The selection consequences of competition in plants have been traditionally interpreted based on a “size‐advantage” hypothesis – that is, under intense crowding/competition from neighbors, natural selection generally favors capacity for a relatively large plant body size. However, this conflicts with...
In species in which both sexes have similar ornamentation, the ornaments often function as sexual or social signals in both sexes. However, males and females may use ornaments in different signalling contexts. We previously demonstrated that carotenoid-based bill colour of...
Release of fish captured by recreational anglers is a common practice due to angler conservation ethics or compliance with fisheries regulations. As such, there is a need to understand the factors that influence mortality and sub-lethal impairments to ensure that...
In most natural plant populations, there is a strong right-skewed distribution of body sizes for reproductive plants—i.e. the vast majority are relatively small, suppressed weaklings that manage not just to survive effects of crowding/competition and other hazards but also to...
The potential role of alternative reproductive tactics in circumventing premating isolating mechanisms and driving hybridization between species has long been recognized, but to date there is little empirical support from natural systems. Hybridization occurs between bluegill (Lepomis macrochirus)...
Male parental care in vertebrates often involves both defensive and nurturing behaviors. Whether androgens differentially mediate these two types of behaviors, or a trade-off exists between them, has been studied by behavioral endocrinologists for years but predominantly in species with...
We conducted an experiment using freshwater painted turtles (Chrysemys picta) to determine if keeping turtles out of water for an hour enhances anoxia recovery following a simulated bycatch event in nets (i.e., 12 hrs of submergence at 25°C). Traditional...
Few studies have examined vertebrate models of invasive species to explore parasite release as a proposed mechanism through which host species might become invasive. In this study, we examined evidence for parasite release in invasive American bullfrogs (Rana catesbeiana/Lithobates...
The energetic costs of providing parental care are widely documented, but rarely do studies consider the role of environmental variation (e.g., predation pressure) in this context. Here, we tested if variation in nest predation pressure influenced the energetic costs of...
The consequences of stress on the behaviour of wild creek chub Semotilus atromaculatusoutside the reproductive period were studied using a single intra‐coelomic injection of cortisol, suspended in coconut butter, to experimentally raise plasma cortisol levels. Behaviour between cortisol‐treated, sham‐treated...
The foraging ecology of fish is often considered to be the primary determinant of body shape due to tight links between morphology, swimming performance, and foraging efficiency. Fish foraging on littoral benthic macroinvertebrates typically have a deeper body shape than...
Competition is generally regarded as an important force in organizing the structure of vegetation, and evidence from several experimental studies of species mixtures suggests that larger mature plant size elicits a competitive advantage. However, these findings are at odds with...
Theory has produced contrasting predictions related to flowering time overlap among coexisting plant species largely because of the diversity of potential influences on flowering time. In this study, we use a trait‐based null modelling approach to test for evidence of...
The density dependence of demographic parameters and its implications for population regulation have long been recognized. Recent work has revealed potential effects of density on mating systems and sexual selection, but few studies concurrently assess the consequences of density on...
Urbanization and agricultural practices can lead to alterations in stream habitat quality. However, there have been few attempts to understand if these alterations influence the health and condition of fish, or their ability to respond to multiple stressors. This study...
Status signals are linked to fighting ability and enable competitors to gain access to resources without risking injury in aggressive combat. The relationship between testosterone (T), a hormone that mediates aggression, and signals of status is well studied in males...
To date, most studies of commercial fisheries bycatch have focused on mortality at time of capture as an endpoint. However, sub-lethal indicators of organismal condition have the potential to reveal mechanisms associated with mortality (both at time of capture and post-release)...
In lakes and rivers of eastern Ontario (Canada) commercial fishers use hoop nets to target a variety of fishes, but incidentally capture non-target (i.e., bycatch) gamefish species such as northern pike (Esox lucius). Little is known about the...
Turtles are caught as bycatch in commercial fisheries in both inland and marine waters. Turtle mortality associated with bycatch is concerning, as life-history characteristics of turtles, including high juvenile mortality and delayed sexual maturity, make them particularly susceptible to population...
Experimental evidence suggests that competition among plant species is generally hierarchical and that relatively large species are at a competitive advantage when competition is predominantly above‐ground. However, regional species pools are dominated numerically by relatively small plant species, and...
The capture of non-target species is a conservation issue in many commercial fisheries. Bycatch reduction devices (BRDs) are commonly used as mitigation tools to improve selectivity of fishing gear and thus reduce bycatch. The aim of this paper was to...
Bycatch of turtles in passive inland fyke net fisheries has been poorly studied, yet bycatch is an important conservation issue given the decline in many freshwater turtle populations. Delayed maturity and low natural adult mortality make turtles particularly susceptible to...
Conspicuous ornamentation has been linked to immunological and physiological condition in males of many species. In species where both sexes are ornamented, it is unclear whether the signal content of ornaments differs between males and females. We examined the immunological...
The glucocorticoid (GC) stress response is thought to be an individual trait associated with behaviour and life history strategies. Studies exploring such relationships typically assume measured hormone values to be repeatable within an individual. However, repeatability of GCs has proven...
Androgens are known to mediate aggressive and defensive behaviour in many vertebrate species. However, high concentrations of androgens might also conflict with the expression of nurturing behaviours and therefore a trade‐off can exist between aggressive and nurturing behaviours during parental...
The diets of 99 pumpkinseed sunfish Lepomis gibbosus from a pair of small, adjacent lakes in Ontario, Canada, were estimated from their stomach contents, trophically transmitted parasites and stable isotopes of carbon and nitrogen in fish tissue. The three methods...
Catch and release is a common practice among recreational anglers. In instances when fish are deeply hooked, the proper techniques for promoting survival are poorly understood, although evidence suggests that the fishing line should be cut rather than attempting to...
As the number of invasive species increases globally, more and more native predators are reported to shift their diet toward invasive prey. The consequences of such diet shifts for the health of populations of native predators are poorly studied, but...
As the number of invasive species increases globally, more and more native predators are reported to shift their diet toward invasive prey. The consequences of such diet shifts for the health of populations of native predators are poorly studied, but...
Polymorphisms of the juvenal plumage in birds have received little study in comparison to other plumages. We investigate a polymorphism in the juvenal plumage of the Yellow Warbler (Setophaga petechia) in southeastern Ontario, Canada. Yellow Warblers in juvenal...
Behavioral thermoregulation is expected to be critical in determining the capacity of reptiles to respond to climate warming and how that response will vary with latitude. We used radio-telemetry to compare behavioral thermoregulation among ratsnake (Elaphe obsoleta) populations...
Turtles are vulnerable to population declines in response to even low levels of additional adult mortality, for instance bycatch mortality. Inland commercial fisheries that use passive gears such as fyke nets cause the drowning of some freshwater turtles. To reduce...
A recent study of Ratsnakes (Elaphe obsoleta) in Texas found that adult mortality was higher for females than males, consistent with the cost of reproduction in snakes being higher for females. To determine whether the same pattern prevailed...
In species that provide parental care, care for offspring is often accompanied by an increase in locomotor activity and a decrease in feeding opportunities which can negatively impact endogenous energy reserves. Depletion of parental energy stores and declines in nutritional...
Regulation of the hypothalamic–pituitary–adrenal (HPA) axis is a key component of the vertebrate stress response. Prior studies have found that variation in HPA responses were correlated to measures of fitness and physiological condition. In addition, sexually-selected traits have also been found to...
Using a long-term study population of wild smallmouth bass Micropterus dolomieu in a connected river-lake system, we investigated whether circulating glucocorticoid (cortisol) and androgen (testosterone) concentrations are influenced by reproductive investment and nesting environment in fish providing nest-guarding paternal care...
Wild fish are frequently exposed to multiple stressors, but the influence of previous or ongoing stress on an animal's subsequent response is poorly understood. Using wild‐caught bluegill sunfish (Lepomis macrochirus) as a model, we used exogenous hormone implants...
Background and aims – The leaf size/number trade-off has been recently established as a wide-spread and highly predictable relationship associated with between-species leaf size variation. In this study, we examine whether this trade-off relationship also applies at the between-plant (within-species)...
Little is known about the acarofauna associated with wood-boring beetles in Canada, including long-horned beetles (Coleoptera: Cerambycidae). Herein, we assessed the prevalence, abundance, diversity, phenology, and attachment location of mesostigmatic mites (Acari: Mesostigmata) associated with Monochamus scutellatus (Say), and tested...
Leaf-borne vibrations are potentially important to caterpillars for communication and risk assessment. Yet, little is known about the vibratory environment of caterpillars, or how they detect and discriminate between vibrations from relevant and non-relevant sources. We measured the vibratory ‘landscape’...
Leafing intensity—number of leaves produced per unit of supporting (nonleaf, aboveground) dry mass—determines the size of a plant’s “bud bank”, i.e., the number of axillary meristems per unit plant body or shoot size. This in turn determines the plant’s capacity...
Freshwater turtles are susceptible to drowning in commercial fishing nets and this is a major conservation concern. Methods to mitigate turtle bycatch mortality typically involve reducing the capture of bycatch using gear modifications. Another method to reduce mortality is to...
Anthropogenic noise can mask animal signals that are crucial for communicating information about food, predators and mating opportunities. In response to noise masking, signallers can potentially improve acoustic signal transmission by adjusting the timing, frequency or amplitude of their signals...
Evidence that infectious diseases cause wildlife population extirpation or extinction remains anecdotal and it is unclear whether the impacts of a pathogen at the individual level can scale up to population level so drastically. Here, we quantify the response of...
Localized antipredator behaviors have been observed in a wide variety of taxa. Recent work has also shown that animals that provide parental care adjust their behavior when faced with variation in offspring predation pressure. This variation in offspring predation pressure...
Size-selective harvesting associated with commercial and recreational fishing practices has been shown to alter life history traits through a phenomenon known as fishing-induced evolution. This phenomenon may be a result of selection pathways targeting life-history traits directly or indirectly through...
While social interactions influence vertebrate endocrine regulation, the dynamics of regulation in relation to specific behaviors have not been clearly elucidated. In the current study, we investigated whether androgens (testosterone) or glucocorticoids (cortisol) play a functional role in aggressive offspring...
According to traditional theory, superior competitive ability in plants generally requires relatively large plant body size. Yet even within the most crowded vegetation, most resident species are relatively small; species size distributions are right-skewed at virtually every scale. We...
Many fish species respond to low temperature by inducing mitochondrial biogenesis, reflected in an increase in activity of the mitochondrial enzyme cytochrome c oxidase (COX). COX is composed of 13 subunits, three encoded by mitochondrial (mt)DNA and 10 encoded by...
We investigated sexual size dimorphism and trophic morphology dimorphism in Eastern Garter Snakes (Thamnophis sirtalis) to test predictions derived from the reproductive role hypothesis. Our first objective was to examine whether structures involved in feeding (head and jaws)...
Angling is a popular recreational activity across the globe and a large proportion of fish captured by anglers are released due to voluntary or mandatory catch-and-release practices. The handling associated with hook removal and return of the fish to their...
We reviewed the literature in an attempt to determine the importance of aseptic technique when implanting electronic tags in fish. Given that there was negligible information on this topic we embarked on a study where bluegill (Lepomis macrochirus)...
Contemporary theory predicts that the degree of mimetic similarity of mimics towards their model should increase as the mimic/model ratio increases. Thus, when the mimic/model ratio is high, then the mimic has to resemble the model very closely to still...
Bycatch from marine commercial fisheries has been regarded as a global conservation concern for decades. Fortunately, some headway has been made in mitigating bycatch problems in marine fisheries. Freshwater commercial fisheries, however, have been relatively understudied. Although freshwater yields comprise...
Advances in research on bird vocalizations often follow the development of new recording technologies and analytical techniques (Baptista & Gaunt 1994, Baker 2001). As recently as a decade ago, ornithologists recorded birdsong onto magnetic tape and analysed sounds with a...
Variation in the level of competition for mates and territories is likely to influence the behaviour of competitors. The start of the dawn chorus in singbirds is influenced by a variety of internal factors (e.g. circadian rhythms) and external factors (e.g. light...
Do the transcriptional mechanisms that control an individual's mitochondrial content, PGC1α (peroxisome proliferator-activated receptor γ coactivator-1α) and NRF1 (nuclear respiratory factor-1), also cause differences between species? We explored the determinants of cytochrome c oxidase (COX) activities in muscles from 12...
Mitochondrial content, central to aerobic metabolism, is thought to be controlled by a few transcriptional master regulators, including nuclear respiratory factor 1 (NRF-1), NRF-2 and peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α). Though well studied in mammals, the mechanisms by which these...
Although bycatch is well known and well studied in marine fisheries, comparatively little is known about bycatch in freshwater fisheries. Even basic information on bycatch composition and mortality in freshwater is unavailable, given that few inland jurisdictions require reporting of...
