The proximate mechanisms underlying the evolution and maintenance of within-sex variation in mating behaviour are still poorly understood. Species characterized by alternative reproductive tactics provide ideal opportunities to investigate such mechanisms. Bluegill (Lepomis macrochirus) are noteworthy in this...
We tested the prediction that the main stems of four common deciduous tree species grow phototropically as saplings in the forest understory in response to variable canopy structure. Our predictions were confirmed for Fraxinus americana, Acer saccharum, and ...
Using a sample of 24 common deciduous angiosperm trees of the Eastern Deciduous Forest region of North America, we tested the hypothesis that leaf size variation across species can be interpreted in terms of a trade‐off between individual leaf mass...
Body temperature affects nearly all processes of ectotherms. Reptiles do not generate sufficient body heat to regulate their body temperature internally and therefore use behavioural thermoregulation. We determined whether thermoregulatory effort varied among seasons in an environment where large temporal...
It is well established that extra‐pair young are present to varying degrees in nests of most avian species. However, the timing of extra‐pair copulations during a female's fertile cycle is not well known, nor is how these copulations translate into...
Dominance relationships structure many animal societies, yet the process of rank attainment is poorly understood. We investigated acquisition of social dominance in winter flocks and its fitness consequences in male black-capped chickadees (Poecile atricapillus) over a 10-year period. Age was...
To understand variation in resistance to parasites within host populations, researchers have examined conditions under which immunity is induced and/or is costly. Both host sex and age have been found to influence immune expression and subsequently are likely factors influencing...
Blood sampling is useful for the study of behavior, ecology, and physiology. Here we describe this technique, report our success, and discuss its advantages over the previously described techniques.
Birds meet the energetic demands of egg formation by using either endogenous reserves (capital breeding) or recently ingested nutrients (income breeding). Examining these strategies in migratory birds has been difficult because of the inability to assign the origin of egg...
Organismal performance curves are important functions for the study of reptilian ecology and evolution, but their interpretation can be affected strongly by the choice of analytical approach. We first use an example from the literature to demonstrate that excluding biologically...
There are two prominent, nonmutually exclusive hypotheses to explain the timing of reproduction in animals: energetic constraint and adaptive behaviour.
We tested these hypotheses by quantifying the costs and benefits of nesting at different times in the season for male...
Freshwater environments are currently experiencing an alarming decline in biodiversity. As a result, scientists and managers must look for alternative management techniques to protect these aquatic systems. One such option that has potential to protect freshwater environments from numerous threats...
Conservation biologists increasingly face the need to provide legislators, courts and conservation managers with data on causal mechanisms underlying conservation problems such as species decline. To develop and monitor solutions, conservation biologists are progressively using more techniques that are physiological...
Three southeastern Ontario lakes have responded differently to human disturbances in their catchments over the past 150 years. Catchments of Round and Long lakes were once subjected to deforestation and apatite mining but currently have no local watershed disturbances. Meanwhile...
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...
In territorial species, increased density is often linked to an increase in aggressive interactions, which may result in trade‐offs between competitive behavior and nest construction. We examined the impact of nesting in areas of high‐density versus low‐density nest boxes on...
We studied parental behavior in six syntopically breeding species of centrarchid fishes to determine whether energetic costs could contribute to our understanding of the diversity of parental care. We used a combination of underwater videography, radio telemetry and direct observation...
The ecological risks of polynuclear aromatic hydrocarbons (PAH) in aquatic sediments will vary with both toxicity and bioavailability to aquatic biota. While there are standardized protocols to test the acute toxicity of sediment-borne compounds to aquatic invertebrates, there are none...
The goal of the current study was to examine the physiological disturbances in walleyes Sander vitreus that occurred during the different phases of a live‐release angling tournament. To achieve this, we took blood and white muscle samples from walleyes during...
Tree Swallows (Tachycineta bicolor) show one of the highest levels of extra-pair mating among bird species, yet extra-pair copulations are rarely observed. Despite the suggestion that extra-pair copulations could be taking place away from nest sites, very little is known...
Fish welfare issues are increasingly appearing on social and political agendas and have recently gained prominence in fisheries literature. By focusing on examples from recreational fishing, this paper challenges some of the previous accounts of fish welfare. Issues of concern...
Phylogeographic analyses using mitochondrial DNA (mtDNA) have revealed many examples of apparently deep historical subdivisions (‘phylogroups’) within many vertebrates. It remains unclear whether these phylogroups represent independently evolving, adaptively differentiated lineages or groups that show little functional differentiation and, hence...
Sperm competition occurs when the sperm of more than one male compete to fertilize the eggs of a female. In reptiles, sperm competition is particularly prevalent and is an important agent of sexual selection in males. Spermatogenesis in reptiles can...
Many fishes are characterized by intense sperm competition between males that use alternative mating tactics. In externally fertilizing fishes, males’ proximity to females during spawning can be an important determinant of fertilization success. Here, we assess how mating tactic, body...
Identifying microhabitat preferences is important in understanding distributions of organisms and crucial to focusing conservation efforts. The Five-Lined Skink (Eumeces fasciatus) is a rock-dwelling diurnal lizard that, in Canada, is considered a species of “special concern” under the recently passed...
Females involved in extrapair mating are generally thought to obtain indirect benefits through increased offspring quality. We investigated this in the barn swallow, Hirundo rustica, a socially monogamous passerine in which females seem to have a preference for elaborately...
Foraging behavior under the risk of predation has interested biologists for decades. Here, we examine paternal genetic effects on foraging decisions of bluegill (Lepomis macrochirus) larvae sired by males adopting alternative life histories. We use split in vitro...
Like many teleosts, male bluegill sunfish (Lepomis macrochirus) provide sole parental care. To understand some of the proximate costs of parental care, we measured body condition and plasma levels of testosterone (T), 11-ketotestosterone (11KT) and cortisol...
Variation in intrauterine exposure to hormones associated with variation in the sex of litter mates has well‐established and far‐reaching effects on sexual development in some mammals. Research on this phenomenon in reptiles is scant, but suggests that lizards may follow...
Kin selection theory has been one of the most significant advances in our understanding of social behavior. However, the discovery of widespread promiscuity has challenged the evolutionary importance of kin selection because it reduces the benefit associated with helping nestmates...
Cercariae of many digenean trematodes target particular developmental stages of their hosts. For some digeneans that are parasites of amphibians, infection appears timed to host metamorphosis. The success and timing of metamorphosis is itself affected by a number of factors...
There are several examples of sex-biased parasitism of invertebrate hosts. Sex biases in parasitism could be explained by differences between males and females either in exposure to or susceptibility to parasites. Our results show that for the common spreadwing damselfly, ...
The role of sperm number and quality in male competitiveness was investigated using in vitro fertilization experiments with bluegill (Lepomis macrochirus). Bluegill males use one of three mating tactics: ‘sneakers’, which streak spawn; ‘satellites’, which mimic females; and...
Guidelines for ammonia toxicity in fish are often determined using static exposure tests with immature fish over a 96-h period. These results may not be relevant to aquaculture, hauling or angling tournament scenarios where mature fish can be exposed to...
Parental investment theory states that an individual will trade‐off present and future reproductive potential to maximize lifetime reproductive success. Only when parental care is costly in terms of reduced future reproductive potential should individuals be sensitive to changes in the...
The impact of variation in water temperature and dissolved oxygen on recovery of largemouth bass Micropterus salmoides from exercise was examined. For this, largemouth bass were first exercised and recovered for either 1, 2 or 4 h at ambient water temperatures...
We investigated the link between thermal quality and the effectiveness of thermoregulation in milk snakes in a thermally challenging environment. We defined thermoregulatory effectiveness as the extent to which an individual maintains its body temperature (Tb)...
Factors influencing habitat selection may be scale dependent, leading to different selection patterns at different spatial scales. By limiting habitat-selection studies to a single scale, important selection patterns could be missed. Despite this danger, many studies investigate habitat selection at...
Immune traits may trade off against one another, or against other life history traits such as growth, development, and reproduction. Breeding introduces additional constraints on investment in immunity that may differ for each sex. During contests for access to females...
The Cerulean Warbler (Dendroica cerulea) is currently the focus of considerable management interest; however, our ability to develop effective management strategies is hampered by a dearth of life history and basic behavioral data. Here, we present information on...
Although most habitat characteristics are known to be continuously variable in space, practicality dictates that most habitat-selection studies at the spatial scale of the territory treat within-territory habitat as essentially homogeneous. However, the limitations associated with such a compromise have...
The genetic compatibility hypothesis proposes that females should mate with genetically dissimilar males whose alleles best complement their own, resulting in greater offspring heterozygosity. It predicts that genetic similarity between social pairs will be positively related to the proportion of...
The size of achromatic (black, white, gray) plumage patches serves as a male status signal in many species of birds, but variation in the colors of these patches has received little attention. We assessed the relation between achromatic plumage reflectance...
We use the natural propensity for least flycatchers (Empidonax minimus) to form dense territorial clusters to test the hidden lek hypothesis as an explanation for clustering behavior. The hidden lek hypothesis proposes that socially monogamous males can cluster...
During live‐release angling tournaments in North America, fish are typically retained in livewells onboard boats during the angling day. Mortality of fish occurs at some tournaments, and wave intensities and livewell conditions may influence mortality levels. This study used two...
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...
Predicting ecological consequences of climate change will be improved by understanding how species are affected by contemporary climate variation, particularly if analyses involve more than single ecological variables and focus on large-scale climate phenomena. I used 18 years of data from...
Pentachlorophenol (PCP) is a general metabolic poison used extensively as a biocide in many industrial applications and as such is a contaminant in many bodies of water (Rao 1978, Jones 1981). A primary action of PCP is the uncoupling of...
To resolve conflicting field observations regarding the action of sexual selection, we used breeding experiments and paternity analysis of the 927 resulting offspring to assess how male size, condition, tail length, genetic similarity to the female, and variation in operational...
Why do females of many species mate with more than one male? One of the main hypotheses suggests that female promiscuity is an insurance mechanism against the potential detrimental effects of inbreeding. Accordingly, females should preferably mate with less related...
Sperm competition results in the evolution of ejaculate characteristics such as high sperm density, high motility, and fast sperm swimming speed. A fundamental assumption of sperm competition theory is that ejaculates with high motility and fast-swimming sperm have an advantage...
Theoretical studies have shown that variation in density regulation strongly influences population dynamics, yet our understanding of factors influencing the strength of density dependence in natural populations still is limited. Consequently, few general hypotheses have been advanced to explain the...
We investigated benefits of polyandry and phenotypic correlates of male mating success in black ratsnakes. We used 10 microsatellite loci to identify the sires of 375 hatchlings from 34 clutches with known mothers. Multiple paternity occurred in 88% of clutches...
The rapidly declining Golden-winged Warbler (Vermivora chrysoptera) is of conservation concern owing in part to hybridization with the closely related Blue-winged Warbler (V. pinus). These species hybridize extensively in eastern North America and over the past...
