Reduced fitness of secondary females in a polygynous species: a 32-yr study of Savannah sparrows.

The evolution of mating systems reflects a balance of the often-conflicting interests of males and females. Polygyny, a mating system in which males have multiple mates, presents a fitness benefit to males, but the consequences for females are less clear. Females with polygynous social mates may suffer reduced fitness, especially secondary females who typically receive less male support.

Seasonal dynamics in the mammalian microbiome between disparate environments.

Host-associated bacterial microbiomes can facilitate host acclimation to seasonal environmental change and are hypothesized to help hosts cope with recent anthropogenic environmental perturbations (e.g., landscape modification).

Cumulative cultural evolution and mechanisms for cultural selection in wild bird songs.

Cumulative cultural evolution, the accumulation of sequential changes within a single socially learned behaviour that results in improved function, is prominent in humans and has been documented in experimental studies of captive animals and managed wild populations. Here, we provide evidence that cumulative cultural evolution has occurred in the learned songs of Savannah sparrows. In a first step, "click trains" replaced "high note clusters" over a period of three decades.

Expanding the frame around social dynamics and glucocorticoids: From hierarchies within the nest to competitive interactions among species.

The effect of the social environment on individual state or condition has largely focused on glucocorticoid levels (GCs). As metabolic hormones whose production can be influenced by nutritional, physical, or psychosocial stressors, GCs are a valuable (though singular) measure that may reflect the degree of "stress" experienced by an individual. Most work to date has focused on how social rank influences GCs in group-living species or how predation risk influences GCs in prey.

Natal experience and pre-breeding environmental conditions affect lay date plasticity in Savannah Sparrows.

Phenotypic plasticity allows organisms to adjust the timing of life-history events in response to environmental and demographic conditions. Shifts by individuals in the timing of breeding with respect to variation in age and temperature are well documented in nature, and these changes are known to scale to affect population dynamics. However, relatively little is known about how organisms alter phenology in response to other demographic and environmental factors.

Captive-reared migratory monarch butterflies show natural orientation when released in the wild.

Eastern North American migratory monarch butterflies () have faced sharp declines over the past two decades. Captive rearing of monarch butterflies is a popular and widely used approach for both public education and conservation. However, recent evidence suggests that captive-reared monarchs may lose their capacity to orient southward during fall migration to their Mexican overwintering sites, raising questions about the value and ethics of this activity undertaken by tens of thousands of North American citizens, educators, volunteers and conservationists each year.

Shades of grey: host phenotype dependent effect of urbanization on the bacterial microbiome of a wild mammal.

Background: Host-associated microbiota are integral to the ecology of their host and may help wildlife species cope with rapid environmental change. Urbanization is a globally replicated form of severe environmental change which we can leverage to better understand wildlife microbiomes. Does the colonization of separate cities result in parallel changes in the intestinal microbiome of wildlife, and if so, does within-city habitat heterogeneity matter? Using 16S rRNA gene amplicon sequencing, we quantified the effect of urbanization (across three cities) on the microbiome of eastern grey squirrels (Sciurus carolinensis).

The Effect of Egg Laying on Feather and Plasma Corticosterone Concentrations in Turkey () Hens.

Phenological differences in energy demand (i.e., reproductive status) might influence the measurement of corticosterone.

Early-Life Corticosterone Body Condition Influence Social Status and Survival in a Food-Caching Passerine.

Individuals undergo profound changes throughout their early life as they grow and transition between life-history stages. As a result, the conditions that individuals experience during development can have both immediate and lasting effects on their physiology, behavior, and, ultimately, fitness. In a population of Canada jays in Algonquin Provincial Park, Ontario, Canada, we characterized the diet composition and physiological profile of young jays at three key time points during development (nestling, pre-fledge, and pre-dispersal) by quantifying stable-carbon (δ13C) and -nitrogen (δ15N) isotopes and corticosterone concentrations in feathers.

Effects of early-life exposure to sublethal levels of a common neonicotinoid insecticide on the orientation and migration of monarch butterflies ().

Migratory insects use a variety of innate mechanisms to determine their orientation and maintain correct bearing. For long-distance migrants, such as the monarch butterfly (), these journeys could be affected by exposure to environmental contaminants. Neonicotinoids are synthetic insecticides that work by affecting the nervous system of insects, resulting in impairment of their mobility, cognitive performance, and other physiological and behavioural functions.

Research Note: Quantifying corticosterone in turkey (Meleagris gallopavo) feathers using ELISA.

The measurement of corticosterone in feathers is an appealing tool for assessing glucocorticoids in wild and domestic bird species. Feather corticosterone measurements can be performed noninvasively and can provide a means for comparing glucocorticoid secretion between individual birds; thus, such measurements can be used to assess the welfare of domestic poultry. The focus of this study was to assess the validity of detecting corticosterone in turkey (Meleagris gallopavo) feathers using an ELISA and investigate differences between genetic lines.

Measurement of free glucocorticoids: quantifying corticosteroid binding capacity and its variation within and among mammal and bird species.

Plasma glucocorticoid (CORT) levels are one measure of stress in wildlife and give us insight into natural processes relevant to conservation issues. Many studies use total CORT concentrations to draw conclusions about animals' stress state and response to their environment. However, the blood of tetrapods contains corticosteroid-binding globulin (CBG), which strongly binds most circulating CORT.

Reframing conservation physiology to be more inclusive, integrative, relevant and forward-looking: reflections and a horizon scan.

Applying physiological tools, knowledge and concepts to understand conservation problems (i.e. conservation physiology) has become commonplace and confers an ability to understand mechanistic processes, develop predictive models and identify cause-and-effect relationships.

Into the wild: microbiome transplant studies need broader ecological reality.

Gut microbial communities (microbiomes) profoundly shape the ecology and evolution of multicellular life. Interactions between host and microbiome appear to be reciprocal, and ecological theory is now being applied to better understand how hosts and their microbiome influence each other. However, some ecological processes that underlie reciprocal host-microbiome interactions may be obscured by the current convention of highly controlled transplantation experiments.

Low dose prenatal testosterone exposure decreases the corticosterone response to stress in adult male, but not female, mice.

Gonadal steroid hormones affect the organization of the brain during sensitive periods of development, resulting in sex differences in the neuroendocrine function and behaviour of the offspring. Although alterations in developmental testosterone exposure have been hypothesized to play a role in male-biased neurodevelopmental disorders, the underlying mechanisms remain unknown. The present study investigated the hypothesis that early prenatal exposure to low concentrations of testosterone might affect the control of stress responses in later life.

It's what's on the inside that counts: stress physiology and the bacterial microbiome of a wild urban mammal.

The microbiome's capacity to shape the host phenotype and its mutability underlie theorization that the microbiome might facilitate host acclimation to rapid environmental change. However, when environmental change occurs, it is unclear whether resultant microbiome restructuring is proximately driven by this changing external environment or by the host's physiological response to this change. We leveraged urbanization to compare the ability of host environment (urban or forest) versus multi-scale biological measures of host hypothalamic-pituitary-adrenal (HPA) axis physiology (neutrophil : lymphocyte ratio, faecal glucocorticoid metabolites, hair cortisol) to explain variation in the eastern grey squirrel () faecal microbiome.

Raising young with limited resources: supplementation improves body condition and advances fledging of Canada Jays.

Food availability early in life can play a vital role in an individual's development and success, but experimental evidence for the direct effects of food on body condition, physiology, and survival of young animals in the wild is still relatively scarce. Food-caching Canada Jays (Perisoreus canadensis) begin breeding in the late winter and, therefore, rely on either cached food or seemingly limited quantities of fresh food to feed nestlings in the early spring. Using a 2-yr food supplementation experiment conducted during the nestling period and 40 yr of observational data on food supplemented by the public, we examined whether food quantity during early life influenced the physiology, body condition, timing of fledging, and survival of young Canada Jays in Algonquin Provincial Park, Ontario, Canada.

Social and physiological drivers of rapid colour change in a tropical toad.

Dynamic sexual dichromatism occurs when males and females differ in colouration for a limited time. Although this trait has been primarily studied in cephalopods, chameleons, and fishes, recent analyses suggest that dynamic dichromatism is prevalent among anurans and may be mediated through sexual selection and sex recognition. Yellow toads, Incilius luetkenii, exhibit dynamic dichromatism during explosive breeding events at the onset of the rainy season: males change from a cryptic brown to a bright yellow and back again during the brief mating event.

Autumn freeze-thaw events carry over to depress late-winter reproductive performance in Canada jays.

Evidence suggests that range-edge populations are highly vulnerable to the impacts of climate change, but few studies have examined the specific mechanisms that are driving observed declines. Species that store perishable food for extended periods of time may be particularly susceptible to environmental change because shifts in climatic conditions could accelerate the natural degradation of their cached food. Here, we use 40 years of breeding data from a marked population of Canada jays () located at the southern edge of their range in Algonquin Provincial Park, Ontario, to examine whether climatic conditions prior to breeding carry over to influence reproductive performance.

A roadmap for urban evolutionary ecology.

Urban ecosystems are rapidly expanding throughout the world, but how urban growth affects the evolutionary ecology of species living in urban areas remains largely unknown. Urban ecology has advanced our understanding of how the development of cities and towns change environmental conditions and alter ecological processes and patterns. However, despite decades of research in urban ecology, the extent to which urbanization influences evolutionary and eco-evolutionary change has received little attention.