Ivana Schoepf

University of Alberta | UAlberta · Department of Science (Augustana Campus)

1. While the reasons for group-living have been studied for decades, little is known about why individuals become solitary. 2. Several previous experimental studies could demonstrate that group-living can arises as a consequence of ecological constraints. 3. It has been argued that reproductive competition between group members leads to significant...

The social organization of species ranges from solitary-living to complex social groups. While the evolutionary reasons of group-living are well studied, the physiological mechanisms underlying alternative social systems are poorly understood. By studying group-living and solitary individuals of the same species, we can determine hormonal correlate...

When hosts have a long coevolutionary history with their parasites, fitness costs of chronic infection have often been assumed to be negligible. Yet, experimental manipulation of infections sometimes reveals effects of parasites on their hosts, particularly during reproduction. Whether these effects translate into fitness costs remains unclear. Her...

Climate change models often assume similar responses to temperatures across the range of a species, but local adaptation or phenotypic plasticity can lead plants and animals to respond differently to temperature in different parts of their range. To date, there have been few tests of this assumption at the scale of continents, so it is unclear if t...

Multiple factors affect seed predation, including seed traits, habitat type, seed predator community composition, predation risk, and seasonality. How all these factors and their interactions simultaneously influence seed predation has rarely been tested experimentally in situ. Here, we assessed the relative contribution of the factors driving seed...

Background Within the same species, individuals show marked variation in their social dominance. Studies on a handful of populations have indicated heritable genetic variation for this trait, which is determined by both the genetic background of the individual (direct genetic effect) and of its opponent (indirect genetic effect). However, the evolu...

Complex genetic and phenotypic relationships are theorized to link different fitness components but revealing the correlations occurring among disparate traits requires large datasets of pedigreed populations. In particular, the association between traits beneficial to social dominance with health and fitness could be antagonistic, because of trade...

Plastic traits, such as variable behavior and physiology, are front‐line components of adaptive responses to dynamic challenges. For example, plastic responses to parasites and pathogens are essential to both resistance and tolerance of infection; yet, these responses can also be associated with high costs, including immunopathology, loss of homeos...

Glucocorticoid hormones allow individuals to rapidly adjust their physiology and behavior to meet the challenges of a variable environment. An individual’s baseline concentration of glucocorticoids can reflect shifts in life history stage and resource demands while mediating a suite of physiological and behavioral changes that include immune modula...

Boldness, the willingness of individuals to engage in risky behaviour, is one of the most studied personality traits. It has been measured using a variety of tests; however, measuring a behaviour using different assays may lead to a jingle fallacy. The few studies that have attempted to determine whether these different assays are comparable have p...

Energy is limited and must be allocated among competing life-history traits. Reproduction is considered one of the most energetically demanding life-history stages. Therefore, the amount of energy an individual invests in reproduction might carry fitness costs through reduced energy allocation to other activities such as health maintenance. We inve...

An individual’s ability to survive harsh conditions might depend on its available energy, and also on its health, which is expected to decline as conditions deteriorate. Yet, we know little about how health and energy expenditure are shaped by harsh environmental conditions in free-living vertebrates. Here, we studied how African striped mice (Rhab...

Personality in free-living individuals has predominantly been measured under standardized laboratory conditions. Such measurements have been then linked to life-history traits, fitness and survival. Yet, it remains unclear how such personality measurementsreflectthevariationshownbyfree-livingindividuals,ifthe same measurements were taken directly i...

An individual′s survival and fitness depend on its ability to effectively allocate its time between competing behaviors. Sex, social tactic, season and food availability are important factors influencing activity budgets. However, few field studies have tested their influences. The African striped mouse (Rhabdomys pumilio) lives in highly seasonal...

Personality in free-living individuals has predominantly been measured under standardized laboratory conditions. Such measurements have been then linked to life-history traits, fitness and survival. Yet, it remains unclear how such personality measurements reflect the variation shown by free-living individuals, if the same measurements were taken d...

Exogenous and endogenous environmental factors can have simultaneous additive as well as interacting effects on life-history traits. Ignoring such interactions can lead to a biased understanding of variability in demographic rates and consequently population dynamics. These interactions have been the focus of decades-long debates on the mechanisms...

Individual recognition, the ability to discriminate between members of a social group according to their distinctive characteristics, is a sophisticated form of social recognition. Several laboratory studies demonstrated individual recognition in rodents, but not under natural conditions. We combined behavioral observations and an experiment to ass...

Oxytocin (OT) and arginine vasopressin (AVP) are produced in the brain. Due to their importance in modulating social behaviour, these two neuropepetides have been extensively studied in captivity, yet few data are available from the field. Here we report the findings from an immunohistochemistry study, where we measured density of OT and AVP in dif...

Vertebrates obtain most of their energy through food, which they store mainly as body fat or glycogen, with glucose being the main energy source circulating in the blood. Basal blood glucose concentration (bBGC) is expected to remain in a narrow homeostatic range. We studied the extent to which bBGC in free-living African striped mice (Rhabdomys pu...

The development and persistence of personality in nature are counterintuitive because, in heterogeneous environments, personality is expected to limit the degree of behavioural flexibility. Recent work has shown that personality and behavioural flexibility might be linked, but their interaction is not well understood and could be elucidated by stud...

An individual's home range determines its access to resources, significantly influencing its fitness. Food availability and population density are considered to be among the primary factors influencing home range sizes; however, no study has experimentally tested whether these two factors affect home range sizes independently. This is important as...

Little is known about the extent to which solitary individuals differ in their social behaviour from group-living ones within the same species. Using the socially flexible African striped mouse, we tested through a series of dyadic encounters in a neutral arena whether group-living mice that later became solitary differed from their philopatric con...

Environmental change poses challenges to many organisms. The resilience of a species to such change depends on its ability to respond adaptively. Social flexibility is such an adaptive response, whereby individuals of both sexes change their reproductive tactics facultatively in response to fluctuating environmental conditions, leading to changes i...

The size of an individual’s home range is an important feature, influencing reproduction and survival, but it can vary considerably among both populations and individuals. The factors accounting for such variation are still poorly understood, and comprehensive long-term field studies considering various environmental factors that influence home ran...