Search results for "Reproductive success"
showing 10 items of 165 documents
Assessing the Cost of Mounting an Immune Response
2003
International audience; The evolution of parasite resistance has often been assumed to be governed by antagonistic selection pressures. Defense against pathogens, by mounting an immune response, confers evident benefits but may also incur costs, so that the optimal level of defense is expected to depend on the balance between benefits and costs. Although the benefits of immune surveillance are well known, estimates of costs are still equivocal. Here we studied the behavioral and physiological modifications associated with exposure to a onreplicating antigen (lipopolysaccharide [LPS] of Escherichia coli) in a passerine species, the house sparrow (Passer domesticus).We further investigated wh…
Parental experience of a risky environment leads to improved offspring growth rate.
2014
Abstract Parasites (or diseases) are major selective force for the evolution of life history traits and parasite-host evolution. Mothers can show a variety of responses to parasites during pregnancy with different consequences for them or their offspring. However, whether information in the maternal environment before pregnancy can cause a change in the phenotype of the offspring is unknown. To avoid the confounding effect of pathogens and to reduce the risk of direct effect of mother's immune activation, we injected female laboratory mice with lipopolysaccharides (LPS) before mating. In order to provide a constant information on the potential infectious risk of the environment, females wer…
Optimal allocation of reproductive effort: manipulation of offspring number and size in the bank vole
2001
The number of offspring attaining reproductive age is an important measure of an individual's fitness. However, reproductive success is generally constrained by a trade-off between offspring number and quality. We conducted a factorial experiment in order to study the effects of an artificial enlargement of offspring number and size on the reproductive success of female bank voles (Clethrionomys glareolus). We also studied the effects of the manipulations on growth, survival and reproductive success of the offspring. Potentially confounding effects of varying maternal quality were avoided by cross-fostering. Our results showed that the number of offspring alive in the next breeding season w…
Reproductive costs and litter size in the bank vole.
1995
The potential reproductive costs for free-ranging bank vole (Clethrionomys glareolus) offspring and mothers were assessed by manipulating litter size and by determining the effects of nursing varied numbers of offspring. Litter enlargement did not increase the number of weanlings per mother. The mass of juveniles was significantly lower in the enlarged litters and higher in the reduced litters, compared to the control group. However, the survival of juveniles from weaning aged three months did not depend on their mass at weaning. Data from a previous study (Mappes et al. 1995) indicated that a higher mass at weaning may increase juveniles' abilities to maturate and breed during their summer…
Maternal effort and male quality in the bank vole, Clethrionomys glareolus.
1999
Parental investment in reproduction is adjusted according to potential benefits in terms of offspring survival and/or mating success. If male quality affects the reproductive success of a female, then females mating with high-quality males should invest more in reproduction. Although the subject has been of general interest, further experimental verification of the hypothesis is needed. We studied whether female bank voles (Clethrionomys glareolus) adjusted their maternal effort according to male quality, measured as mating success. To enable the measurement of maternal effort during nursing separately from male genetic effects the litters were cross-fostered. Further, the genetic backgroun…
Offspring growth, survival and reproductive success in the bank vole: a litter size manipulation experiment.
1998
To estimate the optimality of brood size, it is essential to study the effects of brood size manipulation on offspring survival and reproductive success. Moreover, testing the generality of the hypothesis of reproductive costs requires experimental data from a diversity of organisms. Here I present data on the growth, survival and reproductive success of bank vole Clethrionomys glareolus individuals from manipulated litters. Furthermore, the survival of mothers whose litter size was manipulated was studied. At weaning, the mean weight of pups from enlarged litters was lower and from reduced litters higher compared to control litters. After winter, at the start of the breeding season, indivi…
Experimental manipulation of breeding density and litter size: effects on reproductive success in the bank vole
1999
1. Reproductive success of individual females may be determined by density-dependent effects, especially in species where territory provides the resources for a reproducing female and territory size is inversely density-dependent. 2. We manipulated simultaneously the reproductive effort (litter size manipulation: ± 0 and + 2 pups) and breeding density (low and high) of nursing female bank voles Clethrionomys glareolus in outdoor enclosures. We studied whether the reproductive success (number and quality of offspring) of individual females is density-dependent, and whether females can compensate for increased reproductive effort when not limited by saturated breeding density. 3. The females …
Predictive Capacity of Boar Sperm Morphometry and Morphometric Sub-Populations on Reproductive Success after Artificial Insemination
2021
The aim of the study was to compare the morphometric features of sperm head sizeand shape from the Pietrain line and the Duroc×Pietrain boar crossbred terminal lines, and toevaluate their relationship with reproductive success after artificial insemination of sows producedfrom crossbreeding the York, Landrace and Pietrain breeds. Semen samples were collected from 11sexually mature boars. Only ejaculates with greater than 70% motility rate and <15% of abnormalsperm were used for artificial inseminations (AI) and included in the study. Samples were analyzedusing an ISAS®v1 computer-assisted sperm analysis system for eight morphometric parameters ofhead shape and size (CASA-Morph). Sub-populat…
Scientific Reports
2020
.-- Halimubieke, Naerhulan et al.
Stabilising selection on immune response in male black grouse Lyrurus tetrix
2017
Illnesses caused by a variety of micro- and macro- organisms can negatively affect individuals’ fitness, leading to the expectation that immunity is under positive selection. However, immune responses are costly and individuals must trade-off their immune response with other fitness components (e.g. survival or reproductive success) meaning that individuals with intermediate response may have the greatest overall fitness. Such a process might be particularly acute in species with strong sexual selection because the condition-dependence of male secondary sexual-traits might lead to striking phenotypic differences amongst males of different immune response levels. We tested whether there is s…