Plant competition experiments commonly suggest that larger species have an advantage, primarily in terms of light acquisition. However, within crowded natural vegetation, where competition evidently impacts fitness, most resident species are relatively small. It remains unclear, therefore, whether the size...
In many species, individuals prefer mates that are genetically dissimilar at the major histocompatibility complex (MHC), likely because it improves offspring resistance to pathogens. Here, we provide the first characterization of the MHC class II peptide binding region in bluegill...
The blacklegged tick, Ixodes scapularis, is established in several regions of Ontario, Canada, and continues to spread into new geographic areas across the province at a rapid rate. This poses a significant public health risk since I. scapularis...
Water availability is a primary regulator of plant productivity and species richness in arid and semi‐arid ecosystems, but its influence in other habitats is much less clear partly because experimental manipulations of water are relatively rare. How important is...
Identifying the mechanisms of ecological change is challenging in the absence of long-term data, but stable isotope ratios of museum specimen tissues may provide a record of diet and habitat change through time. Aerial insectivores are experiencing the steepest population...
Mate choice experiments are essential to further our understanding of sexual selection, but can be challenging to design and conduct with most wild animals. 3D printing technology is creating opportunities to conduct mate choice experiments in the field by facilitating...
Competitive ability in plants is defined traditionally by a ‘size advantage’ hypothesis – i.e. larger species are generally expected to be more successful under competition because of greater capacity for resource capture, and thus capacity to deny resources to...
Despite a growing body of literature on the impacts of recreational fisheries on wild populations, surprisingly little is known regarding how individual differences in fish behaviour and their interaction with a baited hook influences hooking injury. We used an underwater...
Propagule pressure has consistently been identified as a primary factor in invader success, and reducing it can be one of the most effective methods for preventing the establishment of non-native species. However, when policy is implemented to reduce propagule pressure...
Parental care is an essential life-history component of reproduction for many animal species, and it entails a suite of behavioural and physiological investments to enhance offspring survival. These investments can incur costs to the parent, reducing their energetic and physiological...
Each remote sensing technique has its unique set of strengths and weaknesses, but by combining techniques the classification accuracy can be increased. The goal of this project is to underline the strengths and weaknesses of Synthetic Aperture Radar (SAR), LiDAR...
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...
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...
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...
In many songbirds, individuals have repertoires of multiple song types, some of which may be shared with others in the local area. Hypotheses about the evolution of song repertoires differ as to whether selection acts primarily on repertoire size itself...
Stress can have sublethal effects that are manifested either immediately or at spatial or temporal scales that are removed from the stress event (i.e., carryover effects). We tested whether a short-term elevation of plasma cortisol would result in seasonal carryover...
In North American sunfishes (Lepomis: Centrarchidae) ♂♂ build nests and provide solitary parental care for the young. In this paper I provide for bluegill (L. macrochirus) a detailed account of ♂♂ which do not build nests...
Sperm competition is widespread among animal taxa and considered a major force in sperm evolution. Recent comparative studies have indicated that sperm competition selects for high sperm production capacity and long and fast-swimming spermatozoa across species. Here, we examine the...
Laboratory-based studies of locomotory performance in many taxa have noted that individuals form stable hierarchies of organismal performance. Though laboratory studies of teleost fishes have consistently demonstrated individual repeatability of swimming performance, this phenomenon has rarely been studied in the...
Carbon sequestration in soils that have previously been depleted of organic matter due to agriculture is an important component of global strategies to mitigate rising atmospheric CO2 concentrations. Extensive areas of low productivity farmland have been abandoned from agriculture...
Lentic (i.e., lake) and lotic (i.e., river) environments differ in several biotic and abiotic variables such as water velocity, productivity, thermal regimes, and depth. These variables can interact with important factors such as sex, body size, and life-history stage to...
Male largemouth bass (Micropterus salmoides) provide sole parental care over a 4–6‐wk period to a single brood, fanning the eggs to keep them oxygenated and free of silt and defending the brood until the offspring develop antipredator tactics...
The stress response—increases in circulating glucocorticoids following a stressor—is typically considered adaptive, but few studies address the fitness consequences of individual variation in stress response. Generally, due to negative consequences of prolonged elevation of glucocorticoids, animals should have a transient...
The global decline in many species of migratory birds has focused attention on the extent of migratory connectivity between breeding and wintering populations. Stable-hydrogen isotope (δD) analysis of feathers is a useful technique for measuring connectivity, but is constrained by...
In species with extrapair mating, females may choose a social mate who will contribute to the successful raising of their brood and a sire who can enhance the genetic quality of offspring. Female choice of social mate and genetic sire...
In fish, sex determination is a plastic process regulated by a relatively small number of genes that, in turn, leads to a cascade of organism level effects. In other animal taxa, intersexual variation is widespread and has implications in the...
We examined the relationship between bait and lure size and type and body size, injury, and handling time for northern pike Esox lucius, an important recreational fisheries resource in much of North America and Europe. Bait type and size...
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...
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...
Secondary succession was documented throughout a long-term study of two abandoned hay fields in south-eastern Ontario. In one field (Field 1), eighteen plots (measuring 100 m2) were established. Nine of these plots were ploughed to bare ground and...
We observed the responses of the AN2 interneuron in the Pacific field cricket, Teleogryllus oceanicus, a cell implicated in eliciting avoidance flight away from bats, to acoustic stimuli representing the echolocation calls of bats as well as field recordings...
Hosts often differ in their degree of parasitism and their expression of resistance. Yet very little is known about how the availability (and allocation) of resources to parasites at pre-infective stages influences their success in initiating parasitism, or in inducing...
Flowering plants often exhibit declining investment in gametes, seeds, and floral organs among sequentially blooming flowers within inflorescences. However, few experimental studies have determined the relative importance of proximate underlying causes such as architectural constraints or resource competition among flowers...
Although in birds and mammals sex‐specific differences in organismal performance and physiology are well documented, comparatively little is known about the influence of sex or reproductive status on fish performance or metabolism.
In this study, the resting cardiovascular performance of...
Low frequency of reproduction among iteroparous organisms is most often observed among female ectothermic vertebrates and is thought to be a strategy used to defer reproductive costs. We assessed reproductive costs of male water snakes (Nerodia sipedon) to...
Colonial breeding can evolve in response to benefits afforded by clumped individuals, such as reduced predation and increased ease of assessing potential mates. However, colonial breeding can also impose costs such as increased disease transmission or increased cuckoldry. Here, we...
An important problem in understanding the evolution of parasite host range is determining the extent to which parasite fitness varies among host species and the factors affecting that fitness variation. We present a detailed investigation on the patterns of host...
Under sperm competition, a male’s fertilization success depends largely on the ejaculate characteristics of competing males. Theoretical models predict that, in external fertilizers, increased risk of sperm competition should result in selection for increased sperm swimming speed. To test this...
Sperm traits (morphology, motility and concentration within ejaculates) and various correlates of male quality (age, body condition, spawning location and timing) were studied in bluegill Lepomis macrochirus, breeding in both the interior and periphery of six colonies in Lake...
Conservation programs use breeding protocols to increase genomic divergence (by mating genetically dissimilar individuals) in an attempt to circumvent population declines resulting from inbreeding depression. However, disruption of either beneficial gene complexes or local genetic adaptations can lead to outbreeding...
Black ratsnakes (Elaphe obsoleta obsoleta) prey extensively on both birds (eggs and nestlings) and mammals. There is conflicting evidence, however, regarding whether the snakes specialize on birds during the birds' nesting season or whether predation on birds is...
The relationship between productivity and species diversity was investigated at the quadrat level for three old-field plant communities that varied in time since the last major disturbance from cultivation. A positive relationship between productivity (estimated by above-ground dry biomass) and...
Although alternative mating tactics are found in males of many species, little is known about tactic-specific adaptations to sperm competition and the mechanism by which fertilization success is obtained. We now report on the sperm investment patterns of males that...
A few studies have shown that male and female invertebrates differ in immunity and that these differences appear related to differences in sexual dimorphism and gender differences in life histories. Melanotic encapsulation of foreign objects in insects is one form...
Aquatic and pulmonate snails were evaluated for their suitability as biomonitors of habitat recovery following an experimental oil spill in a freshwater marshland. The mystery snail, Viviparus georgianus, and the mimic pondsnail, Pseudosuccinea columella, were used as sediment...
The purpose of this study was to determine the effects of inter-nesting spacing, proximity to forest edge, settlement and nest-building date, availability of nesting material, history of the nest-box, and nest box bird and female and male age, on both...
Although alternative mating tactics are found in males of many species, little is known about tactic-specific adaptations to sperm competition and the mechanism by which fertilization success is obtained. We now report on the sperm investment patterns of males that...
Synchronous variation among animal populations affects the vulnerability of endangered species and is relevant to understanding population fluctuation generally. We analyzed data collected over 18 years from two populations of black rat snakes (Elaphe o. obsoleta), a species...
Population ecology requires reliable population samples. We assessed sampling reliability for black rat snakes (Elaphe obsoleta) using 1724 captures obtained by two different methods: trapping at communal hibernacula and opportunistic capture of snakes at large. Recapture intervals indicated that opportunistic...
Milkweed leaf beetles (MLBs; Labidomera clivicollis Chrysomelidae) are parasitized by a subelytral mite, Chrysomelobia labidomerae (Tarsonemina: Podapolipidae). We show that C. labidomerae is transmitted between MLBs when they copulate, and can reduce the survival of nutritionally stressed beetles. We investigated...
Sexual dimorphism is a widespread phenomenon among animals (Darwin, 1871; Andersson, 1994). Differences between the sexes come in many forms, in- cluding both morphology (e.g., size, shape, coloration) and behavior (e.g., risk-taking or defensive behavior). Sexual differences in physiology also...
Genomic introgression among divergent taxa following human-mediated secondary contact is a growing concern for the management and conservation of aquatic biodiversity. We simulated the composition of taxa following admixture and hybridization by independently altering three variables: (1) initial proportion of...
We examined the availability and motility of sperm from parental and sneaker male bluegills (Lepomis macrochirus), a colonially nesting sunfish (Family Centrarchidae) with male parental care and a high incidence of cuckoldry by both sneaker and satellite males...
Studies aimed at determining why female birds often produce offspring sired by males other than their social mates generally compare traits of social and genetic mates. Here I examine paternity patterns in nests of the same female red–winged blackbirds (...
