bluuebunny/crossref_metadata_2025 huggingface dataset:
Aspects of the winter metabolism of ruffed grouse (Bonasa umbellus) with special reference to energy reserves
Authors: Thomas V. G. , Lumsden H. G. , Price D. H.
Published: August 2008

Plasma glucose, free fatty acids, and triglycerides were measured in captive ruffed grouse (Bonasa umbellus) acclimatized to deep winter conditions, and in controls held at 22 °C. Levels of these metabolites indicated a significant hyperglycemia in the winter-acclimatized grouse, but no lipolytic response was observed. The glycogen content of the liver and pectoral muscles of grouse acclimated to −10 °C for 4 weeks was significantly higher than the control levels. The percentage ether-extractable lipid content of wild grouse collected from January to August was low (5.91–9.17% of dry weight) and showed no significant changes during these months. The pectoral muscles and liver made up 31.8–36.6% and 1.14–1.64% of the total body weight, respectively, but marked changes in the proportions of these tissues did not occur from January to August.Ruffed grouse contain very small energy reserves. The respective roles of carbohydrates and fats in thermogenesis are discussed, as well as estimates of the energy available from fat and glycogen reserves compared with the daily energy requirements of grouse. The importance of regular feeding, together with behavioral and plumage adaptations which restrict heat loss, is emphasized in the maintenance of an energy balance during winter conditions.
Mate selection in threespine sticklebacks (Gasterosteus)
Authors: Hay D. E. , McPhail J. D.
Published: August 2008

Earlier studies suggest that the freshwater form of the threespine stickleback (Gasterosteus aculeatus) may be reproductively isolated from the anadromous form. In this study, assortative mating is examined as a possible isolating mechanism between the two forms. Mate selection tests were conducted in which (1) courting males were simultaneously exposed to receptive females of both forms, and (2) receptive females were simultaneously exposed to both forms of courting males. The results demonstrate clearly that in choice situations matings between similar phenotypes are more likely than matings between dissimilar phenotypes.
Walrus ethology. I. The social role of tusks and applications of multidimensional scaling
Authors: Miller Edward H.
Published: August 2008

Social behavior of male Pacific walruses. Odobenus rosmarus (L.), summering (i.e. outside the breeding season) on an Alaskan hauling ground is described. Social interaction on land is mostly agonistic. Visual presentation of tusks and striking with tusks feature prominently in most agonistic interactions: vocal communication occurs in a minority of them. Agonistic interactions are analyzed in R- and Q-approaches with MIN1SSA, a fully non-metric multidimensional scaling procedure programmed in the Guttman-Lingoes series. Large body size and long tusks characterize dominant walruses. Dominants are most frequently aggressive and threatening, and least frequently exhibit submissive, defensive, protective, and avoidance behavior. Subordinate walruses show the opposite trend. Walruses are bullies; individuals strongly disadvantaged in body size or tusk length, or both, receive numerous strikes and visual threats. Walruses tend to initiate agonistic interactions with smaller individuals. Walrus tusks are important in fighting, a fact which constrains evolutionary ritualization of their visual display.
Effect of angiotensin II and corpuscle of Stannius extract on total and ionic plasma calcium levels and blood pressure in intact eels (Anguilla rostrata Lesueur)
Authors: Bailey J. R. , Fenwick J. C.
Published: August 2008

A comparison of the effects of angiotensin II and saline extract of the corpuscles of Stannius on plasma electrolytes and blood pressure in eels was carried out. Angiotensin II caused an increase in plasma ionic calcium and blood pressure but had no effect on total plasma calcium or sodium. Corpuscular extract caused a decrease in plasma ionic calcium but had no effect on the other parameters. These findings indicate a possible role of the corpuscular secretions in binding plasma ionic calcium.
Lethal levels of pH for brook trout, Salvelinus fontinalis (Mitchill)
Authors: Daye P. G. , Garside E. T.
Published: August 2008

Fingerling brook trout, Salvelinus fontinalis (Mitchill), were subjected to acute and chronic pH stress for maximum periods of 10 000 min in a series of dilutions of sulfuric acid or sodium hydroxide at 10 and 20C after acclimation at 15C and pH 6.8. Lethal limits of pH were estimated to be pH 3.5 and 9.8 at both temperatures. There were no observable differences in the resistance times at lethal pH stresses between test temperatures. The order of death was not significant in relation to length or weight of the fish.
The gross anatomy and histology of the nervous system of the metacestode of Hymenolepis microstoma
Authors: Webb Rodney A. , Davey Kenneth G.
Published: August 2008

The central nervous system of the metacestode of Hymenolepis microstoma consists of three levels of ganglia. The bilateral cerebral ganglia, joined by a broad transverse commissure, are situated posteriad to the outer rostellar capsule. The bilateral rostellar ganglia, joined by a medial transverse commissure and a dorsal and a ventral circular commissure, are situated between the inner and outer rostellar capsules. The single rostral ganglion is found within the inner rostellar capsule. Numerous nerves and connectives are given off from the various ganglia; the nerves innervate the tissues and organs of the scolex and presumptive neck of the metacestode. Histologically, the ganglia and large commissures consist of a rind of nerve cell bodies surrounding a compact core of neuropile. A delimiting sheath or capsule is not present. Glial tissue is absent. Muscle cells, tegumental cells, and flame cells may interdigitate with the nerve cells. The nerve cell bodies give off numerous neurites that pursue a tortuous course through the neuropile.
Lungworms (Metastrongyloidea: Pseudaliidae) of harbor porpoise Phocoena phocoena (L. 1758)
Authors: Arnold P. W. , Gaskin D. E.
Published: August 2008

Lungworms were collected from 60 harbor porpoises shot at sea during May to August of 1970 and 1971 in the Bay of Fundy. These have been compared with related species from other odontocetes in order to evaluate the literature on pseudaliids and provide a consistent treatment of the family. This study also gives data on the occurrence of lungworms in odontocetes from Canadian waters. Keys to genera and selected species of pseudaliids in cetaceans are included.The following are redescribed: Pseudalius inflexus (Rudolphi 1808), Stenurus minor (Kuhn 1829), Torynurus convolutus (Kuhn 1829), Halocercus invaginatus (Quekett 1841), and H. taurica Delyamure, in Skrjabin 1942 from harbor porpoise, Phocoena phocoena, collected in eastern Canada; Stenurus globicephalae Baylis and Daubney 1925 from Globicephala melaena, G. macrorhyncha, and Grampus griseus (new host record); Stenurus arctomarinus Delyamure and Kleinenberg 1958 and Pharurus pallasii (van Beneden 1870) n. comb, from Delphinapteras leucas; Torynurus dalli (Yamaguti 1951) from Phocoenoides dalli; and Pharurus alatus (Leuck-art 1848) from Monodon monoceros. Pseudalius inflexus, H. taurica, and S. arctomarinus are reported for the first time from North American hosts; S. globicephalae, P. pallasii, P. alatus, and all the pseudaliids from Phocoena phocoena are reported from new host localities.Torynurus alatus is considered a synonym of Pharurus alatus. Stenurus arcticus (including previously proposed synonyms Strongylus arcticus, Pseudalius arcticus) is considered a synonym of Pharurus pallasii.Halocercus ponticus Delyamure 1946 is considered synonymous with H. invaginatus.
Oestrus, copulation, and related aspects of reproduction in female eastern chipmunks, Tamias striatus (Rodentia: Sciuridae)
Authors: Smith Donald A. , Smith Lorraine C.
Published: August 2008

Weekly livetrapping in a southeastern Ontario woodlot throughout 2 years of aboveground activity by Tamias striatus lysteri, plus supplementary data, provided information on changes in the external genitalia of female chipmunks before, during, and alter oestrus. The main stages are described and tentatively named. Oestrus was marked by a deep pink, greatly distended vulva and eventually by an elongated aperture. Our finding that oestrus lasted at least 3 days and up to 10 days is new. Post-oestrus, in which the vulva was less distended, persisted throughout half or most of gestation. There was much variability among individuals in the duration of oestrus and related stages. Copulatory behavior is described. Most observations of oestrus and copulation in Canada relate to the summer breeding season.In our local population, breeding occurred in both spring and summer, 1972, but only in spring, 1973. There was considerable variability among individual females of breeding age regarding participation in one or both breeding seasons in 1972. Among females breeding in the summer of 1972, those that had bred in the spring came into oestrus near the time when their spring young emerged from their burrows, and later than those that had not bred in the spring.
Canadian Nymphomyiidae (Diptera)
Authors: Kevan D. Keith McE. , Cutten-Ali-Khan Felicity E. A.
Published: August 2008

A new genus and species, Oreadomyia albertae, is described from the mountains of western Alberta. This differs in several important adult characters from the three previously known genera and species of Nymphomyiidae, particularly in the possession of mouthparts (which are rather unlike those of other Diptera), in the form of the compound eyes, and in the virtually apterous condition. It is placed in a new subfamily, Oreadomyiinae. Further records of Palaeodipteron walkeri Ide are given for New Brunswick. These include examples of the previously unknown, fully alate adults. The systematic position of the Nymphomyioidea is briefly discussed. The group is retained in a separate suborder, Archaeodiptera. An appendix gives a list of arthropods trapped at the same site as O. albertae.
Stress and adrenocorticosteroid dynamics in the goldfish, Carassius auratus
Authors: Fryer James N.
Published: August 2008

In goldfish serum, cortisol was found to constitute 77.6% of the adrenocorticosteroids measured by a competitive protein-binding radioassay. Adult goldfish maintained on a photoperiod of 14 h light: 10 h dark in November exhibited no significant variation in serum corticosteroid concentration throughout the 24-h cycle. Goldfish maintained in an 8L:16D photoperiod in June exhibited two peaks in serum adrenocorticosteroid concentration. Four hours before the onset of the light period and 4 h after the onset of the light period, serum corticosteroids were significantly higher than those observed at the midpoint of the dark period. After sham injection, swimming in shallow water, or a thermal shock, but not a handling disturbance, circulating levels of corticosteroids were significantly higher than in undisturbed fish. Betamethasone injected 24 h before a thermal stress completely blocked the stress-induced increase in serum corticosteroids observed in vehicle-injected and uninjected goldfish, demonstrating the potency of this steroid as a blocker of the pituitary–interrenal axis in this species.
The effects of embryonic exposure to pheasant vocalizations in later call identification by chicks
Authors: Bailey E. D. , Ralph K. M.
Published: August 2008

Pheasant chicks exposed la cock attraction cluck calls during the final week of incubation had a significant affinity for that call when tested as chicks. No particular day during incubation was more important than any other for the sound input to produce this affinity. However, a cumulative input over several days produced a stronger effect than any single day of sound exposure.Exposure of embryos to alarm calls produced the same sort of affinity for that sound as was produced by the attraction call. In each case, control chicks, not exposed to sounds as embryos, had a significantly lower affinity for any given sound than treated birds. The importance of the various auditory aspects of pheasant communication as well as interpretation of the meaning of vocalizations is determined during late embryonic development. Social attachments apparently develop auditorially first, with visual associations occurring later in maturational development.
The biology of Gammarus (Crustacea, Amphipoda) in the northwestern Atlantic. XI. Comparison and discussion
Authors: Steele D. H. , Steele V. J.
Published: August 2008

Available data on some aspects of the biology of 10 species of Gammarus are summarized and compared. It is concluded that the main adaptation allowing these species to occupy their extensive geographic range from the North Pole to the Gulf of Mexico is variation in body size. The large size of northern species (G. wilkitzkii and G. setosus) results in the production of a single, large, well-timed brood, which is released within the short period of optimum conditions. The medium-sized species (G. oceanicus, G. duebeni, G. finmarchicus, and G. obtusatus) produce several medium-sized broods spread through the longer optimum season. The small species (G. lawrencianus, G. tigrinus, G. stoerensis, and G. mucronatus) can produce a large number of small broods per female and also mature second generations in the much longer and warmer optimum season characteristic of the southern environment.
Cephalic sense organs of the rat hookworm, Nippostrongylus brasiliensis—form and function
Authors: Wright K. A.
Published: August 2008

The compliment of cephalic sensory structures of Nippostrongylus brasiliensis, the rat hookworm, was examined by electron microscopy. Each amphid contains 13 sensory dendrites whose dendritic processes enter a cuticle-lined amphidial canal that opens through a lateral amphidial pore. Amphids also contain two dendrites whose dendritic processes end in extracellular space that opens around the other dendritic processes. Processes from these neurons project into adjacent hypodermis. Hypodermis around sensory dendrites of the amphidial canal contains vacuoles that appear to open to the extracellular space. The delimiting membrane of this space is continuous with closely infolded membrane stacks that project posteriorly into the hypodermis. Neither supporting cells, nor glandular cells could be clearly identified associated with amphids or papillae. Papillae are of two types. Six type I mechanoreceptive papillae (each composed of only one sensory dendrite) occur most anteriad. These may be "stretch" receptors sensitive to pressures put on any area of the highly inflated cephalic cuticle. Four type II mechanoreceptors (containing two sensory dendrites each) are probably sensitive to direct pressure. The triradiate oral opening is separated from sense organs by a circumoral annulus of dense cuticle. The muscular esophagus makes direct contact with thin hypodermis around the mouth, and esophageal cuticle contacts body cuticle at the oral opening; no stoma is present.
Predatory behavior of the zebra spider, Salticus scenicus (Araneae: Salticidae)
Authors: Dill Lawrence M.
Published: August 2008

The zebra spider (Salticus scenicus), a small jumping spider, orients towards prey detected by its lateral eyes whenever the angle subtended by such prey exceeds 5.5°. The velocity of the prey is not involved in the determination of reactive distance, but only moving objects elicit orientation. The probability that orientation is followed by stalking is a function of both prey size and velocity, but the effects of these parameters on reactive distance for stalking were not determined. The zebra spider's stalk velocity declines progressively as it nears its (stationary) prey, and the probable optimality of this behavioral tactic is discussed.
Blubber fat deposition in mysticeti whales
Authors: Ackman R. G. , Hingley J. H. , Eaton C. A. , Sipos J. C. , Mitchell E. D.
Published: August 2008

Blubber fats from six fin whales, four sei whales, and one humpbacked whale taken in Nova Scotian waters have been studied. Dorsal, lateral, and ventral samples were compared for thickness, fat contents of inner and outer layers, and the iodine values of the recovered fats. The concept that in "fat" mysticeti whales the iodine value is higher in the inner blubber than in the outer blubber was supported by the results. It is concluded that iodine value fluctuations in one animal in a fattening stage represent surplus polyunsaturated acids deposited first in the inner layer and first in the ventral area. Correspondingly, the outer dorsal blubber is the most stable. Species differences correspond to those for Antarctic animals.
Layering and tissue composition in the blubber of the northwest Atlantic sei whale (Balaenoptera borealis)
Authors: Ackman R. G. , Hingley J. H. , Eaton C. A. , Logan V. H. , Odense P. H.
Published: August 2008

Sei whale and fin whale blubbers are infiltrated by increasing amounts of connective tissue fibers with depth from the epidermis, However, the blubber of sei whales differs from that of fin whales in that it is also interrupted by a definite layer of collagenous and elastic fibers, which in the dorsal blubber is well separated from the muscle proper, but which in the lateral and ventral blubber is progressively closer to the muscle. The layers are discussed in terms of neonatal development and of fat turnover in the adult.
Hematozoa of the passeriforms of the Tantramar Marshes, New Brunswick
Authors: Bennett Gordon F. , Cameron Marilyn , White Ellen
Published: August 2008

The prevalence of hematozoa in 3096 passeriforms of 70 species collected from 1972 to 1974 from the Tantramar Marshes in New Brunswick and 518 birds of 28 species from Charlotte County, New Brunswick, collected in 1973 was analyzed with respect to the effect of (i) climate, (ii) aerial application of insecticide, and (iii) large-scale environmental alteration. The effect of climate was found to be marked and of such magnitude as to mask other effects that may have arisen as a result of man's interference with the natural environment. The data presented represent the first analysis of the hematozoa of passeriforms for the New Brunswick region and may serve as baseline information for future studies using the prevalence of avian hematozoa as a criterion of environmental quality.
A field-trip microtechnique for studying fish leukocyte chromosomes
Authors: Legendre Pierre
Published: August 2008

An ideal technique for field cytotaxonomy of fishes should be rapid, efficient, and time- and distance-independent. It should work on small as well as big specimens, and it should be amenable to air-drying. A technique meeting these requirements is as follows. A few drops of whole blood are collected from the specimens during field trips and kept in culture medium. In the laboratory, the medium is changed, Phytohemagglutinin is added, and the cells are cultivated at room temperature for about 3 days, after which air-drying fixation is performed. For very small specimens, the blood from several individuals may be pooled in one culture vessel.
Parasites of Fundulus diaphanus (LeSueur) (Pisces: Cyprinodontidae) in certain Nova Scotian freshwaters
Authors: Wiles Michael
Published: August 2008

Over 90% of 829 banded killifish from three Nova Scotian locations were infected with at least one parasitic species. Protozoans, monogeneans, digeneans, cestodes, nematodes, acanthocephalans, and a crustacean and a molluscan species occurred in the fish. All species recovered are reported for the first time from Fundulus diaphanus in Nova Scotia and 12 are new host records. Five of the non-digenean larval genera found were probably accidental parasites.
Delayed mortality following thermal stress in three species of intertidal pelecypod molluscs (Modiolus demissus, Mya arenaria, and Mytilus edulis)
Authors: Waugh D. L.
Published: August 2008

Determination of delayed mortality following thermal stress in three species of intertidal pelecypod molluscs (Modiolus demissue, Mya arenaria, and Mytilus edulis) shows that substantial mortality may occur for some considerable interval following removal of a potentially lethal thermal stress. In general, delayed mortality is greater in short-term bioassays (< 96 h) than in long-term bioassays (> 96 h). Moreover, the extent of delayed mortality is evident much earlier in bioassays lasting less than 12 h than in longer bioassays.These observations are discussed in relation to the determination of levels of safety for environmental pollutants.
Distribution of the avian hematozoa of North America
Authors: Greiner Ellis C. , Bennett Gordon F. , White Ellen M. , Coombs Richard F.
Published: August 2008

The literature pertaining to the prevalence of avian hematozoa in North America, north of Mexico, together with unpublished records from the files of the International Reference Centre for Avian Malaria Parasites, have been collated and analyzed with respect to the distribution of parasite genera by region, host family, and vertical stratification of nesting sites. The blood parasites of 57 026 birds of 388 species (representing 55 families) breeding in North America are the basis of this analysis. A total of 21 048 (36.9%) birds harbored one or more species of Haemoproteus (19.5%), Leucocytozoon (17.7%), Trypanosoma (3.9%), Plasmodium (3.8%), microfilariae (3.1%), and Haemogregarina/Lankesterella (0.6%). The continent was arbitrarily divided into seven regions along a topographic basis. Overall hematozoan prevalence varied markedly from region to region, as did the relative frequencies of the different genera. Overall hematozoan prevalence also varied markedly from avian family to family, as did the relative frequencies of the different genera. Nine families had prevalences of 50% or more, while 16 families had prevalences of 5% or less; sea- and shore-birds were nearly hematozoan-free. Prevalence of blood parasites is correlated with the vertical stratification of nesting sites when considered on a localized geographic basis but no correlation exists when the results are pooled from the continent.
Occurrence of Thelohania sp. and Pleistophora sp. (Microsporida: Nosematidae) in Choristoneura fumiferana (Lepidoptera: Tortricidae)
Authors: Wilson G. G.
Published: August 2008

Two previously unreported microsporidia have been found parasitic in the spruce budworm (Choristoneura fumiferana). These are described briefly and assigned to the genera Thelohania and Pleistophora.
Migration, development, and condition of Trichobilharzia ocellata (Trematoda: Schistosomatidae) in homologous challenge infections
Authors: Ellis James C. , Bourns T. K. R. , Rau Manfred E.
Published: August 2008

Ducks previously infected with Trichobilharzia ocellata were challenged by exposure to conspecific cercariae. Comparisons were made among worms recovered from teased or squashed tissue or located in sections, after first, second, or multiple challenges. Contrasting with 24 h clearance in initial infections, schistosomula were retained in the skins of challenged birds, mainly in the stratum corneum, for up to 7 days. Parasites reached the lungs as early as day 1 in first and second challenges but more than 50% of these were adhering to bronchial walls in mucoid material. After third challenge, worms were seen in the lung on day s 3–7 but 35–83% of these were coated with lymphoid cells. Schistosomula were found in the livers of 16/19, 4/15, and 2/20 birds examined after first, second, and multiple challenges respectively, most being in sinusoids surrounded by lymphocytes. No worms assignable to challenge infections were found in the hosts' intestinal veins. Parasites which survived 7 days in challenge infections reached lengths of about 300 μm, about 10–15% of the normal value. Those from 16/19 birds retained cercarial features such as tegumental spines, eyespots, and head organs.
The lambing period of mountain sheep: synthesis, hypotheses, and tests
Authors: Bunnell Fred L.
Published: August 2008

Data on lambing periods from 30 populations of North American mountain sheep are reviewed. Among all populations lambing begins later and duration is shorter at more northern altitudes (p < 0.00006). Correlations are enhanced (p < 0.00003) when latitude is replaced by a phenological index incorporating altitude. Termination of lambing is not correlated with latitude or with phenological index. Two broad patterns are evident. Populations feeding on vegetation of less predictable growth patterns ("desert type") have lengthy lambing seasons; populations feeding on vegetation exhibiting more predictable growth patterns ("alpine type") have shorter lambing seasons, typically two oestrous cycles in length. Definition of "types" by latitude or sheep taxonomy reveals significant differences in lambing periods, but correlations are enhanced when "types" are defined on the basis of habitat.Among taxa, birth weights are correlated with female body weight (rs = 0.87). Birth weights are heavier in extreme environments, seasonal growth patterns are expressed better in the alpine type, and early weight gain is most rapid in the northernmost subspecies. All populations show a strong central tendency with regard to peak lambing (17 May ± 6.8 days). Departures from that tendency respond more to predictability of vegetation than to thermal stress or predation pressure.
Seasonal changes in growth rate, feed intake, growth hormone, and thyroid hormones in young male reindeer (Rangifer tarandus tarandus)
Authors: Ryg Morten , Jacobsen Endre
Published: August 2008

The levels of thyroxine (T4), triiodothyronine (T3), and growth hormone (GH) in blood serum from young male reindeer have been measured and compared with changes in body weight and feed intake during ad libitum and restricted feeding. All three hormones fluctuated during the year. T3 changed in response to changes in feed intake. T4 and GH seemed to have basic seasonal patterns, which were modified by differences in feed intake. GH rose to high levels in late winter – early spring. T4 levels were higher in summer than in winter, corresponding roughly to changes in weight gain and feed intake.
The Ruby-throated Hummingbird and its major food plants: ranges, flowering phenology, and migration
Authors: Bertin Robert I.
Published: August 2008

The Ruby-throated Hummingbird (or rubythroat, Archilochus colubris) and several of its major food plants were examined to assess the importance of rubythroat versus insect pollination, the overlap of geographical ranges, and the synchrony between migration and flowering times. Seed set of Impatiens biflora was increased 8–17% by rubythroat and insect visitation over the level achieved by insects alone. The rubythroat's range is not contiguous with that of any of 22 putative food plants examined, but is nearly coincident with the range of certain forest types, perhaps reflecting the importance of sap for food. A new method was developed to estimate peak flowering times of plants from herbarium data. Based on these data and field observations, only one rubythroat food plant (Impatiens biflora) had peak flowering times close to peak rubythroat migration times throughout their shared range. Rubythroats and their North American food plants are facultative mutualists, with the plants apparently having been evolutionarily more labile.
Breeding habitat selection and home range of radio-marked black ducks (Anas rubripes) in Maine
Authors: Ringelman James K. , Longcore Jerry R. , Owen Jr. Ray B.
Published: August 2008

Telemetry techniques were used to monitor the movements and habitat use of 13 female and 7 male black ducks (Anas rubripes) in an inland breeding region of south central Maine in 1977–1980. Black ducks preferred persistent emergent, broad-leaved deciduous forested, and broad-leaved deciduous scrub–shrub wetlands over unconsolidated organic bottom, needle-leaved evergreen forested, and broad-leaved evergreen scrub–shrub ponds. Birds also made frequent use of small ephemeral pools and streams throughout the breeding period. Nests were located in several habitats ranging from wetland sites to upland areas 1.5 km from the most frequently used pond. Home range size averaged 119 ha for females and 231 ha for males and did not differ by reproductive stage. Three pairs used only a single pond during the incubation period. Home ranges were linear (linearity index = 2.8), averaging 1956 m long for females and 2755 m for males. Wetlands used most by hens during incubation recesses were not always those located closest to the nest. Radio-marked ducks that returned in subsequent breeding seasons demonstrated fidelity to the previously used home range. Pair bonds of marked birds lasted until day 19 or 20 of incubation for initial nesting attempts.
The zoogeography of the freshwater mussels of the Taconic and southern Green mountain region of northeastern North America (Mollusca: Pelecypoda: Unionacea)
Authors: Smith Douglas G.
Published: August 2008

The Taconic and southern Green mountains form a system of ridges drained by four watersheds in eastern New York and western New England: Lake Champlain and the Housatonic, Hudson, and Connecticut rivers. Ten species of mussels distributed among the Margaritiferidae and Unionidae are recorded, based on museum records and recent collections, from the area. The presence of species representing two regional faunas, the Mississippian and Northern Atlantic Slope, indicates that some western streams of the Taconic Mountain region were connected with both the Atlantic coastal and interior Mississippian drainages during the Late Pleistocene. However, a divide has persisted along the north–south trend of the two mountain chains that has prevented late glacial east–west migration between the Hudson River – Lake Champlain systems in eastern New York and the Connecticut River – Housatonic River systems in western New England.
Seasonal change in the amount of visual pigment in the retinae of fish
Authors: Allen Donald M. , Loew Ellis R. , McFarland William N.
Published: August 2008

The total amount of two visual pigments, rhodopsin and porphyropsin, extracted from retinal photoreceptors of three trouts and a cyprinid, changes seasonally. In Salmo gairdneri, Salmo trutta, and Salvelinus fontinalis maintained in an outdoor raceway at constant temperature (8 °C) the total amount of visual pigment increased about twofold during the winter, though the proportions of rhodopsin and porphyropsin were relatively unchanged. In eastern common shiners, Notropis cornutis, sampled from a stream, visual pigment increased by about fourfold in winter as compared with summer, and porphyropsin rose from about 17 to 68% of the total amount. A later sample of summer and winter shiners revealed no difference in the density of visual pigment within individual rods.An increased amount of visual pigment will broaden the overall pigment absorptance spectrum and a concomitant increase in porphyropsin will further broaden and shift absorptance toward longer wavelengths. Thus, change in total amount of visual pigment represents a new dimension in the way that visual pigment absorptance can be dynamically altered in certain fishes.
Why do male butterflies visit mud puddles?
Authors: Adler Peter H. , Pearson David L.
Published: August 2008

This study is the first to demonstrate that Na budgets of male and female Lepidoptera differ. At the time of emergence, male imported cabbage butterflies, Pieris rapae L., have significantly more total body Na than females. Older males collected from the field show a significantly lower level of body Na than freshly emerged males, whereas freshly emerged females and older, field-collected females show no difference. It is suggested that feeding from soil may help restore losses of Na in males. A single female, through oviposition, may lose nearly 75% of the total body Na with which it emerged. The lepidopteran mating system involving transfer of spermatophores is postulated as one causative factor for sexual differences in body Na levels.
Sterile matings initiate the breeding season in the bank vole, Clethrionomys glareolus. A field and laboratory study
Authors: Westlin Lilian M. , Nyholm Erik
Published: August 2008

The start of the breeding season of overwintered female bank voles, Clethrionomys glareolus, and also the start of breeding in young of the year, was characterized by a general occurrence of sterile ovulations. Similarly, in laboratory experiments, 23 out of 42 young virgin females failed to become pregnant after the first mating, and often mated several times before becoming pregnant. The experiments indicated that the sterile ovulations were attributed to temporary sterility of the females during maturation either at adolescence or at the beginning of the new breeding season, and not a result of (1) initial ovulations of the season being spontaneous, (2) male sterility, or (3) male-induced pregnancy blockage.
Temperature regulation in the Black Vulture
Authors: Larochelle Jacques , Delson Jeffrey , Schmidt-Nielsen Knut
Published: August 2008

Metabolic rate, body temperature, and heat dissipating mechanisms of the Black Vulture were studied under laboratory conditions. The metabolic rate (6.5 W) was close to the predicted one. The body temperature showed considerable variations with air temperature, ranging from 37.7 °C at 15 °C to 42.9 °C at 45 °C. The area of featherless skin on the head and neck changed with the body temperature, thus indicating a role in heat dissipation, and we conclude that these featherless skin areas can be adjusted according to the need for temperature regulation.
Life cycle characteristics of northern Peromyscus maniculatus borealis
Authors: Millar John S.
Published: August 2008

Life cycle characteristics of northern Peromyscus maniculatus borealis were examined in the laboratory in order to identify specific adaptations to strongly seasonal environmental conditions. Although northern P. m. borealis are demographically K selected, body weight (19.2 g), gestation time (26.3 days for postpartum litters), litter size (5.0), birth weight (1.87 g), age at weaning (21.4 days), weight at weaning (9.26 g), growth rates (0.35 g/day), and energy requirements for lactation (181% increase attributable to five offspring) are all similar to those of other subspecies of P. maniculatus. General demographic conditions do not appear to have been important in the evolution of the life cycle characteristics of P. maniculatus.
Seasonal variation in two species of unionid clams from Manitoba, Canada: respiration
Authors: Huebner Judith D.
Published: August 2008

Respiration is proportional to the 0.769 power of dry weight for Anodonta grandis and the 0.898 power of dry weight for Lampsilis radiata at all temperatures and in all months tested. The log of oxygen consumption increases linearly with temperature for both species up to 24 °C. Q10 values are high but show no season-, temperature-, or size-related relationships. There is no evidence of seasonal acclimation of respiration in either species.
Exchangeable sodium pool size and turnover in relation to diet in reindeer
Authors: Staaland H. , Holleman D. F. , Luick J. R. , White R. G.
Published: August 2008

Sodium pool size and transfer rate was estimated in reindeer (Rangifer tarandus L.) using intravenous and intraluminal injections of 22NaCl. Body water pool size and water transfer rate was estimated with 3HOH. Reindeer were consuming diets high in sodium (Na) and potassium (K) (commercial livestock ration), low in Na and high in K (summer grazing), and low in Na and K (lichens). The exchangeable Na pool size (milliequivalents per kilogram body weight) in reindeer given the high sodium diet (61 ± 2) was similar to other mammalian species. A marked decline in the pool (to 36 ± 3) was noted when reindeer were grazing summer vegetation in central Alaska and the Na pool was also low (46 ± 5) when they were fed lichens. Concentrations of Na in plasma, saliva, urine, and feces were directly correlated with the exchangeable Na pool size. Sodium transfer rates for reindeer given the high Na diet or grazing were two- to three-fold higher than daily Na intake rates. Loss of Na in feces and urine were of roughly equal importance in reindeer fed lichens or at pasture. Signs of Na insufficiency indicated by a salivary Na:K ratio of less than 2:1 were noted when the Na pool size declined below 40 mequiv./kg body weight. Evidence is presented for an extremely rapid replenishment of the Na pool following Na supplement of the diet.
Experimental studies on acarine predator–prey interactions: the effects of predator density on immature survival, adult fecundity and emigration rates, and the numerical response to prey density (Acarina: Phytoseiidae)
Authors: Eveleigh Eldon S. , Chant D. A.
Published: August 2008

Laboratory experiments revealed that increasing the density of the immature instars of Phytoseiulus persimilis had little effect on their survival rates. However, due to the high prey requirements of the immature instars of Amblyseius degenerans and the tendency for underfed individuals of this species to become cannibalistic, their survival rates decreased with increasing predator density. Increasing predator density reduced the fecundity of P. persimilis and caused its numerical response to prey density to reach plateaux at increasingly lower levels of fecundity as the predator density increased. In contrast, increasing predator density did not affect the fecundity of A. degenerans to such an extent and its numerical response appeared eventually to reach maximum levels when sufficient prey were available. The emigration rates of P. persimilis tended to increase with increasing predator density whereas those of A. degenerans increased or decreased depending on the density of the predators and the prey.
Octopamine in insects: neurotransmitter, neurohormone, and neuromodulator
Authors: Orchard Ian
Published: August 2008

The biogenic amine octopamine is widely distributed within the nervous system of invertebrates. This review examines the role of octopamine in insects and shows that octopamine can act as a neurotransmitter, a neurohormone, and a neuromodulator. Examples of its neurotransmitter role are found in the firefly lantern and also possibly in the glandular lobe of the corpora cardiaca of locusts. Octopamine is also present in the haemolymph of cockroaches and locusts where it functions as a neurohormone, controlling the release of trehalose and lipid from fat body. In locusts, an identified octopaminergic neuron innervates the extensor-tibiae muscle of the hind legs. This neuron inhibits a myogenic rhythm of contraction and relaxation found in a proximal bundle of muscle fibers, and modulates the activity expressed by motoneurons which innervate the extensor-tibiae muscle. Octopamine is, therefore, a neuromodulator in this system. The functional significance of octopamine in insects is discussed with special reference to its association with general arousal phenomena.
On the cardioinhibitory role of water immersion per se in ducklings (Anas platyrhynchos) during enforced submersion
Authors: Jones David R. , Butler Patrick J.
Published: August 2008

Experiments were done to clarify the contribution of water immersion per se to the cardiac chronotropic response to enforced submergence in ducklings. Four protocols were used in which one or more of the factors claimed to affect diving heart rate were controlled. Heart rate fell rapidly in the first few seconds of submergence in all protocols. This initial fall was unaffected by changes in head position or by breathing 100% oxygen for 5 min before diving. Also, sudden withdrawal of input from lung receptors or cessation of activity in central respiratory neurones did not affect onset of diving bradycardia. We conclude that about one-third of diving bradycardia in ducklings is caused by water immersion per se.
Diet quality and food limitation in herbivores: the case of the snowshoe hare
Authors: Sinclair A. R. E. , Krebs C. J. , Smith J. N. M.
Published: August 2008

Arguments concerning the regulation of animal populations through food shortage are hampered by the difficulty of measuring available food. This is avoided by considering how animals respond to declining food supplies. Three alternatives exist: (a) maintain a constant rate of food intake by including more poor food, (b) increase the quantity eaten to compensate for poor quality, or (c) eat only high-quality foods and thus decrease the quantity eaten. Experiments with snowshoe hares (Lepus americanus) fed ad libitum food of different crude protein values, show hares maintain a relatively constant intake rate as quality falls. This result allows us to use mean diet quality to predict whether animals can maintain body weight under natural conditions. The threshold diet quality below which weight loss occurred was 11% crude protein in the laboratory. There is a strong correlation between diet crude protein and faecal crude protein. By collecting faecal pellets in the field, one can monitor the diet of the population. If faecal crude protein falls below 7.5%, animals lose weight as a result of insufficient good food. Field data for 1977–1980 show faecal protein for some animals dropping below this level in late winter of 1979 when the hare population was near its peak density.
Cardiovascular changes in the unanaesthetized lingcod (Ophiodon elongatus) during short-term, progressive hypoxia and spontaneous activity
Authors: Farrell A. P.
Published: August 2008

Cardiac output [Formula: see text] and arterial blood pressures in the ventral and dorsal aortae (PVAnd PDA) were measured directly and simultaneously in the lingcod. The branchial and systemic conductances to blood flow (Gg and Gs) were calculated. During progressive hypoxia [Formula: see text], Gg, Gs, PVA, and PDA were all reduced when the water [Formula: see text] decreased below 45 mmHg (1 mmHg = 133.322 Pa). Spontaneous activity was characterized by an initial bradycardia and concurrent reduction in [Formula: see text], Gg, Gs, PVA, and PDA. Longer periods of activity were subsequently followed by a period of restitution where [Formula: see text], Gg, Gs, PVA, and PDA were all elevated.The beat by beat oscillations in flow were usually synchronized with, and in the same direction as, those in vascular conductance during both activity and hypoxia. This synchrony was most apparent between Gs and [Formula: see text] during the rapid cardiovascular adjustments occurring with activity. It is suggested that the observed relationship between flow and conductance changes was a result of passive changes in conductance when flow was altered, plus an active component which involved reflex vasoactivity.
The effects of testosterone and scopolamine HBr on the aggressive behaviour of male voles, Microtus townsendii
Authors: Gipps J. H. W.
Published: August 2008

Two substances were shown to have a significant effect on the aggressive behaviour of male voles of the species Microtus townsendii in neutral arena dyadic encounters in the laboratory: testosterone was used to increase aggression in small males, and scopolamine HBr, an anticholinergic, was used to decrease it in large males. After the effects of these two substances on the behaviour of male voles in the laboratory had been determined, both were used in a field study of the role of social behaviour in the ecology of M. townsendii.Subadult males between 20 and 44 g, implanted subcutaneously with Silastic capsules containing testosterone, investigated each other less and fought more than control males with dummy implants. They also fought less than adult control males weighing 45 g or more. As expected, the onset of male aggression at sexual maturity in this species appears to be androgen dependant.Adult male M. townsendii weighing 45 g or more with implants containing scopolamine HBr fought significantly less than control males with dummy implants. Scopolamine HBr reduced intermale aggression very effectively whilst apparently not affecting coordinated motor activity.
Critical periods and pivotal temperatures for sexual differentiation in loggerhead sea turtles
Authors: Yntema C. L. , Mrosovsky N.
Published: August 2008

Eggs of loggerhead sea turtles, Caretta caretta, were incubated at constant temperatures ranging from 24 to 34 °C. At temperatures of 32 °C or above all embryos developed into females as judged by histology of the gonads. At 28 °C or below all developed into males. At 30 °C there were approximately equal numbers of both sexes; 30 °C therefore is the pivotal temperature for the thermal effects on sexual differentiation in this population of turtles. The direction of sexual differentiation is not determined by temperature throughout incubation but by the levels prevailing during a critical period. Experiments with temporary alterations of temperature, either upwards or downwards from the pivotal value, localized the critical period to somewhere between stages 12 and 22 of embryonic development. Definition of the critical period in sea turtles should prove useful both in further work on the theoretical aspects of the phenomenon and in conservation programmes for sea turtles.
Reaction of Percina nigrofasciata, Ammocrypta beani, and Etheostoma swaini (Percidae, Pisces) to conspecific and intergeneric skin extracts
Authors: Smith R. J. F.
Published: August 2008

Percina nigrofasciata, Ammocrypta beani, and Etheostoma swaini respond to conspecific skin extract with an alarm reaction which consists of remaining motionless or showing greatly reduced activity. This freezing response was often preceded by rapid darting in E. swaini and accompanied by cryptic colouration and movement to cover in both E. swaini and P. nigrofasciata. Percina nigrofasciata and E. swaini responded significantly to extracts of the other two species. Ammocrypta beani showed a significant response to P. nigrofasciata extract but not to extract from E. swaini. All three species possess darter-type club cells in their epidermis.
A method to trap rodents in snow, sleet, or rain
Authors: Keller Barry L. , Groves Craig R. , Pitcher Edward J. , Smolen Michael J.
Published: August 2008

A bucket shelter for use with live traps has been developed and employed in over 20 000 live-trap nights during winter trapping of small mammals. This shelter is easily prepared, is relatively inexpensive, can be employed in large numbers, and affords good protection of traps.
Cl−, K+, and acid–base balance in rainbow trout during exposure to, and recovery from, sublethal environmental acidification
Authors: Booth J. H. , Jansz G. F. , Holeton G. F.
Published: August 2008

A review of pertinent literature is provided. Previous research showed that fish exposed to sublethal environmental acidification have reduced blood pH, plasma [HCO3−], and [Cl−] and increased plasma [K+]. Simultaneous sampling from blood and water was used to characterize changes in Cl−, K+, and acid–base regulation in rainbow trout during a 5-day exposure to pH 4 followed by a 24-h recovery period at pH 7. At pH 4, there was a continuous loss of Cl− (49.8 μmol/kg per hour), and K+ (23.0 μmol/kg per hour) to the water. Blood ion concentrations did not change in a corresponding manner. Blood pH and plasma [HCO3−] decreased continuously owing to a net uptake of acid from the water. Recovery at pH 7 involved uptake of Cl− from, and loss of K+ to, the water. Plasma [K+] returned to normal but there was no significant change in plasma [Cl−] during this 24-h period. Internal acid–base parameters recovered much more quickly owing to a net excretion of acid into the water. The more rapid recovery of acid–base balance suggests that branchial acid–base and ionoregulatory mechanisms may be only loosely linked. The irregular changes in blood ion concentrations indicate that considerable ionic and osmotic exchanges between the plasma, the remainder of the extracellular space, and the intracellular space must result from exposure to pH 4.