249 research outputs found
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
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.
Population dynamics of enteric parasites in the endangered Vancouver Island marmot (Marmota vancouverensis)
No full textThis article was originally published as: Gourlay, K.P., McAdie, M.L., & Gorrell, J.C. (2024). Population dynamics of enteric parasites in the endangered Vancouver Island marmot (Marmota vancouverensis). Journal of Parasitology, 110(4), 300-310. https://doi.org/10.1645/24-20Enteric parasites can have wide-ranging effects throughout an ecosystem, often driving coevolutionary and ecological processes. Parasites have long been overlooked in conservation efforts because of the negative impact inflicted on their hosts; however, parasites make up a significant component of Earth’s biodiversity and host conservation efforts need to be parasite inclusive. The Vancouver Island marmot (VIM), Marmota vancouverensis, is an endangered alpine rodent endemic to Vancouver Island, British Columbia, Canada. Captive-bred VIMs are released to augment the wild population, but their susceptibility to parasites is unknown. The objectives of this study were to describe the diversity, prevalence, severity, and temporal variation of VIM enteric parasites. Noninvasive fecal samples were collected from wild and captive marmots and analyzed using a modified McMaster fecal egg floatation technique to indicate parasite prevalence and relative mean abundance. We identified oocysts and ova from 3 parasite taxa including a protozoan coccidium not previously described in the VIM (prevalence 68%), an ascarid nematode Baylisascaris laevis (prevalence 82%), and an anoplocephalid cestode Diandrya vancouverensis (prevalence 8%). Depending on the species, comparisons revealed variation in parasite infection by sex, by colony, and between wild and captive VIMs, but not among age classes or by female reproductive status. Finally, captive VIMs displayed significant monthly variation in parasite prevalence and mean egg abundance, suggesting a seasonal influence on parasite egg shedding. This information is critically important for future research investigating the influences of these trends on the health, ecology, and conservation of VIMs and their parasites.This research was funded by a Discovery Grant from the Natural Sciences and
Engineering Research Council of Canada (#RGPIN-2018-06764) and an Innovation HUB grant from Co-operative Education and Work-Integrated Learning Canada to J.C.G. K.P.G. completed this research as an undergraduate student and was supported by a REACH scholarship from Vancouver Island University
Ultrastructure and Phylogeny of the Spermatozoa of the Infraorders Thalassinidea and Anomura (Decapoda, Crustacea)
No full textPublished in book: JAMIESON, B. G. M., Ausro, J., & JUSTINE, J.-L. (eds), Advances in Spermatozoal Phylogeny and Taxonomy. Mem. Mus. natn. Hist. nat., 166: 251-263
Diversity among rare and common congeneric plant species from the Garry oak and Okanagan shrub-steppe ecosystems in British Columbia: Implications for conservation
No full textThis article was originally published as: Hersh, E.W., Wheeler, E.J., Costanzo, B., Ramakrishnan, A.P., Miscampbell, A.E., Ritland, C., Whitton, J., Gorrell, J.C., & Harrower, W. (222). Diversity among rare and common congeneric plant species from the Garry oak and Okanagan shrub-steppe ecosystems in British Columbia: Implications for conservation. Botany: An International Journal for Plant Biology, 1-14. https://dx.doi.org/10.1139/cjb-2022-0064It is often assumed that the northern peripheral populations of species’ ranges are genetically depauperate due in part to founder effects from postglacial colonization. The majority of federally protected plant species are peripheral in Canada, yet we have little information about their patterns of genetic diversity and structure. In British Columbia, the majority of these protected plant species occur in two threatened habitats: the Garry oak and Okanagan shrub-steppe ecosystems. Using universal noncoding chloroplast DNA markers, we investigated genetic diversity and genetic structure in four rare and common plant species pairs inhabiting these two ecosystems. We found that rare species had lower genetic diversity than their common congeners, and detected contrasting patterns of regional diversity and structure based on ecosystem. Species from the Garry oak ecosystem showed lower genetic diversity in the northern deglaciated region and significant differentiation between regions, likely due to limited dispersal between Vancouver Island and the mainland. Species from the Okanagan shrub-steppe, however, tended to have uniform diversity across their range and lack regional structure. This study provides an important first look at the phylogeographic patterns of four rare plant species in British Columbia.https://viurrspace.ca/bitstream/handle/10613/26088/GorrellCJB2022.pdf?sequence=3Funding was provided by the Ecosystems Branch of the British Columbia Ministry of Environment and Climate Change Strategy and the Environment and Climate Change Canada, Priority Places Funding
Seasonal, 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
The Ultrastructure of the Spermatozoon of Dromidiopsis edwardsi Rathbun, 1919 (Crustacea: Brachyura: Dromiidae): Confirmation of a Dromiid Sperm Type
No full textArticle published in: Aust. J. Zool., 1993, 41, pp. 537-548
Voyage of discovery? A comment on Koch et al. "A voyage to Terra Australis: human-mediated dispersal of cats"
No full textThe origins of feral cats in Australia may be understood with the help of molecular studies, but it is important that hypotheses be tested with appropriate sampling and methodology. We point out several shortcomings in the analysis by Koch et al. (BMC Evol Biol 15:262, 2015; "A voyage to Terra Australis: human-mediated dispersal of cats". Dryad Digital Repository, 2015), present a reanalysis of part of the study and discuss the challenges of elucidating the early history of feral cats
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