Male alternative reproductive tactics have been described in many mating systems. In fishes, these tactics typically involve a territorial male that defends a spawning site or nest and a parasitic male that uses sneaking or female mimicry to steal fertilizations...
Parasites are thought to play a role(s) in the evolution of host traits. Evidence for their roles comes from studies examining parasite-mediated selection. Odonates are model insects and water mites and gregarine protozoans model parasites, for such investigations. These parasites...
According to the maternal manipulation hypothesis, females manipulate the phenotypes of their offspring by selecting favourable incubation conditions. In oviparous black ratsnakes (Elaphe obsoleta Say in James, 1823), females manipulate offspring phenotype through nest-site selection. This study aimed to determine whether...
Recreational boating continues to grow in popularity, yet little is known about the effects of noise disturbance from boating on fish. Therefore, this study evaluated the organism‐level cardiovascular disturbance associated with different recreational boating activities using largemouth bass (Micropterus...
We investigated whether the use of primary or secondary behavioural defences is related to prey sensory thresholds using two species of North American katydids, Neoconocephalus ensiger and Amblycorypha oblongifolia. Male katydids produce intense calling songs to attract mates, and...
Sexually dimorphic traits often reflect factors limiting the reproductive success of animals. Thus, most sexually dimorphic traits can be directly linked to the reproductive role of each sex. Sexual dimorphism in trophic structures (e.g. beak, jaws, teeth), however, often lacks...
The decline of Golden-winged Warblers (Vermivora chrysoptera) has been attributed in part to hybridization with a sister species, the Blue-winged Warbler (V. pinus), which lacks the black throat patch typical of the Golden-winged Warbler. Understanding the signal function...
Male songbirds typically mate-guard by closely following the female during her fertile period. At dawn, males may sing near the nest or roost to direct their chorus at mates. Recent evidence suggests males may also be involved in singing interactions with...
Elemental concentrations in tree-rings from red and white oak trees at six sites across Southern Ontario, Canada, were assessed to determine whether they passively record changes in geochemical cycling in the presence of environmental stress. Periods of stress were defined...
Elemental concentrations in tree-rings from red and white oak trees at six sites across Southern Ontario, Canada, were assessed to determine whether they passively record changes in geochemical cycling in the presence of environmental stress. Periods of stress were defined...
The warty birch caterpillar Drepana bilineata produces two distinct types of vibrational signals (mandible drumming and anal scraping) during interactions with conspecifics. Vibrational signalling is characterized using standard and high‐speed videography synchronized with laser‐doppler vibrometry, and behavioural experiments test the...
Certain tiger moths (Arctiidae) defend themselves against bats by phonoresponding to their echolocation calls with trains of ultrasonic clicks. The dogbane tiger moth, Cycnia tenera, preferentially phonoresponds to the calls produced by attacking versus searching bats, suggesting that it...
How females allocate resources to each offspring and how they allocate the sex of their offspring are two powerful potential avenues by which mothers can affect offspring fitness. Previous research has focussed extensively on mean offspring size, with much less...
The influence of body size on metabolic rate, muscle enzyme activities and the underlying patterns of mRNA for these enzymes were explored in an effort to explain the genetic basis of allometric variation in metabolic enzymes. We studied two pairs...
A whole-lake acoustic telemetry array was utilized to monitor the three-dimensional position of 20 largemouth bass (Micropterus salmoides). Code division multiple access (CDMA) technology enabled the simultaneous monitoring of the 20 transmitters (equipped with pressure and temperature sensors)...
Increasing anthropogenic pollution from urban centers and fossil fuel combustion can impact the carbon and nitrogen cycles in forests. To assess the impact of twentieth century anthropogenic pollution on forested system carbon and nitrogen cycles, variations in the carbon and...
Many animals exhibit pronounced shifts in ecology (e.g., habitat use, diet) as they grow. The central goal of this study was to determine whether habitat use and movement patterns of juvenile black ratsnakes (Elaphe obsoleta) differed from patterns...
Blue‐winged (Vermivora pinus) and golden‐winged warblers (Vermivora chrysoptera) have an extensive mosaic hybrid zone in eastern North America. Over the past century, the general trajectory has been a rapid replacement of chrysoptera by pinus in a...
Understanding the causes of variation in feather colour in free-living migratory birds has been challenging owing to our inability to track individuals during the moulting period when colours are acquired. Using stable-hydrogen isotopes to estimate moulting locality, we show that...
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...
This study evaluated how different angling practices affect the short‐term post‐release behaviour of nest‐guarding male black bass, Micropterus spp. Male largemouth bass, M. salmoides (Lacepède), and smallmouth bass, M. dolomieu(Lacepède), were angled from their nests and subjected to treatments...
At present, there is a reasonable understanding of the independent effects of catch-and-release (C&R) angling stressors, such as air exposure and water temperature, on endpoints such as physiological disturbance, behavioural impairment and mortality. However, little is known about the multiplicative...
The mating system of flowering plant populations evolves through selection on genetically based phenotypic variation in floral traits. The physical separation of anthers and stigmas within flowers (herkogamy) is expected to be an important target of selection to limit self‐fertilization...
This study was intended to discover whether forcing largemouth bass (Micropterus salmoides) to swim at 0.5 body lengths/second following exercise would expedite recovery relative to fish recovered in static water. Exercise resulted in a suite of physiological disturbances...
Recent attention has focused on genetic compatibility as an adaptive function for why females engage in extrapair mating. We tested the genetic compatibility hypothesis in tree swallows (Tachycineta bicolor) over five breeding seasons using data from ten microsatellite...
A whole‐lake acoustic telemetry observatory situated in eastern Ontario was used to continuously monitor the three‐dimensional position of 20 largemouth bass (Micropterus salmoides) over a 120‐h period during the winter and a separate 120‐h period during the early...
Foraging behaviour under the risk of predation has important consequences on an individual's survivorship and fitness. In bluegill (Lepomis macrochirus), we have recently shown that offspring sired by males of alternative life histories differ in their foraging behaviour...
Continent-wide variation in hydrogen isotopic composition of precipitation is incorporated into animal diets, providing an intrinsic marker of geographic location at the time of tissue growth. Feathers from migratory birds are now frequently analyzed for stable-hydrogen isotopes (δD) to estimate...
Despite the fundamental role played by long-distance dispersal in population dynamics, the mechanisms promoting or inhibiting dispersal by migratory songbirds are poorly understood. We used stable-hydrogen isotopes (δD) to evaluate several long-distance dispersal hypotheses in the Cerulean Warbler ( Dendroica cerulea...
For the past three years, our research group has monitored the behaviour and activity of largemouth bass (Micropterus salmoides) year-round at the Warner Lake Ecological Observatory (WLEO) in eastern Ontario. The core of the WLEO is a novel...
Individual variation in morphology has been linked to organismal performance in numerous taxa. Recently, the relationship between functional morphology and swimming performance in teleost fishes has been studied in laboratory experiments. In this study, we evaluate the relationship between morphology...
Past studies of offspring sex ratios in birds have often relied on sexually size dimorphic species where nestling sex could be determined based on weight at a given age. DNA‐based sexing techniques allow us to assess the accuracy of those...
We examined two components of reproduction in a population of golden-winged warblers in the initial stages of hybridization with blue-winged warblers. First, we used genetic analyses of mate choice to determine whether copulations outside the social pairbond (extra-pair copulations; EPCs)...
We studied parental provisioning rates and nestling body condition in an introgressed population of Golden-winged Warblers (Vermivora chrysoptera) in eastern Ontario. Twelve nests were monitored until the young fledged; six nests were parented by phenotypically pure Golden-winged Warbler males and...
Complex birdsong is a classic example of a sexually selected ornamental trait. In many species, females prefer males with large song repertoires, possibly because repertoire size is limited by the size of song control nuclei which reflect developmental success. We...
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...
