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Samuel Prystupa Gregory R. McCracken Robert Perry Daniel E. Ruzzante 《Ecology and evolution》2021,11(9):4763
Arctic Grayling (Thymallus arcticus) are among the most widely distributed and abundant freshwater fish in the Yukon Territory of Canada, yet little information exists regarding their broad and fine‐scale population structures or the number and size of these populations. The estimation of population abundance is fundamental for robust management and conservation, yet estimating abundance in the wild is often difficult. Here, we estimated abundance of an Arctic Grayling population using multiple genetic markers and the close‐kin mark‐recapture (CKMR) method. A total of N = 1,104 Arctic Grayling collected from two systems in Yukon were genotyped at 38 sequenced microsatellites. We first identified structure and assessed genetic diversity (effective population size, ). Collections from one of the systems (Lubbock River) comprised adults and young‐of‐the‐year sampled independently allowing the identification of parent–offspring pairs (POPs), and thus, the estimation of abundance using CKMR. We used COLONY and CKMRsim to identify POPs and both provided similar results leading to indistinguishable estimates (95% CI) of census size, that is, = 1858 (1259–2457) and 1812 (1229–2389). The accuracy of the population abundance estimates can in the future be improved with temporal sampling and more precise age or size‐specific fecundity estimates for Arctic Grayling. Our study demonstrates that the method can be used to inform management and conservation policy for Arctic Grayling and likely also for other fish species for which the assumption of random and independent sampling of adults and offspring can be assured. 相似文献
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Esa Koskela Pinja Juutistenaho Tapio Mappes Tuula A. Oksanen 《Evolutionary ecology》2000,14(2):99-109
According to parental investment theory, nest defence activity should be related to the reproductive value of the offspring.
Alternative hypotheses suggest that defence activity may, for example, depend upon the conspicuousness of the young. Studies
concerning this topic have been carried out almost exclusively on birds and experimental data on the diversity of organisms
is lacking. Bank voles Clethrionomys glareolus were used to study the effects of the number and age of offspring upon the pup defence activity of mothers. Male bank voles
are infanticidal and thus an adult male was used as a predator. Defence trials were conducted in the laboratory and filmed
for subsequent analysis. Litter sizes were divided into three treatment groups: reduced (−2 pups), control (±0 pups) and enlarged
(+2 pups). In order to study the effect of offspring age upon maternal defence activity the trials were conducted twice: when
the pups were 3 and 8 days old. Defence activity increased with the number of offspring and enlarged litters were most actively
defended. This result supports parental investment theory and conclusions drawn by earlier studies of birds. However, in contrast
to the conclusions of earlier studies, older offspring were defended less than the younger ones. Whilst new-born pups are
totally defenceless against predators their vulnerability decreases as they age. Therefore, we suggest that maternal aggression
in female bank voles is related to the value as well as to the vulnerability of the offspring. The validity of this explanation
and the determinants of parental investment decisions in small mammals in general deserve further study.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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Offspring sex ratios correlate with pair-male condition in a cooperatively breeding fairy-wren 总被引:3,自引:0,他引:3
We examined sex allocation patterns in island and mainland populationsof cooperatively breeding white-winged fairy-wrens. The markeddifferences in social structure between island and mainlandpopulations, in addition to dramatic plumage variation amongmales both within and between populations, provided a uniquesituation in which we could investigate different predictionsfrom sex allocation theory in a single species. First, we testthe repayment (local resource enhancement) hypothesis by askingwhether females biased offspring sex ratios in relation to theassistance they derived from helpers. Second, we test the malequality (attractiveness) hypothesis, which suggests that femalesmated to attractive high-quality males should bias offspringsex ratios in favor of males. Finally, we test the idea thatfemales in good condition should bias offspring sex ratios towardmales because they are able to allocate more resources to offspring,whereas females in poor condition should have increased benefitsfrom producing more female offspring (Trivers-Willard hypothesis).We used molecular sexing techniques to assess total offspringsex ratios of 86 breeding pairs over 2 years. Both offspringand first brood sex ratios were correlated with the pair-male'sbody condition such that females increased the proportion ofmales in their brood in relation to the body condition (masscorrected for body size) of their social partner. This relationwas both significant and remarkably similar in both years ofour study and in both island and mainland populations. Althoughconfidence of paternity can be low in this and other fairy-wrenspecies, we show how this finding might be consistent with themale quality (attractiveness) hypothesis with respect to malecondition. There was no support for the repayment hypothesis;the presence of helpers had no effect on offspring sex ratios.There was weak support for both the male quality (attractiveness)hypothesis with respect to plumage color and the maternal conditionhypothesis, but their influence on offspring sex ratios wasnegligible after controlling for the effects of pair-male condition. 相似文献