Nesting structures are important for successful reproduction in most birds, and, because of this, geographic variation in nest morphology and composition are usually interpreted as adaptations to breeding in different environments. We compared the structure of nests of Yellow Warblers...
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...
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...
Although host parasite interactions can affect the ecology and distribution of species, virtually nothing is known about range-wide variation in haematozoan levels in North American birds. We investigated haematozoan prevalence and parasitemia in 112 adult male cerulean warblers (Dendroica...
We used data collected over 3 years at two study sites to quantify the rates and consequences of multiple paternity and to determine the opportunity for selection on male and female northern water snakes (Nerodia sipedon). We sampled...
The transition from outcrossing to self-fertilization is one of the most common evolutionary trends in plants1. Reproductive assurance, where self-fertilization ensures seed production when pollinators and/or potential mates are scarce, is the most long-standing and most widely accepted...
Gender in flowering plants is governed by a complex interplay of genetic and environmental factors. The perennial aquatic herb Sagittaria latifolia displays remarkable variation within and among populations in gender expression, from monoecious populations composed of plants with differing numbers...
Fish have some of the most complex mating systems known in the animal kingdom. With the advent of powerful genetic markers and an emerging mathematical framework to calculate parentage, it is now possible to analyze genetic relatedness and gene flow...
Traditional population genetics theory assumed that at some level in the hierarchy of genetic diversity there existed 'demes' in which males and females mate at random. Polygynous mating systems or individual variance in reproductive success were considered complications which altered...
We used data from a nine-year study to assess how these factors contribute to female-biased sexual size dimorphism in males, although both sexes approached their asymptotic size at the same rate.
DNA‐based methods of determining parentage in birds have revealed that apparent reproductive success can be very different from true reproductive success. Our main goal in this study was to provide estimates of true annual and lifetime reproductive success of male...
We examined the geographic distribution of biochemical genetic and life history characteristics of 16 populations of pumpkinseed Lepomis gibbosus within four east-central Ontario watersheds to determine (1) if populations within watersheds were more alike for either of these traits than...
In colonies of bluegill, some males provide parental care for broods in nests, whereas other males steal fertilizations and do not provide parental care. Using experimental pond populations of bluegill of known genotype (determined through protein electrophoresis), we demonstrate that...
I collected data on 27 pumpkinseed populations in eastern and central Ontario and conducted a transplant experiment with one of those populations to test growth competition-related predictions of several life history models.
Sexual selection and mating systems are thought to be influenced by the relative contribution of the sexes toward production of offspring. Food abundance should influence the value of each sex's contribution to the production of offspring and, thereby, the level...
Growth energy build‐up and partitioning by immature bluegill sunfish were studied over the summer months from May to September 1984. Fish sampled in May showed low condition and low lipid reserves. Condition was restored to summer levels within the following...
Growth in the first summer of life was compared in nine coexisting fish species with different life history strategies. Relative to hatching size, the various species grew 6- to 10-fold in length and up to 1000-fold in weight. Growth patterns...
During 1960 and 1961 we studied periodically flooded wetlands dominated by the trees Larix laricina, Thuja accidentalis, and Ulmus americana along transects from lake margins to the upland in the Rideau Lakes Region of Ontario. This vegetation shows distinct belts...
