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...
It is generally expected that small, isolated populations will suffer reduced fitness due to inbreeding, yet few studies have investigated the relation between population characteristics, inbreeding and fitness. Among Ontario populations of the short‐lived, perennial plant Aquilegia canadensis, large...
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...
Declining nest success of forest birds in fragmented habitat has been attributed to increased nest predation. Better understanding of this problem and potential solutions to it require information on why nest predators are attracted to habitat edges. Toward this end...
Molecular genetic studies have suggested that apparently nonbreeding males (‘floaters’) may account for a significant proportion of extra‐pair paternity (EPP) in avian populations. Attempts to determine the influence of breeding density on EPP are therefore confounded by the presence of...
Sociality is associated with increased risks of parasitism, predation, and social competition, which may interact because social stress can reduce immunity, and parasitized individuals are more likely to fall prey to a predator. A mechanism allowing evolution of sociality in...
Life history theory predicts that ectotherms living in warm thermal environments should mature early because of fast juvenile growth, but it is unclear whether such early maturity will occur in the absence of conditions that promote fast juvenile growth. To...
In January 1998, the worst ice storm of the last century hit regions of southeastern Ontario, Quebec, New Brunswick, and the northeastern United States. Using multiple standard regression and classification trees, we examined the ice damage in a mature, deciduous forest...
Long-term data collected from an old-field community suggest that physical and environmental patterns alone may be insufficient to account for different patterns of succession. Using a simple Lotka–Volterra model to represent competition between early and late succession guilds, we add...
Increased mortality in the presence of stress may result from stress-reduced availability of energy for immune function, coupled with the presence of pathogens or parasites. We tested the hypothesis that stress reduces antiparasite responses of damselflies Ischnuraverticalis (Hagen) to...
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...
The spawning behavior of male and female largemouth bass Micropterus salmoides (Lacépède) was studied in central Illinois during the spring of 1998 to examine patterns of muscular activity associated with different spawning related behaviors and to evaluate whether electromyogram (EMG...
Least flycatchers (Empidonax minimus) are socially monogamous birds that form tight territorial aggregations on the breeding grounds. We designed five polymorphic microsatellite loci for assigning parentage to offspring within least flycatcher clusters. The number of alleles per locus...
Population ecology requires reliable population samples. We assessed sampling reliability for black rat snakes (Elaphe obsoleta) using 1724 captures obtained by two different methods: trapping at communal hibernacula and opportunistic capture of snakes at large. Recapture intervals indicated that opportunistic...
Milkweed leaf beetles (MLBs; Labidomera clivicollis Chrysomelidae) are parasitized by a subelytral mite, Chrysomelobia labidomerae (Tarsonemina: Podapolipidae). We show that C. labidomerae is transmitted between MLBs when they copulate, and can reduce the survival of nutritionally stressed beetles. We investigated...
Sperm competition is a major force in sexual selection, but its implications for mating–system and life–history evolution are only beginning to be understood. The well–known sneak–guard model predicts that sneaks will win in sperm competition. We now provide empirical confirmation...
We examined habitat selection by breeding Cerulean Warblers (Dendroica cerulea) at three spatial scales in eastern Ontario over three years (1997–1999). Territories were characterized by well-spaced large trees, with high canopies and dense foliage cover at heights between...
We studied the effects of catch‐and‐release angling on rock bass Ambloplites rupestris a small but common centrarchid species in North America. A field study of hooking injury and mortality was conducted in Lake Erie at a water temperature of 16°C...
A general model in thermal ecology predicts that ectotherms should stop thermoregulating when the costs outweigh the benefits. Support for this model comes from studies of warm‐temperate species, but the extent to which the model can be extrapolated to species...
Mites belonging to several unrelated groups are commonly found in freshwater habitats. The true water mites comprise a taxon of actinedid acariform mites, which is referred to as Hydrachnidiae. Hydrachnidiae have flourished to become by far the most numerous...
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...
Chironomid (Diptera: Chironomidae) head capsules were studied from a core of recent sediments from shallow, macrophyte-dominated Lake Opinicon, Ontario, Canada, to determine if assemblages have changed in response to lake-level changes and other watershed disturbances, including deforestation and agriculture. Our...
The fitness consequences of self‐fertilization are largely determined by how self‐pollination occurs. Within‐flower self‐pollination (autogamy) may be advantageous, since it can provide reproductive assurance without much seed or pollen discounting. In contrast, between‐flower self‐pollination (geitonogamy) provides no reproductive assurance and...
While studying the nesting ecology of black snake rats ( Elaphe obsoleta [Say]; snakes : Colubridae) in eastern Ontario, we discovered that their eggs were very well protected by the Nicrophorus pustulatus (Herschel) (Coleoptera: Silphidae). The beetle appears to be parasitoid of the...
This study investigated the accuracy of 50-m fixed-radius, 100-m fixed-radius, and variable circular-plot point counts to estimate the actual density of breeding Cerulean Warblers (Dendroica cerulea) during the 1997 and 1998 breeding seasons, in Ontario, Canada. Density estimates were compared...
We stored blood samples of Eastern Phoebes (Sayornis phoebe) in a lysis buffer (“QLB”) that has been used successfully to preserve blood samples of many other species. We found that although samples from adults were not affected greatly...
Directional asymmetry (DA) has received considerably less attention than fluctuating asymmetry (FA) in the literature. Evidence for DA, however, is building among insect taxa. We examined asymmetries in two wing traits within both sexes of the damselfly Calopteryx maculata (Beauvois)...
Patterns of divorce and extrapair mating can provide insights into the targets of female choice in free-living birds. In resident, site-faithful species with continuous partnerships, the better options and the incompatibility hypotheses provide the most likely explanations for divorce. Extrapair...
