater than that of those from the high-density parental populations. Over-winter Survival of F(2) generation voles did not differ between the two treatments. Our results suggest that maternal stress affected over-winter Survival of first generations but not second generations. Reduced immunocompetence, resulting from high population density stresses, transferred to offspring may be a factor in annual (winter) population declines. Because the effect is transitory, i.e. immunocompetence of F(2) voles is not affected, reduced immunocompetence resulting from high density stresses would not contribute to lengthy periods of low population densities that are characteristic of multi-annual population fluctuations.
Pernilla Jonsson - One of the best experts on this subject based on the ideXlab platform.
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Determinants of reproductive success in voles: space use in relation to food and litter size manipulation
Evolutionary Ecology, 2002Co-Authors: Pernilla Jonsson, Tommi Hartikainen, Esa Koskela, Tapio MappesAbstract:Spacing behaviour of female mammals is suggested to depend on the distribution and abundance of food. In addition, food limitation has been found to constrain the reproductive success of females. However, whether females maximize their reproductive success by adjusting space use in relation to current food availability and reproductive effort (e.g. litter size) has not been experimentally studied. We examined these questions by manipulating simultaneously food resources (control vs. food supplementation) and litter sizes (control vs. plus two pups) of territorial female bank voles ( Clethrionomys glareolus ) in large outdoor enclosures. Females with supplementary food had smaller home ranges (foraging area) and home range overlaps than control females, whereas litter size manipulation had no effect on space use. In contrast, the size of territory (exclusive area) was not affected by food supplementation or litter size manipulation. As we have previously shown elsewhere, extra food increases the reproductive success of bank vole females in terms of size and proportion of weaned offspring. According to the present data, greater overlap of female home ranges had a negative effect on reproductive success of females, particularly on Survival of offspring. We conclude that higher food availability increases the reproductive success of bank vole females, and this effect may be mediated through lower vulnerability of offspring to direct killing and/or detrimental effects from other females in the population. Moreover, it seems that when density of conspecifics is controlled for, home range sizes of females, but not territoriality, is related to food resources in Clethrionomys voles.
