bluuebunny/crossref_metadata_2025 huggingface dataset:
Feeding performance of toads at different acclimation temperatures
Authors: Stevens E. Don
Published: March 2009

I studied the ability of toads to capture and eat mealworms at 5, 10, 15, 20, 25, 30, and 35 °C They were tested in an arena with prey moving at constant velocity (20°/s) on a circular track. Feeding performance decreased at both high and low temperatures and was greatest at 20 °C The changes in feeding performance were much greater than they are for metabolic rate or jumping performance. The Q10 from 10 to 20 °C was 5.9.
Winter survival and habitat use of orphaned and non-orphaned moose calves in southern Quebec
Authors: Jolicoeur Hélène , Crête Michel
Published: March 2009

Survival, movements, home ranges, habitat selection, and diets of 13 orphaned and 13 non-orphaned moose calves were compared during their first winter. Survival of four other calves that became separated from their mothers was also monitored. The study took place during three winters between December 1978 and April 1983. Overall, winter survival rates between the two groups did not differ. When mortality did occur, it involved solitary (orphaned and separated) calves during a severe winter. Movements and home-range sizes of the two groups were also similar. Biomass of forage on winter sites, forage utilization, and importance of tree cover were similar on sites chosen by orphaned and non-orphaned calves. Minor differences were observed in the order of preference of browse species. Five solitary calves were involved in either temporary or permanent associations with other moose.
Redescription of Bouvieriella carcinophila (Chevreux, 1889) (Eusiroidea: Calliopiidae) from northern British Columbia and its proposed synonomy with Leptamphopus paripes Stephensen, 1931
Authors: Shaw D. Patrick
Published: March 2009

Two species within the "long-gnathopod" group of the amphipod superfamily Eusiroidea have been examined and found to be extremely similar morphologically; they are not sufficiently distinct to be retained as separate taxa. Bouvieriella carcinophila (Chevreux, 1889) (Eusiroidea: Calliopiidae) is redescribed from material collected from a fjord in northern British Columbia. The species is shown to be a senior synonym of Leptamphopus paripes Stephensen, 1931, and affinities with related eusiroidean genera are discussed.
Thinking with and without oxygen: energy metabolism in vertebrate brains
Authors: Suarez Raul K.
Published: March 2009

A survey of the information available on the biochemical differences between anoxia-sensitive brains of mammals and anoxia-tolerant brains of aquatic turtles reveals that the latter maintain membrane ion gradients, ATP concentrations, and, to a limited extent, electroencephalographic (EEG) activity, while metabolic rate is depressed during prolonged anoxia. In contrast, mammalian brains are unable to maintain ATP concentrations, ion gradients, and EEG activity during ischemia or anoxia despite a dramatic (albeit transient) Pasteur effect. This evidence indicates that rates of ATP utilization decrease during anoxia in anoxia-tolerant brains, while they are maintained (and not matched by glycolytic ATP production) in anoxia-sensitive brains. The implications with respect to possible mechanisms of "metabolic arrest" and the evolution of anoxia tolerance in vertebrate brains are discussed.
Variable and constrained features of the ornithine–urea cycle
Authors: Nener Jennifer C.
Published: March 2009

The physiological importance of urea biosynthesis differs widely among ureogenic animals. Many terrestrial animals synthesize urea as a mechanism for detoxifying NH3 and (or) [Formula: see text], while elasmobranchs and some species of amphibians with osmoconforming strategies produce urea and retain it within the body as an osmolyte. The ornithine–urea cycle is highly constrained in terms of enzyme composition and tissue localization. Other features of the pathway vary adaptively among organisms that produce urea for different functions. Adaptive features of the pathway include the occurrence of different isozymes, subcellular compartmentation of enzymes, and the regulation of urea synthesis. This review identifies the constrained and variable features of the urea cycle and attempts to place these features within an adaptive and evolutionary framework.
Comparative osteology and intergeneric relationships of the tongue soles (Pisces; Pleuronectiformes; Cynoglossidae)
Authors: Chapleau François
Published: March 2009

This article contains the first detailed osteological study of several flatfish species belonging to the three currently recognized genera of tongue soles (Cynoglossidae). The resulting information was used to reassess, following the cladistics methodology, the monophyletic status of the family and to put forward a hypothesis of generic relationships. The polarity of the character states was determined by outgroup comparison using the Soleidae as the sister group of the Cynoglossidae and the Achiridae as the sister group of the soleid–cynoglossid lineage. An analysis of numerous characters corroborated the monophyletism of the Cynoglossidae. It was also found that the genus Symphurus (Symphurinae) is monophyletic and is the sister group of the monophyletic Cynoglossus–Parapaglusia (Cynoglossinae) lineage. Parapaglusia was shown to be monophyletic, but no evidence was found to corroborate a similar status for Cynoglossus. An examination of the osteology of more species belonging to the speciose genera Symphurus and Cynoglossus is needed to further test this hypothesis of relationships.
Megalobatrachonema (Chabaudgolvania) waldeni n.sp. (Nematoda: Kathlaniidae) from the intestine of the northwestern salamander, Ambystoma gracile (Baird)
Authors: Richardson Jane P. M. , Adamson Martin L.
Published: March 2009

A new species of kathlaniid nematode, Megalobatrachonema waldeni, from the intestine of the northwestern salamander, Ambystoma gracile, in British Columbia is described. The new species is placed in the subgenus Megalobatrachonema (Chabaudgolvania) as it lacks valves in the oesophageal bulb. Megalobatrachonema waldeni differs from the two other members of this subgenus, M. elongatum (Baird, 1958) and M. terdentatum (Linstow, 1890), in having large cervical alae and distinctly separate lips, and in lacking hypodermal lip peduncles and a pseudosucker. Megalobatrachonema waldeni has simpler onchia, smaller spicules, and a more prominent swelling at the base of the oesophageal corpus than M. elongatum, and differs from M. terdentatum by its distinct corpus swelling, more anterior excretory pore, fewer caudal papillae, and longer tail.
Helminthes intestinaux du Renard commun (Vulpes vulpes L.) dans le Massif central (France)
Authors: Deblock S. , Pétavy A. F. , Gilot B.
Published: March 2009

In the course of an epidemiological survey of Echinococcus multilocularis (Leuckart, 1863), causative agent of alveolar hydatid disease, the autopsy of 154 red foxes, Vulpes vulpes (L.), captured in the Department of Cantal between November 1984 and February 1985 disclosed 144 cases of intestinal helminthiases. Helminths consisted of cestodes and nematodes; no trematodes were found. Multiple infestations were very frequent. Cestoda recorded consisted of the following species: Mesocestoides litteratus (Batsch, 1786) (40 cases; 26%), Taenia crassiceps (Zeder, 1800) (36 cases, 24%), Echinococcus multilocularis Leuckart, 1863 (23 cases, 14.9%), Taenia polyacantha Leuckart, 1856 (17 cases, 11.4%), Amoebotaenia paradoxa (Rudolphi, 1802) (8 cases, 5.2%), and Taenia pisiformis (Bloch, 1780) (2 cases, 1.3%). The following Nematoda were recovered: Uncinaria stenocephala (Railliet, 1884) (90 cases, 58.4%), Toxocara canis (Werner, 1782) (79 cases, 51.3%), Toxascaris leonina (Linstow, 1902) (39 cases, 25.3%), Trichuris vulpis (Froelich, 1789) (25 cases, 16%), Pterygodermatites affinis (Jaegerskioeld, 1904) (6 cases, 4%), and undetermined Trichostrongylidae (4 cases, 2.7%). Hosts were not examined for Trichinella sp. The cartography of each helminthiase revealed propitious areas of maintenance of the parasite. Echinococcus multilocularis had a very limited distribution compared with other taeniid species with a near-identical life cycle. Unknown ecological factors may have an adverse effect on the free stage (egg) of the cestode. The nematode Pterygodermatites affinis is reported here for the first time in France.
Community structure of zooplankton in eastern Hudson Bay
Authors: Rochet Martine , Grainger E. H.
Published: March 2009

Twenty-five zooplankton stations in eastern Hudson Bay were grouped into four geographical regions on the basis of salinity and temperature. One region, of high salinity and low temperature in deep water, showed a preponderance of arctic zooplankton. The second, with moderate salinity, low temperature, and shallow depths, supported mainly meroplanktonic larvae. The third, less saline and warmer in the upper levels, supported a euryhaline fauna, and the shallower fourth region sustained a fauna with still wider salinity tolerance. Strong pycnocline development supported a near-surface euryhaline fauna below which the arctic faunal element was concentrated in deeper water. Less stratified water, where pycnocline development was slight or absent, inhibited establishment of a euryhaline fauna and permitted a greater near-surface presence of the arctic zooplankton. The major zoogeographic element in eastern Hudson Bay, and probably in most of the bay, is arctic, reflecting the continuity of this area with the primarily arctic waters of the Canadian archipelago and the surface of the Arctic Ocean. Carried cyclonically around the bay, the arctic fauna penetrates the eastern sector, especially north of the Belcher Islands. The euryhaline fauna indicates the influence of James Bay, mainly in the southeastern extremity of the bay.
The influence of nesting habitat on reproductive success of the lesser snow goose
Authors: Jackson Sandra L. , Hik David S. , Rockwell R. F.
Published: March 2009

The quality of nesting habitat and the influence of vegetation height on reproductive success of the lesser snow goose (Chen caerulescens caerulescens) were examined. In 1984, geese nesting in tall willow bushes (Salix ssp.) were more successful than individuals nesting in shorter willows, or in areas with no willows at all. In particular, individuals nesting in tall willows lost fewer eggs to depredation or abandonment, resulting in a greater number of goslings leaving the nest after hatch. The effect of willow height on reproductive success was independent of female age and relative nest initiation date, both of which are known to affect reproductive success. The degree of the habitat effect was not as great in 1986, but the geese nesting in willow bushes did tend to have greater reproductive success. Since spring environmental conditions influence both the availability and quality of nest sites, the potential importance of the effect of nesting habitat on reproductive success probably varies among years.
Time budget and parental behavior of breeding American Black Oystercatchers (Haematopus bachmani) in British Columbia
Authors: Purdy M. A. , Miller E. H.
Published: March 2009

A study on parental behavior in American Black Oystercatchers (Haematopus bachmani) in British Columbia revealed sexual differences and seasonal variation in behavior. Before the egg-laying period, females tended to forage more, whereas males were more aggressive and alert. Females initially incubated more than males, but the sexes shared incubation duties almost equally toward the end of the incubation period. Males remained aggressive throughout incubation, but female aggression declined after eggs were laid. Females did most of the brooding, but the sexes participated equally in foraging for chicks and feeding them. After their eggs hatched, parents were more alert and aggressive toward other species. Patterns of parental care in oystercatchers appear to be related to their relatively large size, long-term mate fidelity, longevity, specialized feeding behavior, and sedentary life style, compared with other shorebirds.
Mechanisms of glycolytic control during facultative anaerobiosis in a marine mollusc: tissue-specific analysis of glycogen phosphorylase and fructose-2,6-bisphosphate
Authors: Storey Kenneth B.
Published: March 2009

Changes in the activity of glycogen phosphorylase and the content of fructose-2,6-bisphosphate (F-2, 6-P2) were monitored in tissues of the whelk, Busycotypus canaliculatum, over a 21-h course of environmental anoxia. Tissue-specific responses to anoxia were seen with respect to phosphorylase content: in the radular retractor muscle and foot, the content of phosphorylase a expressed rose rapidly over the initial hours of anoxia (maximal increases were 4.3- and 2.5-fold, respectively) while in the gill, content dropped 2-fold during anoxia. Phosphorylase content was modulated by two mechanisms, changes in the percentage of enzyme in the active a form and changes in the total amount (a + b) of enzyme expressed. Anoxia stimulated a dramatic reduction in F-2,6-P2 content in five tissues. In the ventricle, content fell by 224-fold with a t1/2 of only 35 min. Levels in gill, radular retractor, hepatopancreas, and kidney fell to 2.5–3.5% of control values within the first 8 h of anoxia. F-2,6-P2 content in foot muscle was not altered during anoxia. Changes in glycogen phosphorylase activities and F-2,6-P2 contents help to produce tissue-specific responses of glycolysis to environmental anoxia that acknowledge competing metabolic demands including metabolic rate depression, changes in fuel use, anaerobic energy needs, and carbohydrate use for anabolic purposes.
Interindividual proximity and the probability of winter survival in the bank vole, Clethrionomys glareolus
Authors: Karlsson A. Fredric
Published: March 2009

Interindividual proximity was examined during two prewinter seasons as a possible demographical agent in a bank vole (Clethrionomys glareolus) population near Uppsala, Sweden. While the proportion of nonoverwintering voles found in clusters in the 1st year was approximately the same (40%) from October to December, in the 2nd year, with lower population density, it fluctuated from 20 to 80%. Mean number of voles per shared center of activity was approximately the same (2–2.3) during all months compared. In October 1983 the proportion in these centers of nonoverwintering compared with overwintering voles was significantly lower. Individuals that shared centers compared with those that never did survived better and center sharing occurred significantly more often than was expected by chance. The change of centers of activity to more rocky from less rocky environments among nonoverwintering voles significantly more often resulted in center sharing. In overwintering but not in other females there was a strong positive correlation between the choice of microhabitat and month. As the prewinter season progressed, the preference of overwintering females for the most rocky environments increased. In males no significant pattern was observed. Proximity, though possibly primarily an effect of microhabitat preference, may increase the chance of both survival and successful reproduction in the following spring.
The suboral complex in the Müller's larva of Pseudoceros canadensis (Platyhelminthes, Polycladida)
Authors: Lacalli Thurston C.
Published: March 2009

The small suboral nerve in the Müller's larva of Pseudoceros canadensis is shown to arise from cells clustered beneath the median suboral rejectory cell of the circumoral ciliary band. The fact that the nerve arises within the suboral region rather than outside it is important in the context of comparative studies on related larval forms whose nervous systems have similar and presumably homologous suboral nerve centres.
Demersal fish and decapod crustacean fauna of the upper continental slope off Nova Scotia from LaHave to St. Pierre Banks
Authors: Markle Douglas F. , Dadswell Michael J. , Halliday Ralph G.
Published: March 2009

Four 200-m depth strata were sampled for fish and decapod crustaceans on the upper continental slope (400–1200 m) off Nova Scotia. There was more-or-less continuous replacement of fish fauna with depth. Numerically dominant fishes in the upper two strata (< 800 m) were Sebastes spp., Phycis chesteri, and Glyptocephalus cynoglossus. Predominant fishes in the lower two strata (> 800 m) were Centroscyllium fabricii, Synaphobranchus kaupii, and Coryphaenoides rupestris. Nezumia bairdii was relatively abundant throughout the depth range sampled. The ichthyofauna of the upper slope was similar to that off the Middle Atlantic States and off Newfoundland at comparable depths, but qualitative differences existed in losses of some and additions of other species. Dominant decapod crustaceans in the shallowest stratum (200–400 m) were Pontophilus norvegicus, Plesiopenaeus edwardsianus, and Panalus propinquus. This stratum appeared to be a transition zone between shelf and slope decapod faunas. More species occurred and at higher densities in the deeper strata; predominant were Acanthephyra spp., Pasiphaea tarda, Metacrangon jacqueti, and Sabinea hystrix. The decapod fauna off Nova Scotia is similar to that of the mid-Atlantic Bight but less diverse.
Nest attendance by adult Pied-billed Grebes, Podilymbus podiceps (L.)
Authors: Forbes Mark R. L. , Ankney C. Davison
Published: March 2009

In 1984, we monitored diurnal attendance by adult Pied-billed Grebes, Podilymbus podiceps (L.), on nests found in the emergent vegetation of ponds located near Minnedosa, Manitoba (55°16′N, 99°50′W). Adults increased attendance on nests over the egg-laying period; by the time four of six to eight eggs had been laid, adults spent roughly 90% of daylight time on nests. Nest attendance remained high during the post-laying period, but declined to between 75 and 85% of monitoring time later in the hataching period. Time of day did not affect the amount of time spent by adults off the nest. Previous visits by observers to nests on a given day, however, had a profound effect in that adults spent less time on "disturbed" than on "undisturbed" nests during the laying period, but more time on disturbed nests during the hatching period. Females accounted for roughly 70% of the total time spent by adults on nests during the hatching period, but were equal to males in this regard during the laying and post-laying stages. Our data suggest that nest attendance by both sexes before clutch completion largely determines onset of incubation and consequently the hatching interval for Pied-billed Grebe broods. Neglect of eggs by adults after the onset of hatching, however, may exaggerate hatching intervals.
Xenocanthus, a new genus of inquiline Scarabaeidae from southeastern Venezuela (Coleoptera)
Authors: Howden H. F. , Gill B. D.
Published: March 2009

Xenocanthus singularis n.gen., n.sp. from the Guayanan region of Venezuela is described and figured. The relationship of Xenocanthus to the termitophilous genera Scarabatermes Howden and Scarabaeinus Silvestri is discussed. All three genera are placed in the Ceratocanthinae, which in turn is related to the Hybosorinae and, to a lesser degree, to the Troginae.
The larval instars of Cnephia ornithophilia (Diptera: Simuliidae), a black fly with a variable molting pattern
Authors: Colbo M. H. , Okaeme A. N.
Published: March 2009

The larval instars of Cnephia ornithophilia could not be distinguished using morphometric characteristics. Nine larval instars were distinguished when larvae were individually reared and shed head capsules were collected and examined. From the data on individually reared larvae it is clear that growth between instars in the same individual and growth between larvae in the same instar are extremely variable. It was also determined that the final size of the last instar is variable and that the final dimensions of individual sclerites are poorly correlated, i.e., a large head capsule may have short or long antennae. The first instars were also unusual in having greatly reduced sclerotization of the head capsule.
Cranial lesions possibly associated with Skrjabingylus (Nematoda: Metastrongyloidea) infections in martens, fishers, and otters
Authors: Addison E. M. , Strickland M. A. , Stephenson A. B. , Hoeve J.
Published: March 2009

Skulls of 631 martens (Martes americana), 810 fishers (Martes pennanti), and 373 otters (Lutra canadensis) collected throughout Ontario were examined for frontal bone lesions possibly induced by sinus nematodes of the genus Skrjabingylus. No lesions were found in marten skulls. Lesions were present in 13.4% of otter skulls and their distribution was similar between sexes and among age-groups. Among fishers, 11.6% of skulls exhibited lesions. Frequency of lesions tended to increase with age, and adult male fishers had fewer than adult females. Lesions were characterized by discolouration, swelling, and perforation of frontal bones in descending order of frequency. Lesions were largely confined to the pars temporalis of the frontal bones with a small number also found on the pars frontalis.
Lake acidity and the distribution and abundance of water striders (Hemiptera: Gerridae) near Sudbury, Ontario
Authors: Bendell Barry E.
Published: March 2009

The presence of major water strider species was recorded in a survey of 53 lakes covering a wide range of acidity near Sudbury, Ontario. The mean pH of lakes on which Metrobates hesperius and Trepobates inermis were found was significantly higher than the mean pH of lakes from which they were absent. Metrobates hesperius was never found at pH < 5.1. There was no evidence that the distributions of Gerris spp. were related to lake acidity. Quantitative sampling was undertaken to examine the relationship between the abundance of Rheumatobates rileyi and lake acidity, and any concomitant relationship to fish. A highly significant positive relationship was found between densities of R. rileyi and lake pH, but no relationship was found with the presence or absence of fish.
Manipulation of intruder pressure in red squirrels (Tamiasciurus hudsonicus): effects on territory size and acquisition
Authors: Boutin Stan , Schweiger Sabine
Published: March 2009

The effect of intruder pressure on territory size has been investigated in many species of birds but in few species of mammals. We manipulated intruder pressure in an island population (21 adults) of territorial red squirrels (Tamiasciurus hudsonicus) in summer by removing (5) and adding (22) squirrels. When territorial squirrels were removed, neighbouring individuals expanded their territories. Breeding females that did so allowed their young to remain on part of the expanded territory while young from other females settled off the mother's territory. Adding squirrels did not result in a decrease in territory size. Although the introduced squirrels had previously held territories, they did not challenge residents. Instead they behaved as floaters (squirrels without territories); they never called and they occupied areas devoid of territorial squirrels. We conclude that intruder pressure prevents red squirrels from increasing their territory size but increased intruder pressure in the form of floaters or juvenile recruits does not lead to a decrease in territory size.
Mycophagie chez le sanglier et hypothèses sur son rôle dans la dissémination des spores de champignons hypogés
Authors: Génard Michel , Lescourret Françoise , Durrieu Guy
Published: March 2009

Microscopic study of wild boar (Sus scrofa scrofa) faeces collected in the French Mediterranean zone reveals a frequent consumption of ectomycorrhizal fungi. Hypogeous species are predominant. Mycophagy is more important in forest stands than in open areas. Hypotheses are proposed on the role of the wild boar in the dissemination of hypogeous fungi spores, which is necessary for forest regeneration: the boar would not play an important role in the recolonization of deforested areas, but may favour the genie mixing of spatially separated fungi populations.
Risk taking in parasitized sticklebacks under threat of predation: effects of energetic need and food availability
Authors: Godin Jean-Guy J. , Sproul Cathryn D.
Published: March 2009

Threespine sticklebacks (Gasterosteus aculeatus L.) parasitized by the cestode Schistocephalus solidus (Miiller) have a greater need for energy than uninfected fish, and therefore should be hungrier and more willing to compromise safety from predation for foraging gains. We hypothesized that the magnitude of this trade-off is directly related to the fish's parasite load (i.e., energy requirement) and food abundance. After being frightened by a model heron, sticklebacks fled shorter distances, remained motionless and cryptic for shorter periods, returned sooner to forage in a food patch near the predator, and remained active longer in the patch with increasing parasite load. The correlations of these responses with fish parasite load were significant most consistently at the highest food density tested, and suggest that the fish were taking a greater risk of predation with an increasing level of parasitic infection, particularly when the potential energetic gain from foraging was high. On average, the fish stayed longer in the food patch near predation hazard and consumed more food during this period with increasing prey density in the patch. However, individual feeding rate was independent of parasite load and food density, suggesting that the parasite places a constraint on the fish's foraging effort.
Histochemical localization of Na+–K+ ATPase and carbonic anhydrase activity in gills of 17 fish species
Authors: Conley David M. , Mallatt Jon
Published: March 2009

Activities of two enzymes considered to be involved in NaCl regulation, Na+–K+ ATPase and carbonic anhydrase, were localized in gill epithelia of 14 teleost, 2 agnathan, and 1 shark species through light microscopic histochemistry. Findings were confirmed by use of appropriate inhibitors (ouabain, acetazolamide). Na+–K+ ATPase activity was detected in chloride cells of most marine teleost species (six of eight) and of marine leopard shark and hagfish, but never in freshwater fish gills. In general, this finding agrees with past biochemical assays showing gill Na+–K+ ATPase activity to be highest in marine teleosts. Staining for carbonic anhydrase took one of three patterns among species: gill pavement cells or chloride cells, or both, were stained. Interspecific distribution of these patterns bore little relation to taxonomy or to habitat salinity, although chloride cells of euryhaline teleosts seemed more likely to stain than chloride cells of stenohaline teleosts, freshwater or marine. Given the lack of a definite correlation with salinity, it is concluded that fish gill carbonic anhydrase may not function in NaCl regulation as much as in acid–base regulation; the enzyme's role in preventing systemic pH imbalance is discussed.
n – 3 Docosapentaenoic acid in blubber of dam and pup grey seals (Halichoerus grypus): implications in the Inuit diet and for human health
Authors: Ackman R. G. , Eaton C. A.
Published: March 2009

n-3 Docosapentaenoic acid (22:5n – 3) is shown to constitute as much as 6% of the total fatty acids in six sets of dam–pup blubber samples from grey seals, Halichoerus grypus. Relative to fish oils, this fatty acid is several times more plentiful in the seal fats that form an important part of Inuit diets. Consideration of intakes of ω-3 fatty acids as therapeutic agents for cardiovascular and other health disorders in man should include this quantitatively important fatty acid of seal fats.
The distribution of protons and chloride ions across the erythrocyte membrane of the toad Bufo marinus
Authors: Tufts B. L. , Randall D. J.
Published: March 2009

Proton and chloride ion distributions were measured across the erythrocyte membrane of the toad Bufo marinus over a broad range of extracellular pH values. Intracellular pH was measured using both the freeze–thaw method and the 5,5-dimethyl-2,4-oxazolidinedione method. The results indicate that these ions are passively distributed in a Donnan equilibrium across the erythrocyte membrane. There is, however, a consistent difference between the erythrocyte pH obtained via the freeze–thaw method and that obtained via the 5,5-dimethyl-2,4-oxazolidinedione method. This difference apparently results from a "suspension effect" at the liquid junction potential of the pH electrode encountered when measuring the haemolysate pH.
Reproductive success of the male lumpfish (Cyclopterus lumpus L.) (Pisces: Cyclopteridae): evidence against female mate choice
Authors: Goulet Denis , Green John M.
Published: March 2009

Characteristics of male lumpfish (Cyclopterus lumpus) and features of their nests were examined as potential factors affecting male mating success. The number of eggs guarded by a male was not correlated with male length. Nest location variables, i.e., depth, distance offshore, and distance to the nearest male, were not related to mating success. Nest topography and degree of nest concealment were also not significant factors influencing male reproductive success. Multiple regression analysis revealed that no combination of factors could significantly explain the variation in male mating success. The hatching success of an egg mass was not predictable on the basis of the size of the guarding male. Desertion and abandonment of eggs occurred among males regardless of size. Hatching success of eggs was not associated with any of the nest features measured. Most egg masses hatched regardless of male characteristics or nest features. These factors suggest that mate choice by females is not an important factor in male reproductive success.
Variation in saddle patch pigmentation in populations of killer whales (Orcinus orca) from British Columbia, Alaska, and Washington State
Authors: Baird Robin William , Stacey Pam Joyce
Published: March 2009

Patterns of pigmentation of the post dorsal fin patch, or saddle patch, were analyzed from photographs of 372 resident and 99 transient killer whales (Orcinus orca) from British Columbia, Alaska, and Washington State. Of the five types of saddle patch analyzed, all were observed on residents, but only two occurred on transients. Differences in saddle patch shapes were independent of age and sex. Saddle patch pigmentation patterns were similar among clans within a community. Pigmentation patterns differed significantly between the resident and transient forms, between northern and southern residents, between northern and Alaskan residents, and between southern and Alaskan residents. As the saddle patch shape may be heritable to a large degree, these differences suggest genetic isolation of the populations. If so, this technique may be used to delineate stocks of killer whales from other areas.
The biology of Euparyphus Gerstaecker and Caloparyphus James occurring in madicolous habitats of eastern North America, with descriptions of adult and immature stages (Diptera: Stratiomyidae)
Authors: Sinclair B. J.
Published: March 2009

Biological information is given for the following four species of Oxycerini (Diptera: Stratiomyidae) occurring in madicolous habitats of eastern North America: Euparyphus stigmaticalis Loew, Euparyphus brevicornis Loew, Caloparyphus greylockensis (Johnson), and Caloparyphus tetraspilus (Loew). Descriptions of immature and adult stages are included for each species, and a key to the immature stages is given.
Intercolony natal dispersal in the Columbian ground squirrel
Authors: Wiggett Darwin R. , Boag David A.
Published: March 2009

Dispersal of Columbian ground squirrels (Spermophilus columbianus) among 16 colonies located in the Sheep River – Gorge Creek drainage of southwestern Alberta was studied from 1973 to 1986. In total, 73 intercolony movements involving 66 different animals were recorded. Intercolony dispersal movements were strongly biased towards males and were almost exclusively undertaken by 1-year-old squirrels (yearlings). The timing of emigration from the colonies studied was highly synchronous and was correlated with the dates of emergence of new litters. Yearling females that dispersed tended to leave at a later date than did yearling males. Most (91%) animals that dispersed moved to colonies <4 km away but movements of up to 8.5 km were recorded. There was no difference in median distance dispersed for male and female yearlings (2.0 and 1.8 km, respectively). Dispersing squirrels departed from colonies in nonrandom directions apparently following such features as trails and drainage systems. Such movement seemed to enhance the squirrels' chances of successfully locating nearby colonies. Minimum known survival rates while in transit for yearlings were 16% for males and 11% for females. Estimates of actual survival in transit for yearlings were 26% for males and 30% for females.
Foraging-substrate use by house wrens nesting in natural cavities in a riparian habitat
Authors: Guinan Daniel M. , Sealy Spencer G.
Published: March 2009

Foraging behaviour and substrate use by the primarily insectivorous house wren (Troglodytes aedon) were studied during the 1982 breeding season at 10 natural nesting sites in the dune-ridge forest, Delta Marsh, Manitoba. The foraging variables, i.e., time of season, gender, nesting stage, nest site, and time of day, interacted significantly. Wrens gleaned prey off substrate in 82.5% of the prey captures observed. Foraging behaviour varied greatly among the nest sites studied because of prevailing local differences in habitat, and possibly prey availability. The plant species from which wrens gleaned their prey correlated closely with the availability of the substrates in the habitat surrounding each nest site.
Modulation of a rhythmically active crayfish muscle by the neuropeptide proctolin
Authors: Beilin Silvia A. , Pasztor Valerie M.
Published: March 2009

Whole-animal studies have indicated that the neuromodulators octopamine, serotonin, and proctolin have multiple effects upon the central crustacean ventilatory system. We were interested in determining if these modulators have a complementary peripheral effect in augmenting the muscle power output in a ventilatory muscle. The availability of the biogenic amines and the presence of proctolin-like immunoreactivity in motor axons of the second maxilla indicate that the ventilatory system may be a target for those neuroactive substances. Intracellular recordings and isotonic muscle tension measurements were made on an isolated preparation of a ventilatory muscle. The amines and the peptide were applied by superfusion in normal saline. Of the three substances only protocolin had a modulatory action, which was seen as significant increases in both nerve-evoked and glutamate-evoked muscle contractions. An enhancement of the amplitude of excitatory postsynaptic potentials occurred at a subset of synapses.
Extracellular fluid volume and the initiation of salt gland secretion in ducks and gulls
Authors: Hughes Maryanne R.
Published: March 2009

The effect of intraperitoneal NaCl loading on extracellular fluid volume, plasma concentration, and initiation of salt gland secretion was measured in freshwater- and sea water-acclimated Glaucous-winged Gulls, Larus glaucescens, and Mallards, Anas platyrhynchos. In both species salt loading was associated with a significant increase in plasma [Na] and [Cl]. In freshwater- and sea water-acclimated gulls the extracellular fluid volume increased and salt gland secretion occurred; in freshwater- and seawater-acclimated ducks the extracellular fluid volume decreased and salt gland secretion did not occur.
Intracellular formation of calcium concretions by phagocytic cells in freshwater mussels
Authors: Silverman Harold , Richard Pamela E. , Goddard Russell H. , Dietz Thomas H.
Published: March 2009

The gills of freshwater unionid mussels contain large accumulations of extracellular calcium phosphate concretions. Connective tissue cells located in specific areas in the gills of these animals are the site of concretion formation. The cell type responsible for concretion formation appears to differentiate from an undifferentiated precursor cell by accumulating endocytic vesicles and producing amorphous membrane-bound granules from active rough endoplasmic reticulum and Golgi apparatus. In the most mature of the cells, these granules occupy most of the cytoplasm. Concretions are initiated within the amorphous granules as observed using stereo-pair transmission electron microscopy. These connective tissue cells exhibit phagocytosis, and can ingest India ink particles and colloidal gold. Colloidal gold is internalized through an endocytic mechanism within vesicles. Gold can be observed in the amorphous granules, implying fusion of such endocytic vesicles with the amorphous granules. While the exact mechanism of concretion formation is not understood, the cellular site of formation has been identified. Further, protein synthetic activity as well as endocytic activity appear necessary for concretion production.
Nest height of Black-billed Magpies: is it determined by human disturbance or habitat type?
Authors: Dhindsa Manjit S. , Komers Petr E. , Boag David A.
Published: March 2009

The impact of human disturbance on the choice of trees in which to nest and the heights at which to place the nests by Black-billed Magpies (Pica pica) was studied by comparing nest placement in three areas: A, urban with frequent human disturbance at the nest; B, urban with occasional disturbance; and C, suburban with minimal disturbance. Magpies nested in conifers more frequently than expected, based on availability, in all three areas. Neither absolute nor relative nest height (nest height/tree height) changed over the 2 years of this study, despite frequent human disturbance. The relative nest height did not differ from that 12 years before the current study was initiated. Moreover, nest height (absolute and relative) did not change when 10 pairs renested at new sites in 1987 in area A (after their original nests failed because of a spring snowstorm) even though the original nest sites had been periodically climbed to examine nest contents. Magpies used taller trees in area B than in area A but maintained the same relative nest height, which suggests that they either nested at an optimum height in the trees for ecological reasons or placed their nests as high as they could in the urban environment. Birds in suburban area C nested in shorter trees and at relatively lower levels than those in the urban areas, probably in response to the habitat type. The relative height of magpie nests was significantly greater in urban than in suburban habitat for conifers but not for deciduous trees, this variable being relatively constant within each habitat. Thus, habitat type seemed to have the greatest influence on nest height of magpies, but human disturbance did cause magpies to change trees for renesting in the same season.
Seasonal variation in thyroid morphology and secretion in the white whale, Delphinapterus leucas
Authors: St. Aubin D. J. , Geraci J. R.
Published: March 2009

Thyroid activity was examined in white whales, Delphinapterus leucas, during three phases of their annual cycle: spring migration from oceanic wintering grounds, summer occupation of an estuary in Hudson Bay, and return migration in fall. Circulating levels of thyroxine (T4) and triiodothyronine (T3) were significantly higher in summer. Histologically, thyroid epithelial cells were cuboidal during spring, became columnar during summer, and reverted to a cuboidal morphology in fall, changes consistent with increased synthesis and secretion of hormones during the estuarine phase. Small follicles, abundant in spring and fall samples, were relatively less numerous in summer specimens. Occupation of warm estuaries may be an important stimulus to thyroid hormone secretion, perhaps allowing the whales to mobilize subcutaneous fat stores for somatic growth in an energetically less demanding environment.
Effect of heart rate and hypoxia on the performance of a perfused trout heart
Authors: Farrell A. P. , Small S. , Graham M. S.
Published: March 2009

While adrenergic stimulation and increased filling pressure of the heart are recognized to increase cardiac stroke volume in the trout heart, the effects of factors such as heart rate and oxygen supply have not been examined. The present study used isolated, saline-perfused trout hearts to determine the maximum cardiac performance during hypoxic perfusion and during changes in pacing frequency similar to the range of heart rate observed in intact trout. The threshold oxygen tension of the perfusate was between 25 and 46 Torr (3.33–6.13 kPa) for maintaining resting and maximum cardiac ouput, but was between 46 and 67 Torr (6.13 – 8.93 kPa) for maintaining maximum power output. Increasing the pacing frequency from 30 to 58 beats/min did not produce a proportionate increase in the maximum cardiac output because maximum stroke volume was reduced significantly. It is suggested that the reduction in maximum stroke volume occurs because atrial filling time is compromised at higher pacing frequencies in the isolated perfused heart.
Female dimorphism and physiological colour change in the damselfly Argia vivida Hagen (Odonata: Coenagrionidae)
Authors: Conrad K. F. , Pritchard G.
Published: March 2009

Female Argia vivida appear as two distinct colour morphs in each of two populations studied in British Columbia, Canada. Males and both female morphs also experience a temperature-related physiological colour change. Individuals are "dark phase" at ambient shade temperatures below approximately 20 °C and change to "bright phase" at temperatures above 20 – 24 °C, particularly when basking. Individuals of either colour phase will attempt to mate. Bright phase males reflect not only visible light but also ultraviolet light. Observations of marked individuals and experiments in which males were offered live females (singly or as a pair containing each morph) pinned to long grass stems indicated that males do not show a preference for either female colour morph. The two female morphs do not differ in size, nor do males that mate with each morph. A male removal experiment revealed no change in the relative number of females of each morph that mated each day, suggesting that the morphs do not differ in their ability to attract males or to avoid excessive matings. Several social, ecological, and genetic explanations for sustaining the female dimorphism in the population are discussed.
Temporal–spatial variation in white-tailed prairie dog demography and life histories in Wyoming
Authors: Menkens Jr. George E. , Anderson Stanley H.
Published: March 2009

Variation in population density and life history traits were studied in six white-tailed prairie dog (Cynomys leucurus) populations in Wyoming using mark – recapture techniques. All life history traits (except juvenile sex ratios) and population density exhibited significant variation within towns between years and among towns in the same year. Temporal and spatial habitat variation significantly affects juvenile body mass but not adult body mass, which, in turn, results in the observed variation in life history traits. We conclude that white-tailed prairie dogs are dynamic reproducers and that their population age distributions are neither stable nor stationary. Use of life tables to study life history patterns of this species or of similar species would be inappropriate because of a failure to meet a basic assumption of life table models.
Electrophoretic evidence for multiple origins of triploid forms in the Ambystoma laterale–jeffersonianum complex
Authors: Lowcock Leslie A. , Bogart James P.
Published: March 2009

Variable allele frequencies and a wide range of genotypes in samples of triploid Ambystoma laterale–jeffersonianum (LLJ) hybrids indicate that these forms have arisen on many occasions. Though suggested previously, we show here the first clear evidence that this has taken place, with examples from two loci (Pgm-B, M-Aat-A) that have different biogeographic allele distributions. (i) A polymorphism at Pgm-B in Ambystoma laterale, otherwise restricted to northwestern Ontario, was found in both diploid A. laterale and co-occurring LLJ triploids in southern Ontario, where it is confined to the tip of the Bruce Peninsula. Diploids and triploids not possessing the allele also occur here and throughout the range of the A. laterale–jeffersonianum complex in eastern North America. (ii) An east coast A. laterale polymorphism at the M-Aat-A locus is also represented in both the homozygous and heterozygous condition within syntopic diploids and triploids in single populations. These data demonstrate multiple origins of triploidy, suggest continual gene exchange between diploids and triploids, and are analogous to data presented for other hybrid complexes of Ambystoma. The origins and distribution of the alleles in question are briefly considered, as they are of some biogeographic interest.
Use of song types by the Chestnut-sided Warbler: evidence for both intra- and inter-sexual functions
Authors: Kroodsma Donald E. , Bereson Rachel C. , Byers Bruce E. , Minear Edith
Published: March 2009

Males of many wood warbler (Parulinae) species use different song types in different contexts, yet the exact functions of the two main song type categories remain unclear. We studied the use of songs by both experimental (males whose mate had been removed from the territory) and control male Chestnut-sided Warblers (Dendroica pensylvanica) during the dawn hour and midmorning throughout the breeding season. Unpaired males sang more accented-ending songs and fewer unaccented-ending songs than paired males during all observation periods. Accented-ending songs appeared to be used primarily in the absence of intrasexual stimuli, and the percentage of unaccented-ending songs that was used during the nesting cycle appeared to fluctuate directly with the intensity of defense by the male of both his female and his territory. During courtship the male sang accented-ending songs on those infrequent occasions when he did sing in the immediate presence of his female, regardless of her location and the presence or absence of other males. These critical observations seem most consistent with the conclusion that the accented-ending songs are primarily intersexual. The unaccented- and accented-ending categories of song types appear to be used mainly as intra- and inter-sexual messages, respectively.
Differential habitat occupancy by goldeneye ducklings (Bucephala clangula) and fish: predator avoidance or competition?
Authors: Beattie Leslie A. , Nudds Thomas D.
Published: March 2009

Two hypotheses have been proposed to account for disjunct habitat occupancy between breeding Common Goldeneye (Bucephala clangula) ducks and fish: competition and predator avoidance. Both experimental and correlational evidence suggest that competition for food explains why goldeneyes and their broods tend to use habitats in which numbers of fish are low. However, rejection of the predator avoidance hypothesis has been based on correlational evidence only. In experiments, we tested the hypothesis that avoidance of predatory fish affects habitat use by goldeneyes by examining the responses of goldeneye ducklings (hatched in captivity from eggs collected in the wild) to the presence of predatory and nonpredatory fish models in an aquatic arena. Although response behaviours generally decreased with age, this was not the result of habituation to the testing procedure; responses of the oldest ducklings (9 weeks old) were not different from those of ducklings of similar age who had not been previously exposed to the models. When the presence of the models affected duckling behaviour, group cohesion increased and diving activity decreased, but the intensity of these responses did not differ toward models of predatory and nonpredatory fish. Furthermore, measurements of duckling movements did not indicate that ducklings were actively avoiding the models. Our experimental evidence indicates that avoidance of predatory fish does not appear to be an important determinant of habitat use by goldeneye ducklings.