In seasonal environments animals organize their behaviour around annual cycles of resource availability. Wild black-capped chickadees are most likely to hoard food in autumn. At this time of year chickadees are also reported to have a larger hippocampus, a brain...
The fee-bee song of male black-capped chickadees (Poecile atricapillus) is considered a single-type song that singers transpose up and down a continuous frequency range. While the ability to shift song pitch in this species provides a mechanism for...
My general goal in this paper was to quantify both the precision and accuracy of snout-to-vent length measurements in black ratsnakes, a large constricty colubrid.
Using near-infrared videotaping we measured the nocturnal flight times of six species of eared moths (Amphipyra pyramidoides Guenée, Caenurgina erechtea (Cramer), Feltia jaculifera (Guenée), Phlogophora periculosa Guenée, Lymantria dispar (Linné), and Ennomos magnariaGuenée) in cages in which they...
Quantifying and documenting succession has been a challenge to ecologists for many years. A variety of measures have been generated but do not seem to have been widely adopted. We propose the use of an intuitive and quantifiable measure that...
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...
It is widely argued that defended prey have tended to evolve conspicuous traits because predators more readily learn to avoid defended prey when they are conspicuous. However, a rival theory proposes that defended prey have evolved such characters because it...
In animals where males engage in signalling interactions, females might evaluate male–male contests to inform their reproductive choices. We used interactive playback to engage territorial male black-capped chickadees (Poecile atricapillus) of known dominance status in countersinging contests with...
THE TREE SWALLOW (Tachycineta bicolor) has been the focus of a diversity of research that is rivaled by few other bird species. A quick search through the Science Citation Index reveals over 400 manuscripts either focusing on or involving...
Rainbow smelt (Osmerus mordax) is a recent invader to the lakes of the Hudson Bay drainage in northwestern Ontario, Canada. In some systems, the invasion has been linked to an increase in mercury (Hg) concentration in native predatory...
Female colour polymorphism in coenagrionid damselflies is genetically determined for the 4 spp. so far studied. No size differences between (female) morphs have been reported. In another sp., size differences between morphs do exist but the genetic basis of the...
Implementation, validation and first implementation of ultrasonic cardiac transmitters in Micropterus salmoides largemouth bass. Although many studies report the use of transmitters for telemetry of heart rate ( f C) in fish, few studies provide sufficient detail to allow rapid...
Leptocerid caddisflies have a wide variety of case forms, and therefore it might seem difficult to establish behavioral homologies at the family or generic levels. We videotaped case building in representatives of 9 genera in 8 leptocerid tribes and compared...
Retene (7‐isopropyl‐1‐methylphenanthrene) is a naturally formed polycyclic aromatic hydrocarbon (PAH) that causes teratogenicity in fish larvae and induction of cytochrome P450 (CYP1A) enzymes. Retene occurs at high concentrations (≤3,300 μg/g dry wt) in surface sediments contaminated by resin acids from...
We present direct experimental evidence of pheromone use in six species of Arrenurus and indirect evidence for four species, including members of the subgenera Megaluracarus, Truncaturus, and Arrenurus. Water in which females were housed elicited arrestant behaviour in...
This study investigated how demographic characteristics of black rat snakes Elaphe obsoleta are affected by the length of the active season, and also used the resulting demographic data to determine the proximate factors responsible for male‐biased sexual size dimorphism (SSD)...
Paleolimnological analysis of microfossils and physical sediment characteristics in 210Pb and Ambrosia dated sediment cores, along with diatom-inferred total phosphorus concentration [TP] reconstructions, were used to determine the trophic histories (ca 200 years) of four lakes within the Rideau Canal...
Intra- and interspecific contact rates of 12 adult (five females, seven males) raccoons (Procyon lotor) were recorded while these animals fed at a rural garbage dump 40 km north of Kingston, Ontario, Canada from 15 June to 5...
We tested for predator-induced plasticity in development and growth of embryos and young tadpoles of green frogs (Rana clamitans). We expected to observe developmental plasticity in response to the leech, Macrobdella decora, because the leech represents a high, but unpredictable, risk...
Many evolutionary models and empirical studies of parasite‐host interactions consider single species of parasites exploiting single host species. However, many parasites are generalists in that they parasitize more than one host species (often many more) and establish associations with other...
Mating in plants is usually mediated by animals, yet few studies have determined whether the mating system of plant populations changes in response to variation in the taxonomic composition or to the foraging behavior of animal pollinators. Here, I investigate...
We present experimental evidence for a water-borne female-produced sex pheromone in aquatic parasitengonine mites. Water that has contained adult female Arrenurus manubriator Marshall will elicit arrestant behaviour in conspecific adult males, and if the cue is sufficiently strong, the males...
Male song reflects the quality of the singer in many animals and plays a role in female choice of social and copulation partners. Eavesdropping on male-male vocal interactions is a means by which females can compare different males’ singing behavior...
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...
Thermoregulation is thought to be the most important factor influencing habitat selection by terrestrial ectotherms, at least in temperate climates. The cost‐benefit model of thermoregulation predicts that ectotherms should invest more in thermoregulation when the costs of doing so are...
Parasites may be expected to become locally adapted to their hosts. However, while many empirical studies have demonstrated local parasite adaptation, others have failed to demonstrate it, or have shown local parasite maladaptation. Researchers have suggested that gene flow can...
Variation in immune responsiveness within and among species is the subject of the emerging field of ecological immunology. The work reported here showed that individuals of Lestes forcipatus Rambur differ in their likelihood of mounting immune responses, and in the...
Gene flow is fundamental to evolutionary processes but knowledge about movements of individuals and their offspring necessary for gene flow is scant. We investigated potential ecological components of genetic connectivity within a population of black rat snakes (Elaphe obsoleta...
Male northern water snakes (Nerodia sipedon) have high variance in reproductive success relative to females. We used DNA-based paternity analyses from a 3-year study of two marsh populations of water snakes to investigate the factors that contribute to...
Male smallmouth bass (Micropterus dolomieu) and largemouth bass (Micropterus salmoides) care for their offspring from fertilization until the offspring disperse after becoming capable of avoiding predators. We used activity transmitters to monitor round-the-clock parental activity of...
Understanding how life histories influence reproductive success under uncertain conditions is necessary to predict population dynamics. For many organisms, protracted reproduction may increase expected offspring recruitment in variable environments, requiring that temporal patterns of reproduction be considered when developing management...
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...
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...
A newly developed flight simulator allows monarch butterflies to fly actively for up to several hours in any horizontal direction while their fall migratory flight direction can be continuously recorded. From these data, long segments of virtual flight paths of...
Hypolimnetic oxygen depletion has been accelerated in many lakes due to cultural eutrophication. However, the extent and magnitude of environmental change is difficult to ascertain due to the lack of historical records. Larval Chironomidae (Diptera) are useful proxy indicators of...
We describe age‐related reproductive performance and recapture rates of tree swallows (Tachycineta bicolor Vieillot) based on a 25‐year study of a nestbox population in south‐eastern Ontario, Canada (1975–99).
Performance improved from first‐time breeders to intermediate‐aged birds. Nest initiation advanced...
Most physiological processes are temperature‐dependent. Thus, for ectotherms, behavioural control of body temperatures directly affects their physiology. Ectotherms thermoregulate by adjusting habitat use and therefore thermoregulation is probably the single most important proximate factor influencing habitat use of terrestrial reptiles...
Otolith analyses were used to back‐calculate young‐of‐the‐year (YOY) yellow perch Perca flavescens hatch‐date estimates to interpret broad length distributions observed within a small Great Lake, Lake St. Clair, and a small inland lake, Lake Opinicon, during 1998. For the Great...
Large‐scale natural habitat disturbances can play major roles in structuring the distribution of individuals and ecosystems, and can exert substantial selective pressures. The magnitude of these effects depends on the spatial and temporal scale of the disturbance, as well its...
Three previous studies have disagreed on whether breeding synchrony increases nest success through reduced nest predation in Red‐winged Blackbirds (Agelaius phoeniceus) in eastern North America. We used data from an 11‐yr study of redwings in eastern Ontario, Canada...
We provide evidence for conspecific acoustic communication in caterpillars. Larvae of the common hook-tip moth, Drepana arcuata (Drepanoidea), defend silk nest sites from conspecifics by using ritualized acoustic displays. Sounds are produced by drumming the mandibles and scraping the mandibles...
Mean daily mobility estimates for smallmouth bass Micropterus dolomieu from mark‐recapture (47·5±12·5 m) were less than from conventional telemetry (77·1±10·6 m). The relationship developed in a respirometer between the activity transmitter and swimming speed (r2=0·99, P < 0·001, ...
Lake eutrophication is a problem in many areas of Ontario, although the history of nutrient enrichment is poorly documented. The aim of this study was to construct a diatom-based transfer function to infer past phosphorus levels in Ontario lakes using...
We measured the 24-h flight activity patterns of 84 species of Nearctic Lepidoptera representing 12 ultrasound-earless and seven ultrasound-eared families to examine the evolution of the diel flight periodicities (DFPs) and auditory defences of these insects. Most species tested showed...
Theories of parental care evolution predict that genetic relatedness will be an important variable in the amount of care a parent provides. However, current inferences of relatedness–based parental investment from studies in humans and birds remain challenged. No study has...
