bluuebunny/crossref_metadata_2025 huggingface dataset:
Field thermal ecology of the eastern short-horned lizard (Phrynosoma douglassi brevirostre) in southern Alberta
Authors: Powell G. Lawrence , Russell Anthony P.
Published: March 2009

Phrynosoma douglassi brevirostre has a median body temperature (Tb) of 32.9 °C in southeastern Alberta, with a sharply peaked and negatively skewed Tb frequency. The range of the Tb frequency distribution in daylight hours during the active season (activity temperature range) is wide (20.0 °C). The realized thermal niche is approximately 7 °C wide, centred loosely on the median Tb. The populations examined are active over a wide range of ambient temperatures. With regard to substrate temperature and air temperature at 10 cm, the populations examined are intermediate between thermoconformity and thermal independence, but with regard to air temperature at 1 m they display more thermal independence. Habitat use is most varied on sunny days. Tb is not significantly different between situations, indicating that shuttling is an important thermoregulatory strategy. There is a significant difference in median Tb between small lizards and large lizards, but not between either of these size groups and medium-sized lizards. Small lizards utilize significantly warmer substrates than the other two size groups. Large lizards are more closely coupled to substrate temperature, and less closely coupled to air temperature, than small lizards. Medium-sized lizards have a wider realized thermal niche than the other two size groups and are intermediate in their thermal relations relative to the other two size groups.
Solitary living and extraterritorial movements of wolves in relation to social status and prey abundance
Authors: Messier François
Published: March 2009

This study examines three factors encouraging wolf (Canis lupus) dispersal: prey abundnance, age of the animals, and their sex. Factors are related to the frequency at which wolves (n = 54) dissociated from their packs and (or) engaged in extraterritorial movements. From December to April, radio-collared pup, yearling, and adult pack members were observed alone in 28, 57, and 21% of the observations, respectively. A low prey base did not increase solitary living or excursion frequency of pups, did increase both traits in yearlings, and increased only solitary living among adults. Yearling and adult females were dissociated from their packs more frequently than males. Yearling females travelled more frequently outside their territories than did yearling males. On average, pup, yearling, and adult individuals made 1.1, 3.0, and 1.0 extraterritorial excursions per year, respectively. Such movements, mostly in winter, are interpreted as predispersal forays (failed dispersal), but also as an immediate action to survive through a temporary resource failure. Dispersal in wolves appears as a gradual and dynamic dissociation process extended over a period of a few months to a few years and beginning as early as 10 months of age. During extraterritorial movements, solitary wolves did not use areas between pack territories more intensively. A total of 23 pack excursions were witnessed, significantly more in the low prey area.
A comparison of foraging by Eptesicus fuscus (Chiroptera: Vespertilionidae) in urban and rural environments
Authors: Geggie J. F. , Fenton M. B.
Published: March 2009

We compared the foraging activity of populations of Eptesicus fuscus in rural and urban settings in eastern Ontario and western Quebec by monitoring their echolocation calls and by radio tracking individuals during the summer of 1980. Foraging was detected in all of the rural and urban habitats we monitored. There were no significant differences in the levels of foraging activity over different urban habitats, but the overall foraging rates were significantly higher in the rural than in the urban areas. Foraging in rural areas was significantly higher in residential zones and over water and was less common in parkland and farmland. Bats in rural areas foraged among aggregations of insects at lights, a pattern of behaviour not seen among urban bats. Differences in foraging rates and the fact that rural bats spent significantly less time away from their roosts suggest that prey density was lower in the urban setting. Although urban habitats appear to provide E. fuscus with a wealth of roosting sites, food supplies are lower there.
Attachment sites, phenology, and growth of larvae of Eylais sp. (Acari) on Dytiscus alaskanus J. Balfour-Browne (Coleoptera: Dytiscidae)
Authors: Aiken R. B.
Published: March 2009

Larvae of aquatic mites are common ectoparasites of aquatic beetles. A population of Dytiscus alaskanus (Coleoptera: Dytiscidae) studied in a central Alberta lake was parasitized by members of the genus Eylais (Acari: Hydrachnellae). Mites attached preferentially in the costal–subcostal region of the ventral surface of the hindwings. Afferent blood flow in the costa and subcosta and the numerous blood sinuses in this region provide an abundant food source. The smallest (= youngest) larvae were taken on the first beetles caught in early spring, indicating that some mite larvae overwinter on the host. Mites grow rapidly, reach maximum size in late June and July, and then enter the nonparasitic phase of the life cycle. Rates of parasitism (proportion of beetles with parasites) was highest in early spring, declined throughout the summer, and rose again in the fall. In this way, the parasitic phase of the mites life cycle occurs at the same time as the peak in the population of adult beetles. There was constant recruitment throughout the year into the population of larval mites indicating asynchronous cohorts or more than one mite species.
Population biology of Urocleidus adspectus Mueller, 1936 (Monogenea) on Perca flavescens in New Brunswick
Authors: Cone D. K. , Burt M. D. B.
Published: March 2009

The population biology of Urocleidus adspectus parasitizing gills of Perca flavescens in a small New Brunswick lake is described. The parasite has an annual cycle in which worms overwinter as inactive adults. In spring, they lay eggs and many worms die. A short generation time (14 days at 20 °C) allows transmission throughout summer and well into fall. Perch acquire infections during the first few months of life and thereafter annually lose and reacquire infections. The intensity of U. adspectus peaks during July and generally increases with age of the host. Length–frequency distributions of parasites on four host age-classes (1, 2, 3–4, and 5 and older) indicate that they grow larger on larger hosts. Seasonal monitoring of length–frequency distributions revealed that spring growth of overwintering worms and onset of spring invasion commence earlier on mature perch than on immature perch. The results are discussed in relation to our understanding of fish parasite populations in small lakes.
Effects of environmental parameters on the foraging behavior of three species of wintering dabbling ducks (Anatini)
Authors: Hepp Gary R.
Published: March 2009

Foraging behaviors of wintering gadwall (Anas strepera), pintail (Anas acuta), and green-winged teal (Anas crecca carolinensis) were studied at Bodie Island, North Carolina. Foraging speed (metres per minute) and rate of foraging (dips per minute) did not differ by sex, but significant monthly variation of foraging components occurred for all species. Ducks fed at faster rates and increased their foraging speed as winter progressed. Stepwise multiple regression procedures were used to test the effects of day length (minutes), mean daily temperature (degrees Celsius), mean daily wind speed (kilometres per hour), water depth (centimetres), and density of foraging individuals on the temporal variation in rate and speed of foraging. Changes in the foraging speed and rate of dipping of winter ducks were significantly related to decreases in day length and average daily temperatures. Other environmental parameters had variable effects on foraging behavior. Estimates of total prey biomass did not vary significantly during winter; however, changes in the distribution of prey sizes may have contributed to changes in foraging behavior. Greater foraging speed and rate of dipping may have been a behavioral mechanism which increased ingestion rate and minimized foraging time, thereby allowing wintering ducks to reduce thermal stress through modification of activity patterns and selection of more favorable microclimates.
Individual identification of bluntnose minnows (Pimephales notatus) by means of naturally acquired marks
Authors: Pot Willem , Noakes David L. G.
Published: March 2009

Bluntnose minnows (Pimephales notatus) can be recognized as individuals by the pattern of spots, most of which are caused by trematode cysts, on their dorsal surfaces and pectoral fins. Nesting males were captured, photographed, and released on several occasions. The pictures, as well as preserved collected specimens, allowed detailed study of the patterns of spots and enabled identification of many individuals. The behavior of the fish indicated no serious disturbance by the procedure.
A further contribution to the taxonomy of the genus Tubificoides Lastockin (Oligochaeta: Tubificidae)
Authors: Brinkhurst R. O.
Published: March 2009

The species of the genus Tubificoides with hair setae and with at least some bifid setae as opposed to pectinate setae in the dorsal bundles are reviewed. Tubificoides insularis (Stephenson) is removed from synonymy with T. benedii (d'Udekem), and T. apectinatus (Brinkhurst) is divided into that species and two new species, Tubificoides pseudapectinatus and T. parapectinatus. Four other new species are described, T. imajimai, T. swirencoides, T. scoticus, and T. bakeri. Three other taxa are described but not named because of lack of adequate material. Tubificoides amplivasatus (Erseus) is reported from Scotland. Nearly all Tubificoides species have more limited distributions than were apparent when the genus was expanded by Brinkhurst and Baker (1979. Can. J. Zool. 57: 1553–1569).
The effects of toe clipping on the survival of the meadow vole (Microtus pennsylvanicus)
Authors: Pavone Leo V. , Boonstra Rudy
Published: March 2009

A total of 68 pairs of female and 72 pairs of male voles were used to examine the effect of toe clipping on the survival of Microtus pennsylvanicus. Toe clipping did not significantly influence female life-span (average difference in life-span was 0.1 weeks) (p > 0.05), but did lower male life-span (p = 0.07). On average, toe-clipped male voles lived 2.1 weeks less than the controls. We suggest that the difference, although not statistically significant, may be biologically important. Shortening of life-span may have been a result of increased movement by toe-clipped males, brought upon by vole–vole interactions, into unfamiliar, possibly suboptimal habitats where increased mortality may have occurred.
Web-monitoring forces exerted by orb-web and triangle-web spiders of the family Uloboridae
Authors: Opell Brent D.
Published: March 2009

Differences in web structure and cephalothorax features suggest that Hyptiotes cavatus should exert more force while monitoring its vertical triangle-web than Uloborus glomosus exerts while hanging beneath the hub of its horizontal orb-web. When this hypothesis was tested by measuring the force that instars of each species exerted on a horizontal thread, Hyptiotes cavatus was found to exert significantly more force throughout development than did Uloborus glomosus. This relationship holds when either first femur length or body weight is used as an index of spider size.
A new species of Tetrastemma (Nemertea, Monostilifera) from San Juan Island, Washington, U.S.A.
Authors: Stricker Stephen A.
Published: March 2009

A new species of monostiliferous hoplonemertean, Tetrastemma phyllospadicola, is described from specimens collected on San Juan Island, Washington, U.S.A. The worms occur in great abundance on intertidal growths of the surfgrass Phyllospadix scouleri Hooker. The distinctive morphological characteristics of T. phyllospadicola are described, and aspects of its reproductive biology and natural history arc reported.
A note on the significance of the neck organ of Leptodora kindtii (Focke) (Crustacea, Cladocera)
Authors: Halcrow K.
Published: March 2009

On the basis of ultrastructural comparisons between the neck organ of Leptodora and similarly located structures in other branchiopod crustaceans, it is suggested that the organ is involved in ion transport rather than respiration, as has previously been suggested.
The effect of worker loss on temporal caste structure in colonies of the honeybee (Apis mellifera L.)
Authors: Winston Mark L. , Fergusson Linda A.
Published: March 2009

The influence of colony population and brood area on worker longevity and foraging age were investigated in the honeybee, Apis mellifera L. Workers began foraging at younger ages and had shorter life-spans in colonies from which a majority of the worker population had been removed than in control colonies. This simulated loss in worker population was similar to naturally occurring events in feral colonies such as predation, swarming, nest damage, and (or) disease, as well as to some common management manipulations performed by beekeepers. Foraging age was negatively correlated with the area of eggs and larvae and was not correlated with pupal area. These results indicate that honeybee colonies are able to adjust temporal caste structure in response to rapid changes in colony conditions such as worker loss. The flexibility in temporal division of labor may be based on the inactive workers increasing their activity levels following stress by compressing the normal ontogeny of worker activities into a shorter time span.
The efficiency of yarding behaviour by white-tailed deer as an antipredator strategy
Authors: Messier François , Barrette Cyrille
Published: March 2009

This study shows that white-tailed deer (Odocoileus virginianus) reduce their vulnerability to coyote (Canis latrans) predation by congregating in a traditional wintering area (yard). Distribution of deer and coyotes were monitored within a 36-km2 yard [Formula: see text] and the surrounding area. Coyote pairs and packs preferentially used areas of low deer density where only 12% of the deer wintered; 18 of 23 deer killed by coyotes were located in these areas. We postulate that the greater number of runways in high deer density areas enhanced escape from coyotes. By congregating in a yard during winter months, deer also benefited from a lower coyote:deer ratio. Territorial behaviour kept the coyotes from concentrating in the yard. We consider yarding behaviour to be an antipredator strategy in addition to an energy-conserving strategy.
Effects of photoperiod and temperature on ovarian activity in the Indian murrel, Channa (Ophiocephalus) punctatus (Bloch)
Authors: Garg S. K. , Jain S. K.
Published: March 2009

Channa punctatus (Bloch) is a seasonal breeder and spawns during the monsoon season. Ovarian regression occurs at a time when day length begins to shorten and temperature reaches a seasonal minimum, while the ovarian recrudescence coincides with the increase in day length and temperature. The close relationship between increasing day length and temperature suggests that these two factors are in some way involved in inducing gonadal recrudescence. Responses of the ovary to various combinations of photoperiod and temperature were studied during the postspawning and preparatory periods. Temperatures of 25 °C and above, regardless of photoperiod, were more favorable for the formation of yolky oocytes and ovarian development occurred as a function of warm temperature even under conditions of continuous darkness or continuous light. These studies have revealed that ovarian recrudescence, which normally occurs during the prespawning period, can be advanced by photothermal manipulations. It was concluded that photoperiod may be responsible for timing the seasonal reproductive activity; nevertheless, the rate of photosexual response is temperature dependent.
Circuli development on body scales of young pond-reared walleye (Stizostedion vitreum)
Authors: Glenn C. L. , Mathias J. A.
Published: March 2009

The development of circuli on the scales of young walleye were related to fish size and age. The species first develop scales in the caudal peduncle region of the body when the fish are approximately 30 mm in total body length and about 36 days old. Scale growth and circulus formation are directly related to body growth, with maximum deposition occurring in late July and early August. Seldom are circuli continuous ridges surrounding the scale focus; rather the number of lateral and central circuli are dependent on scale shape, body size, and time. The distances between respective circuli of all age groups examined were relatively constant except for a progressive increase in intercircular spaces between the first four circuli of fish aged 36–64 days. Within each age group the mean intercircular distances between the first 10 to 12 circuli tended to decrease with distance from scale focus. Cteni develop on caudal scales when scales have four to five circuli and when walleye are about 6 weeks of age.
Gastropod intermediate hosts and transmission of Parelaphostrongylus odocoilei, a muscle-inhabiting nematode of mule deer, Odocoileus h. hemionus, in Jasper National Park, Alberta
Authors: Samuel W. M. , Platt T. R. , Knispel-Krause S. M.
Published: March 2009

Over 11 000 gastropods from Jasper National Park, Alberta, were examined (1976–1977) for larvae of Parelaphostrongylus odocoilei. Seven species of gastropods were infected: Deroceras laeve (5.3%), Zonitoides nitidus (1.5%), Euconulus fulvus (1.3%), Discus shimeki (1.2%), Zonitoides arboreus (0.8%), Vitrina limpida (0.7%), and Discus cronkhitei (0.6%). Examination of deer feces collected throughout the year (1974–1980) for first-stage larvae of P. odocoilei indicated maximum numbers were passed in March and April. All deer became infected as fawns in autumn apparently by accidently ingesting infected gastropods.
Ephemeroid wing venation based upon new gigantic Carboniferous mayflies and basic morphology, phylogeny, and metamorphosis of pterygote insects (Insecta, Ephemerida)
Authors: Kukalová-Peck Jarmila
Published: March 2009

Gigantic as well as very large mayflies from the middle Upper Carboniferous (Westphalian) strata of Europe and North America are described: the adult and nymph of Bojophlebia prokopi n. gen., n. sp. (Bojophlebiidae n. fam.) and the nymphs of Lithoneura piecko n. sp. and Lithoneura clayesi n. sp. (Syntonopteridae). Evolution of ephemerid wing venation during 300 million years is summarized. Autapomorphic, apomorphic, and plesiomorphic character states of venation are categorized. Venational nomenclature of Recent Ephemerida is emended based on its evolutionary changes. Evidence that wing veins occurred primitively as a pair of fluted sectors is documented in Carboniferous mayflies in the costa, subcosta, radius, anal, and jugal. Ephemeroids and odonatoids are sister groups that share the veinal anal brace AA fused with CuP at an area important for flight. Ancestral Odonatoephemerida are the sister group of the extinct haustellate Paleoptera. The Carboniferous nymphs bear three pairs of almost homonomous thoracic wings and, on the abdomen, nine pairs of legs and nine pairs of tracheal gills (wing homologues). This proves that abdominal legs have been totally reduced in Recent Ephemerida except for the claspers (gonopods) and that tracheal gills are not flattened legs. The metamorphic instar probably originated in relatively young instars. Insectan cerci developed from segmented, arched, functional legs of abdominal segment 11, which were still present in this primitive condition in Carboniferous Monura.
Reallocation of Indialona macronyx (Daday, 1898) (Cladocera, Chydoridae) to the genus Alona
Authors: Rajapaksa R. , Fernando C. H.
Published: March 2009

Based on the examination of material including the types of Alona macronyx Daday, currently considered as belonging to the genus Indialona, we have reallocated the species to the genus Alona. Alona macronyx is definitely not in the genus Indialona. It has many diagnostic features of Alona but some of its features are unique. A detailed redescription and known distribution of the species are given.
Digestion of forage components by pine and meadow voles
Authors: Servello Frederick A. , MacPherson Sandra L. , Kirkpatrick Roy L. , Webb Jr. Kenneth E.
Published: March 2009

A Van Soest analysis of feed and fecal samples from 24 digestion trials with pine voles (Microtus pinetorum) and 18 digestion trials with meadow voles (Microtus pennsylvanicus) was used to examine the digestive capabilities of these species and the effect of feed constituents on fiber digestion. The neutral detergent soluble fraction of feeds and forages (NDS) was the most readily available for voles. Percent neutral detergent fiber (NDF) digestibility was variable and inversely related (P = 0.0001) to the percent NDF of the diets for both pine and meadow voles. NDF digestibility was not related (P > 0.30) to the percentage of lignin in the NDF or acid detergent fiber (ADF). NDF digestion accounted for 15 and 21% of the dry matter digested by pine voles and meadow voles, respectively, on a high fiber diet (40% NDF).
Vocalizations and vocal mimicry in captive harbor seals, Phoca vitulina
Authors: Ralls Katherine , Fiorelli Patricia , Gish Sheri
Published: March 2009

Vocalizations recorded from captive harbor seals are described and illustrated. Pups of both sexes vocalized, but females over 1 year of age rarely vocalized. Sexually mature males were the most vocal animals. Two adult males produced sounds that mimicked one or more English words and phrases, which is noteworthy in view of the rarity of demonstrated vocal learning in mammals. Although similar in many ways to other seal sounds, these speechlike sounds contained a variety of human speech cues. We speculate that male harbor seals may mimic other males in the wild.
Ecology of the dominant copepod species at a Low Arctic site
Authors: Hebert Paul D. N.
Published: March 2009

Four species of calanoid copepod regularly co-occur in tundra ponds near Churchill, Manitoba. Despite the physical uniformity of the habitats they occupy, twofold variation in body size and fivefold variation in brood size existed among conspecific populations of each species. Size shifts were concordant in the sexes, but the extent of sexual dimorphism was size dependent in each species. Size differences among populations persisted through two summers. The three herbivorous species showed parallel variation in body sizes and fecundities, while the predatory species did not. The size covariation in the herbivorous taxa may reflect significant overlap in resource use despite their size divergence.
The micromorphology of the antennae of the blueberry leaf-tier moth, Croesia curvalana (Kft.) (Lepidoptera: Tortricidae)
Authors: Langmaid Wilfred M. , Seabrook W. D.
Published: March 2009

The micromorphology of the antennae of the blueberry leaf-tier moth Croesia curvalana (Kft.) (Lepidoptera: Tortricidae) is described. The number and distribution of the various sensilla types were examined, and comparisons made between males and females as well as with other species. Sensilla observed were sensilla trichodea, chaetica, coeloconica, styloconica, and aurillica. There are sexual differences in the numbers and distribution of sensilla. Their distribution on the antenna bears a resemblance to that described for other Lepidoptera and is very similar to that described for other Tortricidae. A refined technique for removal of the protective scales from the antennae to facilitate observation of the sensilla is reported.
Scanning electron microscopy and histochemistry of embryonic envelopes of the porcupine tapeworm, Monoecocestus americanus (Cyclophyllidea: Anoplocephalidae)
Authors: Conn David Bruce
Published: March 2009

Eggs of Monoecocestus americanus (Stiles 1895), a tapeworm of North American porcupines, were studied with regard to the basic structure of embryonic envelopes. Observations were made by light microscopy of whole eggs and scanning electron microscopy of eggs within cryofractured gravid proglottids. Concomitant histochemical tests were made on eggs and gravid proglottids embedded and sectioned in methacrylate plastic. The gravid uterus had numerous diverticula, each containing several eggs. The uterine lumen was filled with a material positive for nonsulfated acid mucopolysaccharides. The material adhered to the eggs, giving them their characteristic spinose surface when teased from the proglottid. Each egg included an oncosphere larva surrounded by an oncospheral membrane, pyriform embryophore, inner and outer envelopes, subshell membrane, and embryonic capsule. Overall, the structural and histochemical characteristics of these layers were similar to those described for other cyclophyllideans, with only minor variations.
An emendation of the generic diagnosis of Phoreiobothrium Linton, 1889 (Tetraphyllidea: Onchobothriidae) with a detailed description of bothridia and hooks
Authors: Caira J. N.
Published: March 2009

Hook terminology for the three-pronged hooks of Phoreiobothrium Linton, 1889 is reconciled with that for two-pronged hooks such that the two outermost prongs are considered homologous with the prongs of a two-pronged hook and the third inner prong is termed the basal prong. Scanning electron microscopy was performed on the scolex of Phoreiobothrium lasium Linton, 1889 and the solid nature of the bothridia was reconfirmed. Examination of material of all four species of Phoreiobothrium leads to the conclusion that each species possesses three-pronged hooks that are hollow and open to the outside via pores. The bothridia of each species are considered to be horizontally divided into two loculi, the posterior one being recessed and vertically subdivided. The diagnosis of the genus Phoreiobothrium is emended, and the four species allocated to it are redescribed. Phoreiobothrium is determined to be a monophyletic group on the basis of two synapomorphies and a key to the four species of the genus is presented.
Ultraviolet transmission by the ocular media of goldfish: implications for ultraviolet photosensitivity in fishes
Authors: Hawryshyn Craig W. , Chou B. Ralph , Beauchamp Ross D.
Published: March 2009

Spectral transmittance of goldfish (n = 10) ocular media was measured in the 320- to 750-nm range with a spectrophotometer modified to eliminate problems associated with chromatic aberration and beam scattering. Absolute transmittance in the visible range was 0.8 at 400 nm and 0.95 at 750 nm. Transmittance below 400 nm dropped off to 0.3 at 340 nm and exhibited high variability between individuals. Linear regression analysis showed that ultraviolet (UV) transmittance was not systematically related to age, body weight, standard length, or ocular diameter of fish. Low UV transmittance of the ocular media was shown to influence the UV peak spectral sensitivity by narrowing the action spectrum on the short wavelength side and displacing the UV peak sensitivity to longer wavelengths. Correcting spectral sensitivity curves for ocular media transmittance resulted in agreement with λmax 370 nm absorption spectrum.
Antipredator strategies of caribou: dispersion along shorelines
Authors: Bergerud A. T.
Published: March 2009

A small herd of 15–31 caribou (Rangifer tarandus) inhabited a shoreline strip of habitat along Lake Superior from 1972 to 1983. By remaining near the shoreline, they were spaced away from the major distributions of wolves (Canis lupus) and lynx (Lynx canadensis) that hunted mainly inland for moose (Alces alces) and snowshoe hares (Lepus americanus), respectively. Lake Superior also provided a means of escape from wolves, and offshore islands constituted safe parturition sites. The persistence of this herd is consistent with the hypothesis that viable caribou populations cannot survive on ranges frequented by high numbers of wolves (maintained mainly by moose prey) unless there are special habitat features providing escape for cows with young calves.
Oxygen transport, tissue glycogen stores, and tissue pyruvate kinase activity in muskrats
Authors: Snyder Gregory K. , Binkley Edward L.
Published: March 2009

Oxygen stores, respiratory properties of blood, tissue glycogen concentrations, and the rate-limiting enzyme for glycolysis, pyruvate kinase, were examined in muskrats (Ondatra zibethicus). Of the potential oxygen stores, lung volume (19.6 ± 0.68 mL/kg), and blood hemoglobin concentration (13.0 ± 0.34 g Hb/100 mL blood) were typical of terrestrial mammals, while concentrations of myoglobin in heart (7.4 ± 0.1 mg Mb/g tissue) and gastrocnemius muscle (13.3 ± 0.5 mg Mb/g tissue) were significantly higher than values from the same tissues in the laboratory rat. Blood P50 (oxygen half-saturation pressure) at pH 7.4, 24.4 ± 1.36 Torr (1 Torr = 133.322 Pa), and Bohr effect, −0.64 ± 0.04, also were significantly different, while the Hill coefficient and buffering capacity were comparable for both species. Of our measures of anaerobic capacity, glycogen concentrations and pyruvate kinase activities in heart, brain, and gastrocnemius muscle of O. zibethicus were all comparable to values obtained for terrestrial mammals. We conclude that muskrats tolerate submersion by adaptations associated with aerobic metabolism, although a review of the literature shows that these adaptations are fully developed only in animals freshly captured during winter.
Varestrongylus alpenae (Nematoda: Metastrongyloidea) in white-tailed deer (Odocoileus virginianus) of Saskatchewan
Authors: Gray J. B. , Samuel W. M. , Shostak A. W. , Pybus M. J.
Published: March 2009

The lungworm nematode Varestrongylus alpenae (Dikmans, 1935) Dougherty, 1945 is reported in Canada for the first time. Dorsal-spined, first-stage nematode larvae were found in 19% of 1098 fecal pellet groups of white-tailed deer (Odocoileus virginianus) randomly collected in central and eastern Saskatchewan. These larvae developed to the infective stage, experimentally, in the gastropods Triodopsis albolabris and Triodopsis multilineata and were infective to captive mule deer (Odocoileus h. hemionus) and white-tailed deer fawns. All of four mule deer and two of three white-tailed deer developed patent infections (mule deer in 43–49 days and white-tailed deer in 54–55 days). Adults nematodes, identified as Varestrongylus alpenae, were recovered from the lung parenchyma of two mule deer. The geographical distribution of V. alpenae in white-tailed deer in North America is discussed.
Effects of salinity on larval tolerance and early developmental rates of four species of echinoderms
Authors: Roller Richard A. , Stickle William B.
Published: March 2009

Larval tolerances and developmental rates of four species and one hybrid cross of echinoderms were determined as a function of salinity. Fertilization and development of Strongylocentrotus droebachiensis (O.F. Muller, 1776), Strongylocentrotus purpuratus (Stimpson, 1857), Strongylocentrotus pallidus (G.O. Sars, 1871), and Pisaster ochraceus (Brandt, 1835) larvae were observed. A hybrid was created by fertilizing eggs of S. droebachiensis with sperm from S. pallidus. Fertilized eggs were placed in filtered, natural seawater (30‰ S) diluted to 30, 27.5, 25, 22.5, and 20‰ S and cleavage and larval development were observed over 32 days. Developmental rates differed among salinity treatments within each species. For each species, embryos and larvae at lower salinities (20, 22.5, and 25‰ S) tended to develop more slowly than those at higher salinities (27.5 and 30‰ S). Pisaster ochraceus and S. droebachiensis larvae survived all salinity treatments throughout the experimental period. The hybrid larvae exhibited salinity tolerances and developmental rates intermediate between values reported for the more stenohaline larvae of S. pallidus and those for the more euryhaline larvae of S. droebachiensis. The interaction of a secondary stressor (food availability) with salinity was examined; algal concentration did not influence the survival, developmental rate, or length of P. ochraceus or S. droebachiensis larvae.
A cytological study of species in the Eusimulium aureum group (Diptera: Simuliidae)
Authors: Leonhardt Karin G.
Published: March 2009

Earlier studies by R. W. Dunbar of the monophyletic (n = 2) Eusimulium aureum group were extended. Additional samples of his forms "A" and "B" (temperate North America), "C" and "D" (northern North America), "E" and "F" (Britain, northern Europe, Leningrad), and "G" (California to Guatemala) were analyzed. Two of Dunbar's forms, "I" (Gibraltar, Britain) and "J" (Mediterranean, Madeira, Azores, Leningrad), have been redefined. "K" (Gibraltar) and "L" and "M" (Canary Islands) are new forms. These are described in terms of fixed inversion differences, sex differential segments, and chromosomal polymorphisms. In a cytophylogeny, the Old World "J" forms the link to the New World "C." A preliminary polytene banding comparison of E. aureum and its putative n = 3 relatives reveals that the Old World forms are ancestral to those of the New World. All palaearctic forms have chiasmate meiosis in males, while all nearctic ones, with the remarkable exception of "G," are male achiasmate. Since male achiasmate meiosis is presumably a prerequisite for the reduction in chromosome number, the male-chiasmate condition of Old World forms is assumed to be due to secondary reversion, a postulate that is supported by the derivative male-chiasmate condition of "G."
Some factors affecting sexual attraction in Ascaris suum (Nematoda)
Authors: García-Rejón L. , Verdejo S. , Sanchez-Moreno M. , Monteoliva M.
Published: March 2009

The response of male and female Ascaris suum to sexual attractant was affected by the number of pheromone-emitting worms and the pH of the medium. The optimum migratory response of both sexes was obtained when three individuals were used as emitting worms. Males and females showed statistically significant responses to sexual pheromones at pH 7.4 whereas they did not respond at pH 5.5 or 9.0.
The influence of food resources on population dynamics in Columbian ground squirrels
Authors: Dobson F. Stephen , Kjelgaard Julia D.
Published: March 2009

Determining the environmental factors that limit the size of populations and examining the influence of environmental factors on population processes (immigration, emigration, survival, and reproduction) are fundamental problems for population ecologists. We conducted an experimental study of population dynamics in the Columbian ground squirrel, Spermophilus columbianus, from 1981 to 1983, in southwestern Alberta, Canada. We supplemented the food resources of two local populations of ground squirrels at different elevations and also monitored two reference (unsupplemented) populations. Population size increased by about 85% annually and population biomass increased by about 94% annually where supplemental food was provided. Reference populations varied in numbers and biomass by less than 40% annually. Because the increase in size of supplemented populations was dramatic, we concluded that food resources probably limited the size of the ground squirrel populations before we began the experiments and that other possible limiting factors were insufficient to check the increases stimulated by supplemental food. Several population processes were influenced by the increased food resources. Immigration of all age-classes was higher to supplemented than to reference populations and favored females. Survival of resident young was higher in supplemented than in reference populations. Reproduction was greatly increased in supplemented populations compared with reference populations, with surviving young residents of 1982 making the greatest contribution to increases in population size. The results were generally similar in the two replicates of the experiment. Competition for food resources appeared to be strongest among yearling and adult females and among young of both sexes.
A new hydrozoan, Geomackiea zephyrolata gen. nov., sp. nov. (Anthomedusae: Pandeidae), from inland marine waters of British Columbia and Washington State
Authors: Mills Claudia E.
Published: March 2009

The hydromedusa Geomackiea zephyrolata gen. nov., sp. nov. is described and illustrated. It has been placed in the subfamily Protiarinae of the family Pandeidae on the basis of its stomach and gonad morphology and the four large perradial tentacles with conical basal bulbs. A new genus has been erected because the medusa is supplied with four broad interradial bulbs, each rimmed by up to eight closely packed solid tentaculae. A total of 29 specimens with bell heights of 0.9–3.5 mm have been collected in the plankton of Saanich Inlet, British Columbia, and Friday Harbor, Washington, between 1978 and 1981. Juvenile as well as adult specimens are described and the cnidome, gametes, seasonal and vertical distributions, and taxonomic affinities within the family Pandeidae are discussed.
The mesopelagic fish fauna of the Newfoundland Basin
Authors: McKelvie D. Scott
Published: March 2009

The mesopelagic fish fauna of the Newfoundland Basin is relatively depauperate. The specimens that were taken, 6760 in number, represented 51 species and 28 families. The majority were rare, 22 species occurring in only one sample and only 8 species occurring in more than 50% of the samples. The myctophid Benthosema glaciale made up 83.5% of all fish collected. Other species included Stomias boa ferox, Bathylagus euryops, Protomyctophum arcticum, and Chauliodus sloani. There are fewer small species in the Newfoundland Basin than in similar samples in the Slope Water. Specimens of B. glaciale and C. sloani were generally larger in the Newfoundland Basin than in the Slope Water.
Egg size, prey size, and sexual size dimorphism in digger wasps (Hymenoptera: Sphecidae)
Authors: O'Neill Kevin M.
Published: March 2009

Female digger wasps invest substantially in each of their offspring, laying relatively few, large eggs and providing the young with the insect prey on which they depend for food. In a study of six species in the genera Philanthus, Bembecinus, and Bembix, it was found that within each species, there is a positive correlation between female body size and both the size of their ovarial eggs and the size of the prey they provision. In five of the six species, females were larger than males on average. It is suggested that the apparent association between body size and certain aspects of parental investment by females may provide the directional selection pressure that results in the evolution of sexual size dimorphism in digger wasps. In one species, males and females have the same mean size, probably because, in this species, selection pressure on male size is similar to that on females.
Seasonal patterns of nest defence by Baird's sandpipers
Authors: Reid Mary L. , Montgomerie Robert D.
Published: March 2009

Parental Baird's sandpipers increased the intensity of their nest defence through the incubation period. One member of each pair was relatively tame, staying closer to the human "predator" and engaging in more risky behaviours than the other, but both parents increased risk taking as the incubation period progressed. Members of this High Arctic population had little potential for renesting during the short breeding season. There was also apparently no change in either predator persistence or nest conspicuousness during the incubation period. Thus none of these factors can explain the seasonal increase in nest defence. We conclude, therefore, that the observed pattern was most likely due to a decrease in the relative difference between the probabilities of parent and offspring survival as predicted by a recent model.
Responses of rufous hummingbirds to midday fasts
Authors: Tooze Zena J. , Gass Clifton Lee
Published: March 2009

This study investigates how rufous hummingbirds regain energy balance after experimentally imposed midday fasts reduce their energy reserves. Net energy balance calculated from food intake, activity budgets, and allometric equations for the costs of flying and perching was highly correlated with change in body weight in laboratory tests of 3 h or more. Individuals accumulated energy and body weight at the same rate after fasts as before, resulting in energy deficits at the end of the day compared with control conditions. Energy balance relative to control values was regained by the following morning, primarily by reducing metabolic costs in the dark through torpor. Net energy intake increased the following day, but this increase was relatively unimportant to reestablishing equilibrium.
Plasma ionic composition of the Atlantic salmon (Salmo salar), white sucker (Catostomus commersoni), and alewife (Alosa pseudoharengus) in some acidic rivers of Nova Scotia
Authors: Lacroix Gilles L.
Published: March 2009

Atlantic salmon (Salmo salar) smolts migrating from two acidic rivers (pH 4.9 and 5.2) had high hematocrit levels (> 50%) and low plasma [Cl−] (< 100mequiv. L−1). The hematocrit level was 10% higher and plasma [Na+] was 17% lower in smolts of the more acidic of the two rivers. Salmon parr in rivers of mean pH 5.0, 5.4, and 6.0 over a 7-month period had high hematocrit levels (> 40%) and low plasma [Cl−] (< 125 mequiv. L−1). Plasma [Na+] and [Cl] were both slightly less (~ 5%) and plasma [K+] was higher (> 1.5 times) in parr from the river of pH 5.0 than in those from the other two rivers. Atlantic salmon smolts were more sensitive to low pH (plasma [Na+] 14% less, [Cl] 17% less, and hematocrit level 37% higher) than parr, and parr of the 0+ age-class were more sensitive (plasma [Na+] 9% less) than 1+ parr. Prespawning white suckers (Catostomus commersoni) and alewives (Alosa pseudoharengus) migrating in a river at pH 4.9 had high hematocrit levels and low plasma [Cl−], and alewives (hematocrit, 66%; plasma [Cl], 65 mequiv. L−1) were more severely affected than suckers (hematocrit, 42%; plasma [Cl−], 91 mequiv. L−1). Plasma [Ca2+] in females of both species was not greatly elevated relative to males (female/male [Ca2+] = 1.21 in suckers and 1.14 in alewives), suggesting a possible impairment of calcium metabolism associated with ovarian development. The physiological effects observed in fish inhabiting soft waters (external [Ca2+] < 0.10 mequiv. L−1) at pH levels of about 5.0 generally correlated well with the laboratory "models" of acid exposure in soft water.
Thermoregulation and energetics of fin and sei whales based on postmortem, stratified temperature measurements
Authors: Brodie Paul , Paasche Arvid
Published: March 2009

It has been postulated that large whales have uniform body temperatures and may experience heat stress in warm waters or when active in colder water. Postmortem (approximately 15 min), stratified body-core temperature measurements of fin and sei whales (Balaenoptera physalus, B. borealis), taken from the commercial catch allocated to the Icelandic fleet, revealed low, mid-core temperatures, which further decreased towards the blubber. This arrangement is considered in terms of reduced thermal maintenance costs and therefore food requirements. The temperature elevation that had been anticipated following intensive pursuit was not evident, a phenomenon that might be explained by propulsive efficiency (a function of internal mechanical design or external hydrodynamic characteristics) and (or) a high thermoregulatory capacity.
Experimental analysis of aggression and spacing behavior in California voles
Authors: Ostfeld Richard S.
Published: March 2009

Spacing behavior is thought to be an important means of population regulation, but the phenomenon itself is poorly understood, especially in cryptic, secretive small mammals, in this study 1 examined the behavior and degree of spacing among California voles (Microtus californicus) freely ranging in a large observation room housing a complex environment. Reproductive males were the most intrasexually aggressive group and also maintained the greatest distances among themselves. Reproductive females were moderately aggressive but did not space themselves more widely than less aggressive, non-reproductive females. Reproductive females approached each other more often, showing a stronger social attraction, than nonreproductive females, while the latter tended to behave amicably towards one another when chance encounters occurred. Thus, the degree of spacing among individuals appears to depend on complex behavioral interactions and is not a simple function of aggression. Reproductive males behaved aggressively at the site of a caged estrous female significantly more frequently than expected by chance, indicating that potential mates constitute the "resource" eliciting most intense competition among males. Reproductive females behaved aggressively at all sites in proportion to the amount of time spent there and thus appeared to compete for "space" or for all resources equally. These results are applied to a recent field study that showed more pronounced territoriality among male than among female M. californicus, and to more general theories of population regulation of microtine rodents.
Breeding cycle of the freshwater mussel Anodonta grandis Say
Authors: Lewis John B.
Published: March 2009

The gonads and marsupia of a population of Anodonta grandis Say in a small, eutrophic lake in the Laurentians were examined for the presence of eggs and glochidia over a period of three summers. The species was found to be a tachytictic (short-term) breeder, contrary to the general opinion that the Anodontinae are bradytictic (long-term) breeders.
Female mate choice and male parental defense behaviour in the cichlid fish Cichlasoma nigrofasciatum
Authors: Keenleyside Miles H. A. , Rangeley Robert W. , Kuppers Bryan U.
Published: March 2009

Female Cichlasoma nigrofasciatum presented with three potential spawning partners of different sizes spawned most often near the medium-sized male. When mate choice was restricted to males of two size classes, females consistently spawned near the larger male. In the former experiment, small males courted females more actively than medium or large males did. This may explain why females occasionally spawned near small males in both experiments. Larger brood-guarding males showed more intensive aggressive behaviour towards an adult conspecific confined near their offspring than did smaller brood-guarding males. Selection will therefore favour the female choice of relatively large mates because such males are likely to be more effective defenders of their offspring.
Développement physique post-natal chez le grand polatouche (Glaucomys sabrinus)
Authors: Ferron Jean , Ouellet Jean-Pierre
Published: March 2009

The objective of this paper is to study the postnatal physical development of the Northern flying squirrel (Glaucomys sabrinus) from birth to the age of 55 days, when it is weaned and its socialization period ends. The effect of growth on weight and on several linear measurements is presented with the corresponding instantaneous growth rates. The timing of different events marking the physical development is also reported. Comparison of our results with those on other sciurid species suggests that arboreal species have a slower physical development than terrestrial species, at least with regard to body weight. Our previous observations on behavioural ontogeny concurs with this hypothesis.