bluuebunny/crossref_metadata_2025 huggingface dataset:
Life history and production of Ephoron album (Say) (Ephemeroptera: Polymitarcidae) in the Valley River, Manitoba
Authors: Giberson D. J. , Galloway T. D.
Published: March 2009

Ephoron album was the dominant summer mayfly in shallow riffles in the agricultural zone of the Valley River, Manitoba, in 1982 and 1983. There was one generation per year; eggs deposited in August hatched in late May of the following year and nymphs developed rapidly during the summer months. The eggs required a cold period to promote hatching and hatching success of eggs treated in the laboratory at −2 °C for varying periods of time was positively correlated to the length of the exposure period. No eggs hatched following exposure to 4 or 10 °C. Production for 1982 was estimated by four methods for the production interval of only 72 days: the instantaneous growth rate method (1.32 ± 0.44 g fresh dry weight∙m−2∙year−1), the Allen curve method (1.32 g∙m−2∙year−1), the removal – summation method (1.43 ± 0.41 g∙m−2∙year−1), and the size–frequency method (1.48 ± 0.51 g∙m−2∙year−1). Confidence intervals (95%) were calculated using the method of C. C. Krueger and F. B. Martin for the size–frequency estimate of production and by bootstrapping for the removal–summation and instantaneous growth estimates.
Cellular localization of pepsinogens by immunofluorescence in the gastrointestinal tracts from four species of fish
Authors: Reifel C. W. , Marin-Sorensen M. , Samloff I. M.
Published: March 2009

Using antiserum against human pepsinogen I and pepsinogen II, we investigated the cellular localization of pepsinogens by immunofluorescence in the stomach and proximal intestine of four species offish (Ambloplites rupestris, Lepisosteus osseus, Lepomis gibbosus, and Perca flavescens). In each species, only the oxynticopeptic cells in the corpus of the stomach stained with antiserum against pepsinogens I and II. Fluorescent cells were absent in the surface epithelium of both the stomach and small intestine. The results indicate that the oxynticopeptic cells are the source of pepsinogen in fish and suggest that these cells contain two immunochemically distinct pepsinogens that share antigenic determinants with human pepsinogens I and II.
Seasonal changes in the freezing tolerance of the intertidal pulmonate gastropod Melampus bidentatus Say
Authors: Loomis Stephen H.
Published: March 2009

The mean lethal temperature of Melampus bidentatus Say ranged from −5 °C in July to −13 °C in December. The percentage of tissue water frozen measured at the mean lethal temperatures was 3% for snails collected in the summer and 74.9% for snails collected in the winter. The supercooling point of the whole snails ranged from −9 °C in September to −6.4 °C in February. The presence of an ice nucleator is indicated by an increase in the supercooling point of the haemolymph from −11.5 °C in the fall to −7.5 °C in the winter. Water content in the snails varied from 2.6 mg water/mg dry weight to 3.6 mg water/mg dry weight; however, there was no correlation between low water contents and an increase in freezing tolerance. Whole animal glycerol contents ranged from 1.14 to 2.96 μmol/g fresh weight and proline contents ranged from 1.20 to 2.19 μmol/g fresh weight. Sorbitol and trehalose were not detected.
Head scarring on male narwhals (Monodon monoceros): evidence for aggressive tusk use
Authors: Gerson Helen B. , Hickie John P.
Published: March 2009

The data presented here provide strong evidence that support the hypothesis that the narwhal's tusk is used during fights between mature males. Evidence of violent fighting among adult males includes high numbers of head scars, broken tusks, and a tusk tip embedded in a skull. Females and immature males had significantly fewer head scars, and immature males had a significantly lower incidence of broken tusks. Among mature males, scar number was positively related to body girth, tusk weight, and tusk girth, but not to tusk length or body length. Relating dominance to the pattern of many head scars on massive mature males with massive tusks is consistent with data from other species for which both anatomical and behavioural observations are available. The lack of significant correlations of tusk length with body length and body girth in mature males is not consistent with the hypothesis that dominance assessment is based on a display of tusk lengths.
Activity budgets of northern pintail hens: influence of brood size, brood age, and date
Authors: Guinn Shirley J. Rushforth , Batt Bruce D. J.
Published: March 2009

Time budgets of pintail brood hen behaviour were collected at Oak Hammock Marsh, Manitoba, from June to August 1979. Hens spent 60.8% of their time at self-maintenance activities (feed, comfort movements) and 34.6% of their time at dominant parental care activities (alert, lead, follow). Hens with large broods allocated more time to self-maintenance than did hens with small broods. Time spent at parental care activities did not vary with brood size. The total time spent at parental care activities was higher for class I than class II broods. However, this pattern was not consistent across activities. Brood age did not influence time spent at self-maintenance. Hens spent more time at self-maintenance (feeding) and less time at parental care in late than in early season. We related this to the hen's need to recover weight lost during incubation, to acquire energy for a complete body plumage molt, and to prepare for fall migration. This paper describes patterns of time allocated to parental care. We conclude that estimates of costs of parental investment during the brood rearing period are also required.
Regulatory peptides in the amphibian pancreas
Authors: Buchan Alison M. J.
Published: March 2009

The pancreas from 11 amphibian species was investigated by immunocytochemical methods for the presence of immunoreactivity to a number of antisera raised to mammalian regulatory peptides. The hormones studied were insulin, pancreatic glucagon, enteroglucagon (glicentin), pancreatic polypeptide, somatostatin, gastrin, gastric inhibitory polypeptide, substance P, bombesin, methionine enkephalin, and vasoactive intestinal polypeptide. Immunoreactive cells were detected in all species with the antisera to insulin, somatostatin, pancreatic glucagon, enteroglucagon, and pancreatic polypeptide. The cells stained by the two glucagon antisera and the pancreatic polypeptide antiserum were identical in all species examined. Fine nerve fibres immunoreactive with the antiserum to vasoactive intestinal polypeptide were demonstrable only in the anuran species Hyla arborea (Hylidae). The remainder of the antisera did not detect either endocrine cells or nerve fibres in the species studied.
Isozyme characterization of 28 cell lines from five insect species
Authors: Harvey G. T. , Sohi S. S.
Published: March 2009

Correct identity of cell lines is essential for their use in any investigation; isozyme patterns of cell cultures can give reliable identification. Starch gel electrophoresis was used to develop isozyme profiles of 8 hymenopteran and 20 lepidopteran cell lines and of the insect species from which they were developed. Species identity of 26 of the cell lines was confirmed. For nine of the cell lines these results support the identity established by serological and chromosomal analyses. For the remaining cell lines they provide the first confirmation of species identity. Isozyme profiles of several cell lines from the same species showed unique characteristics that will be useful in monitoring their identity. Two cell lines (IPRI-OL-7 and IPRI-OL-11) considered to be from Orgyia leucostigma appear to contain isozymes of Choristoneura fumiferana. Other supporting evidence and possible causes of this contamination are discussed. These results demonstrate the usefulness of isozyme profiles for the identification and monitoring of cell cultures.
The significance of supplemental food to polar bears during the ice-free period of Hudson Bay
Authors: Lunn N. J. , Stirling Ian
Published: March 2009

Polar bears were studied near Churchill, Manitoba, to evaluate the possible importance of supplemental food. Once ashore, bears became segregated by age and sex; family groups and pregnant females moved inland into a denning area, while single bears, especially adult males, remained along the coast. Bears were inactive and fed little. Analysis of blood samples taken from bears in the denning area suggested that they also were not feeding. By remaining inactive, they are able to minimize energetic demands and the chance of hyperthermia. After 2 months ashore, some bears, mainly family groups and subadults, fed in the Churchill dump. The data indicated that individual needs and learning were major factors determining which bears used the dump. Adult males did not feed there even though they may have been there previously as cubs or subadults. Bears which fed in the dump were significantly heavier than those which did not. There was no evidence that bears using the dump gained either reproductive or survival advantages. We conclude that polar bears will use supplemental food sources which are available or if they have previously learned their location; however, it is not necessary for their survival.
Mating seasons and fertility of red squirrels in southern Québec
Authors: Lair Hélène
Published: March 2009

The breeding ecology of the red squirrel (Tamiasciurus hudsonicus) was studied in a mixed conifer – hardwood forest in southern Québec between June 1978 and October 1980. There were two mating seasons per year, one in March–April and one in June–July. The average size of 12 litters was 4.2 young (4.6 in 1979 and 4.0 in 1980). The sex ratio (female: male) of young was 23:25. The earliest recorded age at first successful mating was 10 months. In 1979, nearly all females, including yearlings, bred successfully in the spring and 50% of them raised a second litter. In 1980, only adult females produced young in the spring and four of six yearlings reproduced in the summer. A maximum of 29% of all females could have produced two litters in 1980. Differences in birth rate between the two years may be explained by a lower quality and (or) quantity of food resources at mating time rather than a drop in food supply available the previous fall.
Variation in digestive organ size among five species of diving ducks (Aythya spp.)
Authors: Kehoe F. Patrick , Ankney C. Davison
Published: March 2009

Ceca length, small intestine length, and gizzard weight were measured for individuals of five species of diving ducks collected at Long Point Bay, Lake Erie, and Mitchell's Bay, Lake St. Clair, Ontario, in the falls of 1982 and 1983. The five species were Lesser Scaup (Aythya affinis, N = 84), Ring-necked Duck (Aythya collaris, N = 57), Greater Scaup (Aythya marila, N = 54), Redhead (Aythya americana, N = 58), and Canvasback (Aythya valisineria, N = 112). The diets of these species reportedly differ in diversity as well as in amount of fibre, and interspecific differences in gut morphology, not explained by differences in body weight, were accounted for by general differences in diet. Canvasbacks, although the heaviest species, had the shortest ceca, short intestines and light gizzards, presumably because their diet contains the least fibre. Conversely, the relatively small-bodied scaup species had the longest small intestines, likely because of their diverse diets which include animal and plant material. Our results show that morphological differences in waterfowl guts reflect dietary differences at a particular time and location and also illustrate the importance of adjusting gut measurements to body weight before making interspecific comparisons.
Two new species of Plectus with a redescription of Plectus cancellatus Zullini, 1978 (Nematoda: Plectidae) from Canada
Authors: Ebsary B. A.
Published: March 2009

Two new terrestrial species of Plectus from Canada are described and illustrated. Plectus amorphotelus n. sp. and Plectus spicacaudatus n. sp. are distinctive amongst Plectus species because of the absence of caudal glands and cuticularized spinnerets. Plectus amorphotelus is readily recognized by the head that is not set off and by the degenerate, irregularly shaped spinneret. Plectus spicacaudatus is differentiated by the set-off head, the anterior position of the amphids which lie between the cephalic setae bases, and the absence of a spinneret on the pointed tail. Plectus cancellatus females are redescribed and differ from the original description by usually having a blocked cuticle over the entire body, a globular cheilostom, and a fringe of rounded spines at the spinneret base. A key to the females of Plectus species is also provided.
Social interactions of coho salmon (Oncorhynchus kisutch) smolts in seawater
Authors: Paszkowski Cynthia A. , Olla Bori L.
Published: March 2009

The behavior of coho salmon (Oncorhynchus kisutch) smolts was examined under laboratory conditions to determine if the hierarchical–territorial social system characteristic of this species in freshwater persisted in seawater. When held in groups of two to eight fish, hatchery-reared, accelerated underyearling smolts formed hierarchies controlled by a single dominant who was responsible for most of the observed movement, chases, and feeding. Agonistic behavior also occurred within pairs of recently smolted fingerlings from two hatchery stocks with different rearing histories and in groups containing free-ranging fish captured off the Oregon coast. Possible relationships between the observed social behavior and marine distribution patterns of juvenile coho salmon are discussed.
Kupffer's vesicle in Brachydanio rerio: multivesicular origin and proposed function in vitro
Authors: Laale Hans Willer
Published: March 2009

Stage 16+ endomesodermal caudal explants from embryos of the zebrafish, Brachydanio rerio (Hamilton-Buchanan), were maintained in vitro for up to 48 h at 24 ± 2 °C. The development of Kupffer's vesicle by multivesicular coalescence and subsequent atrophy is described. Kupffer's vesicle in the absence of periblast and epidermal ectoderm is shown to be mesodermal in origin and not a remnant of the archenteron. The vesicle similarly would appear to play no role in the mediation of nutrients from the yolk via a modified periblast under conditions of culture.
The Nearctic caddisfly genus Hesperophylax Banks (Trichoptera: Limnephilidae)
Authors: Parker C. R. , Wiggins G. B.
Published: March 2009

Seven species of Hesperophylax are recognized: alaskensis (Banks), consimilis (Banks), designatus (Walker), magnus Banks, minutus Ling, occidentalis (Banks), and mexico n.sp. Hesperophylax alaskensis is reestablished as a valid species distinct from occidentalis. Hesperophylax incisus Banks is placed as a junior subjective synonym of designatus. Hesperophylax oreades Saether is placed as a junior subjective synonym of Psychoronia costalis (Banks). Keys are provided for identification of males, females, and larvae. A hypothesis of phylogeny is proposed in which consimilis is the sister group of all other Hesperophylax; magnus and mexico are sister species and together are the closest relatives of occidentalis, designatus, and alaskensis; designatus and alaskensis are sister species. An interpretation of biogeography is offered, suggesting how geological events affected the origin and distribution of Hesperophylax species. Data on food, life cycle, habitat, and distribution are given. All species appear to be univoltine with extended flight periods. Larvae are opportunistic omnivores, but magnus is more predaceous than the other species. Differences in mandibular morphology between consimilis and the other species are not reflected in the food habits of the larvae. Among Trichoptera the species of Hesperophylax are little differentiated morphologically and most species vary within unusually broad limits; most species occur in a wider range of habitat types than do other Trichoptera. Perhaps those factors represent a genetic plasticity selected for generalized adaptability rather than the habitat specialization of other Trichoptera.
Lack of diet segregation between sexes and age groups in feral horses
Authors: Lenarz Mark S.
Published: March 2009

Past research on large ungulates has suggested that species might minimize intraspecific competition by assuming sex- or age-specific diets. Diet segregation has, in fact, been documented in a variety of taxa but tends to be confounded by sexual dimorphism or differential range use. A hypothesis regarding diet selection was tested using food habits data from feral horses. The results indicate that diet segregation does not take place either between sexes or among age groups.
Ultrastructure of the cysts of Sarcocystis rangiferi from skeletal muscle of reindeer (Rangifer tarandus tarandus)
Authors: Gjerde Bjørn
Published: March 2009

Cysts of Sarcocystis rangiferi from reindeer (Rangifer tarandus tarandus) were examined by transmission electron microscopy. The cysts were located within skeletal muscle cells which were encapsulated by a thick layer of connective tissue. The connective tissue capsule consisted of numerous fibroblasts and a matrix with a moderate number of collagen fibrils, and represents an analogue of the so-called secondary cyst wall of Sarcocystis gigantea and various Besnoitia species. The cysts were limited by a unit membrane, the cyst membrane, which in part was reinforced by a thin subjacent layer of electron-dense material. The cyst surface was covered by closely packed, villiform protrusions, measuring 12–14 μm in length and 8 μm in diameter. The cyst membrane formed vesiclelike invaginations at and between the bases of the protrusions. Cyst ground substance divided the interior of the cyst into numerous compartments containing metrocytes or cystozoites. The cystozoites multiplied by endodyogeny.
Pseudascarophis kyphosi n.gen., n.sp. (Nematoda: Cystidicolidae) from the stomach of the fish Kyphosus cinerascens (Forskål) from Japan
Authors: Ko R. C. , Margolis L. , Machida M.
Published: March 2009

Pseudascarophis kyphosi n.gen., n.sp. (Nematoda: Cystidicolidae) is described for specimens collected from the stomach of Kyphosus cinerascens (Forskål) from the southeast coast of Japan. The new genus is distinguished from all other genera of Cystidicolidae by its oral structure (presence of four submedian, longitudinally directed, digitiform processes in the buccal cavity projecting slightly beyond the oral opening; smooth margined mouth; absence of submedian labia and sublabia; and unique shape of the medial region of the pseudolabia) and numbers of caudal papillae in the male (3 pairs preanal, 7 pairs postanal).
Seasonal dynamics and distribution of American dog tick, Dermacentor variabilis (Say), larvae and nymphs at Birds Hill Park, Manitoba
Authors: Burachynsky V. I. , Galloway T. D.
Published: March 2009

During a 2-year study on the relationships between immature Dermacentor variabilis and their small-mammal hosts near Birds Hill, Manitoba, 739 captures of 427 mammals were examined for ticks. Captures represented 11 mammal species: Clethrionomys gapperi, Lepus americanus, Microtus pennsylvanicus, Mus musculus, Peromyscus maniculatus, Sorex cinereus, Spermophilus franklinii, Spermophilus tridecemlineatus, Tamias striatus, Tamiasciurus hudsonicus, and Zapus hudsonius. Clethrionomys gapperi, M. pennsylvanicus, P. maniculatus, S. franklinii, and Z. hudsonius were most frequently encountered and, with the exception of S. franklinii, infested with larvae and nymphs. Clethrionomys gapperi were most frequently infested by D. variabilis and produced 42.6% and 60.5% of larvae collected in 1979 and 1980, respectively, and over 85% of all nymphs. Peak larval infestation occurred between the last week of May and the middle of June; that for nymphs occurred in July in both 1979 and 1980. Dermacentor variabilis appeared to have a 2-year life cycle in Manitoba. Larvae were spatially aggregated during both years and aggregates were located in different areas of the plots each year. Nymphs were less aggregated than larvae. The distribution of nymphs overlapped that of larvae each year and occupied a greater area on the plots.
Ovarian neutral lipid fatty acid composition varies with state of ovarian growth in landlocked Atlantic salmon
Authors: Wiegand M. D. , Idler D. R.
Published: March 2009

The ovarian neutral lipid fatty acid composition was determined for 22 landlocked Atlantic salmon with gonadosomatic index ranging from 0.75 to 13.6. In fish with gonadosomatic index over 1.3, the proportions of 16:1 and 18:1 increased, while those of 20:5 (n – 3) and 22:6 (n – 3) decreased with increasing gonadosomatic index. The proportion of the other major neutral lipid fatty acid, 16:0, did not vary with gonadosomatic index. Analysis of selected samples did not reveal any relationship between gonadosomatic index and the proportions of the major phospholipid fatty acids, 22:6 (n – 3), 16:0, and 18:1.
A cycle for 45calcium uptake in the rainbow trout, Salmo gairdneri
Authors: Wagner G. F. , Hampong M. , Copp D. H.
Published: March 2009

The rate of in vivo 45Ca uptake was monitored twice weekly over a period of 9 weeks in two different populations of rainbow trout fry. The rate of uptake cycled approximately every 11 days and the two populations appeared to be in synchrony regarding this cycle. The results are discussed in relation to the cyclical pattern of growth exhibited by salmonids.
Effects of habitat quality on growth, age of first reproduction, and dispersal in Gunnison's prairie dogs (Cynomys gunnisoni)
Authors: Rayor Linda S.
Published: March 2009

Populations of the highly social Gunnison's prairie dog (Cynomys gunnisoni) were studied at two sites in south central Colorado. The sites differed in availability of water, duration of the growing season, and the diversity and quantity of edible vegetation. At the lusher site, Quartz Creek, all age- and sex classes weighed significantly more than their counterparts at the more barren site, Blue Mesa. Growth rates and overwinter survival of Quartz Creek young were higher than at Blue Mesa. Two of 5 yearling females raised litters at Quartz Creek, whereas none of 15 yearling females weaned litters at Blue Mesa. Quartz Creek females produced larger litters [Formula: see text] than Blue Mesa females [Formula: see text]. At Quartz Creek, 6 of 17 yearlings dispersed from their natal harem, but none of the 31 yearlings at Blue Mesa dispersed. Thus, in a favorable habitat, Gunnison's prairie dogs were heavier, reached sexual maturity more rapidly, and dispersed at a younger age than in a less favorable habitat. These results provide intraspecific support for Armitage's hypothesis that delayed sexual maturity and dispersal in the large-bodied, social ground squirrels is associated with the age at which immatures attain adult weight.
Yellow perch egg masses deter predators
Authors: Newsome G. E. , Tompkins Jean
Published: March 2009

The entire seasonal reproductive effort of female yellow perch (Perca flavescens and Perca fluviatilis) is contained in a single, tubular, gelatinous egg mass. Predation on these egg masses is potentially a major mortality factor among perch, although reports of its occurrence are lacking. This suggests the egg masses may be protected by an antipredator mechanism that renders them inedible. In a series of feeding trials, no egg masses were consumed when offered to a number of species considered potential predators (eel, white sucker, brown bullhead, yellow perch, three- and nine-spined sticklebacks), although alternate food items were frequently consumed when provided. Examination of stomach contents of potential predators (eel, white sucker) collected from perch spawning sites at the peak of the reproductive period contained no egg masses. Egg masses were not lethal when ingested by a nonselective test fish, hatchery-reared brook trout, suggesting that an unpalatable rather than a toxic substance protects perch egg masses from predation.
Effects of photoperiod and temperature on testes, renal epithelium, and pituitary gonadotropic cells of the threespine stickleback, Gasterosteus aculeatus L.
Authors: Borg Bertil , Peute Jan , Reschke Maria , Hurk Robert van den
Published: March 2009

Sticklebacks were submitted to photoregimes of 8 h L:16 h D or16 h L:8 h D at temperatures of 20 or 9 °C in winter. The long photoperiod stimulated renal hypertrophy at both temperatures. At 16 h L:8 h D at 20 °C, breeding colours and breeding behaviour also appeared. The kidney was least stimulated and the 3β-hydroxysteroid dehydrogenase reactions in the Leydig cells were weakest in the 8 h L:16 h D, 20 °C group. A vigourous spermatogenesis occurred only in this group. The extension of dilated granulated endoplasmic reticulum in the gonadotropic cells was stronger after treatment with long than with short photoperiods, and most obvious at 16 h L:8 h D, 20 °C. The results point to a close correlation between the activity of the gonadotropic cells and steroidogenesis. Spermatogenesis, on the other hand, did not appear to demand very active gonadotropic cells.
Raising black-tailed deer fawns at natural growth rates
Authors: Parker Katherine L. , Wong Beatrice
Published: March 2009

Black-tailed deer (Odocoileus hemionus columbianus) fawns were successfully hand-raised on a formula of whole cow's milk and lamb milk replacer. No dietary gastrointestinal disorders occurred. Feeding schedules and milk volumes were based on both age and weight of the animals. Growth rates of these bottle-raised fawns to 25 days of age (consuming primarily milk) and body weights following weaning at 105 days of age were not significantly different from those of maternally nursed offspring.
The seasonal cycles and vertical distribution of tintinnines in Bedford Basin, Nova Scotia, Canada
Authors: Paranjape Madhu A.
Published: March 2009

The vertical distribution and seasonal cycle of tintinnine species were studied in Bedford Basin at a fixed station on 60 visits over an 18-month period. About 23 species of tintinnines belonging to 9 families were identified but only 12 were numerically dominant. Maximal numbers (102 to 104/L) were found in late summer and fall and minimal numbers (101 to 102/L), in late winter. The hyaline species of tintinnines occurred mostly in summer and fall, while agglomerated species dominated during other seasons. The total tintinnines contributed 35% (range, 3 to 55%) numerically and 2.5% (range, 0.05 to 16%) in terms of carbon to the microzooplankton in the Bedford Basin. The survival strategies employed by some species of tintinnines reasonably explain their seasonal cycle of abundance.
Ventilation and dive patterns of humpback whales, Megaptera novaeangliae, on their Alaskan feeding grounds
Authors: Dolphin William Ford
Published: March 2009

Noncalf humpback whales in Frederick Sound, Alaska, were tracked for periods of up to 12.5 h during July through September 1982, 1983, and 1984. Ventilation and dive patterns in presumably undisturbed humpback whales were characterized for six behaviors. Humpbacks appeared to restrict their dives to 150 m and rarely exceeded depths of 120 m, as determined by echo sounder tracings. Duration of dives and surfacings, number of blows per surfacing, and mean blow interval were positively correlated with the depth to which whales dived. Ventilation and dive variable values were significantly elevated in 1983 relative to 1982 and 1984. This was likely due to an increase in the depth of available prey during the 1983 season. The depth to which a feeding whale dove could be related to the depth of the target prey patch with greater than 84% accuracy based upon ventilation and dive variables.
Energy expenditures for locomotion by barren-ground caribou
Authors: Fancy S. G. , White R. G.
Published: March 2009

Energy expenditure during locomotion on a level treadmill, up and down slopes, and in snow was measured for barren-ground caribou (Rangifer tarandus granti) and compared with that of other species and other subspecies of Rangifer. Highly significant (p < 0.001) linear relationships between [Formula: see text] and walking speed were found for all caribou, indicating that the net cost of walking a given distance was independent of walking speed. The net cost of locomotion (i.e., additional to the cost of standing) for six barren-ground caribou (0.068–0.095 mL O2/(g∙km)) was the lowest of any terrestrial species studied. The mean cost of lifting 1 kg of body weight 1 vertical m was 23 kJ/(g∙m) for slope angles of 4.9 to 6.0°. Caribou recovered 6 kJ/(g∙m) during descent for an average efficiency of 62%. The net cost of locomotion in snow increased exponentially with sinking depth. Energy costs of locomotion in crusted snow were often much higher than those in uncrusted snow in which sinking depth was similar. Brisket height, as an index of leg length, was superior to body weight as a predictor of energy costs of walking for a given individual.
Reproductive patterns of harpacticoid copepods on intertidal macroalgae (Ascophyllum nodosum and Fucus vesiculosus) in Nova Scotia, Canada
Authors: Johnson S. C. , Scheibling R. E.
Published: March 2009

Harpacticoid copepods generally showed marked seasonal variation in abundance on intertidal macroalgae (Ascophyllum nodosum, Fucus vesiculosus) on a moderately exposed rocky shore. In some species (Nitocra typica, Mesochra spp., Harpacticus sp., Heterolaophonte spp.) the sex ratio was unbiased, or biased towards males, at peak population densities in summer and fall, but became biased towards females as density decreased towards winter. In other species (Thalestris purpurea, Parastenhelia spinosa, Amphiascopsis sp.) there was no consistent trend in sex ratio. Most species have a protracted period of reproductive activity between spring and fall, as indicated by the occurrence of ovigerous females and copepodites. Some species (Harpacticus sp., Heterolaophonte discophora, Thalestris purpurea) that were absent from macroalgae during winter reappeared with ovigerous females and copepodites in the spring. Tisbe spp. showed no seasonal fluctuation in abundance or sex ratio: ovigerous females and copepodites occurred throughout the year, suggesting continuous reproduction. Reproductive patterns of harpacticoid species on intertidal macroalgae may be related to seasonal variation in temperature and food supply.
The group size – flight distance relationship in water striders (Gerris remigis)
Authors: Dill L. M. , Ydenberg R. C.
Published: March 2009

When food availability is constant, the distance from which first instar water striders (Gerris remigis Say) initiate escape from approaching (potentially cannibalistic) adults initially rises and then falls with increases in group size. This result cannot be explained by the currently accepted many-eyes hypothesis, which predicts a monotonically increasing relationship between flight initiation distance and group size, resulting from the increased probability of predator detection by larger groups. The results are consistent with an alternative hypothesis, according to which the preferred flight distance results from a trade-off between the costs and benefits of flight and declines with increasing group size due to risk dilution. The gerrids are constrained from achieving their preferred flight distance when tested as individuals, and the adult is able to approach more closely before being detected.
Incubation and brooding shift duration in the Common Murre, Uria aalge
Authors: Verspoor E. , Birkhead T. R. , Nettleship D. N.
Published: March 2009

Within- and between-year variation in incubation and chick-brooding shift duration were studied during the 1981–1983 breeding seasons in Common Murre, Uria aalge, pairs on the Gannet Islands, Labrador. Incubation shifts averaged 17 h (range: 1–38 h) and daytime brooding shifts, 4 h (range: 1–14 h). Brooding shifts that included the night, during which change-overs did not occur, averaged 12 h (range: 7–20 h). No differences in shift duration were detected between the sexes but females incubated more at night than did males and were more likely to initiate their incubation shifts in early morning or late evening than males. There was no evidence that pairs tended to change over at the same time each day or that change-overs of neighbouring pairs were synchronized. Shift duration during chick rearing showed significant differences between 1982 and 1983 and the possibility that this was in response to differences in food availability is discussed.
Growth, physical maturity, and mortality of fin whales (Balaenoptera physalus) inhabiting the temperate waters of the northeast Atlantic
Authors: Aguilar Alex , Lockyer Christina H.
Published: March 2009

Data obtained from the examination of the ear plugs of 665 specimens were used to estimate age-related parameters for the fin whale population inhabiting the temperate waters of the northeastern Atlantic. Samples were collected from 1979 to 1984 at the Spanish whaling stations. The length of the ear plug core strongly correlated with the number of growth layers in whales younger than 25 years of age but showed no correlation in older whales. Readability of ear plug growth layers decreased with age in females but showed no clear trends in males. Minimum size limits of the fishery produced a selective fishing mortality rate in whales up to 5 years of age. Hence, only age-classes older than 5 years have been included in the fitting of the growth curves. Fully grown females are 1.47 m longer than males, but their growth rate is slower. Thus, males reach 95% of asymptotic length at age 9 years, while females reach it at age 13. Fin whales of both sexes attain physical maturity when they are between 20 and 30 years old. Despite growing relatively slower, females are always larger than males and recruitment to the fishery occurs at an age of 5 years in females and 6 years in males. Apparent mortality rates are similar in young whales of both sexes, but are higher in adult females than in adult males; the most plausible explanation for this difference is an increase in mortality associated with reproduction in sexually mature females.
Demography of Clethrionomys gapperi in different habitats
Authors: Bondrup-Nielsen Søren
Published: March 2009

Theoretical considerations indicate that habitat heterogeneity may affect vole population density dynamics. The greater the degree of habitat heterogeneity, the greater the likelihood that a vole population will show stable rather than cyclic density dynamics. A livetrapping study of Clethrionomys gapperi was conducted near Lesser Slave Lake, Alberta, Canada, to examine the effect of habitat on demography and behaviour on this species. Voles in different habitat types differed in spring and late summer density, persistence, ratio of immature to total recruits, transiency, and home range size. There was no difference in litter size of voles among habitat types. Clethrionomys gapperi is not a cyclic species and sexually mature females are territorial. In this study demography of vole populations differed greatly among habitat type and only on one grid in 1 year did the density of sexually mature females reach saturation. Therefore, in each year there was always rooom for territorial establishment of females born in that year. This is unlike the situation for cyclic populations of Clethrionomys spp. in which there is no room for territorial establishment of such females during the peak population phase.
Cysts of unknown etiology in marine fishes of the Northwest Atlantic and Gulf of Mexico
Authors: MacLean Sharon A. , Morrison Carol M. , Murchelano Robert A. , Everline Sherie , Evans Joyce J.
Published: March 2009

Results of light and electron microscopic examinations of cysts of unknown etiology (CUEs) occurring in the gills of Atlantic mackerel, red hake, white hake, cod, haddock, and silver hake are presented. CUEs were found also in gills and viscera of winter flounder, Atlantic croaker, spot, windowpane flounder, and sand lance. CUEs measured 150–400 μm in diameter and consisted of an external fibrous cuticle, usually a thick median band, and a central core that frequently contained eosinophilic vesicles. Structures resembling mitochondria were found in the band and in vesicles of the core, but no other organelles were apparent. Cytochemical staining and ultramicroscopy revealed aggregates of glycogen in the core ground substance; no structural components were stained with Sudan black B or by the Feulgen technique. Extensive encapsulation of CUEs by fibroblasts was typical. Of 717 mackerel examined, 76.8% had CUEs in the gills; numbers ranged from 1 to 353 per fish. The prevalence and intensity of occurrence of CUEs increased with the age of the mackerel.
Avian Haemoproteidae. 24. The haemoproteids of the New World passeriform families Formicariidae, Furnariidae, Mimidae, and Vireonidae
Authors: Bennett Gordon F. , Caines Jennifer R. , Woodworth-Lynas Carla B.
Published: March 2009

The haemoproteids of four families of New World passeriforms are reviewed. Haemoproteus formicarius n.sp. is described from the Formicariidae; Haemoproteus furnarius n.sp., from the Furnariidae; and Haemoproteus vireonis n.sp., from the Vireonidae. Haemoproteus beckeri Roudabush and Coatney, 1935 from the Mimidae is redescribed from the type material.
Age effect analysis of Dermacentor variabilis (Say) adult populations during seasonal activity (Acari: Ixodidae)
Authors: McEnroe W. D. , Specht H. B.
Published: March 2009

The age effect, as measured by survival under modest water deficit stress of adult Dermacentor variabilis, reveals the history of previous questing activity. This method can be used for an age analysis of the population where low density prevents the use of the mark and recapture technique for population estimation.
Vitamin A inhibits amphibian tail regeneration
Authors: Scadding Steven R.
Published: March 2009

The objective of this investigation was to determine what effect vitamin A had on tail regeneration in Notophthalmus viridescens adults, in Ambystoma mexicanum larvae, and in Xenopus laevis tadpoles. Notophthalmus viridescens and Ambystoma mexicanum had their tails amputated and then were treated with retinol palmitate by immersion in concentrations known to cause proximodistal duplications in regenerating limbs. Xenopus laevis tadpoles had their tails amputated and then were treated with either retinol palmitate by immersion, or with retinoic acid administered by implantation of silastin blocks containing retinoic acid. The results ranged from no effect at all at the lower dose levels used, to complete inhibition of tail regeneration at higher dose levels. The degree of inhibition of tail regeneration appeared to be dose dependent. In no case were any duplicated or accessory structures formed analogous to those observed in regenerating limbs. This result suggests that the morphogenetic processes involved in tail regeneration are at least in some ways different from those occurring in limbs, where a similar vitamin A treatment would cause proximodistal duplication or production of accessory limb structures.
Rheological properties of rainbow trout blood
Authors: Fletcher Garth L. , Haedrich R. Tyson
Published: March 2009

The effects of shear rate and red cell concentration on the viscosity of rainbow trout (Salmo gairdneri) blood were evaluated at 0 and 15 °C using a cone-plate viscometer. The viscosity of blood was shear dependent at both temperatures, with the highest values occurring at the lower temperature and shear rate. The viscosity of plasma was not shear dependent. Viscosity of blood increased in a linear fashion between hematocrits of 0 and 40%. Viscosity of the rainbow trout blood was similar to that of arctic char (Salvelinus alpinus), but considerably lower and less shear and temperature dependent than the bloods of winter flounder (Pseudopleuronectes americanus) and shorthorn sculpin (Myoxocephalus scorpius). It is hypothesized that low shear and temperature dependent blood viscosity may be a characteristic of active fish.
Ovarian activity during the annual reproductive cycle and nesting cycle of a wild avian species, the pied myna (Sturnus contra contra)
Authors: Gupta S. K. , Maiti B. R.
Published: March 2009

Ovarian activity was studied during the annual reproductive cycle and nesting cycle in the Indian pied myna (Sturnus contra contra). The investigation was carried out on the basis of gravimetric, histological (gross and quantitative), and histochemical (3β-hydroxysteroid dehydrogenase and lipids) studies. In the ovary of the pied myna, four types of healthy follicles (primordial, small developing, large developing, and yolky) were recognized; the stroma showed gland cells. Steroidogenic activity was marked in the theca and granulosa of the follicles, and it altered with the growth of the follicles. The probable source of stromal gland cells is discussed. The ovarian activity changed over the course of the year with four distinct phases, viz., progressive (February to April), breeding (May), regression (June to July), and nonbreeding (August to January) phases. Ovarian weight, largest follicular diameter, populations of larger follicles, and thecal gland cell mass increased gradually from February through April, became maximal in May, decreased in June and July, and became minimal during August through January. Yolky follicles developed only in May. Stromal gland cell mass was abundant in March, decreased from April to June, was almost absent from July to September, reappeared in October, and gradually increased afterwards. Steroidogenic activity of the thecal and stromal gland cells also changed with the annual ovarian cycle; it was absent during July through September and reappeared in October. The granulosa cells showed steroid activity only in May. During the nesting cycle, ovarian activity increased rapidly from early nest-building to egg-laying periods and declined during incubation and nestling periods; this was evident from changes in ovarian weight, largest follicular diameter, thecal gland mass, and populations of larger follicles. Yolky follicles were seen during late nest-building, egg-laying, and incubation periods. Stromal gland cell mass decreased gradually during the nesting cycle. 3β-Hydroxysteroid dehydogenase activity was maximal in the nest-building period.
Serological evidence of realized feeding niche in Cenocorixa species (Hemiptera: Corixidae) in sympatry and allopatry
Authors: Reynolds J. D. , Scudder G. G. E.
Published: March 2009

The realized feeding niche of Cenocorixa bifida hungerfordi Lansbury and Cenocorixa expleta (Uhler) from saline lakes (500 – 20 000 μS cm−1 at 25 °C) was determined by serological analysis of gut contents. Antisera prepared from 11 common potential foods were tested on Ouchterlony microplate assemblages against corixid gut contents. No consistent differences were seen between corixids collected from different lakes or at different seasons. Their realized feeding niches are similar but not identical; each instar fed somewhat differently. Diets of the two species when sympatric were markedly different from when they were allopatric. The realized niches appear to be restricted in sympatry, but both species concentrated overall on similar foods, suggesting that food was not limiting. However, the exclusion of C. expleta from low salinity lakes may be a result of competition for food, in addition to habitat preferences and other biotic parameters.
Recognition of larvae of the Tetrabothriidae (Eucestoda): implications for the origin of tapeworms in marine homeotherms
Authors: Hoberg Eric P.
Published: March 2009

The Tetrabothriidae represent the dominant group of cestodes, previously known only as adult parasites, in marine birds and mammals. Recognition of their unique plerocercoid larvae provides the first definitive evidence for life history patterns and phylogenetic relationships with other cestodes. Affinities of the Tetrabothriidae and Tetraphyllidea, cestodes of elasmobranchs, are indicated by larval morphology and ontogeny. However, patterns of sequential heterochrony in the ontogeny of the adult scolex of Tetrabothrius sp. appear to be unique among the Eucestoda. Tetrabothriids constitute a fauna that originated by host switching from elasmobranchs to homeotherms, via ecological associations, following invasion of marine communities by birds and mammals in the Tertiary.
Two new species of umagillid flatworms from the 20-rayed antarctic crinoid Promachocrinus kerguelensis
Authors: Shinn George L.
Published: March 2009

Two new endosymbiotic turbellarians from the 20-rayed crinoid Promachocrinus kerguelensis are described from specimens collected off the western coast of the Antarctic Peninsula. Desmote antarcticus sp.n. differs from previously described members of the genus in the shape of the penis stylet, orientation of the terminal branches of the ovaries, and connections of the genital ducts to the exterior. Parafallacohospes bransfieldensis gen. et sp.n. is distinctive among known umagillids in having a pair of broad lobes projecting from each side of the body. The anatomy of the reproductive system is similar to that of Fallacohospes inchoatus Kozloff except that P. bransfieldensis lacks a secondary uterus. In addition, P. bransfieldensis has a functional digestive tract with small intestinal ceca, whereas F. inchoatus, the only species in the genus Fallacohospes, lacks a digestive tract. In this respect, Parafallacohospes appears to be intermediate between Desmote, which has large intestinal ceca, and Fallacohospes. Both new species belong to the subfamily Bicladinae, which includes all other crinoid-inhabiting umagillid flatworms.
Revision and phylogenetic analysis of the Amphilinidea Poche, 1922 (Platyhelminthes: Cercomeria: Cercomeromorpha)
Authors: Bandoni Susan M. , Brooks Daniel R.
Published: March 2009

Systematic relationships of amphilinidean platyhelminth species were investigated. Eight species and three genera are considered valid. Analysis of 46 character states comprising 34 homologous series produced a single phylogenetic tree with a consistency index value of 87%, indicating a very low degree of parallelism in the evolution of amphilinidean morphology. Comparison of host and parasite phylogenies produced a fit of 70%, suggesting a high degree of coevolution between amphilinideans and their teleostean hosts. The geographic distribution of the amphilinideans was compared with four current hypotheses of area relationship for the southern land masses. Consistency index values obtained range from 87.5% to 100%, indicating that vicariance may be sufficient to explain the biogeographic distribution of amphilinidean platyhelminths.
Development of deep-water redfish (Sebastes mentella) larvae, with comparative notes on newly extruded Acadian redfish (Sebastes fasciatus) from the Flemish Cap
Authors: Penney Randy
Published: March 2009

Planktonic redfish larvae of the genus Sebastes were collected from Flemish Cap, an offshore Northwest Atlantic fishing bank east of the island of Newfoundland, Canada. A protocol based on discriminant function analysis and previously published age–length relationships was used to identify specimens of S. mentella and newly extruded (< 9 mm) S. fasciatus. On Flemish Cap, newly extruded larvae of S. mentella and S. fasciatus do not differ significantly in body proportions, fin morphology, or numbers of body myomeres but do differ significantly in pigmentation patterns on the head, nape, dorsal body midline, and numbers of subcaudal melanophores. A developmental series of S. mentella is described in terms of morphometry, meristics, occurrence of head spines, and pigmentation patterns and compared to previously published data on Sebastes spp. from other areas. The utility of various characters in relation to their use as identification criteria is discussed. The results of this morphological analysis support the contention that S. mentella and S. marinus larvae are more similar to each other than either of them is to S. fasciatus.