bluuebunny/crossref_metadata_2025 huggingface dataset:
Allozyme differentiation among gopher tortoises (Gopherus): conservation genetics and phylogenetic and taxonomic implications
Authors: Morafka David J. , L. Gustavo Aguirre , Murphy Robert W.
Published: July 2008

The genetic diversity among 18 loci within and among four species of gopher tortoises was investigated using horizontal starch gel electrophoresis. Within species variation ranged from 2 to 4% by direct count and from 2 to 8% by Hardy–Weinberg expectation. Of the loci resolved, 11–22% expressed variation. The northern and southern populations of Gopherus flavomarginatus could not be distinguished. No fixed differences were observed between G. agassizii and G. berlandieri, as reflected in a Nei genetic distance of 0.008. These latter species may be little more than allopatric populations of G. agassizii. Differentiation between the two remaining species was not extensive; G. polyphemus was only slightly distinct from G. flavomarginatus, being separated by a Nei genetic distance of only 0.006. The two pairs of species were separated by an average genetic distance of 0.200. The evolutionary rates of divergence were observed to be unequal, especially between G. polyphemus and G. flavomarginatus. The overall genetic similarity suggests a relatively recent age of origin.
The relationship between maximum cardiac output and swimming performance in northern squawfish, Ptychocheilus oregonensis: the effect of coronary artery ligation
Authors: Kolok Alan S. , Farrell Anthony P.
Published: July 2008

The objective of this study was to determine whether experimental reductions in maximum cardiac output would reduce the swimming performance of northern squawfish, Ptychocheilus oregonensis. The reduction in maximum cardiac output was accomplished using ligation of the coronary arteries, and the effectiveness of the ligation depended upon fish size. Maximum cardiac output was significantly reduced in coronary-ligated fish greater than 320 g, but was unchanged in smaller fish. The reduction in maximum cardiac output was due to a significant decrease in maximum stroke volume, with no change in maximum heart rate. Despite the significant reduction in maximum cardiac output in the larger fish, there was no significant reduction in critical swimming speed.
Use of space by juveniles in relation to their postnatal range, mother, and siblings: an example in the wild boar Sus scrofa L.
Authors: Cousse Sylvie , Spitz François , Hewison Mark , Janeau Georges
Published: July 2008

Eight juvenile (3–8 months) wild boars belonging to two separate litters, and the mother of each litter, were radiolocated daily. The position of an individual juvenile at the time of each location was classified according to its association with its postnatal range, its mother, and its siblings. Preliminary analysis showed that location relative to the postnatal range was independent of association with the mother and siblings, while association with the mother was positively correlated. Although a degree of attachment to their postnatal range persisted in juveniles, surrounding areas were used preferentially. Juveniles were equally likely to be located in the presence of their mother as without her, but they generally separated from their mother during exploratory phases outside the postnatal range. Individual differences in exploratory behaviour occurred between juveniles from the same litter.
Over-winter movements and diving behavior of female Weddell seals (Leptonychotes weddellii) in the southwestern Ross Sea, Antarctica
Authors: Testa J. Ward
Published: July 2008

The movements and diving behavior of 18 adult female Weddell seals (Leptonychotes weddellii) were determined by satellite telemetry during the over-winter period in 1990 and 1991. Nine seals provided diving and movement data for 8 – 9 months. Seals that normally bred in the eastern part of McMurdo Sound spent most of the winter in the middle and northern parts of McMurdo Sound before the annual shore-fast ice had formed in those areas, or in the pack ice 0–50 km north of the sound and Ross Island. This is a greater use of pack ice, as opposed to shore-fast ice, in winter than was previously believed. Some long-distance movements (one over 1500 km in total) to the middle and northwestern parts of the Ross Sea also occurred. Although highly variable within and between individuals, dives indicative of foraging were primarily to mid-water regions (100 – 350 m) in both years, and were similar to those that have been observed in spring and summer, when Pleuragramma antarcticum is the primary prey of Weddell seals in McMurdo Sound.
The effect of monoterpene concentrations in Sitka spruce (Picea sitchensis) on the browsing behaviour of red deer (Cervus elaphus)
Authors: Duncan Alan J. , Hartley Susan E. , Iason Glenn R.
Published: July 2008

The effect of monoterpene concentrations in Sitka spruce (Picea sitchensis) foliage on the browsing behaviour and preferences of red deer (Cervus elaphus) was studied in a series of 18 choice trials. During each trial, individual hinds were given access to 16 saplings arranged in a symmetrical array and aspects of their feeding behaviour were recorded over 15 min. The principal measures of preference were the number of bites and the biomass removed from each tree. Prior to each trial each tree was subjected to a series of detailed morphological measurements and a subset of trees was sampled for subsequent monoterpene analysis. Multiple regression analysis showed total terpene concentration of needles to have a significant negative influence on both the number of bites and the total biomass removed from each tree. Differences in susceptibility of Sitka spruce trees to browsing are discussed in relation to the observed high intertree variation in terpene concentrations.
Winter habitat use by mule deer in the central interior of British Columbia
Authors: Armleder Harold M. , Waterhouse Michaela J. , Keisker Dagmar G. , Dawson Richard J.
Published: July 2008

We analyzed winter habitat use by 23 radio-collared mule deer (Odocoileus hemionus hemionus) in the central interior of British Columbia, Canada, from February 1982 to March 1989. This research was essential to provide sound biological data for development of a selection silvicultural and planning system that would integrate timber harvesting with the habitat needs of mule deer. Habitat selection was analyzed by comparing deer use with habitat availability of various levels (categories) of the following variables: age, crown closure, species composition, slope, and aspect. Additionally, we compared the use of each category among snow classes. Regardless of snow depth class, use of old stands (> 140 years) by deer was greater than the availability of that age category. Also, the use of old stands was greater in moderate (26–40 cm) and deep (>40 cm) snow depth classes than in the low snow depth class. Areas of winter range dominated by Douglas-fir (Pseudotsuga menziesii) were more often used than areas where other tree species were most common. In the deep snow class, use of both moderate and high crown closures categories exceeded their availability.
Photoperiod effects on body mass, body composition, growth hormone, and thyroid hormones in male collared lemmings (Dicrostonyx groenlandicus)
Authors: Nagy Tim R. , Gower Barbara A. , Stetson Milton H.
Published: July 2008

The purpose of this study was to examine the effect of photoperiod on serum levels of growth hormone (GH) and thyroid hormones (TH), body mass, and body composition in collared lemmings (Dicrostonyx groenlandicus). Collared lemmings undergo seasonal changes in body mass and body composition, being heavier, but relatively less fat, during the winter months. These physiological changes can be induced in the laboratory by exposure to short photoperiod. The present study tests the hypothesis that photoperiod-mediated changes in GH and TH occur simultaneously with, and therefore may regulate or be permissive to, changes in body mass and body composition. Juvenile (19 d of age) or adult (50 d of age) male collared lemmings reared in long photoperiod (LD), 22 h light (L): 2 h dark (D), either remained in LD or were transferred to short photoperiod (SD), 8 h L: 16 h D. After 1, 2, 3, and 4 weeks (juveniles) or 1 and 3 weeks (adults) of treatment, animals were sacrificed. Serum levels of GH, triiodothyronine, and thyroxine were determined. Carcasses were weighed and analyzed for absolute and relative (analysis of covariance) fat-free dry mass, fat, and water. Exposure to SD resulted in an increase in GH, a decrease in TH, an increase in body mass (due to an absolute increase in all body components), a relative decrease in fat mass, and a relative increase in body water. Results are compatible with the hypothesis that a SD-mediated increase in GH is involved in the greater body mass gain observed in SD animals. Decreases in TH resulting from SD exposure, if associated with a decrease in heat production, may be permissive to mass gain.
Transmission of Cyclocoelum mutabile (Digenea) to snails: the influence of temperature on the egg and miracidium
Authors: McKindsey Christopher W. , McLaughlin J. Daniel
Published: July 2008

This study examined the survival and hatching dynamics of eggs of the digenean Cyclocoelum mutabile and the survivorship and infectivity of the miracidia under different temperature regimes. Hatching did not occur at or below 12 °C. Hatching success was similar at 14, 16, and 20 °C (69–73%). Two peaks in hatching were seen. Most eggs hatched within 12 h following immersion in water; a smaller hatching peak occurred about 24 h later. Storing eggs at 12 °C for up to 4 weeks prior to raising the incubation temperature to 14 °C had no effect on hatching success. However, hatching success was dependent on the source of the eggs. Between 62 and 71% of the eggs from faeces and 90–98% of the eggs dissected from flukes hatched under the same protocol. Miracidia hatching from eggs stored for 0–7 weeks at 7 °C prior to hatching at 14 °C did not differ in their infectivity to snails (75–86%). The survivorship of miracidia was higher at lower temperatures and when they were obtained from eggs dissected from the fluke. The longer survival and prolonged infectivity of miracidia at lower temperatures produced the highest transmission efficiency at 14 °C. These results are discussed in relation to the seasonal transmission and ecology of the fluke.
Description of M. uropataginalis (a new muscle), with additional comments from a microscopy study of the uropatagium of the fringed myotis (Myotis thysanodes)
Authors: Glass Phillip J. , Gannon William L.
Published: July 2008

We describe a bundle of skeletal muscle extending between the last caudal vertebrae and the calcar in the distal uropatagium of the fringed myotis, Myotis thysanodes, and we name this muscle M. uropataginalis. This discovery may elucidate the function of the fringe hairs of M. thysanodes and other bats with hairs projecting distally and ventrally along the trailing edge of the uropatagium.
Species-specific sperm attraction in the zebra mussel, Dreissena polymorpha, and the quagga mussel, Dreissena bugensis
Authors: Miller Richard L. , Mojares Jon J. , Ram Jeffrey L.
Published: July 2008

The occurrence of species-specific agents that attract sperm to spawned oocytes of zebra and quagga mussels might explain both the high fecundity of these species and their apparent inability to hybridize in nature. Ethanol extracts of freshly shed oocytes were prepared, dried, and redissolved in aquarium water and tested for sperm-attracting activity by micrometer-controlled pipetting into highly diluted suspensions of recently released sperm. The time course of the sperm responses was quantified by stop-frame video morphometric analysis of sperm density at various distances from the pipette tip. Controls included aquarium water, 10−3 M serotonin solutions used to induce release of sperm and oocytes, and ethanol extracts of aquarium water. Injection of oocyte extracts from both zebra (Dreissena polymorpha) and quagga (Dreissena bugensis) mussels elicited a significant increase in the density of actively motile conspecific sperm, usually within 10 s of extract release. No significant increase in sperm density was observed in response to any of the control solutions, nor was there any significant change in sperm kinematic parameters. Positive sperm responses were also obtained to whole-gonad acid extracts stored for 1 year or boiled. Although full-strength extracts attracted sperm of both species, serial half-dilution of the two extracts showed that a 100-fold higher concentration of attractant was required to attract sperm of the heterotypic compared with the homotypic species. Serotonin had no effect on the kinematics of either species' sperm. This is the first demonstration of sperm attraction to egg extracts in a bivalve.
Sex identification of humpback whales, Megaptera novaeangliae, on the wintering grounds of the Mexican Pacific Ocean
Authors: Medrano L. , Salinas M. , Salas I. , Guevara P. Ladrón de , Aguayo A. , Jacobsen J. , Baker C. S.
Published: July 2008

The sex of 43 humpback whales (Megaptera novaeangliae) from different social groupings in the Mexican Pacific was identified by a molecular analysis of skin biopsy samples. Of the 18 whales sampled from surface-active groups, 17 were males. Three singers were sampled and identified as males. In two cases, whales interrupting and joining a singer without exhibiting agonistic behavior were identified as females. A higher proportion of males was found in the samples collected at the Revillagigedo Islands, reflecting a greater sampling effort on surface-active groups. Preliminary data showed that along the Mexican Pacific coast, the migratory arrival of males corresponds closely to the timing of competitive activity.
Influence of parasitism on the shoaling behaviour of banded killifish, Fundulus diaphanus
Authors: Krause Jens , Godin Jean-Guy J.
Published: July 2008

The banded killifish (Fundulus diaphanus), with other freshwater fish species, is the second intermediate host of the digenean trematode parasite Crassiphiala bulboglossa. We investigated whether and how the shoaling behaviour of parasitized killifish is altered in ways that may facilitate transmission of the parasite to its final host, the belted kingfisher (Megaceryle alcyon). In mixed groups of parasitized and unparasitized killifish, parasitized individuals spent less time in shoals, had fewer neighbours within two body lengths, and occurred more frequently in peripheral shoal positions, where they are risk-prone, than unparasitized conspecifics did. After a simulated predator attack with a model of a stuffed belted kingfisher, parasitized individuals did not increase their shoaling tendency and thus had fewer near neighbours than unparasitized fish. These apparent parasite-mediated behavioural modifications in killifish may result in an increased probability of transmission of the parasite to its final, avian host.
Spatial resource partitioning by sympatric grey fox (Dusicyon griseus) and culpeo fox (Dusicyon culpaeus) in southern Chile
Authors: Johnson Warren E. , Franklin William L.
Published: July 2008

The activity patterns, home-range use, and habitat utilization of sympatric South American grey fox (Dusicyon griseus) and culpeo fox (Dusicyon culpaeus) in eastern Torres del Paine National Park, Chile, were studied to determine how the two species were distributed. Both species were primarily nocturnal. Mean percent daily activity did not differ between species or among seasons, but the grey fox had a greater daily activity rate in summer and fall and the culpeo fox in winter and spring. Seasonal and annual home ranges of culpeo foxes were larger than those of grey foxes, but did not differ between sexes or among seasons. Home ranges of grey and culpeo foxes were interspersed in a mosaic-like arrangement and did not overlap. Grey foxes were located more often in upland shrub transition habitat and in areas of medium cover density. Culpeo foxes were found more often in thickets of trees and in areas of high cover density. Within their home range, matorral shrubland or Nothofagus thicket habitat was selected by all culpeo foxes and by 60% of grey foxes monitored. Interference competition by the culpeo fox may have been important in determining fox distribution.
Distribution of neuroepithelial cells and neurons in the trout gill filament: comparison in spring and winter
Authors: Dunel-Erb Suzanne , Chevalier Claudine , Laurent Pierre
Published: July 2008

Study of the distribution of neuroepithelial cells and neurons along the gill filament of rainbow trout (Oncorhynchus mykiss) showed that the density of neuroepithelial cells is maximal near the extremity of the filament, whereas the density of neurons is maximal at the base of the filament. Comparison of densities in spring and winter shows that in winter, neuroepithelial cell density diminishes whereas neuron density increases; in spring, these relationships are inverted: neuroepithelial cell density increases whereas neuron density decreases.
The adrenocorticotrophic hormone stimulation test: its potential use and limitations in red deer (Cervus elaphus)
Authors: Goddard P. J. , Rhind S. M. , Hamilton W. J. , Macdonald A. J. , Fawcett A. R. , Soanes Carol , McMillen S. R.
Published: July 2008

The adrenocorticotrophic hormone (ACTH) stimulation test was assessed in red deer (Cervus elaphus). Following injection (i.v.) of 0, 100, 250, or 500 μg synthetic ACTH in farmed hinds (5 per group; mean live mass 78 kg), peak plasma cortisol concentrations occurred 30 min later. There was no dose effect on the peak levels attained, but the duration of the response increased with dose. The response of wild hinds (mean live mass 64 kg) to 500 μg ACTH administered at the time of capture was studied. Plasma cortisol concentrations were high prior to ACTH administration (238 ± 17.6 nmol/L; mean ± SE). Eighty minutes later, although concentrations were lower overall, they were significantly higher in ACTH-treated than in control animals (21 per group). Twenty farmed male red deer calves (aged 5 months at the outset; mean live mass 44 kg) were permanently housed after weaning. One hundred micrograms of ACTH was injected at weeks 0 (just after weaning) and 12. At week 12 mean cortisol concentrations were lower both before and after ACTH injection, although ACTH significantly increased plasma cortisol concentration on both occasions. Together these experiments suggest that the ACTH stimulation test can be employed in some classes of red deer but that it is not appropriate when animals have a high initial plasma cortisol concentration.
Effects of nesting location on breeding success of Arctic terns on Machias Seal Island
Authors: Bunin Judah S. , Boates J. Sherman
Published: July 2008

Over a period of several years (1978 – 1981), Arctic terns (Sterna paradisaea) nesting in the inland grassy area on Machias Seal Island had higher hatching and fledging success than those in the peripheral bare-bedrock area. In 1990, the opposite trend was recorded. In 1991, we attempted to determine the source(s) of this variation in breeding success between locations. An egg-exchange experiment was carried out between inland and peripheral sites that effectively eliminated differential egg and (or) chick quality as a source of variation. Following this exchange, success rates no longer differed between the habitats involved, despite the fact that chicks tended to be heavier in the peripheral area. The relative influences of parental quality and habitat quality on breeding success were examined as well. The results suggest that complex interrelationships exist among a variety of external factors (such as weather, food supply, and predation pressure), habitat quality, and the quality of birds choosing to nest in these areas. Breeding success in a given area is determined by the particular combination of these factors, a combination that may vary from year to year, colony to colony, and even in different breeding locations within a single colony in a given year.
Atriotaenia incisa (Cestoda), a parasite of the badger, Meles meles, and the raccoon, Procyon lotor, in Brandenburg, Germany
Authors: Priemer J. , Lux E.
Published: July 2008

Cestodes from four badgers (Meles meles) and eight raccoons (Procyon lotor) were studied. The badgers and seven of the raccoons were taken from the wild near the city of Berlin, Germany. This paper is the first record of Atriotaenia incisa (Railliet, 1899) (Cestoda: Anoplocephalidae) from P. lotor in Europe. Atriotaenia incisa is redescribed and compared with morphological descriptions of the North American species Atriotaenia procyonis (Chandler, 1942), a common parasite of the raccoon in Canada and the United States. No morphological differences were found between the two species and it is suggested that they may be conspecific.
The effects of temperature on external egg membranes in coho salmon (Oncorhynchus kisutch) and the occurrence of soft-shell disease
Authors: Cousins Katherine L. , Jensen John O. T.
Published: July 2008

The occurrence of soft-shell disease in salmon hatcheries in British Columbia was investigated. Soft-shell disease occurred most frequently in chinook (Oncorhynchus tshawytscha) and coho (Oncorhynchus kisutch) salmon, and in years of high water temperature. To test the effects of temperature, coho salmon eggs were incubated in two different temperature regimes (8 and 13 °C) and then subjected to scanning electron microscopy. As incubation progressed, the higher incubation temperature significantly raised the hydrostatic pressure of the egg (p < 0.001), thereby increasing the circumferential tension of the zona radiata. As the surface of the egg increased, the central plugs in the pore canals of the externus were raised upward. At lower temperatures, the surface tension of the egg membrane was reduced and the central plugs retreated into the pore canals. The position of the central plugs in the pore canals of the zona radiata can therefore fluctuate with different temperature regimes. The central plugs appear to be loosely set in the zona radiata, suggesting that this region could provide opportunistic pathogens such as bacteria or fungi with an entry point into the inner egg membrane.
The impact of potential predation upon the foraging behaviour of eastern chipmunks
Authors: Otter Ken
Published: July 2008

Predation risk may have a profound impact upon foraging behaviour. I studied how potential exposure to predation affected the foraging behaviour of eastern chipmunks (Tamias striatus). I measured the time taken to approach a patch ("approach time"), the period of residency in the patch ("patch residence time"), the degree of vigilance, and the size of the load of seeds taken by chipmunks foraging at patches (food trays) in both open and forested sites. Chipmunks have shorter approach times to trays in the open than to trays amongst forest cover. Although the load size taken did not differ between the two sites, chipmunks had increased patch residence time in open patches versus covered patches, as a result of increased vigilance. As load size did not increase with patch residence time in the open patches, foraging in the open provides a lower gain rate than foraging in closed habitats. Chipmunks may require both patch types to maximize their cache of seeds for over-winter survival. Increased vigilance while foraging in open sites may decrease the risk of predation and allow chipmunks to utilize these patches. Thus, the loss in gain rate while foraging in open patches may be offset by the ability to use exposed patches to increase long-term survival.
Limitation and regulation of moose populations: the role of predation
Authors: Ballenberghe Victor Van , Ballard Warren B.
Published: July 2008

An improved understanding of factors limiting and regulating ungulate populations is vital for sound management, especially with regard to controversial factors like predation. We examine the claim that evidence is weak for predation acting as a major factor limiting or regulating moose (Alces alces) populations in North America. Biologists have been inconsistent in defining limitation and regulation, have used these terms interchangeably, and have incorrectly assumed that major limiting factors regulate moose density. Empirical evidence indicates that many moose populations preyed on by both bears (Ursus arctos and U. americana) and wolves (Canis lupus) persist at densities much lower than K/2 when human influence is minimal. Under these conditions, reduction of predator numbers often results in increased moose density. Reduction of moose from high densities with predators held constant results in inversely density-dependent (anti-regulatory) predation and low moose densities for prolonged periods. In ecosystems lacking bears, or in those subject to substantial human influence, predation may not be a major limiting factor, may vary greatly in its impact, and may be overshadowed by interactions among moose, forage, weather, and hunting that primarily determine moose density. We conclude that in naturally regulated ecosystems, predation on moose by bears and wolves is often limiting and may be regulating, and we identify the conditions necessary for this to occur.
Mobility of brown trout in south-central Wyoming streams
Authors: Young Michael K.
Published: July 2008

Stream-resident brown trout (Salmo trutta) have often been considered to have small home ranges. To test this hypothesis, positions of adult brown trout in two streams were monitored from mid-June to early December 1991 and from late September 1992 to early June 1993 by using radiotelemetry. Thirty-seven of the 54 brown trout that were relocated at least once had home ranges greater than 50 m, trout larger than 340 mm moved more than did smaller brown trout, and movement of all fish tended to be greater in autumn. Different movement patterns of large and small fish imply the existence of two life-history strategies.
Influence of reduced food availability on growth of captive American kestrels
Authors: Lacombe Diane , Bird David M. , Hibbard Kathy A.
Published: July 2008

Captive American kestrels (Falco sparverius) were used to model the effect of low prey availability on growth and survivorship potential in nestling raptors. The experimental design consisted of 4 treatments: nestlings were fed ad libitum (100% diet) or on increasingly restricted diets (90, 80, and 70% of the ad libitum diet). Nestlings fed a reduced diet grew significantly more slowly than those fed the ad libitum diet, as shown by the body mass growth constant. The restricted diet had no significant effect on the asymptotic size of the kestrels, i.e., body mass and tarsus and antebrachium lengths. However, young kestrels fed reduced diets (80 and 70%) had a lower body mass at fledging than those fed ad libitum and the 90% diet, although they fledged at the same age. The growth of the ninth primary was slower for birds on restricted diets than for those fed ad libitum. Sexual dimorphism was observed for body mass and antebrachium growth constants, with males growing faster than females. However, females reached a higher asymptotic body mass and antebrachium length, as well as a higher body mass at fledging, than males. Thus, when prey availability is reduced by as much as 30%, nestling kestrels grow more slowly and store less fat, which could lead to poorer postfledging survivability.
The digestive tract of the echinopluteus of Echinocardium cordatum (Echinodermata, Echinoida): its ultrastructure and innervation
Authors: Nezlin Leonid P. , Yushin Vladimir V.
Published: July 2008

The digestive tract of the echinopluteus of Echinocardium cordatum consists of a tubular oesophagus, spherical stomach, and large hemispherical intestine. The oesophagus is constructed from cells of one ultrastructural type and has subepithelial muscles oriented circumferentially and longitudinally. The cardiac and pyloric sphincters separating the stomach from the oesophagus and intestine, as well as the anal sphincter, consist of myoepithelial cells and subepithelial muscles. The cells of both the stomach and intestine are able to absorb nutrients and phagocytize food. Neuron-like cells were detected around the mouth, in the oesophageal epithelium, and around the anal opening. Axonal trunks pass at the base of the oesophageal epithelium and around the sphincters. The rest of the digestive tract is innervated by solitary axons. Catecholamine-containing neurons were found inside the lower lip ganglion, in the two suboral ganglia, and around the anal opening.
Habitat use and movements of postfledging American black ducks (Anas rubripes) in the St. Lawrence estuary, Quebec
Authors: Clugston David A. , Longcore Jerry R. , McAuley Daniel G. , Dupuis Pierre
Published: July 2008

We used radiotelemetry to determine habitat use and movements of 38 female juvenile American black ducks (Anas rubripes) on the north shore of the St. Lawrence estuary, Quebec, from 28 August to 15 November 1991. Ducks separated into three groups based on habitat use: inland, estuarine, and those using a mixture of habitats. Ducks using mixed habitats used the greatest variety of habitat types, flew the greatest distances and most often between night roosts and day foraging areas, and were unlikely to be shot. The mean distance flown between night-use and day-use areas for all ducks increased nearly 50% after the hunting season began (overall mean = 6104 m, range 1500 – 26 384 m). Mean home range size was 27.6 ± 6.5 (SE) km2. Ducks exhibited stronger fidelity to wetlands used at night than to those used during the day. Ducks that were shot spent a high percentage of their time on the estuary (90.1 ± 7.4%) and exhibited high fidelity to a day-use area before the hunting season (73 ± 7.3%).
Numbers, breeding chronology, and breeding success of Common Murres at Bluff, Alaska, in 1975–1991
Authors: Murphy Edward C. , Schauer James H.
Published: July 2008

In 1979–1991, midsummer counts of Common Murres (Uria aalge) at Bluff, Alaska, showed no overall trend but varied in relation to weather conditions on the days of the counts within years and also varied markedly among years in relation to spring weather conditions, timing of breeding, and the number of actively breeding pairs. The high variability in annual mean counts during a period when there was no overall change in numbers indicates that annual differences in counts may reflect differences in colony attendance of adults rather than changes in population size. Both breeding chronology and reproductive success varied among years: breeding chronology was most advanced and reproductive success was highest in years when spring air temperatures were highest. Annual variations in numbers, breeding chronology, and breeding success paralleled those for Black-legged Kittiwakes, but the magnitude of variability in murre numbers and breeding success was much lower than that of kittiwakes. Breeding chronology of Common Murres was earlier at Bluff than at coastal colonies north of Bluff and island colonies in the central Bering Sea; however, comparisons with other studies indicate that there are no easily discerned geographic patterns. Although Bluff is near the northern limit of the breeding range of Common Murres in the eastern Pacific Ocean, there is no evidence of adaptations to shorten the duration of breeding attempts or of a shortened breeding season. In contrast to studies of Common Murres elsewhere, we found that reproductive success did not decline seasonally and breeding success of replacement attempts equaled that of first attempts. Both the very earliest and latest attempts were unsuccessful each year, however, indicating stabilizing selection on the laying dates of murres at Bluff.
Ontogenetic change in survival value of leg autotomy in a wolf spider, Gladicosa pulchra (Keyserling) (Araneae: Lycosidae), during scorpion attacks
Authors: Klawinski Paul D. , Formanowicz Jr. Daniel R.
Published: July 2008

The survival value of leg autotomy during attacks by scorpions (Vaejovis waueri Gertsch and Soleglad, 1972 (Scorpiones: Vaejovidae)) was assessed in three successive instars of the wolf spider Gladicosa pulchra (Keyserling, 1877) (Araneae: Lycosidae). During the first three instars after hatching, spiders were subjected to predatory encounters with adult scorpions. Spider survival due to leg autotomy decreased and the tendency of scorpions to use the sting to subdue the spiders increased with increasing size of wolf spider instars. As spider instar size increased, more scorpion attacks were directed at the cephalothorax and abdomen, resulting in decreased opportunity for larger spiders to utilize leg autotomy as an escape tactic. The decrease in survival and change in scorpion predatory tactics with increasing instar size reflect an increase in the relative body size of the spiders. Therefore, the survival value of an antipredator mechanism may vary with the degree of opportunity to use the mechanism.
The potential regulatory roles of cortisol in recovery from exhaustive exercise in rainbow trout
Authors: Pagnotta Antonella , Brooks Linda , Milligan Louise
Published: July 2008

Exercise to exhaustion, as indicated by near depletion of muscle glycogen stores, resulted in a 2- to 3-fold increase in the levels of plasma cortisol, but there was no consistent effect of exercise on plasma insulin, glucagon, T3 or T4 levels. Treatment of rainbow trout (Oncorhynchus mykiss) with metyrapone (which inhibits cortisol synthesis) 1 h or dexamethasone (which inhibits cortisol release) 24 h prior to exercise successfully blocked the exercise-induced rise in plasma cortisol. Neither metyrapone nor dexamethasone treatment had any effect on exercise performance, as muscle glycogen was depleted and lactate accumulated to the same extent in control and treated fish. Control fish showed the typical blood lactate response to exhaustive exercise: [lactate] peaked at 10–15 μmol∙mL−1 about 2–4 h post exercise and returned to pre-exercise levels within 8 h. The response of blood lactate in cortisol-blocked fish was significantly different: post-exercise levels were rarely greater than 5 μmol∙mL−1 and had returned to resting levels by 2 h. Analysis of tissue metabolite and acid–base status indicated that cortisol-blocked fish recovered faster than did controls. In treated fish, muscle glycogen and lactate levels had returned to pre-exercise levels within 2 h. Blood pH and muscle intracellular pH were also restored to pre-exercise values within 2 h. In contrast, restoration of tissue metabolite and acid–base status in control fish required up to 8 h. The fact that both metyrapone and dexamethasone treatment had the same effects on recovery metabolism suggests that it is the absence of the rise in plasma cortisol, rather than the drug treatment itself, which is responsible for the enhancement of metabolic recovery.
Cloacal anatomy of paedomorphic female Ambystoma talpoideum (Caudata: Ambystomatidae), with comments on intermorph mating and sperm storage
Authors: Trauth Stanley E. , Sever David M. , Semlitsch Raymond D.
Published: July 2008

The cloacal anatomy of paedomorphic female Ambystoma talpoideum was examined using light microscopy and histochemical techniques. Three types of cloacal glands (anterior ventral glands, dorsal glands, and spermathecae) were observed. Glandular morphology and secretory activity were documented from seasonal samples collected in South Carolina. Maximal development of cloacal glands corresponded to a peak in reproductive activity. Sperm-storage glands, the spermathecae, contained sperm in specimens collected from November through February. Although greatly hypertrophied during the breeding season, the anterior ventral glands continue to release secretory material throughout the year. This suggests that these glands could function in capacities other than those related to reproduction. The rudimentary dorsal glands also contain sperm during the breeding season; however, the occurrence of sperm in these glands is considered to be incidental. The cloacal glands of paedomorphs are similar to those of metamorphs. Interbreeding between morphs may occur and thus facilitate the maintenance of both morphs in nature.
Evidence for a trade-off between growth and behavioural activity in giant "Supermice" genetically engineered with extra growth hormone genes
Authors: Lachmansingh Edward , Rollo C. David
Published: July 2008

The "Supermouse," transgenic strain (Tg(MT-1,rGH),Bri2), contains multiple copies of rat growth hormone genes. Supermice exhibit doubled growth rates and body sizes but no increase in mass-specific feeding rates or assimilation efficiencies. Extra growth is achieved entirely by means of increased production efficiency by diverting energy from other processes. Reduction of behavioural activity is one potential mechanism for diverting energy to growth. To test this hypothesis we compared the behavioural time budgets (resting, sleeping, locomotion, wheel running, feeding, drinking, and grooming) of transgenic and normal male mice. The activities of individual Supermice and normal mice in artificial enclosures were videotaped and compared over 24-h periods. The duration of each activity was recorded and compared. Transgenic mice slept 126% as much as their normal counterparts (an increase of 3.4 h/d), and locomotion and wheel running combined were only 53.8% that of normal mice (a decrease of 2.95 h/d). Supermice spent only 77% as much time drinking and 69% as much time grooming as normal mice. No differences in the duration of feeding were found. The evidence suggests a direct trade-off between growth rate and behavioural activity consistent with the "principle of allocation" paradigm for life-history evolution.
Body size and condition, age, plumage quality, and foods of prenesting male cinnamon teal in relation to pair status
Authors: Hohman William L. , Ankney C. Davison
Published: July 2008

Male-biased sex ratios in waterfowl may contribute to sexual selection and permit females to be the deciding sex in mate selection. Male characteristics potentially influencing female choice include male age, size, plumage quality, and body condition (i.e., relative body mass, fat content, or protein content). By examining characteristics of prenesting male cinammon teal (Anas cyanoptera) relative to their pair status we evaluated the predictions that (i) paired males are older and physically superior to unpaired males and (ii) older and physically superior males pair in advance of other males. Diets of paired and unpaired males were similar, as were body size, ingesta-free body mass, fat, breast, and leg muscle protein contents, and testis, liver, and plumage masses. Likewise, pair status was not associated with male age. Body protein content and percentage of alternate plumage were generally greater in paired than unpaired males, but for some unpaired individuals these values were higher than the mean values for paired males. Thus, we found only limited evidence to support the above hypotheses. Our data suggest a possible link between winter nutrition and male participation in reproduction. That is, characteristics which enable males, during winter, to acquire nutrients for initiating and completing the prealternate molt in advance of other males also may be associated with ability to obtain a mate.
Scent marking by Alaskan moose: characteristics and spatial distribution of rubbed trees
Authors: Bowyer R. Terry , Ballenberghe Victor Van , Rock Karen R.
Published: July 2008

We studied scent marking (rubbing of trees) in Alaskan moose (Alces alces gigas) in interior Alaska during 1989. Pole-sized trees were stripped of bark and rubbed by adult female and adult male moose; marking by females occurred during the peak of rut (late September – early October) when most females were in estrus, whereas marking by males was in late rut (mid-October – November). Moose selected white spruce (Picea glauca) as well as trees with particular physical characteristics for marking. The tops of 18.5% of 54 trees marked by moose were dead, whereas only 0.5% of 201 trees available for marking had dead tops. The distribution of scent-marked trees on rutting grounds was not spatially clumped. We hypothesize that rubbing of trees by females advertises their estrus, and that rubbing by males late in rut serves to attract females not successfully bred early in rut and may help prime estrus in these females.
Sources of scent used by prairie voles, Microtus ochrogaster, to convey sexual identity to conspecifics
Authors: Ferkin Michael H. , Ferkin Frederick H. , Richmond Milo
Published: July 2008

The presence or absence of specific odor-producing tissues has been used to suggest phylogenetic relationships among microtine rodents, but has not been related to patterns of social organization. We examined the sources of sex-specific scents in prairie voles, Microtus ochrogaster, using a preference task. Prairie voles have eight sources of sex-specific scents. Four scents, namely those from the urine, feces, anogenital area, and mouth were more attractive to opposite- than same-sex conspecifics. Three scents were attractive to one sex but not the other. Scent from the back of females was attractive to males and scents from the chest and head–neck–ears of males were attractive to females. Scent from the male posterolateral region was attractive to both females and males. We then compared these eight sources of scent with the known sources of scent from meadow voles, Microtus pennsylvanicus, a species whose social system is unlike that of prairie voles. Prairie voles have more sources of sex-specific scent than meadow voles. This difference supports the hypothesis that the number of sources of sex-specific scent is greater in a social species (prairie voles) than in an asocial species (meadow voles).
Seasonal activity and feeding patterns in a population of deer mice (Peromyscus maniculatus gambelii)
Authors: Seabloom Robert W. , Schwab Robert G. , Loeb Susan C.
Published: July 2008

Daily surface activity and feeding patterns of a northern California population of the deer mouse Peromyscus maniculatus were studied each month over a 1-year period. Activity of adults was highest during the early hours of darkness regardless of season, whereas that of subadults was more variable. Food consumption by all age-classes increased significantly during spring and summer, with much of the intake delayed until the latter portions of the activity cycle. Increased food intake during the warm months may have resulted from increased metabolic demand associated with a long photoperiod. The late activity feeding peak in spring and summer was interpreted as a behavioral adaptation in preparation for an extended period of inactivity.
The effect of renesting ability and nesting attempt on egg-size variation in willow ptarmigan
Authors: Sandercock Brett K. , Pedersen Hans Chr.
Published: July 2008

Interclutch variation in the size of free-living willow ptarmigan (Lagopus lagopus alexandrae) eggs was examined at Chilkat Pass, British Columbia. Egg volume (19.9 ± 0.1 cm3; mean ± 1 SE) fell within the range reported for other populations of ptarmigan. Most of the egg-size variation (56.0%) was explained by differences among females, but renesting ability and nesting attempt were also important. The age-class of females and timing of nest loss had no effect on egg-size variation. Females that laid replacement clutches produced eggs in their first nesting attempts (n = 12 females, 102 eggs) that were 4.6% (0.9 cm3) larger than the eggs of birds that did not renest (n = 12 females, 95 eggs). Clutch size decreased between nesting attempts, and there was a 1.6% (0.3 cm3) increase in egg size (n = 12 females, 65 eggs). We suggest that future studies examining the influence of nesting attempt on egg size should also control for renesting ability.
Le système expert « Nereis » des annélides polychètes de France (ordre des Phyllodocida, Amphinomida, Spintherida et Eunicida)
Authors: Jussien N. , Verger V. , L'Hospitalier Y. , Augereau B. , Gillet P.
Published: July 2008

In his Faune de France volume on the errantiate polychaetous annelids, Fauvel (1923) listed only 15 families (not counting the parasitic Histriobdellidae and Ichthyotomidae). There are presently 37 families found along the coast of France and it was, therefore, necessary to revise the key to the families for a compterized systematics software program. The program Nereis was developed by Syspertec using the language Xi Plus.
Seasonal changes in plasma membrane glucose transporters enhance cryoprotectant distribution in the freeze-tolerant wood frog
Authors: King Patricia A. , Rosholt Mary N. , Storey Kenneth B.
Published: July 2008

One of the critical adaptations for freeze tolerance by the wood frog, Rana sylvatica, is the production of large quantities of glucose as an organ cryoprotectant during freezing exposures. Glucose export from the liver, where it is synthesized, and its uptake by other organs is dependent upon carrier-mediated transport across plasma membranes by glucose-transporter proteins. Seasonal changes in the capacity to transport glucose across plasma membranes were assessed in liver and skeletal muscle of wood frogs; summer-collected (June) frogs were compared with autumn-collected (September) cold-acclimated (5 °C for 3–4 weeks) frogs. Plasma membrane vesicles prepared from liver of autumn-collected frogs showed 6-fold higher rates of carrier-mediated glucose transport than vesicles from summer-collected frogs, maximal velocity (Vmax) values for transport being 72 ± 14 and 12.0 + 2.9 nmol∙mg protein−1∙s−1, respectively (at 10 °C). However, substrate affinity constants for carrier-mediated glucose transport (K1/2) did not change seasonally. The difference in transport rates was due to greater numbers of glucose transporters in liver plasma membranes from autumn-collected frogs. The total number of transporter sites, as determined by cytochalasin B binding, was 8.5-fold higher in autumn than in summer. Glucose transporters in wood frog liver membranes cross-reacted with antibodies to the rat GluT-2 glucose transporter (the mammalian liver isoform), and Western blots further confirmed a large increase in transporter numbers in liver membranes from autumn- versus summer-collected frogs. By contrast with the liver, however, there were no seasonal changes in glucose-transporter activity or numbers in plasma membranes isolated from skeletal muscle. We conclude that an enhanced capacity for glucose transport across liver, but not muscle, plasma membranes during autumn cold-hardening is an important adaptation that anticipates the need for rapid export of cryoprotectant from liver during natural freezing episodes.
Vitamin A plasma kinetics in northern fur seals (Callorhinus ursinus), using vitamin A2as a tracer
Authors: Mazzaro Liza M. , Dunn J. Lawrence , Furr Harold C. , Clark Richard M.
Published: July 2008

Vitamin A2(3,4-didehydroretinol), a natural analog of retinol, was used to determine the plasma kinetics of vitamin A in two northern fur seals (Callorhinus ursinus) receiving two levels of vitamin A supplements. After a single oral dose, the time required to reach maximum plasma vitamin A2concentration for both subjects was approximately 2 h, which is much less than the 8–12 h observed with humans. The level of vitamin A supplementation did not affect base-line plasma retinol concentrations or plasma kinetics. The mean sojourn time, the average time spent by a molecule of vitamin A in the body before being lost, was 40 days for one animal and 73 days for the other. The daily vitamin A requirement estimated from the disposal rate was 0.32–0.64 μmol per day for the two animals. The presumed upper safe level was calculated at 1.3–6.4 μmol vitamin A per day. It would appear that the fish diet commonly provided to these animals can meet their vitamin A requirements. Supplementation may only be warranted to offset vitamin loss during storage and handling of the food. However, a conservative approach to supplementation should be used, as chronic vitamin A toxicity is a danger.