Closely related species that use similar resources often differ in their seasonal patterns of activity, but the factors that limit their distributions across seasons are unknown for most species. One hypothesis to explain seasonal variation in the distributions of species...
Parental care can include two general types of behavior: (1) aggressive behavior, which is used to defend offspring from predators; and (2) nurturing behavior, which is used to provide offspring with environmental conditions or resources necessary for survival. Many studies...
Bythotrephes longimanus is an invasive zooplankton predator, negatively impacting zooplankton abundance and diversity in North American lakes. Previous studies have shown that Daphnia populations in lakes move to deeper waters during the day, in the presence of Bythotrephes, a...
The immunosuppressive effects of androgens are a key component of the immunocompetence handicap hypothesis (ICHH). Here, we use bluegill sunfish (Lepomis macrochirus) to test two predictions arising from this hypothesis: (1) natural circulating concentrations of the androgen 11-ketotestosterone...
Chronic, low‐intensity parasite infections can reduce host fitness through negative impacts on reproduction and survival, even if they produce few overt symptoms. As a result, these parasites can influence the evolution of host morphology, behaviour and physiology. The physiological consequences...
Understanding the trade-offs that affect potentially adaptive traits is fundamental to our understanding of evolutionary diversification and speciation. Heterogeneous landscapes may lead to spatial variation in such traits among populations as they may experience different selective pressures. In this study...
The nonconsumptive consequences of predators on prey behavior, survival, and demography have recently garnered significant attention by ecologists. However, the impacts of top predators on free-ranging prey are challenging to evaluate because the most common fright response for prey is...
Through manipulations of sensory functions, researchers have evaluated the various mechanisms by which migratory fish, particularly in lotic systems, locate natal spawning grounds. Comparatively less work has occurred on the ways by which fish in lentic systems locate spawning sites...
Populations of invasive species tend to have fewer parasites in their introduced ranges than in their native ranges and are also thought to have fewer parasites than native prey. This ‘release’ from parasites has unstudied implications for native predators feeding...
The potential role of alternative reproductive tactics in circumventing premating isolating mechanisms and driving hybridization between species has long been recognized, but to date there is little empirical support from natural systems. Hybridization occurs between bluegill (Lepomis macrochirus)...
Male parental care in vertebrates often involves both defensive and nurturing behaviors. Whether androgens differentially mediate these two types of behaviors, or a trade-off exists between them, has been studied by behavioral endocrinologists for years but predominantly in species with...
We conducted an experiment using freshwater painted turtles (Chrysemys picta) to determine if keeping turtles out of water for an hour enhances anoxia recovery following a simulated bycatch event in nets (i.e., 12 hrs of submergence at 25°C). Traditional...
Bycatch of turtles in passive inland fyke net fisheries has been poorly studied, yet bycatch is an important conservation issue given the decline in many freshwater turtle populations. Delayed maturity and low natural adult mortality make turtles particularly susceptible to...
Freshwater turtles are susceptible to drowning in commercial fishing nets and this is a major conservation concern. Methods to mitigate turtle bycatch mortality typically involve reducing the capture of bycatch using gear modifications. Another method to reduce mortality is to...
Anthropogenic noise can mask animal signals that are crucial for communicating information about food, predators and mating opportunities. In response to noise masking, signallers can potentially improve acoustic signal transmission by adjusting the timing, frequency or amplitude of their signals...
Evidence that infectious diseases cause wildlife population extirpation or extinction remains anecdotal and it is unclear whether the impacts of a pathogen at the individual level can scale up to population level so drastically. Here, we quantify the response of...
Moths and butterflies flying in search of mates risk detection by numerous aerial predators; under the cover of night, the greatest threat will often be from insectivorous bats. During such encounters, the toxic dogbane tiger moth, Cycnia tenera uses the...
The quality of winter territory can have important consequences for migratory songbirds throughout the year. In the American Redstart (Setophaga ruticilla), a warbler in which plumage maturation is delayed, yearling males winter in a variety of habitat types...
Auditory sensitivity has often been measured by identifying neural threshold in real-time (online) which can introduce bias in the audiograms that are produced. We tested this by recording auditory nerve activity of the notodontid moth Nadata gibbosa elicited by bat-like...
Ricklefs and O’Rourke compared the diversity of appearance (aspect diversity) in samples of moths attracted to ultraviolet lights in Colorado, Arizona, and Panama. The more species‐rich Panamanian assemblage of moths exhibited proportionately greater diversity of color and form, which supported...
The ultrasonic clicks produced by some tiger moths — all of which possess bat-detecting ears — are effective acoustic aposematic or mimetic signals, conferring protection against aerial hawking bats. Clicks are produced in response to bat echolocation calls. Palatable, silent non-tiger-moth species...
We tested a common prediction of the thermal coadaptation hypothesis in the Northern Map Turtle (Graptemys geographica), an aquatic emydid with pronounced aerial basking. We measured the effect of body temperature on two locomotor performances (swimming and righting) to determine...
Certain tiger moths (Arctiidae) defend themselves against bats by phonoresponding to their echolocation calls with trains of ultrasonic clicks. The dogbane tiger moth, Cycnia tenera, preferentially phonoresponds to the calls produced by attacking versus searching bats, suggesting that it...
How females allocate resources to each offspring and how they allocate the sex of their offspring are two powerful potential avenues by which mothers can affect offspring fitness. Previous research has focussed extensively on mean offspring size, with much less...
The influence of body size on metabolic rate, muscle enzyme activities and the underlying patterns of mRNA for these enzymes were explored in an effort to explain the genetic basis of allometric variation in metabolic enzymes. We studied two pairs...
A whole-lake acoustic telemetry array was utilized to monitor the three-dimensional position of 20 largemouth bass (Micropterus salmoides). Code division multiple access (CDMA) technology enabled the simultaneous monitoring of the 20 transmitters (equipped with pressure and temperature sensors)...
To understand variation in resistance to parasites within host populations, researchers have examined conditions under which immunity is induced and/or is costly. Both host sex and age have been found to influence immune expression and subsequently are likely factors influencing...
Blood sampling is useful for the study of behavior, ecology, and physiology. Here we describe this technique, report our success, and discuss its advantages over the previously described techniques.
The genetic compatibility hypothesis proposes that females should mate with genetically dissimilar males whose alleles best complement their own, resulting in greater offspring heterozygosity. It predicts that genetic similarity between social pairs will be positively related to the proportion of...
The size of achromatic (black, white, gray) plumage patches serves as a male status signal in many species of birds, but variation in the colors of these patches has received little attention. We assessed the relation between achromatic plumage reflectance...
We use the natural propensity for least flycatchers (Empidonax minimus) to form dense territorial clusters to test the hidden lek hypothesis as an explanation for clustering behavior. The hidden lek hypothesis proposes that socially monogamous males can cluster...
Although the evasive flight of eared moths to attacking bats has received much attention in the literature, no studies have been made of the potential costs for this behaviour. We examined the fate of moths that land upon the surface...
Evidence is reported for size‐dependent (allometric) gender allocation in the monoecious, wind‐pollinated annual Ambrosia artemissifolia. Consistent with established theory, the pattern of allometry displayed adaptive plasticity, depending on the environmental cause of variation in plant size. Plant size gradients...
The sub‐lethal effects of catch‐and‐release angling have been poorly studied because of the difficulties in monitoring physiological parameters in free‐swimming fish. Laboratory studies provide the opportunity to examine sub‐lethal effects in controlled environments, but do not incorporate site‐specific characteristics. In...
Molecular techniques have allowed researchers studying mating systems to determine the identity of extra-pair sires, providing more accurate measures of individual realized reproductive success. Yet, an existing problem in such studies is the inability to assign paternity to individuals that...
The thermal coadaptation hypothesis predicts that (1) ectotherms experiencing a narrow range of body temperatures in the wild will evolve to perform well over a narrow range of body temperatures and that (2) the optimal temperature for performance will be...
We investigated the mating patterns in 22 breeding pairs of wild American goldfinches (Carduelis tristis) with respect to their body size, condition, and carotenoid-based, yellow plumage colour. Using reflectance spectrometry, we objectively quantified plumage colours across the bird-visible...
The simple auditory system of noctuoid moths has long been a model for anti-predator studies in neuroethology, although these ears have rarely been experimentally stimulated by the sounds they would encounter from naturally attacking bats. We exposed the ears of...
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...
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...
Syrinx is a newly developed PC-based software package designed for interactive playback of animal vocalizations and for digital sound recording and analysis in the lab or in the field. Syrinx permits flexible modeling of complex vocal interactions in an interactive...
While studying the nesting ecology of black rat snakes (Elaphe obsoleta [Say]; Serpentes: Colubridae) in eastern Ontario, we discovered that their eggs regularly contained larvae of the burying beetle Nicrophorus pustulatus (Herschel) (Coleoptera: Silphidae). The beetle appears to be...
If the primary function of ultrasound-sensitive ears in Lepidoptera is to detect the echolocation calls of insectivorous bats, diurnal species should exhibit signs of ultrasonic deafness. To test this hypothesis we recorded the 24-h (diel) flight activity of a sample...
Brown recently proposed that the “good genes” that females pursue when choosing mates may be individual heterozygosity because more heterozygous mates sire offspring with higher fitness. Further, because heterozygosity might enhance developmental stability, males with more heterozygosity are recognized by...
In an experimental study in Denmark, it was previously found that male barn swallows (Hirundo rustica) with elongated tail streamers obtained an apparent fitness advantage through earlier pairing, an increased frequency of second clutches, and higher total reproductive...
Chemical lights and gelatin capsules prepared using Cyalume® fluid are widely used by researchers and public educators to mark bats, but may be associated with risks to bats from Cyalume leakage. Newly available 2.9-mm x 24-mm lightsticks weigh significantly less...
Here we report a male Prairie Warbler (Dendroica discolor) that was found singing a repertoire of both Prairie Warbler and Black-throated Green Warbler (Dendroica virens) songs, and we describe its response to playback of Black-throated Green Warbler song.
In vitro studies were performed to quantify the qutative allelopathic effect of pollen from Phleum pratense (Aveneae: Poacetae). Extract from ground pollen was paritioned, using ion-exchange chromatography.
In this study, we used pumpkinseed populations in two east-central Ontario lakes to test for age and size-dependent effects on the probability and timing of reproduction of mature females.
Flowering occurrence and allozymic variation were studied in eight local populations of Lemna minor in eastern Ontario, Canada. After 2 years of survey, not a single flower was observed. This absence of flowering suggests the possibility of loss of sexual...
We investigated whether nestling American robins were capable of influencing food distribution in their nests by perceiving that certain sectors of the nest received a relatively high proportion of feedings and positioning themselves accordingly.
We performed an experiment to investigate effects of red leg bands on the behavior of male Red-winged Blackbirds (Agelaius phoeniceus). We presented models having either black, blue, or red leg bands to territorial male Red-winged Blackbirds to test the hypothesis...
We suggest that low-altitude erratic flight in moths is a protean insurance defence against bats, as it should reduce the chance of their being detected by these predators.
Many of the sunfishes (Centrarchidae) hybridize in natural systems, yet little is known about the interactions among hybridizing individuals in nature. We used allozyme electrophoresis to identify interspecific hybrids between bluegill (Lepomis macrochirus) and pumpkinseed (L. gibbosus) in Lake Opinicon...
