Host behaviour should be a key determinant of the acquisition of “sit-and-wait” and nidicolous ectoparasitic arthropods that ambush the host in their environment and/or nest. Here, we tested the association between parasitism and individual differences in exploratory and grooming behaviours...
We observed the number of basking female Graptemys geographica (northern map turtles) at 4 basking sites before and after controlled motorboat disturbances using time-lapse cameras. In the 6 hrs following disturbance, the mean number of turtles basking at a site...
Physiologically, oxidative stress is considered a homeostatic imbalance between reactive oxygen species production and absorption. From an ecological perspective, oxidative stress may serve as an important constraint to life-history traits, such as lifespan, reproduction and the immune system, and is...
Commercially available electrosedation apparatuses (e.g., the Smith‐Root Portable Electroanesthesia System [PES]) are growing in popularity within the fisheries research community. This technology can be used to immobilize fish rapidly and does not require a withdrawal period before fish are released...
In species that provide parental care, care for offspring is often accompanied by an increase in locomotor activity and a decrease in feeding opportunities which can negatively impact endogenous energy reserves. Depletion of parental energy stores and declines in nutritional...
Do the transcriptional mechanisms that control an individual's mitochondrial content, PGC1α (peroxisome proliferator-activated receptor γ coactivator-1α) and NRF1 (nuclear respiratory factor-1), also cause differences between species? We explored the determinants of cytochrome c oxidase (COX) activities in muscles from 12...
Mitochondrial content, central to aerobic metabolism, is thought to be controlled by a few transcriptional master regulators, including nuclear respiratory factor 1 (NRF-1), NRF-2 and peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α). Though well studied in mammals, the mechanisms by which these...
Within crowded natural plant populations, the traditional prediction is that most of the offspring from which future generations are drawn will be contributed by the relatively few individuals belonging to the larger size classes. Yet, the extent to which this...
Defence against parasites and pathogens can be essential, yet not all hosts respond similarly to parasitic challenge. Environmental conditions are thought to explain variation in host responses to parasites.
Lestes forcipatus damselflies emerging later in the season have shown higher...
During vocal contests, animals alter both the timing and the patterning of responses to their opponents. Time-specific responses (such as overlapping an opponent's song) and pattern-specific responses (such as matching the type of an opponent's song) may reveal information about...
Immune ability and immune expression have been viewed as life-history traits that are influenced by such factors as the likelihood of being parasitized, intensity and costs of parasitism, and trade-offs associated with immune expression. In this paper we show that...
We used sequential removal experiments to test whether the resource-holding potential (RHP) of territory “owner” red-winged blackbirds, Agelaius phoeniceus, was superior to that of their first replacements (“shallow floaters”) and subsequent replacements (“deep floaters”). Among the removals were secondyear...
A new method to mark sperm transfer events between birds, using microspheres inserted into males' cloacae, was employed to assess the frequency of extra-pair copulation in a population of tree swallows in Ontario, Canada.
(1) The sensitivity of replacement-series experiments to variations in density was investigated in Agropyron repens, Phleum pratense and Poa pratensis collected from a hayfield in south-eastern Ontario, Canada. All pairwise combinations of species were grown in a replacement-series design...
In an eastern Ontario population of red-winged blackbirds, Agelaius phoeniceus, some males were unsuccessful in obtaining a breeding territory and consequently existed as 'floaters'. However, not all floaters were inferior to territory owners with respect to two morphological correlates...
The lichen flora was sampled at each of the five sites on a near-vertical gneiss rock face. The sites were ranked according to the degree of weathering of the rock surface and were taken to represent different stages in a...
Darwin proposed that the function of the stamen‐style polymorphism in heterostylous plants is to increase the probability of legitimate (compatible) pollinations among the floral morphs. Conspicuous pollen trimorphism in tristylous Pontederia cordata enables a test of the hypothesis. Comparison of...
A semi‐quantitative method is described for the determination of free sugars in lake sediments. The method involves extraction with 70% ethanol, deionization with ion exchange resins, and separation and estimation of the sugars on paper chromatograms. The following sugars were...
