Rebecca Rimbach

University of Münster | WWU

We must differentiate between stressful and harsh environments to understand animals’ resilience to global change. Harshness is not stress. Stressful environments activate the physiological stress response to increase energy avail- ability, while harsh environments inhibit the physiological stress response to save energy.

Wild animals face novel environmental challenges as natural habitats give way to urban areas, with numerous biotic and abiotic differences between the two. Urban ‘stressors’ may elicit a constant release of glucocorticoids via the hypothalamic–pituitary–adrenal (HPA) axis, and chronically elevated glucocorticoid levels can be associated with negati...

Low total energy expenditure (TEE, MJ/d) has been a hypothesized risk factor for weight gain, but repeatability of TEE, a critical variable in longitudinal studies of energy balance, is understudied. We examine repeated doubly labeled water (DLW) measurements of TEE in 348 adults and 47 children from the IAEA DLW Database (mean ± SD time interval:...

Animals that spend more energy than they obtain risk entering allostatic overload, reducing survival and fitness. They are predicted to adjust their daily energy expenditure (DEE) during periods of food scarcity. Adjustments of DEE to changes in food availability have been well-studied in species in temperate zones during winter, but less so in spec...

Urban habitats provide wildlife with predictable, easily accessible and abundant food sources in the form of human food waste. Urban eastern gray squirrels (Sciurus carolinensis) are commonly observed feeding in trash bins, but we lack data regarding the type, quantity and seasonal changes in food waste usage. We observed five trash bins on an urba...

Urbanization is a known widespread phenomenon with profound forms of land use changes. Urban areas are characterized by habitat fragmentation and the replacement of natural habitat by human-made structures impacting various environmental conditions (e.g., natural resources, light and noise level, temperature) and transforming wildlife communities....

Urban wildlife faces unique physiological and behavioral challenges compared to conspecifics which live in less altered natural habitats. Animals in urban habitats are also exposed to urban stressors and commonly make use of inappropriate food sources from trash bins and dumpsters, which may affect their heath status. The goals of this study were t...

The Earth Hologenome Initiative (EHI) is a global collaboration to generate and analyse hologenomic data from wild animals and associated microorganisms using standardised methodologies underpinned by open and inclusive research principles. Initially focused on vertebrates, it aims to re-examine ecological and evolutionary questions by studying hos...

Background Pastoralists live in challenging environments, which may be accompanied by unique activity, energy, and water requirements. Aim Few studies have examined whether the demands of pastoralism contribute to differences in total energy expenditure (TEE) and water turnover (WT) compared to other lifestyles. Subjects and methods Accelerometer...

Insufficient physical activity is a major risk factor for cardiometabolic disease (i.e., unhealthy weight gain, heart disease, and diabetes) in humans and may also negatively affect health of primates in human care. Effects of physical activity on energy expenditure and cardiometabolic health are virtually unstudied in nonhuman primates. We investi...

Continuous multiday ultramarathon competitions are increasingly popular and impose extreme energetic and nutritional demands on competitors. However, few data have been published on energy expenditure during these events. Here, we report doubly labeled water-derived measures of total energy expenditure (in kilocalories per day) and estimated physic...

Matschie’s tree kangaroo (Dendrolagus matschiei) is an endangered arboreal marsupial native to Papua New Guinea. Detailed field studies of its behavior and ecology are scarce due largely to its occupation of remote cloud forests and cryptic nature. Although this species has been in human care since the 1950s, much of its biology is still unknown. T...

Social systems vary within and between species, ranging along a continuum between solitary-living to complex societies. Social systems are emergent properties of interactions between individuals, and these interactions are often modulated by hormones. We investigated the behavioral and hormonal consequences of experimentally imposed social grouping...

Objective High levels of total energy expenditure (TEE, kcal/day) have been documented among numerous human populations such as tropical climate horticulturalists and high-altitude agriculturalists. However, less work has been conducted among highly physically active cold climate populations. Methods In October 2018, TEE was measured using the dou...

Marine mammals are thought to have an energetically expensive lifestyle because endothermy is costly in marine environments. However, measurements of total energy expenditure (TEE; kcal/day) are available only for a limited number of marine mammals, because large body size and inaccessible habitats make TEE measurements expensive and difficult for...

Studying how different environmental parameters, such as resource availability and ambient temperature, affect growth rates aids to understand the evolution of different growth strategies. Low levels of food availability restrict growth, and high ambient temperature can constrain growth via trade-offs between body temperature maintenance and heat p...

African elephants, the largest land animal, face particular physiological challenges in captivity and the wild. Captive elephants can become over- or under-conditioned with inadequate exercise and diet management. Few studies have quantified body composition or water turnover in elephants, and none to date have examined longitudinal responses to ch...

Individuals that are capable of accumulating appropriate fat stores are assumed to have selective advantages when food becomes scarce. Similar to species from temperate zones, some species inhabiting arid areas accumulate fat stores prior to periods of food limitation. Yet, we have little knowledge concerning seasonal variation in body composition...

In many species, males follow alternative reproductive tactics (ARTs), where one tactic (called bourgeois) has much higher reproductive success than alternative tactics followed by males with lower competitive ability. The extent to which ARTs differ in energetic costs is unknown, but it is important to understand the fitness payoffs of ARTs. We st...

Family groups with helpers occur in several species of fish, birds and mammals. In such cooperatively breeding species all group members help with raising the offspring, i.e. parents and offspring from previous litters. While the ecological reasons and ultimate consequences of allo-parental care have been studied in detail, we know little about its...

There was an error published in J. Exp. Biol. (2017) 220, 837-843 (doi: 10.1242/jeb.151449). A mistake was made by the authors in the calculation of RMR values. The corrected Results section, tables and figures follow and we indicate where the significance of relationships changed. There are no changes to the conclusions of the paper. Mass-Adjusted...

Diverse motivational triggers, including diet, elicit stereotypic behavior. We investigated whether diets comprised of different protein levels but similar levels of energy were associated with the occurrence of locomotor stereotypies in the striped mouse Rhabdomys dilectus chakae . In a first experiment, 20 stereotypic and 20 non- stereotypic (10...

Resting metabolic rate (RMR) influences energy allocation to survival, growth, and reproduction, and significant seasonal changes in RMR have been reported. According to one hypothesis, seasonal changes in RMR are mainly attributable to seasonal changes in ambient temperature (Ta) and food availability. Studies on species from the temperate zone in...

To maximize their fitness, individuals of one sex can display discrete reproductive phenotypes, called alternative reproductive tactics (ARTs). Individuals following ARTs show behavioural variation, which might result in differences in energy intake and expenditure. However, few studies have compared activity budgets and non-sexual behaviour of ind...

It has often been proposed that bolder, more explorative or more active individuals also have a higher resting metabolic rate (RMR), indicating metabolic costs of these personality types. However, such individuals might often be restless and thus excluded from RMR datasets, leading to a significant sampling bias. We tested (1) whether such a bias o...

In response to variation in food availability and ambient temperature (Ta), many animals show seasonal adaptations in their physiology. Laboratory studies showed that thyroid hormones are involved in the regulation of metabolism, and their regulatory function is especially important when the energy balance of an individual is compromised. However,...

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...

Dietary protein deficiency influences the behavioural phenotypes of mammals. We studied whether protein deficiency during gestation and/or post-weaning heightened anxiety, reduced memory recall and influenced competitive ability in the African striped mouse Rhabdomys dilectus chakae. Mice were subjected to five protein diet treatments, which they r...

Elevated risk of disease transmission is considered a major cost of sociality, although empirical evidence supporting this idea remains scant. Variation in spatial cohesion and the occurrence of social interactions may have profound implications for patterns of interindividual parasite transmission. We used a social network approach to shed light o...

The level of dietary protein determines the onset of reproduction, affects offspring growth and maturation, and hence influences life-history traits and fitness. However, to date, the long-term life-history consequences of protein deficiency are not well understood. We studied the transgenerational effects of different levels of dietary protein on...

Numerous animal species currently experience habitat loss and fragmentation. This might result in behavioral and dietary adjustments, especially because fruit availability is frequently reduced in fragments. Food scarcity can result in elevated physiological stress levels, and chronic stress often has detrimental effects on individuals. Some animal...

Habitat fragmentation and anthropogenic disturbances are of major concern to the conservation of endangered species because of their potentially negative impact on animal populations. Both processes can impose physiological stress (i.e. increased glucocorticoid output) on animals, and chronically elevated stress levels can have detrimental effects...

Non-invasive methods to assess stress hormone output via fecal glucocorticoid metabolites (FGCMs) have become a powerful tool in behavioral studies and conservation biology because they allow exploring the link between behaviour, an animal´s socio-ecological environment and its adrenocortical activity. However, FGCM levels are influenced by numerou...

Interspecific aggression amongst nonhuman primates is rarely observed and has been mostly related to scenarios of resource competition. Interspecific infanticide is even rarer, and both the ultimate and proximate socio-ecological factors explaining this behavior are still unclear. We report two cases of interspecific infanticide and five cases of i...