Decontaminating recreational watercraft, and fishing, sailing or watersports equipment after use can reduce the overland dispersal of aquatic invasive species (AIS) among lakes. Recommended methods include pressure-washing, rinsing with hot water, using cleaning agents, or air-drying, but the extent of...
As species shift their ranges and phenology to cope with climate change, many are left without a ready supply of their preferred food source during critical life stages. Food shortages are often assumed to be driven by reduced total food...
According to the traditional “Size Advantage” (SA) hypothesis, plant species with larger body size are expected to be more successful when competition is intense, that is, within severely crowded vegetation. Recent studies in old‐field habitats, however, have shown that those...
We examined whether particular years of mast seed production in sugar maple (Acer saccharum) are associated with increased likelihood of cohort recruitment success into the sapling stage over three decades of heavy browsing pressure from white-tailed deer in...
Glucocorticoid hormones facilitate responses to environmental challenges by mediating diverse physiological and behavioral changes, including resource mobilization and altered reproductive effort. Elevated glucocorticoids might indicate that an individual is facing high levels of environmental challenges and thus, elevated concentrations might be associated with...
Colonist quantity, quality, and arrival frequency can all individually drive the dynamics and extinction of new populations. However, we do not understand which has the strongest influence, nor the circumstances under which their relative importance may change. We conducted a...
Aposematism is an evolved, cross-species association between a preys’ unprofitability and the presence of conspicuous signals. Avian predators have been widely employed to understand the evolution of these warning signals However, insect predators are abundant, diverse, and highly visual foragers...
The selection consequences of competition in plants have been traditionally interpreted based on a “size‐advantage” hypothesis – that is, under intense crowding/competition from neighbors, natural selection generally favors capacity for a relatively large plant body size. However, this conflicts with...
The capture of non-target species is a conservation issue in many commercial fisheries. Bycatch reduction devices (BRDs) are commonly used as mitigation tools to improve selectivity of fishing gear and thus reduce bycatch. The aim of this paper was to...
Regulation of the hypothalamic–pituitary–adrenal (HPA) axis is a key component of the vertebrate stress response. Prior studies have found that variation in HPA responses were correlated to measures of fitness and physiological condition. In addition, sexually-selected traits have also been found to...
Using a long-term study population of wild smallmouth bass Micropterus dolomieu in a connected river-lake system, we investigated whether circulating glucocorticoid (cortisol) and androgen (testosterone) concentrations are influenced by reproductive investment and nesting environment in fish providing nest-guarding paternal care...
Female choice for male ornamental colouration has been demonstrated in a number of different taxa. Among fishes, most studies have been conducted in a laboratory setting and show that females prefer more colourful male ornaments. In this study, we observed...
Researchers are becoming interested in testing whether investment in growth and/or development trades off against investment in parasite defence. We tested this idea by examining relations between development of Wood Frogs (Rana sylvatica) and susceptibility to lung nematodes (Rhabdias ranae)...
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...
We examined whether differences among hosts in timing of emergence of phenotypic attributes might affect their probability of return to an emergence pond, and hence success of mites.
We examined the relationship between non-polar lipid density, parasite density and paternity of male bluegill sunfish, Lepomis macrochirus, and four condition factors: (1) Fulton’s condition factor, K; (2) the relative condition factor, Kn; (3) the relative mass index, Wr; and...
Toward the end of the breeding season, migratory songbirds face crucial tradeoffs between the timing of reproduction, molt, and migration. Using stable hydrogen isotopes, we show that male American redstarts investing in high levels of reproduction late in the season...
Water mites (Acari: Hydrachnida) are unusual among the typically cryptic freshwater fauna in that many species are brightly colored red or orange, and also appear to be distasteful to fish. This apparent aposematism (use of color to warn...
Avian populations often consist of breeding residents and nonbreeding floaters. It is usually assumed that floaters are lower-quality individuals that do not reproduce, but floater tactics and potential reproductive success have rarely been examined carefully. To assess the potential reproductive...
We tested the responses of two bird species which nest on unmovable substrates (e.g., cavities and walls) to simulated and actual egg damage in their nest. Tree Swallows (Tachycineta bicolor) and Barn Swallows (Hirundo rustica) removed...
The size and shape of the black bib in Black-capped Chickadees varies among individuals and may signal information about age and sex, as found in other species with similar plumage badges. By photographing and measuring bibs of wintering adults in...
We used morphological and breeding data from a 2-year field study of red-winged blackbirds (Agelaius phoeniceus) to test the hypothesis that males characterized by low levels of bilateral asymmetry (i.e., high developmental competence) realize a reproductive advantage. Specifically...
We investigated the relative effects of low pH and high iron on a water mite, Arrenurus manubriator and an aquatic insect, Chironomus riparius. Eggs and active stages were exposed in static renewal toxicity tests to pH 6, 5, 4...
Depending on the circumstances under which extra-pair mating occurs, theory makes opposing predictions about how reproductive synchrony should influence extra-pair paternity. This study investigated which sex initiated extra-pair mating in the yellow warbler, whether extra-pair behaviour and extra-pair paternity were...
Least flycatchers (Empidonax minimus) and American redstarts (Setophaga ruticilla) overlap in the use of food resources on their breeding grounds, promoting high levels of interspecific aggression by the socially dominant flycatcher. We examined the role of...
Earlier studies have shown that extracts from pollen of Phleurn pratense reduce pollen germination and seed set in Elytrigia repens (L.) Nevski (Poaceae), but the effect of in situ pollen from P. pratense on seed set in E. repens in...
Increased disease and parasitism are a well-documented cost of group living for colonial birds and mammals, but we now show that disease in offspring of fish may be reduced by nesting in colonies. The aquatic fungus Saprolegnia sp., which is...
We recorded variation in body size and ventral plumage coloration in a population of individually marked Eastern Phoebes. We found no significant difference in percentage gray area between males and females.
The call of male Scudderia curvicauda (Orthoptera: Tettigoniidae) consists of a series of phrases, and each phrase contains syllables. Females respond to the male signal with ticks that follow male phrases after a specific period of time. Pair formation takes...
In this paper I examine the relative abundance of N. Putulatus in an eastern Ontario burying beetle community, as well as its reproductive behavior in the laboratory. My goal is to provide information aimed at improving our understanding of competitive...
Black-capped Chickadee (Parus atricapillus) song consists of two pure tonal notes: "fee bee" (see NORM in Fig. 1). Frequency descends during the fee note (termed glissando), and there is a drop in frequency between the fee and the bee (termed...
Hypervariable genetic markers, including a novel locus-specific marker detected by a mouse major histocompatibility complex probe, reveal that multiple paternity is common in families of polygynous red-winged blackbirds (Agelaius phoeniceus). Almost half of all nests contained at least...
Two groups of largemouth bass, Micropterus salmoides, were reared in the laboratory. One group was reared on an artificial, passive diet (frozen brine shrimp) whereas the second was reared on a natural, active diet (cultured zooplankton). Observations on the...
Laboratory studies were conducted on 15 schools of blackchin shiners, Notropis heterodon, to determine if they altered their structure in response to changing environmental demands. The hypothesis tested was that fish schools should sacrifice a flat, hydrodynamically efficient structure...
The comment by Peck on our note "A double-brooded Eastern Kingbird" brings up a valid point. Since the female involved was not banded, we cannot be absolutely sure that the same female was responsible for both nests.
Risks taken by female red‐winged blackbirds (Agelaius phoeniceus) in defence of their young were recorded for individuals with differing past investment but identical expected benefits. Investment was manipulated by switching clutches of equal size between nests differing in...
The use of frequency, duration, and patterns of frequency change over time to identify 39 species of North American and African bats by their search phase echolocation calls is described. The data were obtained from an oscilloscope display of the...
Responses of nonflying moths to ultrasound: the threat of gleaning bats. Can. J. Zool. 59: 525-529. Stationary and walking tympanate moths (Arctiidae, Geometridae, Noctuidae, and Notodontidae) exhibited discrete behavioural responses to electronically simulated bat echolocation calls. The presence of a...
We played a variety of sounds to Myotis lucifugus occupying a New Hampshire barn in August 1975 using a recording and playback system which reproduced sounds from 15 to over 100 kHz. The M. lucifugus responded to 'distress' calls of...
Eastern chipmunks (Tamias striatus) were studied in Algonquin Park in 1968 and at Chaffey's Lock, Ontario, in 1969 and 1970, employing a combination of trapping, marking, and systematic observation. Spring breeding occurred in all years. No summer breeding...
A reversed-phase thin-layer chromatographic (TLC) procedure using layers of Kieselguhr G impregnated with triolein, castor oil or paraffin oil is described. Eighteen identified and eight unknown derivatives of chlorophylls a, b and c can be resolved from the parent...
Nesting preference for areas cleared of woody debris over areas cluttered with such debris was indicated by more nesting in cleared areas at the beginning and end of the breeding season, and more spawning activity in cleared areas. During heavy...
Raised three species of Peridea in sealed petri dishes and jars. Described feeding habits, the success of raising these species in captivity, and the various life stages.
Measures of physiological response of northern largemouth bass to various temperatures were taken to ascertain the degree of adaptation of the bass to its environment. These measures include hemoglobin, red-cell count, arterial blood oxygen, oxygen capacity, and lactic acid. The amount...
