Male sunfishes build nests and provide care for eggs spawned therein. It is shown here that small non-nesting male pumpkinseed and bluegill will intrude during conspecific spawnings, to fertilize eggs. Such behaviour cuckolds the males which care for the brood.
We have compared the echolocation and feeding behaviours of Myotis lucifugus, M. californicus, M. volans, and M. auriculus based on observations and recordings of bats in the field. Myotis lucifugus and M. californicus...
Analysis of the clicks produced by some arctiid moths shows that their acoustic characteristics (power spectra and frequency–time structures) are remarkably similar to those of frequency-modulated echolocation calls produced by many bats as they close with their prey. We suspect...
Macroinvertebrate populations associated with Myriophyllum exalbescens, Potamogeton richardsonii, and Vallisneria americana were compared with those on plastic ‘plants’ similar in morphology to P. richardsonii. The density of organisms varied according to macrophyte species (Myriophyllum ≫ Potamogeton > ...
The purpose of this study was to determine whether parental investment decisions are made on the basis of cumulative past investment or the prospects of expected benefits minus costs. Through clutch size manipulations at nests of Redwinged Blackbirds, Agelaius phaeniceus...
1. As part of an overall study of the social behavior of the little brown bat, Myotis lucifugus, we compiled the vocal repertoire of this gregarious species in its natural habitat. Ten vocalizations were identified and associated with certain behavioral...
The purpose of this study was to determine whether the yellow warbler (Dendroica petechia) derives any benefits from nesting in close proximity to its own and other species in reducing predator pressure or the incidence of brood parasitism...
The ears of moths we tested in Canada and CSte d'Ivoire are most sensitive to sounds between 20 and 40 kHz, and much less sensitive to sound over 65 kHz. The insectivorous bats most commonly encountered in these (and other)...
Analysis of the stomachs of 2435 pumpkinseeds (Lepomis gibbosus) showed that the diet was made up largely of chironomid larvae, molluscs, isopods, with lesser quantities of amphipods, Trichoptera larvae, and Ephemeroptera nymphs. Cladocera were only important to the...
The histology and carbohydrate histochemistry of eight teleostean stomachs are compared. Three gross anatomical types of stomachs are described and their shapes appear to correlate somewhat with feeding habits. Each type can be divided histologically into a corpus and pylorus...
Analysis of the fish faunas of Lake Opinicon and other small, cold temperate Ontario water bodies shows that the component species differ in body size, morphology, abundances, habitats, diurnal and seasonal habitat utilization patterns, diets, dietary changes with age, reproductive...
Seventeen of the 24 species of Nearctic Arctiidae which we examined produced sounds under a variety of tactile and acoustic stimuli. Seven of 14 sound-producing species tested emitted their sounds in response to the hunting cries of insectivorous bats or...
A comparative study of the diets of five year classes of perch in Lake Opinicon showed Year class 0 to be mainly Cladocera feeders, the Year class II to take a diversified range of insect larvae, whereas from Year class...
The submerged macrophyte community of Lake Opinicon was sampled by a combination of quadrats and line transects in 1972 and 1973. Mean organic biomass was 248 g -m2 with a range of 1 to 1 154 g -m2 ...
Measurements made in shallow lakes and tanks have shown that temperatures near and at the surface of substrates respond significantly to changes in solar radiation, water circulation and substrate color. Temperature differences between light and dark colored natural and artificial...
Changes in aggressive responsiveness to 5 stimulus dummies (Normal, Aggressive, and Subordinate sunfish, Pike, and Minnow) over the 4 periods (Nesting, Spawning, Brooding, and Vacating) of the reproductive phase were studied in 49 ♂ ♂ over two seasons in the...
A survey of fish distribution relative to depth in Lake Opinicon, Ontario, using the strip count method showed 80–90% of the biomass to be concentrated along the lake margins at a depth of up to 2.5 m.
The relationships between harem size, territory size, nest site suitability, and fledging success were studied for a breeding population of redwinged blackbirds (Agelaius phoeniceus). Reproductive success was correlated negatively with female breeding density within territories and positively with...
Behavioral tests using freeze-dried female Red-winged Blackbird models were conducted on 11 territorial males through one breeding season. The intensity of courtship in the tests reflected recruitment success but not territory quality, indicating that those male attributes associated with territory...
The lepidopteran family Arctiidae contains a number of species that emit high frequency sounds when tactually stimulated or exposed to the intense hunting cries of insectivorous bats. The sounds are produced as rapidly repeated clicks generated by the buckling action of...
The strip count method of determining fish densities was investigated for a small lake in a series of inshore sites that differed in their physical and biological characteristics and in the communities of fishes present. Overall total numbers of fish...
The histology and carbohydrate histochemistry of ten teleostean esophagi were compared. Structurally, the four layers of a typical vertebrate digestive tract were consistently present. The epithelium was always stratified and in all but one species (Ictalurus nebulosus) contained taste buds.
Results of a survey of the submerged aquatic macrophytes in 16 sites in southeastern Ontario varying widely in geology and nutrient status are presented. Where comparisons could be made, species were generally found within the same range of specific conductivities...
The arctiid, Cycnia tenera Hiibner exhibits no sexual dimorphism in six out of seven acoustic parameters measured in the sounds emitted by five male and five female specimens. The parameters reveal an extremely high level of variability for both male...
The social calls of 14 Myotis lucifugus (5 adult males; 5 adult females; 2 subadult males; 2 subadult females) produced under controlled conditions were more variable than echolocation calls made by hunting individuals in the wild. The social calls contained...
Cluster analysis of hybridizing Lepomis gibbosus (pumpkinseedsl and L. macrochirus (bluegills) collected in Lake Opinicon, Ontario, using data on 20 morphological characters in 108 specimens, revealed three groups, the two parental species and a group of hybrids, all of which...
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...
The effect of the insecticide methoxychlor (2,2-bis(p-methoxyphenyl)-1,1,1-trichloroethane) on photosynthetic carbon assimilation by natural phytoplankton populations was determined by incubation of plankton samples in situ at a 1.0-metre depth with [14C]bicarbonate for 4-h periods with or without...
Garbage dumps are at present unavoidable and have considerable impact on areas where they are located. Darlington (1969) reviewed some of the potential effects of dumps, including the inhibition of plant growth by altering soil composition and permeability, and by...
Aggression to model brown-headed cowbirds measured at nests of 34 potential host species shows a positive correlation with rate of parasitism. The data are used to test two hypotheses: (1) that aggression functions as an antiparasite defense reducing parasitism, and...
On clear days the temperature in a mat of floating Lemnaceae was 40 to 11° above that of the surface of the open water. The temperature of the environment 2 cm above or below the plant surface closely followed the...
By analysis of feces collected from bats in the field, we determined that aquatic insects, particularly chironomid Diptera, made up the major portion of the diet of Myotis lucifugus at sites in southern Ontario, northern New York, and Nova Scotia...
Drawing on work with passerine birds, investigations on the self‐selection of photoperiod in a constant environment by pumpkinseed sunfish (Lepomis gibbosus) capable of controlling their lighting have been carried out. Each aquarium with lighting equipment was set up in a...
The effects of interspecific competitive encounters have traditionally been viewed in terms of species replacement, but recent workershave recognised the importance of weak or diffuse competition, which leads only to reduced niche volume. Evidence of such niche restriction...
This paper is a report of some of our efforts to increase knowl- edge about the feeding ecology of insectivorous bats. It includes some consideration of what insectivorous bats eat, structure in bat faunas, the role of activity in resource...
Ecological investigations of the pitcher plant sarcophagid fly (Blaesoxipha fletcheri) indicate that larvae of this species are highly aggressive. The ecological basis of the larval behavior and spacing system is examined in terms of resource utilization. The unusual...
Acetylene reduction by bacteria in the rhizosphere of Glycerin borealis and Typllrc sp. was studied under anaerobic and aerobic conditions. Under anaerobic conditions, when roots and rhizomes were incubated with rhizosphere sediments at 25'C without glucose, acetylene reduction to ethylene...
Free-swimming larvae of five perciform species were collected with tow nets in large numbers in Lake Opinicon from May to August of 1969 and 1970. The species appeared in the same seasonal sequence during the 2 yr: first yellow perch (...
An electronic system for monitoring activity of some echolocating bats in the field is described. An ultrasonic receiver is used to detect the bat cries. Audio-frequency signals from the receiver are processed and converted by the system to characteristic marks...
This study presents data on rates of food and water ingestion by captive Myotis lucifugus and Eptesicus fuscus, the size of prey selected by bats and the culling of insect parts by captive E. Fuscus prior to ingestion.
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...
Structure in the aerial-feeding bat faunas of southeastern Ontario, southern British Columbia, Cameroun, Guyana, and the Philippines is demonstrated on the basis of wing shape and relative ear size. The former is derived from the ratio of the length of...
In equilibrated metamorphic rocks containing coexisting garnet, cordierite, quartz and sillimanite, the exchange of iron and magnesium between cordierite and garnet offers a highly favourable geological thermometer and barometer, because this exchange reaction is insensitive to pressure. Thermodynamic analysis shows...
Nocturnal activity of bats over different environments may be measured using a heterodyning device which converts the ultrasonic echolocating cries to audible "clicks." Preliminary results obtained by this method indicate that bats are more active over lakes than over streams...
The purpose of this paper is to compare and contrast the morphology and ecology of these two species of mice that have evolved in and now inhabit areas with widely different climatic characteristics. Data for P. Leucopus were taken from...
The deciduous teeth of Myotis lucifugus and the sequence of their replacement by the permanent teeth are described. Juveniles possessing erupted adult dentitions were capable of flight and, for the first time, had insect remains in their digestive tracts.
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.
"Swarming" refers to the summer nocturnal flights through hibernacula by the five species of bats known to hibernate locally. A total of 6400 bats was handled during studies of swarming at 10 hibernacula in Ontario and Quebec from 1966 to...
The feeding periodicities of five common cohabiting fish species in Lake Opinicon, Ontario, were defined for the early summer period of accelerated feeding by determining the mean weights of stomach contents per gram of body weight at intervals of 2–3 hr...
In Lake Opinicon, Ontario, the diet of the black crappie, Pomoxis nigromaculatus, undergoes a progressive change from one in which planktonic Crustacea and small-bodied Diptera larvae predominate (in fish of body length from about 60 to 115 mm), to a...
In the course of the rearing program it was found that certain species either prefer food plants other than those recorded in the literature or refuse those which are commonly thought to be preferred.
