Kathreen Ruckstuhl | University of Calgary (original) (raw)

Papers by Kathreen Ruckstuhl

The study explores the dynamics of group living and dominance hierarchies among male Rocky Mounta... more The study explores the dynamics of group living and dominance hierarchies among male Rocky Mountain bighorn sheep (Ovis canadensis). Group living in animals offers advantages like access to resources, yet also fosters competition, often leading to dominance hierarchies. These hierarchies influence resource distribution and aggression levels. This study investigates personality traits, including confidence and aggression, and their correlation with social rank within male bighorn sheep. Through standardized personality tests and observational data, we discerned links between personality and dominance. Age influenced behavior, with younger individuals standing up earlier when approached. More dominant individuals displayed greater confidence, resuming foraging sooner after a human approach. Furthermore, aggression levels correlated with social rank between ages 1 to 6 and then gradually declined with age, with higher-ranking sheep exhibiting fewer antagonistic interactions than middle...

Scientific Reports, Sep 24, 2020

An understanding of the mechanisms influencing prenatal characteristics is fundamental to compreh... more An understanding of the mechanisms influencing prenatal characteristics is fundamental to comprehend the role of ecological and evolutionary processes behind survival and reproductive success in animals. Although the negative influence of parasites on host fitness is undisputable, we know very little about how parasitic infection in reproductive females might influence prenatal factors such as fetal development and sex allocation. Using an archival collection of Dall's sheep (Ovis dalli dalli), a capital breeder that depends on its body reserves to overcome the arctic winter, we investigated the direct and indirect impacts of the parasite community on fetal development and sex allocation. Using partial least squares modelling, we observed a negative effect of parasite community on fetal development, driven primarily by the nematode Marshallagia marshalli. principal component analysis demonstrated that mothers with low parasite burden and in good body condition were more likely to have female versus male fetuses. This association was primarily driven by the indirect effect of M. marshalli on ewe body condition. Refining our knowledge of the direct and indirect impact that parasite communities can have on reproduction in mammals is critical for understanding the effects of infectious diseases on wildlife populations. This can be particularly relevant for species living in ecosystems sensitive to the effects of global climate change. Parasites can negatively affect pregnancy rate 1-3 , offspring survival 4-6 , and offspring size 7. However, very little is known about how prenatal characteristics, such as fetal development and sex allocation, can be influenced by parasitic infections in the mother. Determining the factors that affect prenatal characteristics is key to understanding the ecological and evolutionary mechanisms behind survival and reproductive success in animals 8,9. For instance, fetal development has direct consequences for postnatal physiology, metabolism, growth and immune response (e.g. birds 9,10 , people 11,12 , wild mammals 13 , and various domestic species 14-19), while sex allocation can influence population dynamics through a variety of sex-biased mechanisms (e.g. sex-biased mortality and sexbiased reproduction rate) 20. Parasites can affect fetus development through several pathways including (i) a direct effect of parasite virulence on fetal development or survival causing pregnancy failure (e.g. abortion, fetal mummification, fetal reabsorption), as seen with bacteria such as Brucella abortus and protozoa such as Neospora caninum 21,22 , (ii) an indirect effect of the energetic cost of parasitic infection on the mother (e.g. parasite nutrition, host immune response, appetite depression), resulting in decreased nutrition to the fetus and a developmental delay 23,24 , and (iii) an indirect effect of parasites interrupting or delaying pregnancy due to a negative effect on host condition resulting in delayed ovulation and conception, which can translate to smaller fetus size 25. The few attempts to quantify the effects of parasites on fetal development have focused on humans, where the infection with gastrointestinal helminths can cause delayed fetal growth and premature parturition (reviewed in 26). There is theoretical and empirical evidence supporting the hypothesis that sex allocation can be directly influenced by extrauterine factors 27. The Trivers-Willard hypothesis 28 , for instance, suggests that in polygynous

Proceedings of The Royal Society B: Biological Sciences, Mar 8, 2023

Echinococcus multilocularis ( Em ), the causative agent of human alveolar echinococcosis (AE), is... more Echinococcus multilocularis ( Em ), the causative agent of human alveolar echinococcosis (AE), is present in the Holarctic region, and several genetic variants deem to have differential infectivity and pathogenicity. An unprecedented outbreak of human AE cases in Western Canada infected with a European-like strain circulating in wild hosts warranted assessment of whether this strain was derived from a recent invasion or was endemic but undetected. Using nuclear and mitochondrial markers, we investigated the genetic diversity of Em in wild coyotes and red foxes from Western Canada, compared the genetic variants identified to global isolates and assessed their spatial distribution to infer possible invasion dynamics. Genetic variants from Western Canada were closely related to the original European clade, with lesser genetic diversity than that expected for a long-established strain and spatial genetic discontinuities within the study area, supporting the hypothesis of a relatively recent invasion with various founder events.

International Journal for Parasitology, Sep 1, 2019

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Journal of Applied Ecology, Feb 20, 2015

ABSTRACT 1.In epidemiological studies of wildlife parasites, faecal genotyping has been introduce... more ABSTRACT 1.In epidemiological studies of wildlife parasites, faecal genotyping has been introduced to prevent bias in estimates of parasite prevalence from faecal samples collected in the field. Such an approach could be particularly relevant in the study of Echinococcus multilocularis transmission in urban settings, where estimates of prevalence and patterns of infection in wild canid hosts are key parameters used in zoonotic risk assessment and management. However, no previous study has evaluated the reliability of E. multilocularis faecal prevalence, and individual patterns of infection in definitive hosts remain poorly understood.2.We evaluated faecal genotyping as an epidemiological tool, using E. multilocularis in urban coyotes Canis latrans as our study system. Combining parasitological analysis and multilocus individual genotyping of coyote faeces, we compared faecal parasite prevalence with the prevalence obtained from genotyped faecal samples. Furthermore, we assessed patterns of individual infection, such as re-infection rates and phenology of parasite egg excretion.3.Of 425 feces collected in five urban sites, we genotyped 142 samples (33.4%) corresponding to 60 unique individual coyotes. Number of genotyped samples per coyote ranged between 1 and 10 (mean = 2.3). Genotypes were obtained at 4–6 microsatellite loci and had a mean reliability of 0.9975.4.Faecal prevalence of E. multilocularis in genotyped coyotes was 25.0%, and similar to results previously obtained from non-genotyped faeces. Faecal genotyping allowed estimating a re-infection rate of individual coyotes of 57.1%, and to observe temporal patterns of parasite infection that were not detected using non-genotyped faeces.5.Synthesis and applications. If compared to independent data obtained through coyote post-mortem examination, our results suggest that reliable estimates of overall parasite prevalence in definitive host populations can be efficiently obtained through well-designed field collection and traditional faecal parasitological analysis. However, faecal genotyping allows assessing the dynamics of individual infections, which could otherwise only be estimated by using invasive techniques. Combining faecal genotyping with parasitology has a great potential in assessing zoonotic risk transmission in urban areas, as well as advancing the field of wildlife ecology, disease ecology and conservation.This article is protected by copyright. All rights reserved.

Canadian Journal of Zoology, Aug 1, 2012

Behavioral Ecology and Sociobiology, Aug 14, 2018

Members of a social group must behave similarly for a group to persist. One way for this behaviou... more Members of a social group must behave similarly for a group to persist. One way for this behavioural similarity to occur is through the contagious spread of behaviours. However, there is significant variation in reported rates of behavioural contagion, and the mechanisms governing the spread of a behaviour from one individual to the next are not clear. Why is a behaviour sometimes contagious to a neighbouring individual, and other times not? Here, we examine the contagiousness of vigilance behaviour in bighorn sheep (Ovis canadensis) to determine whether particular characteristics of the vigilance bout affect the probability of contagion. We also investigate whether the vigilance characteristics differ between induced and routine vigilance, and thus might be reliable indicators for the presence of a relevant external stimulus. Results indicate that induced vigilance bouts involve significantly shorter head raise durations, longer first fixed gazes, and higher rates of chewing cessation in comparison to routine vigilance bouts. A fourth variable, looking in single or multiple directions before returning to grazing, did not differ between induced and routine vigilance. Interestingly, chewing cessation was the only one of four variables that predicted whether a vigilance bout would be contagious to a neighbouring sheep. These findings indicate that particular characteristics of a behaviour can affect whether a behaviour spreads to neighbouring individuals. Results are discussed in terms of both attention and learning as potential mechanisms regulating the spread of behaviour between social partners, in addition to providing new insight regarding the potential costs of vigilance behaviour. Significance statement The contagious spread of behaviours is essential for group cohesion and coordination; however, little is known about why some behaviours spread and others do not. Here, we examine whether particular characteristics of a behaviour affect whether it spreads to a neighbouring individual. Using vigilance behaviour in bighorn sheep as our study system, we first demonstrate that the characteristics of vigilance behaviour differ depending on whether the vigilance behaviour was routine or induced (by an external stimulus). We then demonstrate that one of the defining characteristics of induced vigilance (whether an individual ceases chewing at the onset of a vigilance bout) increases the chance of the behaviour spreading to neighbouring individuals. Results suggest that variation in the way that a behaviour is performed can affect how contagious it is.

PLOS Neglected Tropical Diseases, 2021

Echinococcus multilocularis (Em) is a zoonotic parasite considered a global emergent pathogen. Re... more Echinococcus multilocularis (Em) is a zoonotic parasite considered a global emergent pathogen. Recent findings indicate that the parasite is expanding its range in North America and that European-type haplotypes are circulating in western Canada. However, genetic analyses are usually conducted only on a few parasites out of thousands of individuals within each definitive host, likely underestimating the prevalence of less common haplotypes. Moreover, mixed infections with several mtDNA haplotypes in the same host have been reported, but their relative abundance within the host was never estimated. We aimed to 1) estimate the frequency of co-infections of different Em haplotypes in coyotes (Canis latrans) and red foxes (Vulpes vulpes) from western Canada and their relative abundance within the definitive hosts, 2) detect less prevalent haplotypes by sampling a larger proportion of the parasite subpopulation per host, and 3) investigate differences in the distribution of Em haplotypes...

Within host populations the transmission and maintenance of parasite infections are not driven by... more Within host populations the transmission and maintenance of parasite infections are not driven by the contribution of the whole number of infected individuals, but by the contribution of a restricted number of individuals. The host sex has been shown to have a great influence on parasite transmission generating in most host-parasite systems a male-bias in parasite loads. In addition, in some systems male hosts are responsible for the infection of the whole host population. The mechanisms generating sex differences in parasite infection may range from sexual variation in body mass, to hormonal profile and behaviour. All these characteristics are strongly expressed in the Alpine ibex. Moreover ibex present varying degrees of sexual segregation leading sexes to a different use of the space. This behaviour may have profound consequences on parasite transmission: as long as females avoid areas that are frequented by males they may have reduced parasite infection. In this work we investigated our hypothesis mechanistically using a mathematical model to explore whether a different use of space would result in sex-biased parasite infection. We developed an a priori deterministic model, which explores the dynamics of the interaction between male and female ibex with their abomasal parasites. We assumed that the infection rate between hosts and free-living infecting larvae depends on the percentage of spatial habitat overlap between the two sexes. Model simulations show that decreasing area of habitat overlap would lead to males increasing their parasite infection, while in females, intensity progressively decreases. Concomitantly, the host population size experiences a decrease of males coupled with an increase of females

Parasitology, 2021

In a fast-changing and globalized world, parasites are moved across continents at an increasing p... more In a fast-changing and globalized world, parasites are moved across continents at an increasing pace. Co-invasion of parasites and their hosts is leading to the emergence of infectious diseases at a global scale, underlining the need for integration of biological invasions and disease ecology research. In this review, the ecological and evolutionary factors influencing the invasion process of parasites with complex life cycles were analysed, using the invasion of the European strain of Echinococcus multilocularis in North America as a model. The aim was to propose an ecological framework for investigating the invasion of parasites that are trophically transmitted through predator–prey interactions, showing how despite the complexity of the cycles and the interactions among multiple hosts, such parasites can overcome multiple barriers and become invasive. Identifying the key ecological processes affecting the success of parasite invasions is an important step for risk assessment and ...

Animal Behaviour, Nov 1, 2020

Intra-and intersexual selection drives the evolution of secondary sexual traits, leading to incre... more Intra-and intersexual selection drives the evolution of secondary sexual traits, leading to increased body size, trait size and generally increased reproductive success in bearers with the largest, most attractive traits. Evolutionary change through natural selection is often thought of primarily in terms of genetic changes through mutations and adaptive selection. However, this view ignores the role of the plasticity in phenotypes and behaviour and its impact on accelerating or decelerating the expression of sexually selected traits. Here, we argue that sudden changes in selection pressures (e.g. predation pressure) may cause a cascade of behavioural responses, leading to a rapid change in the size of such traits. We propose that selective removal of individuals with the most prominent traits (such as large antlers or horns in male ungulates) induces behavioural changes in the surviving males, leading to a reduction in the growth of these traits (phenotypic expression). To test this idea, we used an individual-based simulation, parametrized with empirical data of male bighorn sheep, Ovis candensis. Our model shows that the expression (phenotype, not genotype) of the trait under selection (here horn size) can be negatively impacted, if the biggest, most dominant males in the population are removed. While the selective removal of prime males opens breeding opportunities for younger, smaller males, we predicted that it would come at the expense of growth and maintenance. As predicted, we observed a rapid decline in average male horn length in our model. We argue that this decline happens because smaller males, instead of allocating energy into growth, divert this energy towards participation in mating activities that are typically exclusively available to prime males. While our model deals with ecological life-history trade-offs, it cannot predict evolutionary outcomes. However, this nongenetic mechanism is important for the understanding of evolutionary processes because it describes how heritable traits can rapidly change because of behavioural plasticity, long before any genetic changes might be detectable.

Animal Behaviour, Sep 1, 2021

Behavioural Processes, Nov 1, 2017

In many ungulate species, social organization of adults is based on a linear dominance hierarchy,... more In many ungulate species, social organization of adults is based on a linear dominance hierarchy, which in turn often positively correlates with age, body mass, and horn/antler size. In contrast to the social behavior of adults and specific mother-offspring interactions, the process of ungulate socialization in juveniles through contacts with other conspecifics is poorly understood, especially for hider species during their initial hiding period. Therefore, we investigated this process in goitered gazelle (Gazella subgutturosa), which is a typical hiding species, and analyzed all contacts between fawns and other conspecifics, omitting mother-young interactions, which are different by nature from other contacts and demands separate consideration. We found that apart from mothers, fawns interacted most often with nonmaternal adult females, less with other fawns and least with adult males and sub-adults. The frequency of the fawns' contacts with conspecifics other than their mother increased during May and early-June, reaching a maximum in late-June, when fawns had the most mobility and independence from their mothers. This frequency decreased in July, when fawns spent more time with their mothers and when they mostly followed the mother's behavior. The interactions of adult males and sub-adults of both sexes with fawns were the most aggressive in character, involving frequent displays of butting and chasing. Aggressive interactions were fewer between adult females and fawns, while fawn-fawn interactions had least aggressive displays. The main cause of interactions between fawns and other conspecifics were attempts of these young gazelles to suckle from other adults and sub-adults, especially frequently from nonmaternal females. Only fawn-fawn contacts were not linked to suckling and seemed to relate mostly to the development of social behavior and dominance hierarchies.

Ardeola, Jul 1, 2018

The Great Bustard population in Xinjiang Province, the Chinese stronghold of Otis tarda tarda, is... more The Great Bustard population in Xinjiang Province, the Chinese stronghold of Otis tarda tarda, is suspect to be declining, but little is known about its trends and numbers. Using the same methods, we compared two former published counts from the province (1988 and 1992) with ours (2013-2016), exhaustively covering the two known bustard areas of Tacheng (summer) and Qapqal (winter). A strong decline (92%) is reported, with a minimum 19 birds found in Tacheng and none in Qapqal. Cooperation between scientists is needed to study the causes of decline in

Biology, Mar 31, 2023

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Biological Conservation, Nov 1, 2022

Diversity, Sep 11, 2022

Ethology Ecology & Evolution, Oct 30, 2019

Behavioural Processes, Oct 1, 2015

In ungulates, predation is often a major cause of infant mortality and likely plays an important ... more In ungulates, predation is often a major cause of infant mortality and likely plays an important role in shaping maternal care strategies that favor progeny survival. The anti-predator strategies of ungulates can be broadly categorized into two groups, hiding infants and following infants. We studied the maternal behavioral strategies of goitered gazelle, which is a typical representative of a hiding species. We found that shortly after birth, goitered gazelle mothers (1) stayed at the greatest distances from their hiding fawns; (2) spent the shortest amount of time together with their fawns, and then only for suckling (during the active phase) which was also the longest inter-suckling intervals (during the hiding phase); (3) kept twins separated in different hiding places and suckled them individually one after the other; (4) changed fawns' hiding places after every active period, travelling with them during the whole suckling bout; (5) oriented their body and muzzle most often toward their hiding young during the fawn's hiding phase; and (6) demonstrated the highest level of vigilance during their approaches to their hiding fawns. The anti-predator strategy of goitered gazelle females was similar to that observed in some North American (Antilocapra americana, Odocoileus hemionus and Odocoileus virginianus) and Eurasian (Dama dama and Capreolus capreolus) ungulate species that also demonstrate hiding behavior. Females of these species live on different continents with disparate environments and different predatory threats, but share antipredator strategies, which are likely the result of convergent evolution in Bovids and Cervids.