bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimal size of territory in the clay-colored sparrow, Spizella pallida
Authors: Knapton Richard W.
Published: August 2008

Territory size in two populations of clay-colored sparrows in Manitoba averaged smaller than those in other open-country species of sparrows. This is probably because the territory was not used by adults for feeding or for gathering food fur the young. Experimental removals of territorial males in mid-May revealed the existence of a surplus of nonterritorial birds, indicating that there is some resistance to taking too small a territory. Investigation of several factors which could influence territory size indicated that nest predation was the most important factor in preventing the territory from becoming a very small size and that the upper limit to territory size was determined proximately by a number of factors including nesting cover and pressure from adjacent territory holders. Most male clay-colored sparrows appeared to preferentially defend an optimal size range of territories in which they maximized their reproductive fitness.
Soaring flight of monarch butterflies, Danaus plexippus (Lepidoptera: Danaidae), during the late summer migration in southern Ontario
Authors: Gibo David L. , Pallett Megan J.
Published: August 2008

Adult Danaus plexippus in southern Ontario frequently engage in soaring flight during their late summer migration. They utilize both ascending air currents (lift) produced by winds blowing up slopes and thermals (bubbles or columns of air that are rising because they are warmer and lighter than the surrounding air). The butterflies appear to be very efficient and exhibit different flying techniques when encountering various types of lift. When the weather is favourable, soaring is the main mode of flight and the butterflies achieve heights above the ground of at least 300 m. Extended soaring flight in thermals was always associated with tail winds.A sample of 18 specimens gave an average mass of 566 ± 81 mg and an average wing loading of 0.018 ± 0.002 g/cm2 (1.77 N/m2). Gliding performance parameters were measured for two specimens ballasted to 450 mg and the results were extrapolated to 600-mg individuals. The energetic advantages of utilizing soaring flight in terms of extension of maximum range is discussed.
Responses of Atlantic salmon alevins to temperature gradients
Authors: Peterson R. H. , Metcalfe J. L.
Published: August 2008

Newly hatched Atlantic salmon (Salmo salar) alevins aggregated in the lowest temperature available in a temperature gradient, possibly because of lower levels of locomotor activity at lower temperatures. At approximately 250 degree-days after hatching, alevins demonstrated a temperature selection capability and no longer aggregated in the lowest temperature. Possible mechanisms underlying the observed distributional change in a temperature gradient are discussed.
Responsiveness of young herring gulls to stimuli from their own and other species: effects of training with food
Authors: Evans Roger M.
Published: August 2008

Young herring gulls (Larus argentatus) are known to emit vocalizations and approach their mew-calling parents when the latter return lo the colony with food for their chicks. In contrast, laboratory-reared young deprived of experience with adults approach and vocalize only rarely lo parental mew calls, although they will respond more strongly to the mew calls of two other species. These results suggest that posthatch experience, such as receipt of food from a calling parent, may be important for the normal development of responses to species typical calls. I tested the effects of food training by exposing young herring gulls, in the laboratory, lo mew calls during feedings. By 7 days of age, responses to herring gull calls increased significantly for young trained with these calls, and the initial tendency for the young to respond selectively to mew calls of the ring-billed gull (L. delawarensis) was reversed. Food training also influenced approach and vocal responses to a visual stimulus (my hand) used to deliver food. Results suggest that approach and vocal responses of young herring gulls may be strongly and adaptively influenced by food conditioning during the first few days after hatching.
A note on the stomach contents of adult Atlantic salmon (Salmo salar, Linnaeus) from Port Burwell, Northwest Territories
Authors: Neilson John D. , Gillis David J.
Published: August 2008

Stomach content analyses on 28 Atlantic salmon captured at Port Burwell, Northwest Territories, in late August, 1977, indicate that invertebrate prey items were the most important by volume. Parathemisto libellula dominated the invertebrate prey group, and Ammodytes sp. was the most important fish in the diet of the salmon analyzed. A range extension for Notoscopelus elongtus kroeyeri was recorded.
Behavioral structure and demography of subarctic Clethrionomys gapperi and Peromyscus maniculatus
Authors: Mihok Steve
Published: August 2008

A subarctic rodent community of Clethrionomys gapperi and Peromyscus maniculatus was censused with multiple-capture traps in contrasting years of population growth. Clethrionomys gapperi was involved in few multiple captures and was caught in small groups. Repeat multiple captures of the same individuals were rare. Mature females were territorial and were mainly caught with mature males. Mature males had large, extensively overlapping ranges and were mainly caught with mature voles. Immatures had small, moderately exclusive ranges and were involved in more multiple captures than were mature voles. Patterns of association in C. gapperi were random.Peromyscus maniculatus was involved in numerous multiple captures and was occasionally captured in large groups. Individuals were often repeatedly captured with the same individuals. Except for mature males, most animals had extensively overlapping ranges. The basic social unit consisted of a mature male, a few mature females, and a number of young. Numerical changes were principally related to variation in juvenile survival and winter mortality. The pattern of multiple captures did not vary over a wide range of conditions. Variation in the frequency of multiple captures was indicative of spatial organization and social structure, and was not related to demographic changes.
A review of the marine Tubificidae (Oligochaeta) of North America
Authors: Brinkhurst R. O. , Baker H. R.
Published: August 2008

Thirty-nine species of marine tubificids are reported here for North America, the list being compared to the known world fauna. Nine of the species are new to science, and several other species are redescribed, leading to revisions of genera and subfamilies. Other species remain to be described by colleagues, and it is apparent that a wide diversity of marine tubificids exists around the world and at all depths in the oceans.
Présence d'Aedes (Ochlerotatus) pullatus (Coquillett) (Diptera: Culicidae) dans les Chic-Chocs, Parc de la Gaspésie, Québec. Implications biogéographiques de cette extension d'aire
Authors: Maire Alain , Picard Luce , Aubin Antoine
Published: August 2008

Aedes pullatus is a typical boreoalpine species with an holarctic but discontinuous distribution. Several alpine mosquito larval habitats were found on Mont Albert (1150 m). Aedes pullatus was the dominant species, whereas Aedes hexodontus was present only sporadically. This locality is by far the southernmost known so far for both species in eastern North America. The larval breeding sites of Ae. pullatus are described. Comparison with habitats described from Eurasia and from the Cordillera shows similarities in all the Holarctic localities: unshaded sites, rock pools or ponds with a rocky bottom, and riparian ponds. Presence of Ae. pullatus in the Chic-Choc Mountains is discussed in regard to the last Pleistocene glaciation. The probable reasons for the distribution of the species in eastern North America are discussed.
Axiopsis caespitosa (Thalassinidea, Axiidae), a new species from the Pacific coast of Colombia
Authors: Squires H. J.
Published: August 2008

Axiopsis (Axiopsis) caespitosa is a new species of the Axiidae from the Pacific coast of Colombia, South America. It has a carina on the carapace behind the cervical groove but is typically axiopsid. One specimen, the female holotype, was trawled in 90 m and is deposited in the Smithsonian Institution, Washington, D.C. The species appears to be the Pacific analogue of the Atlantic species A. (A.) hirsutimana. Differences are fewer spines on the median carina, on the rostrum, and at the transverse suture of the outer uropod, as well as two groups of three spines just behind the cervical groove. Several species of axiid named Calastacus are referred to the genus Axiopsis in view of a strict definition of the former.
The effect of parasitism by Aphidius smithi (Hymenoptera: Aphidiidae) on the food budget of the pea aphid, Acyrthosiphon pisum (Homoptera: Aphididae)
Authors: Cloutier Conrad , Mackauer Manfred
Published: August 2008

Parasitism by Aphidius smithi affected the food budget of its host, Acyrthosiphon pisum, fed on a synthetic diet. During the embryonic stage of the parasite, the weight-specific rates of feeding, food assimilation, and growth were less in parasitized aphids than in controls. In the presence of a developing parasite larva, aphids ingested more food but assimilated it less efficiently; they achieved the same or a higher relative growth rate than nonparasitized aphids as a result of having either a higher feeding rate or a higher efficiency of incorporation of assimilated food, or both. Honeydew excretion was up to 129% higher in aphids containing a parasite larva. Parasitism by A. smithi did not obviate host feeding and capacity for growth until host size was sufficient for the successful development of the parasite larva.It is suggested that the nutritional requirements of the parasite larva differ from those of the aphid. Thus parasitism affects the homeostatic regulation of aphid feeding and food assimilation by causing an imbalance of nutrients in the host's haemolymph.
Metacestodes of moose, Alces alces, of the Chapleau Crown Game Preserve, Ontario
Authors: Addison E. M. , Fyvie A. , Johnson F. J.
Published: August 2008

Lungs, liver, spleen, heart, and kidneys of moose, Alces alces, collected from 1963 to 1965 in the Chapleau Crown Game Preserve of northeastern Ontario were examined for parasites. Thirty-eight of 51 moose (75%) were infected with metacestodes of Taenia hydatigena Pallas, 1766; 40 of 54 (74%) with Taenia krabbei Moniez, 1879; and 36 of 54 (67%) with Echinococcus granulosus (Batsch, 1786). Twenty-two of 51 (43%) moose harboured all three species. Each species was more prevalent in older moose than in young moose and intensity of infections increased with the age of moose. Occurrence of small hydatid cysts decreased and large cysts increased with increasing age of moose. Of 1154 hydatid cysts, 95.3% were in lung tissue, 3.6% in liver, 0.9% in spleen, and 1 cyst (0.1%) was recovered from each of heart and kidney. Degenerate cysticerci of T. hydatigena and T. krabbei were observed in all age groups of moose. There was no apparent relationship between intensity of infection with metacestodes and physical condition of moose.
Demography of populations of deer mice in coastal forest and clear-cut (logged) habitats
Authors: Sullivan Thomas P.
Published: August 2008

This study was designed to test the widely held hypothesis that clear-cut (logged) habitats support higher density populations of Peromyscus than do forested habitats. Deer mouse populations were livetrapped in forest and clear-cut habitats at Maple Ridge, British Columbia, from May 1975 to April 1978. The average density of mice per hectare in the forest was 19.6(1975), 15.8(1976), 22.3(1977), and on the clear-cut areas was 23.3(1975), 16.6(1976), 29.9(1977). The slightly higher number of animals on the clear-cutting in 1975 and 1977 reflected a burst of recruitment in the late summer and fall of each year. The density of mice on clear-cut areas declined during each winter to a level comparable with that of the forest. Juvenile male deer mice were able to enter into the clear-cutting populations during the breeding season in the first year after logging. Recently logged areas may be acting as dispersal or behavioural sinks.
Selectivity of avian predation in declining populations of the vole Microtus townsendii
Authors: Beacham Terry D.
Published: August 2008

The object of this study was to assess the impact of avian predators on Microtus townsendii populations, especially during declines. Four vole populations declined from October 1977 until June 1978, and in the fall of 1977, avian predators accounted for a minimum of 15% of the loss from the tagged vole populations, but this percentage declined during the winter of 1977. The predators selected males and small individuals and mortality accounted for by avian predation was density dependent in the vole populations; denser vole populations suffered higher predation rates.
Ultrastructure of the envelopes of resistant and nonresistant Daphnia eggs
Authors: Seidman Lisa A. , Larsen Jr. John H.
Published: August 2008

During early development, the nonresistant egg of Daphnia had an outer wall of [Formula: see text], and an inner wall approximately the thickness of the plasma membrane. In the same genus at a comparable developmental stage, resistant eggs were surrounded by a three-layered envelope, [Formula: see text] thick. Although the outer layer [Formula: see text] of the latter appeared similar to the outer wall of the nonresistant egg, the middle layer [Formula: see text] resembled the crustacean procuticle. The outer layer developed before the formation of the middle component, and both structures were absent after development resumed. This suggests that the resistant egg envelope is characterized by an additional embryonic cuticle and molt.
Comparison of blood characteristics in plains bison, wood bison, and their hybrids
Authors: Peden D. G. , Kraay G. J.
Published: August 2008

Two hundred and eight blood samples were collected from four plains bison herds, one wood bison herd, and one herd that is assumed to be a hybrid between wood and plains bison. Haemolytic tests were made using 13 cattle blood typing reagents. Red cell carbonic anhydrase alleles were checked using electrophoresis. The frequencies of each blood trait within each of the six herds were determined. Comparisons of all possible pairs of herds for each trait were made and at least two significant differences (P < 0.05) were found in every case. Ten blood characteristics were used to discriminate among the six herds. Bison from Santa Catalina Island, California, were similar to those from the National Bison Range, Montana, and they jointly differed from the herd from Oklahoma and the three from Canada. The Canadian herds, which included wood bison, hybrid bison, and plains bison, were relatively similar to each other. Differences among the plains bison herds were at least as great as those among the two subspecies and their hybrids. These findings are discussed in relation to herd histories and to the variability among North American bison populations.
Adaptive hyperplasia of epidermal chloride-secreting cells in fry of mummichog, Fundulus heteroclitus L., incubated and reared in supranormal salinity
Authors: Tay K.-L. , Garside E. T.
Published: August 2008

Cells, structurally identical with branchial chloride-secreting cells, were observed to be broadly distributed in buccal and pharyngeal epithelia and various regions of the trunk epidermis, in early fry of the mummichog, Fundulus heteroclitus L., that had been incubated in embryonal and alevin stages in sea water concentrated by additional salts to 60‰ salinity, at 20 °C. Although there was some proliferation of these cells in the buccal and pharyngeal epithelia, such apparently adaptive hyperplasia and hypertrophy of these cells did not occur in early fry that had previous incubation and rearing in seawater concentrations of 30, 20, and 10‰ salinity (S), and in fresh water (< 0.5‰ S)
An indication of change in Ligula intestinalis (Linn.) occurrence in spottail shiners, Notropis hudsonius (Clinton), from western Lake Erie, 1929–1977
Authors: Cooper C. Lawrence , Jilek Reid , Crites John L.
Published: August 2008

Larval tapeworms, Ligula intestinalis, were found in the body cavities of only 14 of 1359 spottail shiners collected in the Maumee Bay portion of western Lake Erie. The degree of parasitization of this host species may have changed considerably since 1927–1929.
Seasonal prevalence, pathology, and transmission of the quail heart worm, Splendidofilaria californiensis (Wehr and Herman, 1956), in northern California (Nematoda: Filarioidea)
Authors: Weinmann Clarence J. , Murphy Kevin , Anderson John R. , DeMartini James C. , Longhurst William M. , Connolly Guy
Published: August 2008

Heartworm transmission occurred through the summer months and the presumptive vector was Culicoides multidentatus. Observations on laboratory-reared California Valley quail infected while serving as sentinels indicated a prepatent period of several months and a patent period lasting 18–21 months. Examination of 111 wild quail revealed Splendidofilaria californiensis in 76% of adults and in 44% of juveniles. Mature parasites were encapsulated in the wall of the aorta near its origin, resulting in partial occlusion of its lumen and related pathologic changes. Infections in adult birds, but not in juveniles, appeared heavier in fall than in spring and there were indications of superimposed infections in the former.
Taxonomic congruence in three populations of Quebec brook trout, Salvelinus fontinalis (Mitchill)
Authors: McGlade Jacquie , MacCrimmon Hugh
Published: August 2008

The degree of taxonomic congruence between three methods of classification is examined for three Quebec populations of wild brook trout, Salvelinus fontinalis, from the Matamek–Moisie watersheds. The three methods utilize morphometric, meristic, and electrophoretic characters. Electrophoretic comparison is also made between the Quebec samples and brook trout from the Dorion Hatchery, Ontario. Using discriminant function analysis on data for the three Quebec populations, a subset of nine morphometric measurements was identified with between 84.0 and 92.6% correct classification, and a meristic subset of four characters, including mandibular pores, with between 72.5 and 95.0% correct classification. Electrophoretic analysis has identified a number of newly defined alleles at four loci, from five tissues. The meristic and electrophoretic analyses show congruence in the order of similarity and, therefore, are considered the most suitable methods for classification of the brook trout. Morphometric analysis provides an insight into localized adaptation particularly in response to habitat and resource utilization. An understanding of the taxonomic status of populations of brook trout requires not only a definition of individuals in terms of meristic and electrophoretic profiles, but also morphological characterization, to increase our understanding of their ecology and response to other faunal components.
L'alimentation estivale du campagnol des champs, Microtus pennsylvanicus, Ord.
Authors: Bergeron Jean-Marie , Juillet Jacques
Published: August 2008

Stomach content analyses performed on 272 meadow voles (Microtus pennsylvanicus) revealed that the animal feeds on 35 of the 45 species of plant present in its habitat. Timothy is the most abundant and the most common plant in the vole's diet. The abundance of the plants sampled in the habitat is positively correlated with the abundance of the plants found in the stomach contents. However, some species, like meadow grass (Poa spp.), aredefinitely preferred by the voles since they appear more frequently in the stomach contents than in the habitat. Some feeding habits are also sex dependent.[Translated by the journal]
The karyology of eight species of fish belonging to the family Percidae
Authors: Danzmann Roy G.
Published: August 2008

Four species of fish from the genus Etheostoma, two species from the genus Percina, the yellow perch (Perca flavescens), and the walleye (Stizostedion v. vitreum), from the family Percidae, were examined karyotypically. All species had a diploid number of 48 chromosomes. Similarity in the karyotype of the yellow perch and walleye suggests a monophyletic origin for the subfamilies Percinae and Luciopercinae.Evolution in the family involved pericentric inversions and (or) translocations of chromosomes giving rise to metacentric and submetacentric chromosomes in the genera Percina and Etheostoma. Etheostoma exile, E. flabellare, and E. caeruleum all show a marked reduction in the size of the smallest pair of homologues (group C). The last two pairs of homologues in E. nigrum are of uniform size.
Brachiopod orientation to current direction and substrate position (Terebratalia transversa)
Authors: Eshleman William P. , Wilkens Jerrel L.
Published: August 2008

Brachiopods orient to ambient water currents in order to passively augment active filter feeding. Although Terebratalia transversa does not actively reorient to current flow under laboratory conditions, in situ observations show that they are oriented in a highly specific manner in nature. Approximately 70% of observed animals were oriented with the direction of incurrent pumping parallel to current, the remaining 30% with incurrent pumping perpendicular to current. In all animals the direction of excurrent pumping was perpendicular to current.Factors other than current direction combine to further limit the observed habitat of T. transversa. In the areas sampled they were found only on two of five possible substrate positions with respect to current direction. Areas without current and areas where current velocity exceeds about 3 knots (4.8 km/h) were devoid of brachiopods. This indicates that current within a certain velocity range not only augments normal active pumping but may be an essential requirement for survival.
Étude du benthos d'eau douce dans le haut-estuaire du Saint-Laurent (Québec)
Authors: Vincent B.
Published: August 2008

Benthos samples collected in 37 sites interspersed along a 230 km stretch of the St. Lawrence River, between Lake St. Pierre and Ile aux Oies, were analyzed. The distribution of the main taxa shows the downstream succession of many of the dominant species. Benthic groups of the upstream and downstream sections of the upper estuary are characterized by the hydrobiid B. tentaculata and the viviparid V. georgianus, respectively. The structure of the benthic groups undergoes a gradual change downstream from Gentilly and the samples collected in the lower section add up to a much more heterogeneous community than the samples collected in the upper or the middle reaches of the estuary.[Journal Translation]
Social and reproductive behavior of crabeater seals (Lobodon carcinophagus) during the austral spring
Authors: Siniff D. B. , Stirling I. , Bengston J. L. , Reichle R. A.
Published: August 2008

The social and reproductive behaviors of crabeater seals (Lobodon carcinophagus) were studied from September through November, during 1975, 1976 and 1977. Seals were immobilized, or controlled with a canvas bag over the head, then tagged and measured. Behavioral observations were recorded on all seals encountered.Crabeater seals were classified into three groups: (1) family groups (2) mated pairs, and (3) fast ice concentrations. Family groups consisted of an adult female, her pup, and an adult male. After weaning, the male and female formed a mated pair, and remained together for 1 to 2 weeks or until copulation. Adult females without a pup were joined by a male as they came into estrus, forming the mated pair category. Fast ice concentrations, primarily composed of sexually immature animals ranged from 50 to over 1000 seals and inhabited bays where seasonal ice persisted.Data were obtained on the predatory behavior of leopard seals (Hydrugra leptonyx), which indicated intensive predation on crabeater pups just after weaning; the degree of predation probably declines through the 1st year of life. Crabeater seals older than 1 year are probably seldom attacked by leopard seals. Further studies to determine the impact of this predation on population parameters of the crabeater seal are suggested.
Experimental studies on macroinvertebrate predator–prey impact of pesticides. The reactions of Rhyacophila and Hydropsyche (Trichoptera) larvae to Simulium larvicides
Authors: Muirhead-Thomson R. C.
Published: August 2008

Acute toxicity tests with the predaceous trichopteran larvae of Rhyacophila dorsalis and Hydropsyche pellucidula in a laboratory-simulated stream have shown that both species have a high survival rate after short exposures, 15 min to 1 h, to concentrations of temephos(Abate) and chlorpyrifos methyl that produce a mortality of 90% or more in late-instar Simulium larvae. A similar differential reaction to the synthetic pyrethroid permethrin was demonstrated in the case of Hydropsyche but not Rhyacophila.The implication of these findings is discussed firstly in relation to the environmental impact of Simulium control programmes based on application of larvicides to rivers and streams, and secondly to the wider problem of evaluating the impact of pesticides and allied toxic chemicals on stream ecosystems.It is concluded that although significant differences in tolerance level to some insecticides between prey (Simulium) and predator (trichopteran larvae) can be demonstrated in the laboratory, the margin of safety is not sufficiently wide to assure selective control of Simulium larvae by these chemicals under the less precise conditions of larvicide application in the field.
Daytime surface swarming by Meganyctiphanes norvegica (M. Sars) (Crustacea, Euphausiacea) off Brier Island, Bay of Fundy
Authors: Brown R. G.B. , Barker S. P. , Gaskin D. E.
Published: August 2008

In July–September the euphausiid Meganyctiphanes norvegica (M. Sars) swarms at the surface in daytime off Brier Island, Nova Scotia (ca. 44°15′ N 66°23′ W). Systematic observations of swarming were made, mainly in late August 1974, 1975, 1976, and 1978, supplemented in 1974 and 1975 by the frequency of occurrence of the euphatisiids in the proventriculi of collected greater shearwaters, Puffinus gravis (O'Reilly). Swarms, consisting mostly of immature animals, occurred near an area of turbulence where strong tidal streams ran up against steep underwater ledges, bringing cool subsurface water and also copepods to the surface. Swarming was apparently not an attempt to avoid underwater predators or unfavourable oceanographic conditions, nor was it a means of advancing gonad maturation through exposure to solar irradiation. Swarming was most common in spring tide periods when tidal streams were strongest, and did not occur at all during a neap tide period in late August 1975. It is suggested that M. norvegica swarms were transported passively to the surface by strong vertical turbulence. However, the possibility that they swam actively to the surface in search of copepods and other food passively transported in that way could not be ruled out. It is suggested that the surface swarming of Euphausia pacifica Hansen, the other well-documented survey of the phenomenon, by Y. Komaki in 1967, be reexamined in the light of these conclusions. The significance of surface swarms as food sources for a variety of marine predators is discussed.
Histogenesis of the yolk sac in Malathion-treated chick embryos
Authors: Acorn T. , Gibson M. A.
Published: August 2008

Chick embryos were given a teratogenic dose of Malathion at the 5-day incubation stage and the effects of this treatment on the histogenesis and histochemistry of the yolk sac were studied. The Malathion caused a decrease in the amount of hemopoietic tissue. Also, the endodermal cells had decreased glycogen and lipid storage, decreased glycoprotein and acid mucopolysaccharide staining intensities, and decreased acid phosphatase activity. These observations suggest an interference with carbohydrate and lipid uptake and storage by the yolk sac.
Territorial behaviour of the north temperate labrid, Tautogolabrus adspersus
Authors: Pottle Robert A. , Green John M.
Published: August 2008

A study of territorial behaviour of the cunner, Tautogolabrus adspersus, was carried out in Conception Bay, Newfoundland, in 1977 and 1978. Cunners that overwinter in a torpid state were active only from May to late October of both years. Large males established territories prior to the midsummer spawning season and territories were defended throughout and after that season. Territory size ranged from 16.1 to 74.3 m2 on rocky substrate at depths of 0.7 to 13 m and did not vary significantly with either the size of the resident fish or the degree of intraspecific aggression it exhibited. Nonterritorial males were generally smaller than territorial males and were vigorously excluded from their territories. Only territorial males exhibited interspecific aggression, which was most frequent toward Pholis gunnellus. Territorial females were present in the peripheral areas of some males' territories and were aggressive toward other females. Tagging indicated that most males and some females defend the same territory from year to year, and that territory size remains relatively constant. The proportions of territorial and nonterritorial fish, of either sex, in the population are unknown. The primary function of territorial behaviour in T. adspersus may be the provision of a spawning site from which potential rivals are excluded.
Energy content of Amoeba proteus and Tetrahymena pyriformis (Protozoa)
Authors: Rogerson Andrew
Published: August 2008

The calorific values of two protozoan species, Amoeba proteus and Tetrahymena pyriformis, were investigated for cells cultured at 20 °C, 15 °C, and 10 °C. Temperature had no effect on the energy content of Amoeba but differentiated between Tetrahymena cells cultured at 20 °C and 15 °C over those grown at 10 °C. This suggests that 10 °C is close to the organisms' lower thermal limit and that the cell has a different biochemical composition at this temperature.It is tentatively proposed that differences exist between the energy content of the two protozoan phyla represented. The calorific value of the ciliates may be close to 20.0 J mg−1 dry weight, whereas the sarcodines have a lower value approximating to 17.5 J mg−1 dry weight.
Communal nesting between reproductively active females in a spring population of Microtus pennsylvanicus
Authors: McShea William J. , Madison Dale M.
Published: August 2008

Weekly livetrapping and radiotelemetry of a spring population of Microtus pennsylvanicus revealed communal nesting by reproductively active females. In several instances the communal nesting involved at least one female who was nursing young in the nest. Two of these instances involved what appeared to be more than one litter. Continuous monitoring over a 42-h period of one double litter confirmed the presence of two females who also differed in their nursing rhythms. Occurrences of conesting decreased through the spring, possibly because of increasing temperatures or the disappearance of nest partners.
Pelecitus tubercauda n. sp. (Nematode: Filarioidea) from Geothlypis trichas L. and a redescription of P. fulicaeatrae (Diesing, 1861) López-Neyra, 1956
Authors: Vanderburgh Daryl J. , Anderson Roy C. , Stock T. M.
Published: August 2008

Pelecitus tubercauda n. sp. (Onchocercidae: Dirofilariinae) from the leg of a Common Yellowthroat, Geothlypis trichas L. (Parulidae), is described and Pelecitus fulicaeatrae (Diesing, 1861) López-Neyra, 1956 from the legs of Podiceps grisegena Boddaert (Podicipedidae) is redescribed. The main distinguishing feature of P. tubercauda is the presence in males of prominent granular masses between caudal papillae. Yellowthroats may acquire P. tubercauda sporadically on their wintering grounds.
Aspects of the biology and distribution of pteropods (Gastropoda; Opisthobranchia) from the Bay of Fundy region, Canada
Authors: Newman L. J. , Corey S.
Published: August 2008

Examination of zooplankton samples from the Bay of Fundy and its adjacent waters over a 9-year period revealed two common pteropod species. Limacina retroversa (Thecosomata) and Clione limacina (Gymnosomata). Two other species, Clio pyramidata (Euthecosomata) and Corolla calceola (Pseudothecosomata) were infrequently collected. Long-term horizontal distributional analyses of L. retroversa and C. limacina indicated both seasonal and annual fluctuations in abundance. Reproductive hermaphrodites of L. retroversa were present within the Bay during the spring, and probably spawned during late spring and early fall. The distribution and reproductive stages are discussed in relation to water currents, temperature and salinity parameters, and trophic relationships.
Ecology and behavior of the Cretan agrimi
Authors: Husband Thomas P. , Davis Phillip B.
Published: August 2008

The agrimi (Capra aegagrus cretensis Lydekker), an endangered species of wild goat, was studied on Theodorou Island, Crete, Greece, from May to November 1975 to determine population responses of the agrimi to removals and to document their behavioral patterns. The Theodorou population size was 89 agrimi. A mathematical model of population mortality indicated that the number of animals removed from the island between 1973 and 1975 equalled the expected natural mortality for both sexes. Observations of agrimi showed that they had seasonal and daily activity patterns that minimized their exposure to high ambient temperatures. An age- and sex-specific social dominance hierarchy was found, with old males being most dominant.
Effects of a carbaryl-induced depression in invertebrate abundance on the growth and behavior of American black duck and mallard ducklings
Authors: Hunter Jr. Malcolm L. , Witham Jack W. , Dow Hilary
Published: August 2008

Aerially spraying ponds with carbaryl (Sevin-4-oilR) at 840 g active ingredient/ha reduced biomass and numbers of macroinvertebrates and decreased the growth rates of American black duck, Anas rubripes, and mallard. Anas platyrhynchos, ducklings in Maine. Ducklings on sprayed ponds spent more time searching for food and less time resting, and their rate of movement around the ponds was greater than for ducklings on unsprayed ponds.
Experimental life cycle of Protostrongylus boughtoni (Nematoda: Metastrongyloidea), a lung worm of snowshoe hares, Lepus americanus
Authors: Kralka Robert A. , Samuel W. M.
Published: August 2008

The life cycle of the lungworm Protostrongylus boughtoni Goble and Dougherty, 1943 was completed in intermediate and definitive hosts. Larvae developed to the infective third-stage in the foot of the snail Vallonia pulchella (Miiller, 1774) in 28–30 days at 18 °C. First-, second-, third-, and fourth-stage larvae are described. Patent infections developed in laboratory-reared snowshoe hares, Lepus americanus americanus, each given 50 third-stage P. boughtoni larvae per os 25 to 27 days postexposure. Periods of patency ranged from 41 to 104 days. Patent infections developed in domestic rabbits, Oryctolagus cuniculus, Dutch Belted strain, given 50 or 150 larvae in 25 to 26 days postexposure, but periods of patency ranged from 7 to 13 days and larval output was very low.
The comparative fecundity of two species of Cumacea from the shallow waters of Florida
Authors: Corey Susan
Published: August 2008

The mean fecundities of Spilocuma salomani and Oxyurostylis smithi from the shallow waters of Florida are 31.1 and 52.1 eggs per female, respectively. The fecundities and life history strategies of these two species are compared with those of other species of Cumacea.
Protein digestion in snowshoe hares
Authors: Sinclair A. R. E. , Smith James N. M.
Published: August 2008

Pehrson (Å. Pehrson. 1984. Faecal nitrogen as an index of hare browse quality. Can. J. Zool. This issue) suggests that energy, not protein, is the limiting resource for snowshoe hares in winter. We accept this as an alternative point of view, and we await the publication of evidence to support this view. Pehrson's experiments on protein content of food, faecal protein, and weight loss by mountain hares are difficult to interpret because levels of protein and secondary compounds are confounded. The outcome of Pehrson's laboratory tests does not agree with our field data on snowshoe hares.
DAMAGE SPREADING AND OPINION DYNAMICS ON SMALL-WORLD NETWORKS WITH ASYMMETRIC INFLUENTIAL EFFECTS
Authors: GUAN JIAN-YUE , WU ZHI-XI , WANG YING-HAI
Published: August 2008

We study the asymmetric influential effects in the damage spreading processes, by investigating the opinion dynamics of the Krause–Hegselmann consensus model, wherein the agents sit on the nodes of small-world networks. One agent is randomly selected as the influential agent, which can influence the opinions of other agents with probability p but not vice versa. The damage consists in a sharp change of the opinion of one agent (a randomly selected agent or the influential one) in the initial random opinion configuration. We find that for small values of the influential probability p, there is a damage spreading transition at low values of the confidence bound parameter ε. Interestingly, this transition vanishes for large values of p when the influential agent is damaged in the initial state. We find as well that, there is a critical value of the confidence bound parameter above which the initial perturbation manages to propagate to the whole system. The relationship between the amount of the damage and the influential activity of the perturbed agent is also discussed.
COPS OR ROBBERS — A BISTABLE SOCIETY
Authors: KUŁAKOWSKI K.
Published: August 2008

The norm game described by Axelrod in 1985 was recently treated with the master equation formalism. Here we discuss the equations, where (i) those who break the norm cannot punish and those who punish cannot break the norm, (ii) the tendency to punish is suppressed if the majority breaks the norm. The second mechanism is new. For some values of the parameters the solution shows the saddle-point bifurcation. Then, two stable solutions are possible, where the majority breaks the norm or the majority punishes. This means, that the norm breaking can be discontinuous, when measured in the social scale. The bistable character is reproduced also with new computer simulations on the Erdös–Rényi directed network.
Role of P63 (CKAP4) in binding of surfactant protein-A to type II pneumocytes
Authors: Bates Sandra R. , Kazi Altaf S. , Tao Jian-Qin , Yu Kevin J. , Gonder Daniel S. , Feinstein Sheldon I. , Fisher Aron B.
Published: August 2008

We have recently described a putative receptor for lung surfactant protein-A (SP-A) on rat type II pneumocytes. The receptor, P63, is a 63-kDa type II transmembrane protein. Coincubation of type II cells with P63 antibody (Ab) reversed the inhibitory effect of SP-A on secretagogue-stimulated surfactant secretion from type II cells. To further characterize SP-A interactions with P63, we expressed recombinant P63 protein in Escherichia coli and generated antibodies to P63. Immunogold electron microscopy confirmed endoplasmic reticulum and plasma membrane localization of P63 in type II cells with prominent labeling of microvilli. Binding characteristics of iodinated SP-A to type II cells in the presence of P63 Ab were determined. Binding (4°C, 1 h) of125I-SP-A to type II cells demonstrated both specific (calcium-dependent) and nonspecific (calcium-independent) components. Ab to P63 protein blocked the specific binding of125I-SP-A to type II cells and did not change the nonspecific SP-A association. A549 cells, a pneumocyte model cell line, expressed substantial levels of P63 and demonstrated specific binding of125I-SP-A that was inhibited by the P63 Ab. The secretagogue (cAMP)-stimulated increase in calcium-dependent binding of SP-A to type II cells was blocked by the presence of P63 Ab. Transfection of type II cells with small interfering RNA to P63 reduced P63 protein expression, attenuated P63-specific SP-A binding, and reversed the ability of SP-A to prevent surfactant secretion from the cells. Our results further substantiate the role of P63 as an SP-A receptor protein localized on the surface of lung type II cells.
Prednisolone inhibits PDGF-induced nuclear translocation of NF-κB in human pulmonary artery smooth muscle cells
Authors: Ogawa Aiko , Firth Amy L. , Yao Weijuan , Rubin Lewis J. , Yuan Jason X.-J.
Published: August 2008

Pulmonary vascular remodeling, a major cause for the elevated pulmonary vascular resistance in patients with pulmonary arterial hypertension (PAH), is partially due to increased proliferation of pulmonary arterial smooth muscle cells (PASMC) in the media, resulting in vascular wall thickening. Platelet-derived growth factor (PDGF) is a potent mitogen that may be involved in the progression of PAH. Blockade of PDGF receptors has been demonstrated to have therapeutic potential for patients with severe pulmonary hypertension. Prednisolone is an immunosuppressant shown to have anti-inflammatory and antiproliferative effects on PASMC. This study was designed to investigate whether PDGF and prednisolone affect human PASMC proliferation by regulating the nuclear translocation of NF-κB (a transcription factor composed of 2 subunits, p50 and p65). Treatment of human PASMC with PDGF (10 ng/ml) significantly increased nuclear translocation of p50 and p65 subunits. Inhibition of NF-κB activation or nuclear translocation of p50/p65 significantly attenuated PDGF-induced PASMC proliferation (determined by [3H]thymidine incorporation). In the presence of prednisolone (200 μM), the PDGF-induced nuclear translocation of p50 and p65 subunits was markedly inhibited ( P < 0.05 vs. the cells treated with PDGF alone). These results indicate that PDGF-induced nuclear translocation of NF-κB may play an important role in stimulating PASMC proliferation (and/or enhancing PASMC survival), whereas prednisolone may exert anti-inflammatory and antiproliferative effects on PASMC by inhibiting NF-κB nuclear translocation.
Dissociation of NEPH1 from nephrin is involved in development of a rat model of focal segmental glomerulosclerosis
Authors: Otaki Yasuhiro , Miyauchi Naoko , Higa Mutsumi , Takada Akira , Kuroda Takeshi , Gejyo Fumitake , Shimizu Fujio , Kawachi Hiroshi
Published: August 2008

Focal segmental glomerulosclerosis (FSGS) is a disease showing severe proteinuria, and the disease progresses to end-stage kidney failure in many cases. However, the pathogenic mechanism of FSGS is not well understood. The slit diaphragm (SD), which bridges the neighboring foot processes of glomerular epithelial cells, is understood to function as a barrier of the glomerular capillary wall. To investigate the role of SD dysfunction in the development of FSGS, we analyzed the expression of SD-associated molecules in rat adriamycin-induced nephropathy, a mimic of FSGS. The staining of the SD molecules nephrin, podocin, and NEPH1 had already shifted to a discontinuous dotlike pattern at the initiation phase of the disease, when neither proteinuria nor any morphological alterations were detected yet. The alteration of NEPH1 expression was the most evident among the molecules examined, and NEPH1 was dissociated from nephrin at the initiation phase. On day 28, when severe proteinuria was detected and sclerotic changes were already observed, alteration of the expressions of nephrin, podocin, and NEPH1 worsened, but no alteration in the expression of other SD-associated molecules or other podocyte molecules was detected. It is postulated that the dissociation of NEPH1 from nephrin initiates proteinuria and that the SD alteration restricted in these molecules plays a critical role in the development of sclerotic changes in FSGS.
Humans adjust control to initial squat depth in vertical squat jumping
Authors: Bobbert Maarten F. , Casius L. J. Richard , Sijpkens Igor W. T. , Jaspers Richard T.
Published: August 2008

The purpose of this study was to gain insight into the control strategy that humans use in jumping. Eight male gymnasts performed vertical squat jumps from five initial postures that differed in squat depth (P1–P5) while kinematic data, ground reaction forces, and electromyograms (EMGs) of leg muscles were collected; the latter were rectified and smoothed to obtain SREMGs. P3 was the preferred initial posture; in P1, P2, P4, and P5 height of the mass center was +13, +7, −7 and −14 cm, respectively, relative to that in P3. Furthermore, maximum-height jumps from the initial postures observed in the subjects were simulated with a model comprising four body segments and six Hill-type muscles. The only input was the onset of stimulation of each of the muscles (Stim). The subjects were able to perform well-coordinated squat jumps from all postures. Peak SREMG levels did not vary among P1–P5, but SREMG onset of plantarflexors occurred before that of gluteus maximus in P1 and >90 ms after that in P5 ( P < 0.05). In the simulation study, similar systematic shifts occurred in Stim onsets across the optimal control solutions for jumps from P1–P5. Because the adjustments in SREMG onsets to initial posture observed in the subjects were very similar to the adjustments in optimal Stim onsets of the model, it was concluded that the SREMG adjustments were functional, in the sense that they contributed to achieving the greatest jump height possible from each initial posture. For the model, we were able to develop a mapping from initial posture to Stim onsets that generated successful jumps from P1–P5. It appears that to explain how subjects adjust their control to initial posture there is no need to assume that the brain contains an internal dynamics model of the musculoskeletal system.
A Dopamine–Acetylcholine Cascade: Simulating Learned and Lesion-Induced Behavior of Striatal Cholinergic Interneurons
Authors: Tan Can Ozan , Bullock Daniel
Published: August 2008

The giant cholinergic interneurons of the striatum are tonically active neurons (TANs) that respond with pauses to appetitive and aversive cues and to novel events. Whereas tonic activity emerges from intrinsic properties of these neurons, glutamatergic inputs from intralaminar thalamic nuclei and dopaminergic inputs from midbrain are required for genesis of pause responses. No prior computational models encompass both intrinsic and synaptically gated dynamics. We present a mathematical model that robustly accounts for behavior-related electrophysiological properties of TANs in terms of their intrinsic physiological properties and known afferents. In the model, balanced intrinsic hyperpolarizing and depolarizing currents engender tonic firing and glutamatergic inputs from thalamus (and cortex) both directly excite and indirectly inhibit TANs. If this inhibition, probably mediated by GABAergic nitric oxide synthase interneurons, exceeds a threshold, a persistent K+conductance current amplifies its effect to generate a prolonged pause. Dopamine (DA) signals modulate both the intrinsic mechanisms and the external inputs of TANs. Simulations revealed that many learning-dependent behaviors of TANs, including acquired pauses to task-relevant cues, are explicable without recourse to learning-dependent changes in synapses onto TANs, due to a tight coupling between DA bursts and TAN pauses. These interactions imply that reward-predicting cues often cause striatal projection neurons to receive a cascade of signals: an adaptively scaled DA burst, a brief acetylcholine (ACh) burst, and an ACh pause. A sensitivity analysis revealed a unique TAN response surface, which shows that DA inputs robustly cooperate with thalamic inputs to control cue-dependent pauses of ACh release, which strongly affects performance- and learning-related dynamics in the striatum.