280 research outputs found
Fluctuating effects of genetic and plastic changes in body mass on population dynamics in a large herbivore
No full textRecent studies suggest that evolutionary changes can occur on a contemporary time scale. Hence, evolution can influence ecology and vice-versa. To understand the importance of eco-evolutionary dynamics in population dynamics, we must quantify the relative contribution of ecological and evolutionary changes to population growth and other ecological processes. To date, however, most eco-evolutionary dynamics studies have not partitioned the relative contribution of plastic and evolutionary changes in traits on population, community, and ecosystem processes. Here, we quantify the effects of heritable and non-heritable changes in body mass distribution on survival, recruitment, and population growth in wild bighorn sheep (Ovis canadensis) and compare their importance to the effects of changes in age structure, population density, and weather. We applied a combination of a pedigree-based quantitative genetics model, statistical analyses of demography, and a new statistical decomposition technique, the Geber method, to a long-term data set of bighorn sheep on Ram Mountain (Canada), monitored individually from 1975 to 2012. We show three main results: (1) The relative importance of heritable change in mass, non-heritable change in mass, age structure, density, and climate on population growth rate changed substantially over time. (2) An increase in body mass was accompanied by an increase in population growth through higher survival and recruitment rate. (3) Over the entire study period, changes in the body mass distribution of ewes, mostly through non-heritable changes, affected population growth to a similar extent as changes in age structure or in density. The importance of evolutionary changes was small compared to that of other drivers of changes in population growth but increased with time as evolutionary changes accumulated. Evolutionary changes became increasingly important for population growth as the length of the study period considered increased. Our results highlight the complex ways in which ecological and evolutionary changes can affect population dynamics and illustrate the large potential effect of trait changes on population processes
Spatial genetic structure of Rocky Mountain bighorn sheep (Ovis canadensis canadensis) at the northern limit of their native range
No full textThis is a manuscript version of an article published as: Haines, J.A., Nason, S.E., Skurdal, A.M.M., Bourchier, T., Boutin, S., Taylor, R.W., McAdam, A.G., Lane, J.E., Kelley, A.D., Humphries, M.M., Gorrell, J.C., Dantzer, B., Coltman, D.W., & Hämäläinen, A. (2020). Sex- and context-specific associations between personality and a measure of fitness but no link with life history traits. Animal Behaviour, 167, 23-29. https://doi.org/10.1016/j.anbehav.2020.06.013The Canadian Rocky Mountains are one of the few places on Earth where the spatial genetic structure of wide-ranging species has been relatively unaffected by anthropogenic disturbance. We characterized the spatial genetic structure of Rocky Mountain bighorn sheep (Ovis canadensis canadensis Shaw, 1804) in the northern portion of their range. Using microsatellites from 1495 individuals and mitochondrial DNA sequences from 188 individuals, we examined both broad- and fine-scale spatial genetic structure, assessed sex-biased gene flow within the northern portion of the species range, and identified geographic patterns of genetic diversity. We found that broad-scale spatial genetic structure was consistent with barriers to movement created by major river valleys. The fine-scale spatial genetic structure was characterized by a strong isolation-by-distance pattern, and analysis of neighborhood size using spatial autocorrelation indicated gene flow frequently occurred over distances of up to 100 km. However, analysis of sex-specific spatial autocorrelation and analysis of mitochondrial haplotype distributions failed to detect any evidence of sex-biased gene flow. Finally, our analyses reveal decreasing genetic diversity with increasing latitude, consistent with patterns of post-glacial recolonization of the Rocky Mountains.https://viurrspace.ca/bitstream/handle/10613/23294/Gorrell.CJZ.pdf?sequence=3This is an author supplied, accepted manuscript version of an article published as: Deakin, S., Gorrell, J.C.,
Kneteman, J., Hik, D.S., Jobin, R.M., & Coltman, D.W. (2020). Spatial genetic structure of Rocky Mountain
bighorn sheep (Ovis canadensis canadensis) at the northern limit of their native range. Canadian Journal
of Zoology, 98(5), 317-330. DOI: 10.1139/cjz-2019-0183
Canadian Journal of Zoology is available online at: http://www.nrcresearchpress.com/journal/cjz, and this
article is available at: http://dx.doi.org/10.1139/cjz-2019-0183.Post-print versio
The new kid on the block: Immigrant males win big whereas females pay fitness cost after dispersal - data
No full textThe data and code for residents and immigrants (successful dispersers) and their offspring using 29 years of monitoring from North American red squirrels (Tamiasciurus hudsonicus) in Yukon, Canada. Data obtained with funding from the Natural Sciences and Engineering Council of Canada, Northern Scientific Training Program, and the National Science Foundation.Published. Martinig, A. R., A. G. McAdam, B. Danzter, J. E. Lane, D. W. Coltman, & S. Boutin. 2019. The new kid on the block: Immigrant males win big whereas females pay fitness cost after dispersal. Ecology Letters 23:430–438.</div
Adopting kin enhances inclusive fitness in asocial red squirrels
No full textOrphaned animals benefit from being adopted, but it is unclear why an adopting parent should
incur the costs of rearing extra young. Such altruistic parental behaviour could be favoured if it
is directed towards kin and the inclusive benefits of adoption exceed the costs. Here, we report
the occurrence of adoption (five occurrences among 2,230 litters over 19 years) in asocial red
squirrels (Tamiasciurus hudsonicus). Adoptions were always between kin, while orphans without nearby kin were never adopted. Adoptions were confined exclusively to circumstances in which the benefits to the adopted juvenile (b), discounted by the degree of relatedness between the surrogate and the orphan (r), exceeded the fitness costs of adding an extra juvenile to her
litter (c), as predicted by Hamilton's rule (rb>c) for the evolution of altruism. By focusing on
adoption in an asocial species, our study provides a clear test of Hamilton's rule that explains
the persistence of occasional altruism in a natural mammal population.https://viuspace.viu.ca/bitstream/handle/10613/3207/Gorrell.NC.pdf?sequence=4This is an electronic version of an article that was originally published as: Gorrell, J.C., McAdam, A.G.,
Coltman, D.W., Humphries, M.M., & Boutin, S. (2010). Adopting kin enhances inclusive fitness in asocial
red squirrels. Nature Communications, 1, 1-4. DOI: 10.1038/ncomss1022.
Nature Communications is published by Macmillan Publishers, part of Springer Nature. More
information about the journal can be found at: http://www.nature.com/ncomms/. This article can be
accessed on the Nature.com website at: http://www.nature.com/articles/ncomms1022
Mating order and reproductive success in male Columbian ground squirrels (Urocitellus columbianus)
No full textMultiple mating by females is common in many mammalian species, often resulting in mixed paternity litters. In such mating systems, mating order, male age, and male body mass frequently play an important role in determining male reproductive success. We tested for these effects on male reproductive success in Columbian ground squirrels (Urocitellus columbianus). The mating activity of estrous females was observed, and the occurrence of sperm precedence was tested using microsatellites to determine paternity in a total of 147 litters (434 offspring), including 110 litters (334 offspring) where the mating position of individual males was determined. Females mated with up to 8 males per litter, whereas paternity analyses revealed that only the first 5 males to mate actually sired offspring. The number of offspring sired significantly decreased with position in the mating sequence, showing a strong first male advantage. The extent of this advantage diminished with an increasing number of male mating partners, indicating that sperm competition plays an important role. A male's position in the females' mating sequences was not consistent within and across seasons, suggesting that individual males did not follow distinct reproductive strategies. Rather, males of intermediate age were more successful than young and old males, when corrected for age effects; heavier males were more likely to mate first. We conclude that males gain the largest part of their seasonal reproductive output from mating first with a female due to a pronounced first male advantage but gain considerable additional fitness from mating with additional, already mated females. Copyright 2010, Oxford University Press.
Phenotype and mating success of male harbour seals, Phoca vitulina, at Sable Island, Nova Scotia.
No full textReproductive behaviour and mating success of male harbour seals (Phoca vitulina) were studied at Sable Island, Nova Scotia, between 1992 and 1995. Individually marked males were fitted with time-depth recorders to monitor their activity at sea. Males were also given deuterium labelled water to estimate body composition and energy expenditure during the breeding season. These studies showed reproduction to be as energetically costly for male harbour seals as it is for males of other species. Due to small body size, most male harbour seals cannot energetically afford the extended fast which is characteristic of other breeding pinnipeds, hence they forage during deep diving bouts until females are likely to become receptive. All males changed their diving behaviour during the mating period such that repeated bouts of shallow diving activity, which reflect reproductive behaviour, predominated.Mating success was estimated using microsatellite markers to analyze paternity genetically. The paternity analysis of two cohorts of pups indicated that harbour seals are polygynous, as the most successful male harbour seals may sire as many as 6 pups in a season, but the variance in mating success among males was low, with most males likely to have sired one or no pups. This is consistent with the limited ability of males to monopolize females in the aquatic mating environment, and with the dispersal of females at sea near Sable Island. Females may mate with males from any stretch of the island.Male mating success could not be reliably predicted from any single phenotypic characteristic, however, multivariate analysis identified suites of characteristics which are associated with varying degrees of reproductive success. Relatively large males which hauled out alone and bore wounds from fighting were reproductively unsuccessful, and likely represent individuals who have been defeated in intrasexual competition. The group of males with the highest rate of mating success tended to have the greatest energy stores at the beginning of the mating season, and they started to compete for mates earlier and at greater energetic expense than other males.Thesis (Ph.D.)--Dalhousie University (Canada), 1997
Molecular ecological approaches to studying the evolutionary impact of selective harvesting in wildlife
No full textSeasonal, spatial, and maternal effects on gut microbiome in wild red squirrels
No full textOur understanding of gut microbiota has been limited primarily to findings from human and laboratory animals, but what shapes the gut microbiota in nature remains largely unknown. To fill this gap, we conducted a comprehensive study of gut microbiota of a well-studied North American red squirrel (Tamiasciurus hudsonicus) population. Red squirrels are territorial, solitary, and live in a highly seasonal environment and therefore represent a very attractive system to study factors that drive the temporal and spatial dynamics of gut microbiota.https://viurrspace.ca/bitstream/handle/10613/5417/Gorrell.Microbiome.pdf?sequence=4This is an electronic version of an article that was published as: Ren, T., Boutin, S., Humphries, M.M.,
Dantzer, B., Gorrell, J.C., Coltman, D.W., McAdam, A.G., & Wu, M. (2017). Seasonal, spatial, and
maternal effects on gut microbiome in wild red squirrels. Microbiome, 5, 1-14. DOI: 10.1186/s40168-
017-0382-3
Microbiome is an open access journal published by BioMed Central. More information about the journal
can be found at: https://microbiomejournal.biomedcentral.com/. This article can be accessed at:
http://dx.doi.org/10.1186/s40168-017-0382-3.Article 16
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