A multiterminal neurone, recently identified at the wing-hinge of the atympanate moth Manduca sexta, is shown to respond as a proprioceptor monitoring elevatory movements of the hind wing.
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...
This study empirically tests the prediction that the echolocation calls of gleaning insectivorous bats (short duration, high frequency, low intensity) are acoustically mismatched to the ears of noctuid moths and are less detectable than those of aerially hawking bats.
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...
We investigated the ability of two congeneric species of sunfish to learn to forage on a novel prey item in feeding arenas containing structured habitats.
In a Canadian population of tree swallows, Tachycineta bicolor, DNA fingerprinting has previously shown that half of all broods contain many offspring resulting from extra-pair copulations (EPCs), whereas the other half contain only legitimate offspring.
Recordings of dawn singing by male Black-capped Chickadees (Parus atricapillus) show that each individual sings its fee-bee song at a wide range of frequencies. Males tend to repeat songs at a given frequency but on average after every 41 ±...
Sexual selection and mating systems are thought to be influenced by the relative contribution of the sexes toward production of offspring. Food abundance should influence the value of each sex's contribution to the production of offspring and, thereby, the level...
We studied the flight display of the Bobolink to determine if it functions as a signal of male quality. We tested the hypothesis that flight display is an honest signal of male quality limited by its energetic costs.
We discuss breeding options available to a floater male eastern bluebird and conclude that (1) floater male bluebirds that fill territory vacancies benefit by gaining breeding opportunities in the current breeding season, and (2) indifference to the young is the...
In phoebes, parents of small first broods are able to raise nestlings in better condition. We predict that in harsh years, parents of small first broods would be more likely to renest. Parents of enlarged first broods sacrificed quality of...
Evidence from a variety of sources, including commercial harvesters, Ministry of Natural Resources census data, and field studies, indicates that Bullfrogs in Ontario are less common now than they were in previous decades, and larger ones are particularly hard to...
We suggest that nest temperature or feeding conditions are the most likely factors influencing the differences in male incubation behavior between European and North American populations of barn swallows.
In this paper I synthesize original and published studies of sperm transfer behaviour of 23 genera of water mites from 15 families. The morphology of spermatophores from 16 genera (12 families) is described. Heaviour and/or spermatophores are described.
We demonstrate that the majority of female water snakes in a wild population mate with more than one male for each litter. Field observations indicated that a highly skewed operational sex ratio (3.6:1 M : F) during the breeding season...
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...
The coverable badge hypothesis predicts that non-territorial floaters should conceal their badges and that territory owners should expose their badges. Evidence is presented that suggests owners also benefit by concealing their badges at certain times. Forty territorial male red-winged blackbirds...
The sensory exploitation hypothesis for male courtship trembling was tested by constructing a cladogram of N. Papillator plus nine confamilial ingroup species and three outgroup species using 28 morphological and behavioural characters. Courtship and predatory behaviour were mapped onto the...
Diel and spring/summer space-use and feeding patterns were investigated in an assemblage dominated by five fish species occupying the offshore waters of Lake Opinicon, a shallow mesotrophic lake in southeastern Ontario. We assessed fish distribution and diel movement in May...
We tested whether payoff asymmetries could explain why "floater" red-winged blackbirds seldom escalate contests to acquire territories. We removed territorial male "owners" and allowed floater replacements to claim territories. We then released owners to see how three currencies of payoff...
I propose that the tymbal response in modern arctiids evolved from either flight or walking CPGs and that preadaptive circuitry ancestral to tymbal movements still exists in modern silent Lepidoptera.
In an E Ontario population of northern water snakes basking activity peaked at 09:00 then declined steadily until 14:00 before increasing again. In the field, temperatures of basking snakes averaged (±SE) 26.3 ± 0.7°C, while captive snakes in a thermal...
We examined the influence of body temperature on swimming speed of northern water snakes (Nerodia sipedon) and determined how variation in water temperature influenced their escape response.
Bluegill sunfish (Lepomis macrochirus), exposed to a 22-day subchronic exposure of pentachlorophenol at concentrations of approximately 20 and 75% of the 96-h median lethal concentration (96 h LC50), showed significant reductions in food conversion efficiency measured during the last 10...
Red-winged Blackbirds have bright red epaulets, the size of which appears to be associated with aspects of social dominance and parental behavior. Red-band effects were experimented with to see whether they effected territories, ect.
The term adoption is widely used to describe care of young by unrelated adults. However, only a few studies have quantified the amount of care provided when replacement males feed young, and the effects of this care. Twenty-five male eastern...
This paper uses three different methods to describe the morphology of bluegill of a common random genetic background reared from larvae in four experimental ponds, the fish of each pond differing in average growth rate.
Fledgling sex ratios biased in favor of the less costly sex in sexually dimorphic birds have been used as evidence in support of Fisher's theory that parents should invest equally in sons and daughters. However, such biased sex ratios are...
Male red-winged blackbirds (Agelaius phoeniceus) vary substantially in how much they sing. We tested whether song rate reflected the male’s quality, the quality of his territory, or his frequency of interaction with potential competitors. Song rate declined with...
We present a model and an experimental test for a nonshareable parental-investment behavior (fanning of eggs) using parental male bluegill sunfish. The model predicts that as brood size increases, nonshareable investment into the brood should increase if a parent is...
We present the first experiment to assess band color effects in a natural bird population. 38 territorial male red-winged blackbirds (Agelaius phoeniceus) were randomly assigned to 1 of 2 banding treatments. They received either all red bands (to...
We demonstrate that degree of parasitism by larval water mites (Arrenurus spp.) was associated with reduced condition of males and with lowered fecundity of young females of the damselfly, Enallagma ebrium (Hagen) (Odonata: Coenagrionidae). We also demonstrate that degree of...
Tree swallows engage in extra-pair copulations, creating an opportunity for sperm competition. The aim of this study was to determine whether the pattern of within-pair copulation was consistent with the use of frequent copulation by the male to assure paternity.
The identification of broad classes of DNA probes which detect hypervariable genetic markers in different taxa is invaluable for parentage analysis in wild vertebrates. Restriction-fragment-length polymorphisms, detected by hybridization of a mouse class II major histocompatibility complex (MHC) cDNA probe...
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 success per...
We sampled haematozoa in Red-winged Blackbirds (Agelaius phoeniceus) over three consecutive breeding seasons in eastern Ontario to identify factors that affect the reliability of quantifying parasites as this pertains to testing Hamilton and Zuk's hypothesis of sexual selection...
I found that single male damselflies, Enallagma ebrium, were significantly and consistently parasitized by more larval water mites than were males caught either in tandem or copula with females.
Pumpkinseed (Lepomis gibbosus) inhabiting two shallow ponds that experienced major winterkills matured 1-2 yr earlier and at a smaller size (difference >20 mrn in length) than conspecifics living in an adjacent, nonwinterkill lake.
This article presents the observations of egg laying times of American Robins and test the hypothesis that birds lay their eggs at times when they are normally inactive, because carrying a developing egg constrains female activity.
This study investigates the effects of bromocriptine, a specific dopamine receptor agonist that inhibits secretion of prolactin from the pituitary, on parental care behaviors of nesting male bluegills.
Individual variation in the foraging behaviour of the pumpkinseed sunfish was investigated under laboratory conditions in feeding arenas containing structured and open-water habitats. In general, fish learned to feed on a novel prey item over a 10-day period with both...
The recognition that infanticide, the killing of conspecific young, can hasten or even create a breeding opportunity for the infanticidal adult, has elevated the behavior from pathological to sexually selected.
We conclude that the age-correlated differences in infestation of dragonflies by mites could be a valuable method for determining relative age within odonate populations.
We demonstrate that the probability that an individual nestling received food was related to several indices of begging. When we experimentally prevented parents from feeding part of their brood, both the intensity of begging and the number of feedings subsequently...
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...
Black-capped chickadee (Parus atricapillus) adults are aggressive toward their young after the young have fledged. We examine two hypotheses to explain the function of this aggression. Eight families were observed throughout the period after fledging to see if aggressionfunctions in...
Parent birds generally eat their nestlings' feces when the nestlings are young and carry the feces from the nest as the nestlings get older. This change in behavior may be due to the decline in energy content of the feces...
Flocks of female Red-winged Blackbirds (Agelaius phoeniceus) were maintained in aviaries to determine whether variation in brightness of epaulette or chin plumage correlated with dominance status in nonbreeding situations. No correlation was found between natural plumage variation and...
We describe a technique and apparatus for extracting blood samples from birds in the field. We tested the effect of our technique on the health and behavior of captive Brown-headed Cowbirds (Molothrus ater) and free-living Red-winged Blackbirds (...
