bluuebunny/crossref_metadata_2025 huggingface dataset:
Thyroid hormones and behavioral thermoregulation by Xenopus laevis: differential effects of thyroxine and triiodothyronine
Authors: Dupré R. Keith , Just John J. , Ritchart J. P.
Published: August 2008

The effects of 1 μM 2,4-dinitrophenol, 2.5 × 10−8 M thyroxine, and 2.5 × 10−8 M triiodothyronine on the oxygen consumption and behavioral temperature selection of the African clawed frog, Xenopus laevis, were examined to test the hypothesis that the selection of lower temperatures by thyroxine-treated ectotherms is a secondary result of the calorigenic effect of the hormone. Treatment with the metabolic poison 2, 4-dinitrophenol produced a significant increase in oxygen consumption but had no significant influence on temperature selection by the clawed frogs, suggesting that an increase in oxygen consumption in itself does not induce the selection of lower temperatures by ectotherms. Furthermore, neither thyroxine nor triiodothyronine affected the standard oxygen consumption of the clawed frogs at 23 °C but both significantly affected behavioral temperature selection. Treatment with thyroxine resulted in the selection of significantly lower temperatures than untreated controls. Conversely, treatment with triiodothyronine resulted in the selection of significantly warmer temperatures. These data suggest that thyroid hormones do not affect behavioral thermoregulation of ectotherms via an indirect calorigenic effect but may act directly on the neural regions involved with the sensation and (or) integration of thermal information. These data further suggest independent roles for thyroxine and triiodothyronine in the modulation of temperature selection by anuran amphibians.
Metabolic and hormonal correlates of molting and regeneration of pelage in Alaskan harbor and spotted seals (Phoca vitulina and Phoca largha)
Authors: Ashwell-Erickson Susan , Fay Francis H. , Elsner Robert , Wartzok Douglas
Published: August 2008

Cellular, hormonal, and metabolic changes during annual molts and regeneration of the pelage were studied in two harbor and five spotted seals of different ages. Seals were maintained in an appropriate photoperiod and monitored biweekly to monthly by measuring their serum cortisol, thyroxine, and triiodothyronine and their standardized resting metabolic rate. Concurrently, external signs of their molt (shedding of hair) were recorded, and samples of skin were collected from the midback for histological determination of the duration of the regenerative phase of the pelage cycle. Timing of the molts coincided with those of free-ranging seals in the natural environment. The overall duration of the period of shedding and regeneration, from first descent of the hair bulbs on the face and flippers to full emergence of new hair on the back, was estimated as 120–170 days. During the period of descent of the hair bulbs and initial growth of new hair on the back, the resting metabolic rate declined an average of 18.6% below premolt values, generally reaching its minimum when shedding of the old hair and rapid growth of new hair began. Serum Cortisol generally reached a maximum just before or during the main shedding of hair from the torso, then decreased abruptly to its premolt level or lower during the main period of rapid growth of new hair. Although corticosteroids appear to inhibit protein anabolism, they favor fat catabolism and may in this way help to maintain the slow growth of new hair before and during the first part of the molt. Serum concentrations of thyroid hormones declined to minima early in the molt, then increased to maxima toward the end, when growth of new hair was most rapid.
Energy requirements and survival in embryo mottled sculpin (Cottus bairdi)
Authors: Docker M. F. , Medland T. E. , Beamish F. W. H.
Published: August 2008

Eggs of mottled sculpin, Cottus bairdi, from different parents varied in quantity and quality. Egg weight and number were positively correlated and increased with age and length of the maternal fish. Variation in egg quality included significant differences in water and energy content. Rate of development, metabolic rate, yolk conversion efficiency, and relative survival also varied among clutches. The variations in egg weight and initial water content were not significant to embryo survival. Clutch survival from fertilization to exogenous feeding was directly related to the initial energy concentration of the egg and inversely related to metabolic rate. Metabolic rate and survival were inversely and directly related, respectively, to the efficiency with which yolk was converted to tissue.
Coyote predation on a white-tailed deer population in southern Quebec
Authors: Messier François , Barrette Cyrille , Huot Jean
Published: August 2008

Coyote predation on white-tailed deer was studied in a 155-km2 forested area, including a 36-km2 deer wintering area. Deer hair constituted about 80% of coyote scat volume from January to April, 50% from May to July, and 20% from August to December. Deer consumed in summer were primarily fawns, likely killed by coyotes. Snowshoe hare represented an important prey item from May to December. In winter, coyotes preyed primarily on fawns and older deer, but not necessarily individuals in poorer physiological condition. We conclude that coyotes may have an impact on deer numbers in southern Quebec.
Territory size and ownership in red squirrels: response to removals
Authors: Price Karen , Broughton K. , Boutin S. , Sinclair A. R. E.
Published: August 2008

We monitored size and ownership of red squirrel territories in the southwestern Yukon during the summer following a year of abundant cone crop. Territory boundaries were determined by observing marked individuals. Six individuals and two groups (four individuals per group) were removed to test the hypothesis that the position of territory boundaries are determined by intruder pressure. Removed squirrels were replaced by juveniles or by breeding females which had given up their former territories to their offspring. Replacement occurred within hours of the removal and territory boundaries of the new squirrels were not significantly different from those of the original territory owners. Neighbouring territorial residents did not expand their territories to occupy all or part of the vacated area. The location of territory boundaries were not affected by intruder pressure.
The avian pectoralis: histochemical characterization and distribution of muscle fiber types
Authors: Rosser Benjamin W. C. , George John C.
Published: August 2008

The muscle fibers of superficial (ventral) and deep (dorsal) samples from the pectoralis muscle of 43 species of carinate birds are characterized histochemically on the basis of their myofibrillar adenosine triphosphatase (mATPase) activity after acidic and alkaline preincubations. Muscle fibers are described as slow tonic (alkali-labile/acid-stable mATPase activity) or fast twitch (alkali-stable/acid-labile mATPase activity). Three varieties of fast-twitch fibers are recognized histochemically on the basis of their succinate dehydrogenase (SDH) activity: white (low SDH), intermediate (moderate SDH), and red (high SDH). Slow-tonic fibers are restricted to the deep distal area of the muscle in three species studied. All other muscle is fast twitch. In those species studied, there is a significantly (p ≤ 0.0001) higher proportion of red fibers in the deep area of the muscle as compared with the superficial area. The nature and distribution of the fiber types is characteristic of those vertebrate locomotory muscles most specialized for the rapid output of power. The nomenclature of avian extrafusal skeletal muscle fibers is discussed.
Cardiac responses of bighorn sheep to trapping and radio instrumentation
Authors: MacArthur Robert A. , Geist Valerius , Johnston Ronald H.
Published: August 2008

Heart rates of bighorn sheep (Ovis canadensis canadensis) were recorded during trapping, handling, and immediately following release of animals with electrocardiogram transmitters. Sustained tachycardia, lasting an average of 117.4 min, was demonstrated in four adult ewes and one 3-year-old ram following trapping and radio instrumentation. Cardiac recovery time of released sheep averaged 10.6 × the maximum recovery time recorded for any disturbance to which these animals were subsequently exposed. The utility of electrocardiogram telemetry in evaluating physiological stress during wildlife capture and marking operations is discussed.
Absorption intestinale des protéines sous forme macromoléculaire et leur digestion chez la Truite arc-en-ciel. Étude ultrastructurale et biochimique en relation avec la première prise de nourriture
Authors: Georgopoulou U. , Sire M. F. , Vernier J. M.
Published: August 2008

The epithelial cells of the posterior intestine of the rainbow trout differentiate some structures which, at the first feeding, allow the absorbtion of macromolecular proteins. After a transit across an apical tubulo-vesicular network, two marker proteins (horseradish peroxidase and ferritin) are segregated within an important supranuclear vacuolar system. The activities of a lysosomal protease (cathepsin) and of acid phosphatase increase strongly at the level of posterior intestine when the first feeding occurs. Juveniles can thus absorb and digest macromolecular proteins. Considering the important protein needs during this phase, this process can be of fundamental importance.
Dopamine involvement in the regulation of gonadotropin secretion in coho salmon
Authors: Kraak Glen Van Der , Donaldson Edward M. , Chang John P.
Published: August 2008

The effects of intraperitoneal injections of [D-Ala6,Pro9-N-ethylamide]-luteinizing hormone-releasing hormone (LHRH-A) and pimozide, a dopamine receptor antagonist, on plasma gonadotropin levels and ovulation in coho salmon were investigated. Both LHRH-A (0.02 mg/kg body weight) and pimozide (10 mg/kg body weight) stimulate gonadotropin secretion, with LHRH-A causing a more rapid onset of gonadotropin release and a higher magnitude increase in plasma gonadotropin levels than pimozide. Pimozide caused a marked potentiation of the gonadotropin release response to LHRH-A. Injections of LHRH-A alone and in combination with pimozide were effective means of inducing ovulation, whereas pimozide alone was ineffective. These data support the concept that dopamine participates in the regulation of gonadotropin secretion in teleosts and suggest that dopamine has a minor role in the regulation of ovulatory gonadotropin changes in coho salmon compared with cyprinids.
Dendrogaster (Crustacea: Ascothoracida) parasitic in Alaskan and eastern Canadian Leptasterias (Asteroidea)
Authors: Grygier Mark J.
Published: August 2008

The ascothoracid parasite Dendrogaster is reported from four boreal localities in the Western Hemisphere. Dendrogaster elegans Wagin infests the sea star Leptasterias polaris in Bristol Bay, Alaska, and in the Gulf of St. Lawrence; the eastern specimens have a shorter brood sac middle piece. A lectotype is selected and described for D. arctica Korschelt from L. groenlandica in the eastern Bering Sea; Siberian specimens previously assigned to this species differ from the type in many details. Immature specimens of an unidentified Dendrogaster species have been found in L. floccosa from the Davis Strait.
An ultrastructural study of oogenesis, fertilization, and egg laying in a nemertean ectosymbiont of crabs, Carcinonemertes epialti (Nemertea, Hoplonemertea)
Authors: Stricker Stephen A.
Published: August 2008

The nemertean worm Carcinonemertes epialti occurs ectosymbiotically on brachyuran crabs and becomes sexually mature while feeding on the eggs of its host. Gravid worms possess numerous saccular ovaries that lie among serially arranged diverticula of the intestine. The epithelium surrounding the lumen of each ovary contains germinal cells at various stages of development and somatic cells. Previtellogenic oocytes are typically situated in the subepidermal region of the ovarian epithelium, whereas vitellogenic oocytes tend to occur toward the intestine. The presence of numerous synthesizing organelles in vitellogenic oocytes indicates that at least some yolk constituents are produced within the ooplasm by an autosynthetic method. A supplemental form of heterosynthetic vitellogenesis may also occur, since somatic cells situated next to yolk-forming oocytes possess putative endocytotic vesicles that might help to transport yolk components derived from ingested crab eggs to the developing oocytes. Fully formed primary oocytes in the lumen of the ovary lack extracellular coats and typically measure 70–75 μm in diameter. Following fertilization, several egg strings that characteristically contain about 200 developing embryos are deposited by each gravid female in the egg mass of the crab.
Taxonomy of the genus Tubificoides Lastockin (Oligochaeta, Tubificidae): species with bifid setae
Authors: Brinkhurst R. O.
Published: August 2008

Two new species, Tubificoides fraseri and T. motei, are described and three other species are placed in synonymy: T. foliatus with T. wasselli, T. coatesae with T. brownae, and T. maureri with T. diazi. Most of these decisions refer to species that have been described separately but published jointly by the author and H. R. Baker. The original descriptions were based on separate east and west coast collections from North America that contained species that seemed separable on the basis of the material available but that now appear to belong to fewer widely distributed species. Five other Tubificoides species that lack hair setae are redescribed. Several of the species in this part of the genus seem to be widely distributed in contrast to those members of the genus with hair setae in the dorsal bundles.
Diurnal constancy of feather growth rates in White-crowned Sparrows exposed to various photoperiods and feeding schedules during the postnuptial molt
Authors: Murphy Mary E. , King James R.
Published: August 2008

To estimate the diurnal variation expenditure for feather synthesis during molt we measured the elongation of the primary remiges of White-crowned Sparrows (Zonotrichia leucophrys gambelii) through consecutive 12-h phases. All experimental birds (five groups) were illuminated and fed throughout the first 12-h phase of each cycle, but had various spans of illumination and feeding during the second 12-h phase. In spite of the differing schemes of illumination:feeding (12:12, 16:16, 16:12, 20:20, and 20:12), feather growth did not differ among groups in either 12-h phase. The grand average first-phase growth was 2.07 mm/12 h, compared with 2.05 mm/12 h in the second phase. These data suggest that nutrient expenditure for feather synthesis in White-crowned Sparrows is essentially constant throughout the 24-h cycle.
Courtship, spawning, and parental care behavior of the lumpfish, Cyclopterus lumpus L., in Newfoundland
Authors: Goulet Denis , Green John M. , Shears Tim H.
Published: August 2008

The courtship, spawning, and paternal care behavior of lumpfish, Cyclopterus lumpus, in Broad Cove, Newfoundland, are described. Breeding lumpfish are sexually dimorphic and exhibit a distinct sexual dichromatism during reproduction. Spawning females are larger than males and pale blueish green in color. Male lumpfish nuptial coloration consists of a greyish black body and an orange–red ventral surface and fins. Spawning follows an extended courtship involving nest cleaning, fin brushing, and quivering. Females extrude pink eggs onto the surface of the nest which the male fertilizes. After fertilization, males mold the eggs into the nest, producing funnel-like depressions in the egg mass. Males remain with the eggs throughout the incubation period providing parental care. Pectoral fanning and puffing, the expelling of water from the mouth towards the surface of the egg mass, are the predominant parental care behaviors exhibited throughout the incubation period. Quantitative variation between males in the amount of time spent in parental care was independent of male size. Egg masses are maintained free of invertebrate predators by the male, but males are unable to defend eggs against predation by large groups of cunners, Tautogolabrus adspersus. Puffing behavior was more frequent towards the end of the incubation period than at the beginning. During hatching emergent larvae are swept from the nest site by male fanning and puffing behaviors.
Hematological changes in Cryptobia-infected rainbow trout (Salmo gairdneri)
Authors: Lowe-Jinde L.
Published: August 2008

Rainbow trout, Salmo gairdneri, were experimentally infected with Cryptobia salmositica and total and differential erythrocyte and leucocyte abundances were examined. Total erythrocyte counts were profoundly reduced and were lowest at 4 weeks postinoculation during the peak of infection. Differential erythrocyte number showed significant reduction in mature erythrocytes, degenerating erythrocytes, and erythroblasts. The reduction in mature erythrocytes number was observed from 3 through 8 weeks postinoculation, while erythroblast reduction occurred at 1 through 5 weeks postinoculation. Subsequently, the number of erythroblasts increase and reach control values at 6, 7, and 8 weeks postinoculation. Although the total leucocyte count was not significantly changed, the differential leucocyte abundance showed that granulocytes were significantly increased. Similarly, the rarely seen, circulating, immature granuloblasts were increased. Both granuloblast and granulocyte numbers returned to control values by 8 weeks postinoculation. Thus, the pattern of differential erythrocytic and leucocytic changes reflect an acute parasitemia and a subsequent partial recovery of the infected fish to the parasitemia.
Northern, primitive Tergipedid nudibranchs, with a description of a new species from the Canadian Pacific
Authors: Millen Sandra V.
Published: August 2008

A new tergipedid nudibranch, Cuthona punicea sp. nov., is described from the Canadian Pacific. Primitive features of this species suggest that it is related to the genus Cuthonella Bergh, 1884. Comparison is made with the two extant species in this genus and evidence is presented to include the genus Cuthonella within the genus Cuthona Alder &Hancock, 1855.
An empirical evaluation of coefficients used in residual and allometric adjustment of size covariation
Authors: Reist James D.
Published: August 2008

Univariate computation of residuals or allometric variates should be used to estimate the shape of body parts of ectothermic vertebrates. For studies involving more than one group, three types of relationships may be used to calculate the slopes or allometric coefficients necessary for computing the shape variate: pooled group, common-within groups, and individual-within groups. For both residuals and allometric variates, the pooled and common-within groups coefficients resulted in similar estimates of shape when there was no between-group heterogeneity in relationships. Within-group coefficients resulted in quite different estimates of shape. Heterogeneity of slopes or allometric coefficients resulted in different estimates of shape for the same individual for pooled common-within and within-groups data. Such differences in the shape variates were cumulative in subsequent analyses such that considerably different biological interpretations of group interrelationships resulted. Thus, if any between-group heterogeneity exists in regression or allometric relationships, it is imperative that shape be estimated from the common-within groups relationship.
Feeding association between dolphins and shearwaters around the Azores Islands
Authors: Martin A. R.
Published: August 2008

During a 9-day period in August 1985, several groups of dolphins (Cetacea: Delphinidae) and shearwaters (Aves: Procellaridae) were encountered while actively feeding on the same shoals of fish around the Azores Islands. Detailed observations, made from both above and below water, showed fish apparently being herded by the dolphins into a dense ball that remained just below the sea surface and thus within reach of the birds. Shearwaters mostly ate scraps offish flesh left by the dolphins rather than entire fish and were probably little competition for the mammals. Shearwaters are thought to initiate these associations by actively joining the dolphins and their observed behaviour of following schools of nonfeeding dolphins indicates that such associations are sometimes formed deliberately rather than merely opportunistically. No benefit to the dolphins was apparent from this relationship and it is considered to be commensal.
Modes of transmission and evolution of life histories in zooparasitic nematodes
Authors: Adamson Martin L.
Published: August 2008

A hypothetical phylogeny of life-history patterns in zooparasitic nematodes is presented. It is suggested that the course of evolution of life histories has been strongly influenced by conditions under which parasitism arose; two factors appear particularly important, namely the primitive mode of transmission and the feeding habits of the ancestral populations. Two transmission modes were available at the outset: active penetration (usually cutaneous) and passive oral contamination. Only groups that arose using the former mode developed tissue parasitism and heteroxeneity. With percutaneous transmission, nematodes were forced to respond and adapt to the tissue environment from the beginnings of parasitism, and the penetrating habit probably facilitated experimentation with intermediate hosts. The Enoplida and Tylenchia arose from stylet-bearing predaceous or plant-parasitic fluid feeders adapted to feed on tissues. Cutaneous penetration was probably the primitive transmission mode and these groups were tissue dwelling at the outset. Zooparasitic Rhabditia and Diplogasteria are derived from free-living particulate feeders and the earliest parasitic forms probably fed on the intestinal microflora of the host; tissue parasitism arose secondarily and only in lineages that primitively used penetrative transmission.
Effect of brood size and age on the feeding behavior of adult and juvenile American Coots (Fulica americana)
Authors: Desrochers Barbara A. , Ankney C. Davison
Published: August 2008

From 6 July to 12 August 1984 we studied the effects of chick age and brood size on the foraging behavior of American Coots (Fulica americana). Adults dove more frequently and fed a greater proportion of prey items, captured by diving and pecking, to their chicks when the chicks were young. Adults with large broods fed their young more frequently than did adults with small broods. The frequency of chick dives increased and pecking frequency decreased as the chicks matured. Diving efficiency was greatest in young chicks and in chicks from larger broods, but pecking efficiency was greatest in old chicks, with brood size having no effect. Chicks remained close to their parents, and to emergent vegetation, when they were young and foraged farther away as they grew older. These trends seem to result from increased self-feeding capabilities and decreased dependence on parents as the chicks matured; brood size did not affect most behaviors.
Aggressiveness, incidence of singing, and territory quality of male blue grouse
Authors: Lewis Richard A.
Published: August 2008

The relative aggressiveness and proportion of time spent singing (incidence of singing) were assessed for male blue grouse (Dendragapus obscurus) occupying high- and low-quality territorial sites. Playback experiments were used to assess the relative aggressiveness of males; no support was obtained for the hypothesis that males on high-quality sites are more aggressive than those on low-quality sites. Prior experience with an area may be more important than aggressiveness in determining the quality of territorial site that is obtained. In 1 of 2 years, males on high-quality sites were observed hooting (singing) a greater proportion of the time than were males on poorer sites. A greater incidence of hooting by males on high-quality sites may be one factor that results in more females being observed near these males than near males on less suitable areas, as was found in a previous study.
Changes in structure and location of extracellular matrix of the blastocoel during development of the starfish Pisaster ochraceus
Authors: Abed Mona , Crawford Bruce John
Published: August 2008

The extracellular matrix in the blastocoel of embryos of the starfish Pisaster ochraceus is easily visualized at both the light microscope and transmission electron microscope levels prior to the appearance of mesenchyme cells if the anionic dye alcian blue is included in the fixative. In the early gastrulae, the extracellular matrix is located close the ectodermal and endodermal cells and has four distinct forms: small visicles, amorphous material, granules of densely stained material, and short strands of intermediate staining density. The latter two types are usually associated with one another. A short time later, the extracellular matrix begins to organize into longer strands of intermediate staining density with dense granules located along their length and vesicles and amorphous materials in close association. Initially the strands appear to be unbranched; however, by mid gastrula they have formed an extensive, branched meshwork filling the blastocoel area adjacent the tip of the archenteron. This meshwork consists primarily of the dense granules arranged along the intermediate staining filaments. Crescent-shaped regions of dense granules are occasionally seen in the blastocoel adjacent the ectodermal cells during this period. Similarly shaped regions consisting primarily of vesicles and amorphous material are seen adjacent the endodermal cells. Shortly after the mesenchyme cells appear in the blastocoel, the strands of the meshwork located in the presumptive mouth region are arranged in a radial manner and appear thicker; the dense material is more evenly distributed, and small regularly spaced protrusions are found along their length. The results suggest that a meshwork of strands is gradually built up, probably by self-assembly of components derived from both the ectoderm and endoderm, before the mesenchyme cells enter the blastocoel. The organization of this meshwork of strands appears to be altered after the appearance of the mesenchyme cells which migrate through it.
Influence of reproductive history of parents on meristic variation in offspring in the cyprinodont fish Rivulus marmoratus
Authors: Swain D. P. , Lindsey C. C.
Published: August 2008

Parent fish from one clone of the self-fertilizing cyprinodont fish Rivulus marmoratus were held under constant conditions, and their offspring were examined for meristic variation associated with their position in the oviposition sequence of parents. In all meristic series counted (vertebrae, and anal, dorsal, pectoral, and caudal fin rays) those offspring produced soon after their parents had begun to lay eggs tended to have fewer parts than did those produced longer after the onset of oviposition. Most meristic differences were due to the low counts produced in embryos laid within 8 days of first oviposition; counts differed little among embryos laid at averages of 22, 86, and 158 days after first oviposition. Differences were most significant for dorsal and anal rays and not significant for caudal rays.
An annotated key to the adult males of the northwestern Nearctic species of Paraleptophlebia Lestage (Ephemeroptera: Leptophlebiidae) with the description of a new species
Authors: Harper Françoise , Harper P. P.
Published: August 2008

An illustrated key to the males of the northwestern Nearctic species of Paraleptophlebia Lestage is presented together with a short account of the taxonomy and the ecology of the species. Paraleptophlebia aquilina n.sp. is described and illustrated. Paraleptophlebia sculleni Traver is reinstated as a valid species and how it differs from P. gregalis (Eaton), with which it had been synonymized, is described. The status of P. memorialis (Eaton) and that of P. temporalis (McDunnough) are redefined.
Seasonal occurrence of, development of, and the influences of selected environmental factors on the larvae of Prosimulium and Simulium species of blackflies (Diptera: Simuliidae) found in the rivers of southwestern Alberta
Authors: Shipp J. L. , Procunier W. S.
Published: August 2008

Larval development of Simulium arcticum Malloch (IIL-3), S. defoliarti Stone and Peterson (IIS-14.15), and S. tuberosum Lundström (FG) was documented for four rivers in southwestern Alberta from 1982 to 1984. Simulium arcticum (IIL-3) and S. tuberosum (FG) had seven instars; these two species were multivoltine with two or three generations per year, while S. defoliarti (IIS-14.15) was univoltine. Water temperature, river discharge, and turbidity were the only environmental factors of five parameters measured that were significantly correlated with the seasonal development of larvae of S. arcticum (IIL-3), S. defoliarti (IIS-14.15), S. vittatum Zetterstedt complex, S. tuberosum (FG), and Prosimulium onychodactylum Dyar and Shannon complex. Also, we speculate on the effect that food quality and quantity have on larval growth and development of blackfly species that breed in mountain rivers.
Effects of dietary aluminum sulphate on reproductive success and growth of Ringed Turtle-Doves (Streptopelia risoria)
Authors: Carrière D. , Fischer K. L. , Peakall D. B. , Anghern P.
Published: August 2008

Elevated levels of aluminum have been reported in surface waters and in certain aquatic organisms including aquatic insects. Toxic effects have been demonstrated in fish and it has been suggested that aluminum affects avian reproduction. In this study Ringed Turtle-Doves were assigned to a control group fed a diet reduced in calcium and phosphorus and to a treated group fed the same diet supplemented with 0.1% aluminum. A 4-month feeding period with aluminum sulphate did not result in any effect on egg production, fertility, or hatchability. Egg permeability was decreased initially but subsequently recovered to a normal level. Dietary aluminum sulphate did not affect plasma calcium, phosphorus, or magnesium of adults nor did it affect the pattern of growth and the final weight of chicks feeding on the same diet. Bone aluminum levels of breeding females averaged twice those of the controls (P < 0.05). The pattern of accumulation between the two sexes was significantly different (P < 0.05). Growth of juvenile Ringed Turtle-Doves was not affected by dietary levels of aluminum sulphate up to 1500 ppm, although aluminum tended to accumulate in the bones of the sternum. No significant influence of aluminum on reproduction or growth, at levels similar to those likely to occur in the environment, could be found in the course of our laboratory experiment.
Winter habitat preferences of juvenile salmonids in two interior rivers in British Columbia
Authors: Swales S. , Lauzier R. B. , Levings C. D.
Published: August 2008

The winter distribution and abundance of juvenile salmonids was investigated in various main channel and off-channel habitats in the Coldwater and Nicola rivers in the southern interior region of British Columbia. Catches were generally low in all main channel habitats, with coho salmon and steelhead trout being most abundant and chinook salmon and Dolly Varden char being present in smaller numbers. Coho salmon and steelhead trout catches were generally highest in pools with abundant instream and riparian cover. Steelhead trout was the main species in riprap bank protected areas, although catches were generally low. Highest overall catches were recorded in side channels and off-channel ponds, where water temperatures were usually several degrees higher than in the main river. Coho salmon was the main species in the two Coldwater off-channel ponds with overwintering populations of approximately 4000 and 1000 in 1- and 0.1-ha ponds, respectively (0.4–1.5 fish/m2): overwinter survival of coho salmon in the ponds was estimated to be 87 and 54%, respectively. High densities of coho salmon were also recorded in side channels on the Nicola River (1.5–1.8 fish/m2), together with smaller numbers of chinook salmon and steelhead trout (0.2–0.3 fish/m2). Growth in ponds and side channels appeared to be faster than in main channel habitats. We conclude that juvenile salmonids in the rivers investigated showed considerable habitat segregation during the winter. As in coastal rivers, juvenile coho salmon made extensive use of off-channel ponds, while rainbow trout and chinook salmon were generally most abundant in riprap and deep pools containing log debris, respectively.
Dynamics of caribou and wolves in northern British Columbia
Authors: Bergerud A. T. , Elliot J. P.
Published: August 2008

Major fluctuations in caribou (Rangifer tarandus) numbers have occurred since the settlement of European man in British Columbia. Caribou declined in the late 1930's and 1940's after moose (Alces alces) expanded their range and wolves (Canis lupus) increased. Following a wolf reduction program from 1949 to 1962, the caribou expanded until a high was reached in the late 1960's, after which the herds again diminished as wolf numbers increased and calf recruitment decreased. Three caribou populations were censused between 1976 and 1982, and an experiment was conducted on one of these areas (with the others as controls) to test the effect of wolf numbers on herd growth. The Spatsizi–Lawyers and Level–Kawdy populations inhabited ranges where wolf densities were near 9–10wolves/1000 km2;Spatsizi–Lawyers declined between 1977 and 1982(r = −0.13) and Level–Kawdy declined between 1977 and 1982(r = −0.12). We reduced wolves at the experimental Horseranch population from 10 to 1–4/1000 km2 and these caibou increased from 1977 to 1982 at an average exponential rate of 6% per year. None of the populations were heavily hunted; however, both declining populations had low calf survival with a mean of 55% of the calves dying within the first 2 weeks of life. Calf survival increased significantly at the Horseranch in the 3 years that wolves were reduced. In conclusion, we believe that the Spatsizi–Lawyers and Level–Kawdy populations declined as a result of predation on calves and adults. Yet, if wolves are managed to provide stabilizing recruitments for caribou, it should be possible to dampen the natural fluctuations of caribou and wolves that are frequent in unperturbed systems and maintain higher numbers of both species.
Revision of Hedruris Nitzsch (Nematoda: Habronematoidea) from aquatic vertebrates of North America
Authors: Baker M. R.
Published: August 2008

The five currently recognized Hedruris spp. from North America were compared based on museum and other specimens. Only the following two species were shown to be valid: H. pendula (Leidy, 1851) Chandler, 1919 and H. siredonis Baird, 1858. Hedruris tiara Van Cleave &Mueller, 1932 is shown to be synonymous with H. pendula, whereas H. brevis Walton, 1930 and H. chandleri Freitas &Lent, 1941 are synonymous with H. siredonis. Hedruris pendula is apparently mainly parasitic in freshwater turtles of eastern North America, although it may infrequently occur in fish and frogs. Hedruris siredonis has been reported only in salamanders (Ambystomatidae, Salamandridae, Plethodontidae), apparently throughout North America. This species varies considerably in the size of mature adult worms.
Do white whales, Delphinapterus leucas, carry surrogates in response to early loss of their young?
Authors: Smith T. G. , Sleno G. A.
Published: August 2008

Seven sightings in which mature belugas were seen to persist in carrying inanimate objects leads us to the hypothesis that this might be surrogate behaviour in response to perinatal mortality. The long period of dependence by the calf on its mother would indicate a strong mother–calf bond in this species, which might lead to such an extreme manifestation of protective behaviour.
Symbiosis between salamander eggs and green algae: microelectrode measurements inside eggs demonstrate effect of photosynthesis on oxygen concentration
Authors: Bachmann Marilyn D. , Carlton Richard G. , Burkholder JoAnn M. , Wetzel Robert G.
Published: August 2008

Eggs of the spotted salamander, Ambystoma maculatum, are usually green because of the presence of symbiotic, chlamydomonad algae which inhabit the envelope of each egg. An oxygen-sensitive electrode was used to measure the effect of algal photosynthesis on oxygen concentration inside eggs and within the gelatinous matrix surrounding them. During darkness, oxygen became severely depleted within the eggs, but upon exposure to light oxygen concentrations increased rapidly. Photosynthetic oxygen production by the chlamydomonads exceeded respiratory consumption by the embryo–algae complex and led to oxygen supersaturation inside eggs, even when water surrounding the egg mass was almost anoxic.
Starvation and refeeding in Tribolium castaneum (Herbst). I. Effect on some biochemical components of sixth instar larvae
Authors: Saleem Mushtaq A. , Shakoori A. R.
Published: August 2008

Five days of starvation led to a significant increase in the amylase activity of sixth instar larvae of Tribolium castaneum. Acid phosphatase, alkaline phosphatase, and lactate dehydrogenase activities and glucose, glycogen, free amino acids, and RNA contents showed a significant decrease. Other parameters such as glutamate oxaloacetate transaminase, glutamate pyruvate transaminase, total protein, soluble protein, lipids, cholesterol, and DNA content did not show any significant deviation. On prolongation of starvation for 10 days all the biochemical parameters tested were significantly reduced, except for the amylase activity and cholesterol content, which showed highly elevated values. The total and soluble protein content remained unaltered. Refeeding of starved larvae tended to normalize some of the parameters such as glucose, lipids, glycogen, and DNA. On the other hand, lactate dehydrogenase, acid phosphatase, alkaline phosphatase, glutamate oxaloacetate transaminase, glutamate pyruvate transaminase, free amino acids, and RNA decreased drastically, whereas the soluble protein and cholesterol contents increased considerably in refed larvae.
Reversible arrest of Artemia development by cadmium
Authors: Rafiee Parvaneh , Matthews Christopher O. , Bagshaw Joseph C. , MacRae Thomas H.
Published: August 2008

Under normal conditions, an encysted Artemia embryo undergoes a developmental process that culminates in the gradual, uninterrupted emergence of the prenauplius from the cyst. The hatching membrane surrounding the emerged organism is then ruptured, usually beginning at the posterior end, and a motile nauplius is released. We have observed this process microscopically in the presence and absence of cadmium and report that cadmium disrupts Artemia development in a dose–dependent manner. At 0.1 μM, cadmium slows emergence but nauplii eventually resume rellatively normal development. Emergence and hatching are either delayed considerably or almost entirely prevented at 1 μM cadmium. Cadmium at 10 μM, completely arrests emergence but development continues at a reduced rate, eventually resulting in hatching of some organisms without need for complete emergence. If organisms exposed to 10 μM cadmium are washed, abnormally shaped emerged forms are released and many of these eventually hatch, although in an unusual manner. Cadmium at 10 μM causes complete, rapid precipitation of purified Artemia tubulin at 0 °C but cadmium at the lower concentrations tested has no apparent inhibitory effect on microtubule assembly. Although we do not know the actual cadmium–induced physiological changes that result in abnormal development of Artemia, our results indicate that we can now examine the interdependence of morphological and molecular aspects of Artemia development in a way not previously possible.
Food habits of breeding white-winged scoters
Authors: Brown Patrick W. , Fredrickson Leigh H.
Published: August 2008

Twenty-four adult and 10 duckling white-winged scoters were collected on four lakes in central Saskatchewan during the summers of 1977–1980. Hyalella azteca was the most important scoter food and made up 97% (aggregate percent dry weight) of the diet for 13 breeding females, 84% for 11 breeding males, and 100% for 10 ducklings. Hyalella azteca was consistently the most abundant food organism present in Eckman dredge samples taken at scoter feeding sites. Adults consumed H. azteca that were significantly larger than those consumed by ducklings. Both adults and ducklings fed primarily by diving at sites 1–3 m deep, but adults fed at deeper sites than ducklings. Timing of reproduction in white-winged scoters seems to be closely timed with increases in the biomass and abundance of Hyalella and possibly other invertebrate foods.
The effect of short-term acidification during spring snovvmelt on selected Mollusca in south-central Ontario
Authors: Servos Mark R. , Mackie Gerry L.
Published: August 2008

Limestone and sulfuric acid were used to manipulate the pH of water in three artificial channels in the outflow of Plastic Lake, south-central Ontario, during the spring of 1982. Using artificial channels allowed the manipulation of pH during a natural pH depression (i.e., spring snowmelt) while minimizing confounding factors such as mobilization of metals from aquatic sediments. Addition of sulfuric acid extended and exaggerated the natural pH depression (from pH 5.8 to 4.8) to as low as pH 3.5 over 5 days, while addition of limestone prevented depression of pH below 6.4. Survival and reproduction of the pisidiid clams Pisidium equilaterale Prime and Pisidium casertanum (Poli) and the hydrobiid snail Amnicola limosa Say held in artificial channels were not significantly different (p > 0.05) among treatments. The survival and reproduction of A. limosa was also not affected by exposure to short-term pH depressions (e.g., 5.8 to 4.8; 4.8 to 4.3) in three south-central Ontario streams during spring snowmelt. For various life stages of both P. equilaterale and A. limosa, 96-h LC50 values were below pH 4.0, which was well below the pH observed in any stream in this study. These results suggest that recruitment failure and elimination of A. limosa from acidifying lakes noted in other studies was not a direct result of short-term pH depression during snowmelt.
Premières données sur la dynamique d'une population d'Oikopleura dioica Fol, 1872 (Appendiculaire) en élevage
Authors: Fenaux Robert , Bedo Alain , Gorsky Gabriel
Published: August 2008

Several parameters that characterize a population arising from a single male–female pair of Oikopleura dioica Fol, 1872 (Appendicularia) were studied in our culture system. Egg volume varied by a factor of 1.4. Daily size of individuals in a population followed a Gaussian distribution, and the spread of this distribution increased with time. In a population that arose at 18 °C from 252 eggs, mortality reduced the number of individuals to 162 after 5 days. During the following 4 days, the appendicularians reached sexual maturity and died after gametes were released. The first individuals to mature were males, 115 h after fertilization. Average trunk sizes of mature animals are 942 ± 95 μm for males and 1165 ± 104 μm for females. All appendicularians released their gametes and died 215 h after fertilization. The number of eggs per female showed considerable variation, ranging between 41 and 362, with an average of 170 ± 78. Different causes for mortality during the entire life cycle are analysed.
Population dynamics of the helminth community from migrating blue-winged teal: loss of helminths without replacement on the wintering grounds
Authors: Wallace B. M. , Pence Danny B.
Published: August 2008

The main and interactive effects of host and seasonal factors on abundance of 22 common helminth species from fall and spring migratory blue-winged teal collected in the Texas Panhandle were examined. Although abundances of many common helminth species were greater in immature than adult birds just off the breeding grounds, fall-collected adults had higher abundances of most helminth species than did both juvenile and adult birds from the wintering grounds in Mexico. While total abundance of helminths declined on the wintering grounds to only 54% of that from fall-collected birds, overall species composition and abundances of some helminth species were equivalent in the host population throughout the year, regardless of changing geographic locality and migratory stress. The helminth fauna acquired in the northern latitude breeding grounds was not replaced by an ecologically equivalent fauna in the southern latitude wintering grounds. Only one species, Corynosoma constrictum, was lost without replacement during the wintering period. Schistorphus cucullatus, a parasite of the Raillidae, occurred in birds on the wintering grounds but was lost without replacement on the breeding grounds. Thus, most of these helminth species were capable of ubiquitous transmission across the range of this host and (or) infections of the respective species persisted through the migratory stress period. This study suggests that diversity in the helminth community of a migratory host species over its entire geographic range may largely result from differences between separate populations that have become isolated over time as a result of establishing specific migratory corridors, rather than from the short-term effects of environmental differences between regions representing the extremes of the overall migratory range (breeding and wintering grounds).
Hemolymph responses of Alaskan king crabs to rhizocephalan parasitism
Authors: Shirley Susan M. , Shirley Thomas C. , Meyers Theodore R.
Published: August 2008

Hemolymph from three king crab species, red (Paralithodes camtschatica), blue (P. platypus), and golden (Lithodes aequispina), parasitized by the rhizocephalan Briarosaccus callosus was examined for parasite-induced changes. Protein, hemoglobin, hemocyanin, and glucose concentrations, hemocyte counts, pH, osmolality, and hemolymph ion concentrations were measured. Parasite hemolymph was also examined. Effects on host hemolymph were decreased osmolality and sodium and chloride concentrations, and increased protein, hemocyanin, and glucose concentrations. Not all effects occurred in each host species. Correlations existed in some host species between number of externae and sodium and protein concentrations and shell condition. Protein electrophoregrams of parasitized and unparasitized crabs were similar. The red color of parasite hemolymph was due to hemoglobin averaging 5.8 mg/mL. No parasite hemoglobin was found in the host hemolymph. Electrophoregrams of parasite hemolymph from the three host species were similar. Hemocyanin was present in parasite hemolymph from red and golden king crab hosts. No significant difference in hemocyte count existed between parasitized and unparasitized blue king crabs. Red and golden king crabs exhibited a response that could explain their lower rates of parasitism and less frequent multiple infections, while blue king crabs had little defense against the parasite.
Description of Butlerius canadensis n. sp. (Nematoda: Diplogasteridae) with an emendation of the genus and a proposal for Parabutlerius n. gen.
Authors: Ebsary B. A.
Published: August 2008

Butlerius canadensis n. sp. is described and illustrated from Quebec, Canada. The new species is most similar to B. gerlachi but differs by having the cheilostom aperture divided into 12 cheilorhabdial plates, a more anterior pore-like vulva (V = 41–43% vs. 51–54%), 30 cuticular body ridges with transverse striae forming blocks, and a tail that is at least twice as long as that of B. gerlachi. A new genus, Parabutlerius, is proposed for Butlerius species with a single anterior ovary, a large postvulval sac serving as a spermatheca, and a triangular or keel-like gubernaculum. Butlerius is emended to reflect the transfer of species to the new genus. The following changes are proposed: Parabutlerius monhystera n. comb, (type species), P. degrissei n. comb., and P. macrospiculum n. comb. Keys to the species of Butlerius and Parabutlerius are provided.