Glucocorticoids (GCs) are involved in the regulation of an animal's energetic state. Under stressful situations, they part neuroendocrine response to cope with environmental challenges. Animals react aversive stimuli also through behavioral responses, defined as coping styles. Both captive and wild populations, individuals differ their behavior along a proactive-reactive continuum. Proactive animals exhibit bold, active-explorative social personality, whereas reactive ones shy, less social....

Abstract A general tenet in stress physiology is that the hypothalamic-pituitary-adrenal (HPA) axis predominantly produces one glucocorticoid (GC) response to stressors. However, two main glucocorticoids produced by vertebrates – cortisol and corticosterone show variation across species absolute levels, relative proportions, responsivity. Therefore, focusing on a single GC may not tell whole story. In this study, we measured both water samples collected from five of Dendrobatid poison frogs....

Hormones such as glucocorticoids (colloquially referred to "stress hormones") have important effects on animal behavior and life-history traits, yet most of this understanding has come through correlative studies. While experimental studies offer the ability assign causality, there are methodological concerns that often not considered when manipulating hormones, including glucocorticoids, in wild animals. In study, we examined how elevations cortisol concentrations North American red...

Elevations in glucocorticoid (GC) levels breeding females may induce adaptive shifts offspring life histories. Offspring produced by mothers with elevated GCs be better prepared to face harsh environments, where a faster pace of is beneficial. We examined how experimentally pregnant or lactating North American red squirrels (Tamiasciurus hudsonicus) affected postnatal growth, structural size and oxidative stress (two antioxidants protein damage) three different tissues (blood, heart liver)...

Abstract Adaptive behavioral plasticity can play a beneficial role when population becomes established in novel environment if environmental cues allow the expression of appropriate behavior. Further, itself evolve over time new causing changes way or degree to which animals respond cues. Colonization events provide an opportunity investigate such relationships between and adaptation environments. Here, we investigated evolution behavior during colonization environment, by testing female...

ABSTRACT As a response to environmental cues, maternal glucocorticoids (GCs) may trigger adaptive developmental plasticity in the physiology and behavior of offspring. In North American red squirrels (Tamiasciurus hudsonicus), mothers exhibit increased GCs when conspecific density is elevated, selection favors more aggressive perhaps active under these conditions. We tested hypothesis that elevated cause shifts offspring prepare them for high-density experimentally during gestation or early...

Abstract Parental investment theory predicts that observed levels of parental care afforded to offspring are set by the benefits (to quality and survival) relative costs survival or future reproduction). Although difficult document in mammals, there is often substantial individual-variation amount within species. We measured impact individual variation maternal (“attentiveness” towards motivation) on growth a wild population North American red squirrels ( Tamiasciurus hudsonicus ). used...

Abstract Elevations in glucocorticoid levels (GCs) breeding females may induce adaptive shifts offspring life histories. Offspring produced by mothers with elevated GCs be better prepared to face harsh environments where a faster pace of is beneficial. We examined how experimentally pregnant or lactating North American red squirrels ( Tamiasciurus hudsonicus ) affected postnatal growth, structural size, oxidative stress (two antioxidants and protein damage) three different tissues (blood,...

Abstract Animals are continually faced with the challenge of producing context-appropriate social behaviors. In many instances, animals produce unrelated behaviors across contexts. However, in some instances same produced different contexts, albeit response to distinct stimuli and purposes. We took advantage behavioral similarities mating aggression contexts guppies, Poecilia reticulata, understand how patterns neural induction differ when nonetheless shared While these is growing interest...

Abstract Hormones such as glucocorticoids (colloquially referred to “stress hormones”) have important effects on animal behavior and life history traits, yet most of this understanding has come through correlative studies. While experimental studies offer the ability assign causality, there are methodological concerns that often not considered when manipulating hormones, including glucocorticoids, in wild animals. In study, we examined how elevations cortisol concentrations North American...

Abstract Individuals vary in their behavioral and physiological responses to environmental changes. These are often described as ‘coping styles’ along a proactive-reactive continuum. Studies laboratory populations often, but not always, find that stressors covary, where more proactive (more aggressive active) individuals have lower stress response, specifically measured by hypothalamic-pituitary-adrenal (HPA) axis activity. studies support the possibility of hormonal pleiotropy underlying...

Abstract An increase in maternal stress during offspring development can have cascading, life-long impacts on behavior and physiology, which vary depending the timing of exposure to stressor. By responding stressors through increasing production glucocorticoids (GCs), hypothalamic-pituitary-adrenal (HPA) axis is a key mediator effects – both side mother offspring. At molecular level, are thought be mediated modifying transcription genes, particularly brain. To better understand evolutionary...

Abstract In vertebrates, the glucocorticoid response through hypothalamic-pituitary-adrenal (HPA) axis controls many essential functions, including behavior, metabolism, and ontogenetic transitions. However, there are tradeoffs associated with high levels of glucocorticoids, reduced growth rate lowered immunity. These drive variation in timing development HPA across taxa. anurans (frogs toads), corticosterone has critical roles concentrations can fluctuate to environmental stressors. Given...

Abstract Environmental factors experienced during development can affect the physiology and behavior of offspring. Maternal glucocorticoids (GCs) may convert environmental cues by mother into a cue triggering adaptive developmental plasticity in In North American red squirrels ( Tamiasciurus hudsonicus ), females exhibit increases GCs when conspecific density is elevated, selection favors more aggressive perhaps active mothers under high conditions. We experimentally elevated maternal...