Dispersal is one of the most fundamental components of ecology. Dispersal is also particularly relevant in an era of unprecedented habitat loss and climate change. We used a unique dataset to examine dispersal in gray ratsnakes (Pantherophis spiloides)...
Bird species around the world are threatened with extinction. In North America, aerial insectivores are experiencing particularly severe population declines. To conserve these species, we need to know which life stages have the largest influence on population growth. We monitored...
The hypothalamic-pituitary-interrenal (HPI) axis is centrally implicated in stressor mitigation in teleost fishes. Sustained HPI axis activation can be detrimental to the physiological functioning of an organism and can result in fitness-related trade-offs. Predator-induced mortality is known to be higher...
Recreational boating activity has the potential to generate noise pollution that may influence wild fish. Such noise may be particularly relevant to fish engaged in parental care (PC), where alterations in behaviour could influence individual fitness and productivity of fish...
The spatial structure of populations determines the relative importance of reproduction, survival and movement on population dynamics. However, the mechanisms by which local individuals and immigrants interact and the subsequent effects of immigrants on productivity are poorly known. We developed...
The increasing popularity of catch-and-release angling indicates a need to identify best practices that minimize sublethal injuries, impairments, and mortality. One factor impacting the viability of catch and release is the risk of hooking injury, which can impact survival in...
Many species form social groups with dominance hierarchies. Often, individuals possess a status signal that indicates dominance rank. Songbirds produce songs that are used to attract mates or repel rivals, and acoustic features within songs can also indicate an individual's...
Basking is the primary mechanism used by many freshwater turtles to maintain their body temperature (Tb) in a range that maximizes physiological performance. Basking turtles are easily disturbed by motorboats, but the consequences of the increasingly popular...
While the use of aquatic protected areas that exclude angling might be considered an evolutionarily enlightened management approach to dealing with fisheries‐induced evolution (FIE), there is little empirical data on the effectiveness of this approach at maintaining the diversity of...
Selectively removing fish based on particular traits, such as body size, may shift trait abundance in the remaining population, resulting in a phenomenon called fisheries-induced evolution. Recently, there is growing interest in evaluating the effects of fisheries-induced evolution on fish...
The ideal free distribution concept predicts that organisms will distribute themselves between habi-tats in a density-dependent manner so that individuals, on average, achieve the same fitness in each habitat. In ecto-therms, environmental temperature has a strong impact on fitness, but...
Within species of birds, variation in plumage may allow potential mates or competitive rivals to quickly assess the quality of an individual. Little is known about the role of white tail feather patches (“tail white”) in male Cerulean Warblers (...
Dispersal of native species from the regional pool can recover invaded communities to a pre-invaded state by supplementing declining populations or providing resistant species. However, dispersal may also exacerbate the negative effects of an invader. Introduced species can open or...
Recently, there has been growing recognition that fish harvesting practices can have important impacts on the phenotypic distributions and diversity of natural populations through a phenomenon known as fisheries-induced evolution. Here we experimentally show that two common recreational angling techniques...
The contemporary tackle box for recreational angling is packed with lures that cover the full spectrum of colours with the assumption that colour influences fishing success. Yet, there is little research that identifies how lure colour might influence capture rates...
In short-lived animals, innate immunity is an important component of fitness and quality. Although receivers cannot generally assess a signaler's immune function directly, sexually selected displays such as birdsong may reflect past or current condition. We investigated the degree to...
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...
Baseline glucocorticoid (cort) levels are increasingly employed as physiological indices of the relative condition or health of individuals and populations. Often, high cort levels are assumed to indicate an individual or population in poor condition and with low relative fitness...
It has long been recognized that many hoverfly species (Diptera: Syrphidae) mimic the morphological appearance of defended Hymenoptera, such as wasps and bees. However, it has also been repeatedly suggested that some mimetic hoverflies respond with sounds on attack that...
Sexual bimaturation, an intersexual difference in age at maturity, is a consequence of sexual size dimorphism (SSD). Sexual bimaturation arises through intersexual differences in growth trajectories. In theory, differences in growth trajectories should bias the operational sex ratio in favour...
Bismuth shotshell has been used as a non-toxic alternative to lead but the environmental fate of bismuth has not been studied adequately. In an upland hardwood forest in south-eastern Ontario, Canada, soil beneath mature sugar maple, red maple and bitternut hickory was experimentally manipulated...
The estimation and maintenance of connectivity among local populations is an important conservation goal for many species at risk. We used Bayesian statistics and coalescent theory to estimate short- and long-term directional gene flow among subpopulations for two reptiles that...
Annual reproductive surveys monitored nesting location, reproductive success and the age and size of individually tagged male smallmouth bass Micropterus dolomieu that reproduced in Millers Lake, a 45 ha widening of the Mississippi River, Ontario, and in a 1·5 km...
Roads negatively affect animal populations by presenting barriers to movement and gene flow and by causing mortality. We investigated the impact of a secondary road on a population of black ratsnakes (Elaphe obsoleta) in Ontario, Canada by radio-tracking...
We investigated patterns in the dispersion (i.e. spread and spacing) of plant species traits that are frequently associated with competitive ability, in an old‐field plant community. In contrast with previous studies, we found no evidence for significant over‐ or under‐dispersion...
The importance of multiple enemies from different trophic levels on investment in defence by prey has, with some exceptions, received little attention. Some defences may make the victim more susceptible to other enemies; this latter situation applies to predators and...
Reproductive success of iteroparous insects depends on their own survival as well as that of their offspring and thus adults should consider risk of predation to both themselves and their offspring when selecting a suitable place to lay eggs. We...
The goals of this study were to investigate the possibility of using kernel techniques to estimate male breeding territory size and delineate core areas, focusing on a small nontransmitter bearing bird, the cerulean warbler. We then compared the performance of...
Neolimnochares johnstoni n. sp., the first known nearctic member of this genus, is described from eastern North America based on adults and deutonymphs. The usefulness of the number and arrangement of platelets on the idiosomal dorsum and the degree of...
Whether the Pleistocene has had a disproportionate impact on the recent diversification of temperate species, or played a lesser role in a more protracted process, has been a prominent evolutionary debate for the past decade. We used cytochromeb...
To determine the consequences of dispersal and gene flow for temporary pond water mites (Hydrachnida), we compared distributional, genetic and morphological characters in the closely related species Arrenurus angustilimbatus and A. rufopyriformis. The former has larvae that parasitise and disperse...
Within a network of communicating individuals, animals may gather information about the relative quality of conspecics by eavesdropping on their signalling interactions. For territorial male songbirds, eavesdropping may be a low-cost, low-risk method for assessing the relative quality of the...
Evolutionary ecologists are attempting to explain how parents make behavioural decisions about how much care to provide to their young. Theory predicts that when genetic relatedness to young is decreased by cuckoldry, for example, parents should reduce their care in...
The damselfly, Nehalennia irene (Hagen), has two distinct female colour morphs. Individuals of one morph have male‐like colouration and pattern (androchromes), whereas gynochromes are different from males and androchromes in these respects. In several damselflies, such female‐limited polychromatism is attributable...
We tested for predator-induced plasticity in development and growth of embryos and young tadpoles of green frogs (Rana clamitans). We expected to observe developmental plasticity in response to the leech, Macrobdella decora, because the leech represents a high, but unpredictable, risk...
Many evolutionary models and empirical studies of parasite‐host interactions consider single species of parasites exploiting single host species. However, many parasites are generalists in that they parasitize more than one host species (often many more) and establish associations with other...
Lake eutrophication is a problem in many areas of Ontario, although the history of nutrient enrichment is poorly documented. The aim of this study was to construct a diatom-based transfer function to infer past phosphorus levels in Ontario lakes using...
We measured the 24-h flight activity patterns of 84 species of Nearctic Lepidoptera representing 12 ultrasound-earless and seven ultrasound-eared families to examine the evolution of the diel flight periodicities (DFPs) and auditory defences of these insects. Most species tested showed...
Theories of parental care evolution predict that genetic relatedness will be an important variable in the amount of care a parent provides. However, current inferences of relatedness–based parental investment from studies in humans and birds remain challenged. No study has...
While studying the nesting ecology of black snake rats ( Elaphe obsoleta [Say]; snakes : Colubridae) in eastern Ontario, we discovered that their eggs were very well protected by the Nicrophorus pustulatus (Herschel) (Coleoptera: Silphidae). The beetle appears to be parasitoid of the...
This study investigated the accuracy of 50-m fixed-radius, 100-m fixed-radius, and variable circular-plot point counts to estimate the actual density of breeding Cerulean Warblers (Dendroica cerulea) during the 1997 and 1998 breeding seasons, in Ontario, Canada. Density estimates were compared...
We stored blood samples of Eastern Phoebes (Sayornis phoebe) in a lysis buffer (“QLB”) that has been used successfully to preserve blood samples of many other species. We found that although samples from adults were not affected greatly...
Directional asymmetry (DA) has received considerably less attention than fluctuating asymmetry (FA) in the literature. Evidence for DA, however, is building among insect taxa. We examined asymmetries in two wing traits within both sexes of the damselfly Calopteryx maculata (Beauvois)...
Patterns of divorce and extrapair mating can provide insights into the targets of female choice in free-living birds. In resident, site-faithful species with continuous partnerships, the better options and the incompatibility hypotheses provide the most likely explanations for divorce. Extrapair...
We used data from a 9-year mark–recapture study to determine whether demographic factors could explain female-biased sexual size dimorphism in northern water snakes (Nerodia sipedon). Most males reached sexual maturity at 3 years of age, while most females delayed maturity...
It is widely thought that many apomictic angiosperms exhibit variation in sexual versus apomictic seed production, yet there has been little investigation of the extent to which apomixis varies among or within natural populations. In dioecious Antennaria parlinii, previous...
Previous studies have shown that some female black-capped chickadees (Poecile atricapillus) solicit copulations from males that rank higher in winter flocks than their social mates, and extra-pair paternity in nests occurs commonly enough to be considered a potential...
The ability to produce seeds when pollinators or potential mates are scarce is thought to be one of the main advantages of self-fertilization in flowering plants. However, whether autonomous selfing increases seed set in natural populations has seldom been tested...
In this work, we cloned and characterized 60 (GT) repeat microsatellite sequences from the bluegill sunfish geome. We report the frequency distribution, the lengths, and the proportions of the repeat classes for comparison with microsatellites isolated from other teleost, mammal...
We use data from field experiments and observations of Tree Swallows Tachycineta bicolor defending single and extra nest-sites at nest-box and cavity populations to determine the function of extra nest-site defense behaviour.
Mitochondrial DNA (mtDNA) variation was examined for two nominal subspecies of largemouth bass, Micropterus salmoides salmoides (northern largemouth bass) and M. s. floridanus (Florida largemouth bass).
Black-capped Chickadees (Parus atricapillus) sing a two-note tonal song that has stereotyped frequency parameters (glissando and frequency interval). We hand-reared and tutored pairs of nestlings in acoustic isolation to determine the extent that learning is involved in the production of...
Canonical correspondence analysis (CCA) was used to explore the relationship between measured environmental variables and surficial diatom (Bacillariophyceae) assemblages in alkaline lakes from southeastern Ontario. Total nitrogen (TN), watershed area, alkalinity, and maximum depth each explain significant (P ≤ 0.05)...
We investigated the ability of two congeneric species of sunfish to learn to forage on a novel prey item in feeding arenas containing structured habitats.
The identification of broad classes of DNA probes which detect hypervariable genetic markers in different taxa is invaluable for parentage analysis in wild vertebrates. Restriction-fragment-length polymorphisms, detected by hybridization of a mouse class II major histocompatibility complex (MHC) cDNA probe...
In an experimental study in Denmark, it was previously found that male barn swallows (Hirundo rustica) with elongated tail streamers obtained an apparent fitness advantage through earlier pairing, an increased frequency of second clutches, and higher total reproductive success per...
Nest cavities of Tree Swallows were examined at dawn during the period of territorial establishment to determine if Tree Swallows regularly roost in their cavity.
