Showing papers in "Canadian Journal of Zoology in 1988"
TL;DR: It is concluded that if the error rate of the X variable is thought to be more than a third of that on the Y variable, then the reduced major axis method is preferable; otherwise the least squares technique is acceptable.
Abstract: Most biologists are now aware that ordinary least square regression is not appropriate when the X and Y variables are both subject to random error. When there is no information about their error va...
569 citations
TL;DR: The free-ranging dive pattern of seven adult female northern elephant seals (Mirounga angustirostris) was obtained with time–depth recorders during the first 14 – 27 days at sea following lactation, setting a depth record for pinnipeds.
Abstract: The free-ranging dive pattern of seven adult female northern elephant seals (Mirounga angustirostris) was obtained with time–depth recorders during the first 14 – 27 days at sea following lactation...
317 citations
TL;DR: The metabolic response of penguins and domestic geese to fasting has been studied in detail and it is shown that large birds, in contrast to small species, do not become torpid when they are fasting.
Abstract: Various bird species regularly fast in connection with breeding, migration, or drastic climatic conditions. The metabolic response of penguins and domestic geese to fasting has been studied in deta...
298 citations
TL;DR: Behavioral ecology uses general principles of economic design to generate testable predictions for animal activities in particular environmental situations to study Sociobiology and optimal foraging.
Abstract: Behavioral ecology uses general principles of economic design to generate testable predictions for animal activities in particular environmental situations. Sociobiology and optimal foraging, the t...
293 citations
TL;DR: The frequency of occurrence of brood amalgamation in North American anatids is analyzed and the hypotheses that have been proposed to explain these behaviours are reviewed to erect a theoretical framework which applies to these behaviours.
Abstract: Two forms of brood amalgamation occur frequently in several species of North American waterfowl: (i) pre-hatch brood amalgamation, whereby a female lays her eggs in the nest of another female and t...
219 citations
TL;DR: To evaluate availability of food for passerine birds in a northern hardwood forest, the abundance and distribution of Lepidoptera larvae on the foliage of the dominant tree species and the foraging behaviour used by birds to capture prey from foliage substrates were measured.
Abstract: To evaluate availability of food for passerine birds in a northern hardwood forest, we measured the abundance and distribution of Lepidoptera larvae, a major food type, on the foliage of the domina...
214 citations
TL;DR: A green biotype of the pea aphid, A. pisum, from Lusignan (France), showed very poor performance on the standard Akey and Beck diet, but significant improvement occurred after reduction of the osmotic pressure of the diet and modification of the amino acid component, according to the results of carcass analysis.
Abstract: A green biotype of the pea aphid, A. pisum, from Lusignan (France), showed very poor performance on the standard Akey and Beck diet. Significant improvement occurred after reduction of the osmotic ...
179 citations
TL;DR: Recent studies with newer sampling methods indicate that the biomass of coelenterates, particularly large scyphomedusae, has been underestimated and much quantitative work needs to be done on the underestimation.
Abstract: Coelenterates may be predators or prey of fish, act as intermediate hosts for parasites, or provide shelter. At least 42 species of fish, including such commercially important species as the spiny ...
167 citations
TL;DR: Threespine sticklebacks (Gasterosteus aculeatus L.) parasitized by the cestode Schistocephalus solidus (Miiller) have a greater need for energy than uninfected fish, and therefore should be hungrie...
Abstract: Threespine sticklebacks (Gasterosteus aculeatus L.) parasitized by the cestode Schistocephalus solidus (Miiller) have a greater need for energy than uninfected fish, and therefore should be hungrier and more willing to compromise safety from predation for foraging gains. We hypothesized that the magnitude of this trade-off is directly related to the fish's parasite load (i.e., energy requirement) and food abundance. After being frightened by a model heron, sticklebacks fled shorter distances, remained motionless and cryptic for shorter periods, returned sooner to forage in a food patch near the predator, and remained active longer in the patch with increasing parasite load. The correlations of these responses with fish parasite load were significant most consistently at the highest food density tested, and suggest that the fish were taking a greater risk of predation with an increasing level of parasitic infection, particularly when the potential energetic gain from foraging was high. On average, the fish...
163 citations
TL;DR: The pivotal incubation temperature (that giving 50% of each sex) was estimated for two clutches of eggs from loggerhead sea turtles nesting in each of three areas along the east coast of America.
Abstract: The pivotal incubation temperature (that giving 50% of each sex) was estimated for two clutches of eggs from loggerhead sea turtles (Caretta caretta) nesting in each of three areas along the east c...
144 citations
TL;DR: The decline of phylogenetically based explanations of behavioural evolution is mirrored by the decline in the utilization of behavioural data in systematic analyses, and the tendency of many researchers to confuse character maintenance (stasis) with character origin and divergence (evolution).
Abstract: Early comparative ethologists stressed both phylogenetic (historical) and environmental (selection) factors when searching for explanations of behavioural evolution. The last two decades have witne...
TL;DR: Alevin survival to emergence was high for all species, except for coho and pink salmon at 14 °C, and coho salmon hatched and emerged sooner at all temperatures than the other species.
Abstract: Embryo and alevin survival, time to hatching and emergence, and alevin and fry size of five species of Pacific salmon (Oncorhynchus) were observed at five incubation temperatures (2, 5, 8, 11, and ...
TL;DR: It is suggested that long-term cardiac growth in rainbow trout involves both hyperplasia and hypertrophy.
Abstract: Relative ventricular mass, percent compact myocardium, total protein, DNA content, and myocyte size were determined for rainbow trout, Salmo gairdneri, ranging in size from 10 to 2000 g. Ventricular mass, ventricular total protein, and DNA content increased linearly with body size. The DNA to protein ratio was reduced slightly over a 100-fold range of body size. Myocyte size increased with heart size. However, the estimated 1.7-fold increase in myocyte volume for a 10-fold increase in heart weight was incompatible with a corresponding 10-fold increase in total protein. Since DNA content increased 10-fold it is suggested that long-term cardiac growth in rainbow trout involves both hyperplasia and hypertrophy.
TL;DR: It is found that in seals exercising in the laboratory, that as increased, heart rate during breathing bouts was high and unchanging, and the fraction of time seals spent breathing and overall average heart rate increased with exercise.
Abstract: In terms of a seal's success as a predator, the ability to spend a high fraction of time submerged and yet remain in a steady state is at least as important as that to make long dives. This aspect of seal physiology has received much less attention than has the ability to dive for extended periods and yet is important to the context in which dive-related morphological and physiological specializations are considered. We found, in seals exercising in the laboratory, that as increased, heart rate during breathing bouts was high and unchanging. Heart rate during dives was 25 to 33% of the rate during breathing and was insensitive to metabolic rate. However, the fraction of time seals spent breathing and overall average heart rate increased with exercise. We have confirmed these patterns using very high frequency and acoustic telemetry in freely diving harbour seals in the open sea. Heart rate at the surface was virtually constant at 120 beats/min and independent of dive duration. While the seals were diving,...
TL;DR: Indirect calorimetry was used to estimate metabolic rates and critical dissolved oxygen concentrations for steelhead at intervals between fertilization and complete yolk exhaustio...
Abstract: Indirect calorimetry was used to estimate metabolic rates and critical dissolved oxygen concentrations for steelhead (Salmo gairdneri) at intervals between fertilization and complete yolk exhaustio...
TL;DR: The within-season decline in clutch size was not due simply to replacement clutches or female age, and it is argued that it is also not due to a decrease in food abundance over the breeding season.
Abstract: In many species of birds, clutch size decreases as the season progresses, but this is confounded by the fact that young birds not only often have smaller clutches but also breed later than older females. We examined the effect of time of season on clutch size, hatching success, and fledging success of female tree swallows (Tachycineta bicolor) in their second year (SY) and after their second year (ASY), and compared their reproductive performance while controlling for time of season. For both SY and ASY females, clutch size decreased significantly with later first egg dates, which caused number hatched and number fledged per brood to also decline as the season progressed. However, neither the proportion of eggs hatched nor the proportion of young fledged was correlated with first egg date. The within-season decline in clutch size was not due simply to replacement clutches or female age, and we argue that it is also not due to a decrease in food abundance over the breeding season. Age-related differences i...
TL;DR: Comparing the ratios of herring to sprat otoliths in faeces of captive California sea lions and South American fur seals with the ratios at feeding showed no consistent differences in recovery rates and partial digestion of Otoliths.
Abstract: Analysis of teleost sagittal otoliths contained in scats has been widely used to determine the diet of seals. This method is based on the assumption that relative frequencies of otoliths in scats faithfully reflect those offish in the diet. This assumption has rarely been tested experimentally. We compared the ratios of herring (Clupea harengus) to sprat (Sprattus sprattus) otoliths in faeces (output) of captive California sea lions (Zalophus californianus) and South American fur seals (Arctocephalus australis) with the ratios at feeding (input). Sea lions and fur seals showed no consistent differences in recovery rates and partial digestion of otoliths. Output ratios deviated only slightly from input ratios, the smaller sprat otoliths being underrepresented in the output by 8%. Only about 40% of the otoliths fed to the seals were found in the scats. For both species partial digestion of otoliths led to a 16% underestimation of fish length and a 35% underestimation of fish mass.
TL;DR: Grasshopper assemblages were sampled by sweep net in native tallgrass prairie at Konza Prairie, Kansas, in 1982 – 1986 to assess the influences of fire, topography, and vegetation on local species.
Abstract: Grasshopper assemblages were sampled by sweep net in native tallgrass prairie at Konza Prairie, Kansas, in 1982 – 1986 to assess the influences of fire, topography, and vegetation on local species ...
TL;DR: This field study examined the effects of the developmental stage of offspring on patterns of brood defense in parental male smallmouth bass and found that parental defense increased as offspring progressed from egg to wriggler stages, and peaked before fry "swim-up" from the nest.
Abstract: Life history models of parental care predict that parents should adjust their level of defense to reflect the increasing value of current offspring relative to their own expected future reproduction. This field study examined the effects of the developmental stage of offspring on patterns of brood defense in parental male smallmouth bass (Micropterus dolomieui). Conspecific models of equal length (±1 cm) were used to elicit two defense behaviours: bite and jaw display (a threat display). Parental defense increased as offspring progressed from egg to wriggler (hatched embryos) stages, and peaked before fry "swim-up" from the nest. Parental defense decreased after swim-up. This pattern of brood defense conforms with the life history model of parental care through a brood cycle. Four alternative hypotheses to the life history model are discussed (habituation to the model, nest conspicuousness, food value of offspring, and repeated success in nest defense); each is inadequate in accounting for the observed pa...
TL;DR: Patterns of pigmentation of the post dorsal fin patch, or saddle patch, were analyzed from photographs of 372 resident and 99 transient killer whales from British Columbia, Alaska, and Washington State and suggest genetic isolation of the populations.
Abstract: Patterns of pigmentation of the post dorsal fin patch, or saddle patch, were analyzed from photographs of 372 resident and 99 transient killer whales (Orcinus orca) from British Columbia, Alaska, and Washington State. Of the five types of saddle patch analyzed, all were observed on residents, but only two occurred on transients. Differences in saddle patch shapes were independent of age and sex. Saddle patch pigmentation patterns were similar among clans within a community. Pigmentation patterns differed significantly between the resident and transient forms, between northern and southern residents, between northern and Alaskan residents, and between southern and Alaskan residents. As the saddle patch shape may be heritable to a large degree, these differences suggest genetic isolation of the populations. If so, this technique may be used to delineate stocks of killer whales from other areas.
TL;DR: Twenty-four woodland caribou in the mountains and foothills of west central Alberta were radio collared to obtain information on seasonal movements, location and extent of seasonal ranges, rutting and calving areas, and population status.
Abstract: Twenty-four woodland caribou (Rangifer tarandus caribou) in the mountains and foothills of west central Alberta were radio collared to obtain information on seasonal movements, location and extent ...
TL;DR: A review of the ecology of amphipods belonging to the superfamily Talitroidea (Crustacea, Amphipoda) is presented, and subjects discussed include taxonomy, life history, dispersal, and the ecological factors affecting the survival of shore hoppers.
Abstract: A review of the ecology of amphipods belonging to the superfamily Talitroidea (Crustacea, Amphipoda) is presented. Species of Talitroidea are characteristically able to hop by rapid flicks of the urosome. They include land hoppers, which are true land-inhabiting forms excluded from detailed consideration in this review, as well as aquatic Talitroidea. Aquatic Talitroidea are found throughout much of the world in freshwater, estuarine, and marine conditions in littoral and infralittoral habitats, and an ecological habitat classification is presented. Subjects discussed include taxonomy, life history, dispersal, and the ecological factors affecting the survival of shore hoppers. The synecological role of shore hoppers in the aquatic ecosystem, e.g., in mineralizing primary production, is relatively minor although it may be locally important. The evolutionary ecology of land hopper origins from ancestors resembling shore hoppers is discussed, in the absence of direct evidence, based on likely colonization ro...
TL;DR: Molt was significantly protracted in all White-crowned Sparrows except the 60% premolt group as a result of both increased shedding interval and decreased feather growth rates.
Abstract: It has often been alleged that avian molt can be interrupted or delayed by food deprivation or malnutrition. We examined this experimentally in captive White-crowned Sparrows (Zonotrichia leucophrys gambelii). Beginning either at the natural onset of postnuptial molt or 1 month before its onset, groups of birds were fed either inadequate amounts of a balanced diet (60 or 80% of the ad libitum intake of a control group) or unlimited amounts of a diet deficient only in cyst(e)ine and methionine. Except in the 60% premolt group, the malnourished birds did not postpone or interrupt molt in spite of losses ranging from 20 to 38% of initial body mass. Molt was significantly protracted in all except the 60% premolt group as a result of both increased shedding interval and decreased feather growth rates. Their new plumage weighed less than that of control birds, and their remiges were slightly shorter and often deformed or achromatic. The occurrence of fault bars corresponded to the times when the birds were hand...
TL;DR: An important implication of the results is that managers should not allow moose densities to decline to low levels, because grizzlies can have a greater relative impact on low- than on high-density moose populations and grizzly predation rates were independent of moose density.
Abstract: Radio-collared grizzly bears (Ursus arctos) were sighted daily for approximately 1-month periods during spring, summer, and fall to estimate predation rates. Predation rates on adult moose (Alces alces) were highest in spring, lowest in summer, and intermediate in fall. The highest kill rates were by male grizzlies killing cow moose during the calving period. We estimated that each adult male grizzly killed 3.3–3.9 adult moose annually, each female without cub(s) killed 0.6–0.8 adult moose and 0.9–1.0 adult caribou (Rangifer tarandus) annually, and each adult bear killed at least 5.4 moose calves annually. Grizzly predation rates on calves and grizzly density were independent of moose density and are probably more related to area-specific factors, e.g., availability of alternative foods. An important implication of our results is that managers should not allow moose densities to decline to low levels, because grizzlies can have a greater relative impact on low- than on high-density moose populations and b...
TL;DR: It is substantiated Vladykov's finding that elver size tends to increase with increasing distance from the spawning area, but reject his size/sex hypothesis.
Abstract: Progressive pigmentation of Anguilla rostrata elvers was very similar to that described for A. anguilla. Pigmentation increased rapidly with the advancing season, while total length decreased. The increase in pigmentation was independent of the decrease in length and may have been influenced by increased contact with the substrate. Mean lengths showed significant differences within seasons and between years, and the range of variation was greater than that described by V. D. Vladykov (1966. Verh. Int. Ver. Theor. Angew. Limnol. 16: 1007–1017) for elvers collected from Maryland to Quebec. We substantiate Vladykov's finding that elver size tends to increase with increasing distance from the spawning area, but reject his size/sex hypothesis. The main migration occurred in April and May and was related to decreasing water depth and rising stream temperature. Elvers took about 4 weeks to ascend 180 m above the tidal zone, probably because of a high stream gradient and the absence of tidal influence.
TL;DR: Given the rapid thermal equilibration of most fish with their environment, thermal compensation of metabolic and contractile properties is essential for the maintenance of locomotory capacities over a wide range of temperatures.
Abstract: Given the rapid thermal equilibration of most fish with their environment, thermal compensation of metabolic and contractile properties is essential for the maintenance of locomotory capacities over a wide range of temperatures. The response of fish swimming performance, contractile properties of isolated fibers, myosin ATPase activity, and metabolic systems for ATP generation to short- and long-term changes in temperature have received sufficient study to allow one to identify certain constrained and labile properties. Sustained swimming performance and its components generally have their optimal performance and lowest thermal sensitivity within the range of temperatures frequently encountered by the organism. These principles are particularly well established for isolated enzyme systems. Furthermore, swimming performance and most of its components demonstrate thermal compensation on the evolutionary time scale. Temperature acclimation also leads to compensatory responses which, while quite species-speci...
TL;DR: Killer whales (Orcinus orca) were found to use different physiographic regions of their habitat in unique ways, which most likely represent cultural mechanisms that have been learned through trial and error experiences leading to successful foraging strategies.
Abstract: Killer whales (Orcinus orca) were found to use different physiographic regions of their habitat in unique ways. Resident whales fed more in areas of high relief subsurface topography along salmon m...
TL;DR: The sensitivity towards metal pollution of some population and community characteristics in Collembola was demonstrated based on observations at eight field sites along a transect from a brass mill and neither species number, density, nor species diversity were linearly correlated with metal concentrations but instead showed a bell-shaped distribution.
Abstract: The sensitivity towards metal pollution of some population and community characteristics in Collembola was demonstrated based on observations at eight field sites along a transect from a brass mill. Samples were collected in coniferous forest soils at Gusum, southeastern Sweden, where a local brass mill has created a metal gradient in the surrounding area, with Cu and Zn concentrations in the mor (Oa + Oe) layer close to the mill at levels 50 times above background. Cu concentrations in whole animals increased exponentially in the vicinity of the smelter, but accumulation in body tissues was only observed at background sites. Neither species number, density, nor species diversity were linearly correlated with metal concentrations but instead showed a bell-shaped distribution. The vertical distribution of Collembola was clearly dependent on soil metal concentrations, and their densities at 2 – 10 cm depth were positively correlated with metal concentrations at 0–2 cm depth. The most pertinent information w...
TL;DR: Glycolytic rate depression in marine molluscs involves covalent modification of key regulatory enzymes (e.g., phosphofructokinase, pyruvate kinase) via enzyme phosphorylation.
Abstract: An impressive array of organisms is capable of radically depressing basal metabolic rate and entering a hypometabolic state characterized by a marked reduction of many normal physiological functions. Environmental cues are often the trigger: low oxygen, low temperature, or lack of water, for example. Entry into a hypometabolic state does not, apparently, involve major biochemical reorganization but appears, instead, to result from molecular controls operating at a level "above" that of allosteric regulation of enzymes and "below" that of gene expression. The mechanisms involved are widely applicable to the coordinated inactivation of many cellular processes. Studies of anaerobiosis in marine molluscs provide the most complete information on the molecular mechanisms involved in metabolic rate depression. Glycolytic rate depression in the marine whelk involves (i) covalent modification of key regulatory enzymes (e.g., phosphofructokinase, pyruvate kinase) via enzyme phosphorylation to produce less active en...
TL;DR: A physiological homology between sleep and torpor is demonstrated, suggesting a continuum in energy conservation in times of inactivity, and differences exist in the maintenance of resting and action potentials at low temperatures, whereas seasonal differences exist for dependence of trans-sarcolemmal calcium flux in excitation–contraction coupling.
Abstract: Torpor in mammals and birds is characterized by a periodic lowering of the set point for body temperature regulation to achieve a hypometabolic state for energy and water conservation. Torpor may b...