bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of bovine growth hormone on growth rate, appetite, and food conversion of yearling coho salmon (Oncorhynchus kisutch) fed two diets of different composition
Authors: Markert J. R. , Higgs David A. , Dye Helen M. , MacQuarrie D. W.
Published: August 2008

Paired groups of yearling coho salmon at 10 °C and on a natural photoperiod were fed twice daily either Oregon moist pellets (OMP) or a diet with poultry offal (PO) as the main protein source. The fish were fed either 0.8% body weight per day (dry weight of food (g)/wet weight of fish (g)) or to satiation. Coho in one of the groups for each diet–ration combination received, by intramuscular injection, 10 μg (0.0092 IU) of bovine growth hormone (bGH) per gram body weight one time per week for 56 days. Those in the other group were not treated.Administration of bGH significantly enhanced growth and improved food and protein conversion. Ration level altered the effect of bGH on food and protein conversion as did diet formulation at satiation. The voluntary food intake of bGH-treated fish fed OMP was higher but not significantly different from that of the controls. Diet formulation differences did not significantly affect the growth rate of either bGH-treated or untreated coho at each ration level. Irrespective of the diet–ration combination, bGH administration lead to a significant decline in condition factor.At 56 days, bGH-treated fish had a significantly lower percentage of muscle protein and a significantly higher percentage of muscle water than untreated fish. At present, the use of bGH as a growth promoter for coho salmon is not economical.
Habitat associations and community analysis of South Texas dung beetles (Coleoptera: Scarabaeinae)
Authors: Nealis Vincent G.
Published: August 2008

Baited pitfall traps were used to sample the Scarabaeinae dung beetle fauna in six habitats in South Texas. Habitats were defined according to their soil and vegetative cover characteristics. Most of the 19 scarab species collected displayed marked associations with a particular soil type (sand or clay) and (or) cover (shade or open). The result is the existence of distinct communities of coprophagous beetles, which differ in their species composition, species-abundance relations, and efficiency of dung removal. A discussion of the evolution of these habitat associations and the ecological implications for pasture ecosystems is included.
Association of hypoglycemia and pancreatic islet tissue with micromelia in Malathion-treated chick embryos
Authors: Laley Bertil O. , 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 leg length, blood glucose, and amounts of pancreatic islet tissue were studied during the 11- to 19-day incubation period. The Malathion caused a reduction in leg length (micromelia) and hypoglycemia, which persisted throughout the period studied. The severity of the micromelic condition correlated with the degree of hypoglycemia: the least micromelic embryos were the least hypoglycemic, the moderately micromelic embryos were moderately hypoglycemic, and the severely micromelic embryos were the most severely hypoglycemic. Finally, the Malathion increased differentiation of pancreatic islet tissue, particularly beta tissue. Again, the greatest increases in islet tissue were shown by those embryos exhibiting the most severe micromelic and hypoglycemic conditions.
The migratory route of Cyclocoelum mutabile (Zeder) (Trematoda: Cyclocoelidae) in the American coot, Fulica americana (Gm.)
Authors: McLaughlin J. Daniel
Published: August 2008

The migration of Cyclocoelum mutabile (Zeder) was examined in experimentally infected coots, Fulica americana (Gm.). Newly excysted C. mutabile penetrate the intestine and enter the body cavity within 4 h after administration of metacercariae. Penetration of the liver occurred within 24 h and the flukes underwent a period of development in the liver that lasted for at least 12 days. By day 15 the immature flukes began to leave the liver and 50% of the flukes had entered the abdominal cavity. By day 18 all flukes had left the liver and by day 21 had become established in the air sacs, principally the clavicular air sac, where they mature. The possible significance of the establishment of C. mutabile in the clavicular air sac is discussed.
Remarks on the larvae of two serpulids (Polychaeta) from Barbados
Authors: Lacalli T.
Published: August 2008

Larval development of Sphaeropomatus miamiensis is compared with that of Spirobranchus polycerus. Both species have typical serpulid trochophores, but there are some structural differences between the two, possibly related to differences in diet.
Culture and preliminary observations of follicular isolates from adult zebra fish, Brachydanio rerio
Authors: Laale Hans W.
Published: August 2008

A medium is described for the culture of follicular isolates from adult female zebra fish, Brachydanio rerio. Preliminary observations are made on the behaviour of the cells of the cultured isolates in the absence of an oocyte and ovarian influence.
Parasites of wolves, Canis lupus L., in northeastern Minnesota, as indicated by analysis of fecal samples
Authors: Byman David , Ballenberghe Victor Van , Schlotthauer John C. , Erickson Albert W.
Published: August 2008

Two hundred and four scat fragments of wolves (Canis lupus) were collected from December 1969 through August 1971 in northeastern Minnesota; 74 of these contained parasite ova or larvae. Helminths representing the following genera were identified: (Trematoda) Alaria; (Cestoda) Moniezia and Taeniidae gen.indet.; (Nematoda) Ancylostoma, Uncinaria, Trichuris, Capillaria, Toxocara, and Filaroides. Oocysts of sporozoa of the family Eimeriidae also were observed. The occurrence of Alaria, Ancylostoma, Trichuris, Toxocara, and Capillaria in Minnesota wolves has not been reported previously. The ecological significance of these parasites is discussed.
The function and evolution of aggressive host behavior towards the brown-headed cowbird (Molothrus ater)
Authors: Robertson Raleigh J. , Norman Richard F.
Published: August 2008

Aggression to model brown-headed cowbirds measured at nests of 34 potential host species shows a positive correlation with rate of parasitism. The data are used to test two hypotheses: (1) that aggression functions as an antiparasite defense reducing parasitism, and (2) that cowbirds use host aggression as a cue when searching for nests.Our results suggest that host aggression only serves as an effective antiparasite defense in dense host populations. In low-density populations aggression is probably used as a nest-finding cue by cowbirds, because there are too few neighbouring hosts to mount an effective multispecies mobbing response. Although being aggressive is maladaptive in the latter situation, the evolution of increased aggressiveness is evident, because individuals breeding in dense populations have greater fitness. The adaptive complex is further complicated because host aggression may have a major innate component and a minor learned component.Experiments conducted on different host populations corroborate the hypothesis that hosts with the longer history of sympatry with cowbirds are more aggressive. These data are consistent with the predictions of a simple directional selection model for host aggression.
Patterns of evolution and migration in the arctic ground squirrel, Spermophilus parryii (Richardson)
Authors: Nadler Charles F. , Hoffmann Robert S.
Published: August 2008

Serum transferrins and 11 other genetically controlled proteins representing 17 loci were examined by starch-gel electrophoresis from Siberian, Alaskan, and Canadian populations of Spermophilus parryii. Six transferrin alleles were identified. Arctic populations (S. p. parryii, S. p. osgoodi) were characterized by Tf 6 occurring alone or together with Tf 7 whereas middle and subarctic populations exhibited Tf 7 occurring either alone (S. p. ablusus, S. p. lyratus, S. p. plesius) or together with Tf 5 (S. p. plesius). Tf 8, Tf 9, and Tf 19 constituted local variants. Tf 6 displayed a clinal distribution, increasing in frequency eastward and paralleling a clinal increase in body size. Three PGM2 alleles were observed, the frequencies of which tend to differentiate arctic S. p. parryii from subarctic S. p. ablusus. G6PD-b occurred uniformly in North America and in one Siberian population; a second population (two specimens) exhibited G6PD-a, thereby suggesting that G6PD polymorphism may be present in Siberian S. parryii. The other nine proteins were monomorphic in all Holarctic populations.
Measurements of serum thyroxine and the proportions of rhodopsin and porphyropsin in rainbow trout
Authors: Allen Donald M.
Published: August 2008

Immersion of yearling rainbow trout (Salmo gairdneri) in 0.1 or 1.0 ppm quantities of thyroxine (T4) significantly increased both T4 in the serum and the proportion of porphyropsin visual pigment in the retina. In fish not treated with T4, levels of porphyropsin were higher at 6 °C than at 14 °C. However, under different conditions of light or temperature there was no consistent correlation between serum T4 and percentage of porphyropsin. Furthermore, there was no tendency for individuals higher in porphyropsin to have higher titre of T4, or vice versa. The results generally do not support the hypothesis that serum T4 titre and porphyropsin are physiologically interdependent.
Blocking of impulses in specialized regions of crustacean motor axons
Authors: Lang Fred , Govind C. K.
Published: August 2008

Patterned stimulation blocks impulse propagation in some fine branches of both excitor axons to lobster claw closer muscle. The site of the block was determined by monitoring spikes in the main closer nerve and in one of its primary branches, and excitatory postsynaptic potentials (EPSPs) in muscle fibers. With paired pulses (3- to 8-ms interspike interval) at 5 and 10 Hz, the second of a pair of EPSPs disappears even though primary axon branches are conducting paired spikes. The abrupt disappearance of the second EPSP suggests that it is not due to transmitter depletion but rather to conduction block in fine branches. Unpatterned stimulation at 10 and 20 Hz did not produce blocking. In the single excitor axon to the opener and stretcher limb muscles in lobster and crayfish, patterned or unpatterned stimulation failed to block conduction to the distal opener muscle, thus failing to confirm a finding in crayfish previously reported by others. These results suggest that conduction block at specialized axonal regions may not always have adaptive value.
Circulation and dioptric apparatus in the photophores of Euphausia pacifica: some ultrastructural observations
Authors: Harvey Brian J.
Published: August 2008

The dioptric or light-directing apparatus of the abdominal photophores of Euphausia pacifica is briefly described. Electron micrographs of the lens, reflector, and lamellar ring are presented, with accompanying explanation concerning their probable optical role. Elements of the circulatory system are also discussed, and it is proposed that the 'rod mass' of classical cytologists is a highly ordered capillary bed.
Distinction de biotypes dans des populations du puceron du pois, Acyrthosiphon pisum (Harris), de l'Amérique du Nord
Authors: Auclair Jacques L. , Srivastava P. N.
Published: August 2008

Virginoparae of Acyrthosiphon pisum (Harris) collected from three different localities in the Province of Québec, Canada (Sainte-Thérèse de Blainville, Saint-Jean, and Ile aux Coudres), and two in the United States (states of Kansas and New Mexico) were reared on two normally susceptible host plants: e.g. the broad bean, Viciafaba L., variety Windsor, and the pea, Pisum sativum L., variety Lincoln. Results from growth curves suggest that the former three clones represent one or several biotypes different from the latter two, and results from mortality and rate of reproduction indicate that the clones from Saint-Jean and Sainte-Thérèse are two different biotypes. High mortality on peas indicates further that the clone from Ile aux Coudres is a biotype different from the others, whereas the clones from New Mexico and Kansas may represent only one biotype.
Thermal preferences of mummichog, Fundulus heteroclitus L., and banded killifish, F. diaphanus (LeSueur), (Cyprinodontidae) in relation to thermal acclimation and salinity
Authors: Garside E. T. , Morrison G. C.
Published: August 2008

Frequency distributions corresponding to various levels of thermal acclimation from 5 to 35 °C were recorded for samples of marine mummichog, Fundulus heteroclitus L., and samples of freshwater banded killifish, F. diaphanus (LeSueur), in thermal gradients formed in columns of fresh water (< 0.5‰ salinity) or sea water (32‰ salinity). Mean preferred temperatures comprised roughly parallel but irregularly inflected trends for the two series of tests, within each species. In mummichog, preferred temperatures for corresponding thermal acclimations ranged from 3 to 6 °C higher in tests conducted in sea water. In banded killifish, preferred temperatures for corresponding thermal acclimations ranged from 5 to 8 °C higher in fresh water. Thus, each species regularly preferred higher temperatures in salinity which approximated that of the typical habitat. The inference to be taken is that the unusual salinity for each species places an extraordinary osmoregulative load which influences the reactions of the fish to the series of thermal or other correlated stimuli in the gradient.
A technique for the demonstration of the metacercariae of Apatemon gracilis pellucidus (Yamaguti, 1933) in the deep tissues of the brook stickleback (Culaea inconstans)
Authors: Rau Manfred E. , Gordon David M.
Published: August 2008

A technique originally developed for the clearing of specimens for osteological studies has been adapted for the demonstration of Apatemon gracilis pellucidus metacercariae in the deep tissues of the brook stickleback (Culaea inconstans).
Susceptibility of marine fish to trypanosomes
Authors: Khan R. A.
Published: August 2008

Trypanosomes, some of similar morphology and morphometry, were observed in the blood of seven species of marine teleosts (Pleuronectiformes: American plaice (Hippoglossoides platessoides), yellowtail flounder (Limanda ferruginea), and grey sole (Glyptocephalus cynoglossus); Perciformes: Arctic eelpout (Lycodes reticulatus), spotted wolffish (Anarhichas minor), striped wolffish (A. lupus), and polka-dot seasnail (Liparis cyclostigma)) collected off coastal Newfoundland, Canada. Experiments to ascertain specificity or susceptibility of the trypanosomes were initiated using leeches as vectors. Trypanosomes from pleuronectiform and perciform fish were equally infective to taxonomically related and unrelated species, including a gadiform fish, the Atlantic cod (Gadus morhua). Moreover, Trypanosoma murmanensis of the cod was transmitted to pleuronectiform, perciform, anguilliform, and gadiform fish. No marine fish species tested was insusceptible to trypanosomes isolated from the different hosts. In all fish, there was a progessive increase in size with time, reaching the maximum by 60 days postinfection. No striking differences in morphology or morphometry were apparent among the trypanosomes in recipient fish regardless of host origin. The opinion is expressed that the trypanosomes of these marine fish, which have overlapping geographical distributions, belong to a single species, referrable to T. murmanensis Nikitin, 1927.
Semen production of the American kestrel
Authors: Bird David M. , Laguë Paul C.
Published: August 2008

In 1975, semen was collected by massage from 18 randomly selected captive male American kestrels (Falco sparverius). The period of semen production extended for 103 days, beginning on March 19, while the mean duration of semen production was 73.6 days. Under natural light, semen production began at [Formula: see text] of daily light, peaked about [Formula: see text], and decline considerably around June 21 at [Formula: see text]. Weather factors, i.e., temperature, barometric pressure, did not significantly (P > 0.05) affect semen collections or quality.The following means were calculated: semen volume, 12 μl; sperm concentration, 31 000/mm3; sperm count per ejaculate, 416 000; motility score, 78%; contamination with epithelial debris and urates, 67%; and semen colour, very pale to pale amber.The following significant (P < 0.05) correlations were found: body weight with semen volume (0.48) and sperm count per ejaculate (0.54); egg fertility with sperm count per ejaculate (0.65); semen volume with sperm count per ejaculate (0.84) and sperm motility (0.54); sperm count per ejaculate with sperm concentration (0.78); and sperm motility with sperm concentration (0.59) and sperm count per ejaculate (0.75).
Biology of Philometroides huronensis (Nematoda: Dracunculoidea) in the white sucker (Catostomus commersoni)
Authors: Uhazy Leslie S.
Published: August 2008

White suckers (Catostomus commersoni (Lacépède)) collected from various locations in southern Ontario were examined for Philometroides huronensis Uhazy, 1976. Stages of the parasite were recovered from the peritoneum around the swim bladder, bases of the fins, and the fins. Prevalence of infections was high and intensities relatively low. The parasite was less prevalent in longnose (Catostomus catostomus (Forster)) and redhorse (Moxostoma macrolepidotum (LeSucur)) suckers collected from the same area.Males, female fourth-stage larvae, uninseminated. inseminated, subgravid, and gravid females were recovered from fish collected from southern Lake Huron. Prevalence was 83 to 100% throughout the year and showed no significant seasonal trend. Numbers of worms recovered ranged from 1 to 32 per fish; 77% were infected with from 1 to 7 worms. Intensities of infections varied significantly with season, being highest during fall, winter, and early spring. All age groups of white suckers were infected; however, intensity did not vary significantly with host age. Although P. huronensis was highly prevalent throughout the year and from one year to the next, the life cycle was completed in a single year.The evolution of three valid species in the Philometrinae from the white sucker in North America is proposed, based on the evidence that before Pleistocene glaciation there were three separate forms of white sucker.
The effect of prolactin on sodium flux through the isolated amniotic membrane of the guinea pig
Authors: Holt W. F. , Perks A. M.
Published: August 2008

Amniotic membranes from fetal guinea pigs (0.46–0.87 of term) were maintained in a continuous-flow perfusion cell, with amniotic saline on both surfaces. Prolactin (10 μg/ml; fetal surface) increased the unidirectional diffusional flux of 22Na+ in the fetal–maternal direction (maximum, about 75%; average over 3rd h, 53.6 ± 10.1%). This increase was significant when compared with albumin controls (P < 0.05) and with the initial base-line fluxes (P < 0.01). Albumin controls showed no significant change from the base-line flux. Therefore, prolactin appeared to increase the unidirectional flux of sodium out of the potential amniotic cavity.One membrane, at term and overdue, failed to respond.Experiments on the reverse, maternal–fetal flux of 22Na+ showed no differences between membranes treated with prolactin or albumin. Therefore, prolactin had no effect on the unidirectional flux of sodium into the potential amniotic cavity.Sodium permeability rose dramatically in membranes close to birth or overdue; 22Na+ fluxes increased about 20-fold in both directions.Prolactin appears capable of causing a net movement of sodium through the amnion, out of the amniotic fluid. Also, it is able to slow the movement of water in the same direction. These factors, taken together, suggest a partial explanation for the maintenance of a hypotonic amniotic fluid.
Population dynamics of Newfoundland beaver
Authors: Bergerud Arthur T. , Miller Donald R.
Published: August 2008

The demography of beaver was studied in Newfoundland from 1956 to 1965. Population densities were low and seldom exceeded one colony per 2.6 km2 (1 mi2). About 80% of the adult females were fertile and the number of young per litter averaged 2.7. The annual mortality rate of beavers was about 30% in southeastern Newfoundland. A more detailed study was made of a population living in a 39-km2 (15-mi2) study area. This population had 20, 23, and 24 active colonies, 1958–1960. In 1961 it declined to 18 colonies. We removed the beavers in 1962. The replacement colonies, resulting initially from ingress, were 7 in 1962, 12 in 1963, 17 in 1964, and 15 in 1965. When the population was high in 1958–1960, the fertility of females was high (78%) but the litter size in 1960 appeared to be less than elsewhere. When the population declined in 1960–1961, productivity declined and some animals may have starved over winter. It was concluded that territorial behaviour spaces colonies, dispersing the population within the limits dictated by the availability of water and food resources. However, such a system did not prevent overutilization of food resources and decline of the population from reduced reproduction and increased mortality.
Does ingested albumen stimulate duodenal development in chicken embryos?
Authors: Betz T. W. , Hart D. E.
Published: August 2008

Duodenal development in adenohypophyseoprivic, partially decapitated, white leghorn chicken embryos (n = 9–41) was retarded more significantly when no albumen was swallowed. Addition of cephalic-region adenohypophyseal, chorioallantoic grafts to operated embryos lessened the degree of retardation. Duodenal protein concentration and body growth parameters of weight and toe length were not affected significantly by albumen. However, alkaline phosphatase (EC 3.1.3.1.) specific activity and protein content did respond Therefore ingested albumen could normally stimulate these aspects of duodenal development in chicken embryos.
Observations on the habits and morphology of the sea snake Laticauda colubrina (Schneider) in Fiji
Authors: Pernetta J. C.
Published: August 2008

Fifty specimens of Laticauda colubrina were collected from two localities in the Fiji Islands and variation in a number of nonmetric and morphometric characters recorded. Marked sexual dimorphism is apparent in all characters examined. Details of the habits, diet (reef eels), and reproductive characteristics of this species are given. The function of the black and white banded colour pattern is discussed, and the validity of the currently recognized species of Laticauda is examined.
Predation on Microtus townsendii populations: impact and vulnerability
Authors: Boonstra Rudy
Published: August 2008

The object of this study was to assess the impact of avian and mammalian predators on M. townsendii populations, especially during decline periods. In addition, Errington's hypothesis of differential susceptibility of certain classes of animals to predation was examined. The vole population went through a severe decline in the winter and spring of 1972–1973 and again in the winter and spring of 1973–1974. Intensive searches were made for all pellets and scats from February 1973 to May 1974.Of the tagged animals disappearing, less than 8% in the decline of 1972–1973 and less than 20% in the decline of 1973–1974 could be accounted for by predation. I conclude that predation is not necessary to initiate or maintain a decline. In the tagged animals, neither sex nor any weight class showed any consistent vulnerability to predation when compared with the rest of the tagged population. In the total sample of voles eaten by avian predators, the body weights were consistently lower than those in the trapped population. In the other life-history characteristics examined, voles were eaten at random. I conclude that no animal was more vulnerable to predation than another in the tagged population, but in the total population younger animals may have been.
The genus Cosmocercella Steiner, 1924 (Nematoda: Cosmocercoidea)
Authors: Baker M. R. , Adamson M. L.
Published: August 2008

Cosmocercella anothecae n.sp. from Anotheca spinosa (Hylidae) of Mexico and the generotype C. haberi Steiner. 1924, from Hyla spp. (Hylidae) of eastern North America are described. Cosmocercella anothecae n.sp. most closely resembles C. haberi. These species differ in the number and arrangement of digitiform caudal papillae, shape of the gubernaculum, and size of spicules in males. Cosmocercella haberi lacks the vesiculated 'bursa' mentioned in the original description and this character cannot be used to distinguish this genus. Cosmocercella is characterized, however, by vesiculated rosette male caudal papillae not present in other genera of Cosmocercidae. Raillietnema minor Freitas and Dobbin, 1961, from Phyllomedusa (Hylidae) of South America is reclassified as Cosmocercella minor (Freitas and Dobbin, 1961) n.comb. The genus also includes C. neveri Hsü and Hoeppli, 1933.
Bighorn sheep in winter: do rams maximize reproductive fitness by spatial and habitat segregation from ewes?
Authors: Geist Valerius , Petocz R. G.
Published: August 2008

In bighorn sheep (Ovis canadensis canadensis) the segregation of adult males from females is explained by two hypotheses: first, males exhausted by the rut must avoid females to escape culling predators; second, males ought to segregate from females in such a fashion as to minimize competition and disturbance for the mothers of their prospective offspring. Only the second hypothesis coincides closely with previously known facts about sheep. It predicts that on common winter ranges adult males ought to minimize competition for females by segregating spatially and by habitat selection. This was verified. Although both sexes may occupy a continuous range, they concentrate in different areas; rams have a greater preference for open slopes and ewes for cliffs. This segregation held true even in a winter with exceptional snow depths. Sheep occupied the wintering area in a similar manner in successive years; females were found to be more affected by snow than males. In their habitat preference, rams and ewes acted in accordance with their behavioural types, much as was found to be true for their social behaviour.
Systematics of western North American trout (Salmo), with notes on the redband trout of Sheepheaven Creek, California
Authors: Gold J. R.
Published: August 2008

Phyletic relationships among the six nominal species of western North American trout (genus Salmo), and a yet unnamed form, the redband trout, are discussed in light of present knowledge of zoogeography, morphology, karyology, and genetic similarity. Also included is a description of redband trout from Sheepheaven Creek, California. Redband trout and Kern River golden trout, Salmo aguabonita, are closely related phyletically. They both possess the same chromosome and chromosome arm number, resemble each other in several meristic characters and in external coloration and spotting, and share the same fixed or most common allele at several biochemical–genetic loci. Zoogeographic considerations are not inconsistent with the hypothesis that a redband – S. aguabonita line evolved from an ancestral trout radiating from the North Pacific. It is suggested that the closest living relative to the redband – S. aguabonita line is the rainbow trout. Salmo gairdneri. The cutthroat trouts, Salmo clarki, may be an earlier divergence from this same phyletic line. The Apache trout, Salmo apache, is considered more distantly related to S. clarki than has been previously suggested.
Oxygen–fauna relationships in the pitcher plant Sarracenia purpurea L. with reference to the chironomid Metriocnemus knabi Coq.
Authors: Cameron C. J. , Donald G. L. , Paterson C. G.
Published: August 2008

The aquatic habitat contained within the leaf of the pitcher plant Sarracenia purpurea has a dissolved oxygen concentration consistently in excess of 77% saturation in spite of a high community respiration rate. The oxygen concentration is maintained primarily by diffusion through the wall of the sarcophagus and is not affected by plant photosynthesis. Because of the consistently high oxygen concentrations, the inquiline Metriocnemus knabi is not tolerant of lowered oxygen concentrations as it is adapted to a habitat with a consistently high oxygen concentration.
Pulmonary ventilation: perfusion relationships in terrestrial and aquatic chelonian reptiles
Authors: Burggren Warren W. , Glass Mogens L. , Johansen Kjell
Published: August 2008

Pulmonary ventilation and perfusion have been measured directly in unanaesthetized turtles (Pelomedusa subrufa) and tortoises (Testudo pardalis) during normal air breathing and during the inspiration of both hypoxic and hypercapnic gases. Lung ventilation in air was intermittent in both species and particularly in the turtle was accompanied by transient increases in pulmonary perfusion. Hypercapnia (4% CO2 in air) elicited a twofold to threefold increase in pulmonary perfusion but a sixfold increase in pulmonary ventilation in both species. Consequently the ventilation:perfusion ratio more than doubled in value. Unlike the hypercapnic responses, hypoxia (5% O2 in N2) increased pulmonary perfusion by two to five times but increased pulmonary ventilation by less than two times, and so the ventilation:perfusion ratio fell by one-half during hypoxic exposure. These data are interpreted in terms of intermittent breathing and processes of O2 and CO2 transport.
A numerical taxonomic study of variation in populations of Typhlodromus caudiglans Schuster (Acarina: Phytoseiidae)
Authors: Chant D. A. , Hansell R. I. C. , Rowell H.
Published: August 2008

Variation in morphological characters between Canadian populations of Typhlodromus caudiglans Schuster (Acarina: Phytoseiidae) was examined by the methods of numerical taxonomy. Western populations are separated from the other populations when multivariate tests are used. Two subspecies are proposed, and Typhlodromella nodosus De Leon is synonymized with Typhlodromus caudiglans. Morphological variations between northern and eastern populations are correlated with climatic variables and with host plants.
The binding of zinc to the plasma of winter flounder (Pseudopleuronectes americanus): affinity and specificity
Authors: Fletcher P. E. , Fletcher G. L.
Published: August 2008

The binding affinity of winter flounder plasma proteins for zinc was determined by equilibrium dialysis. The relationship between the percentage of zinc bound and the total zinc present in the system produced a curved line. A Rosenthal type plot indicated that there was more than one binding system for zinc present. The association constant computed from the first slope, 107–108, compared with that of mammalian serum albumin. It required twice the normal total plasma zinc concentration to saturate the higher affinity binding system.All of the plasma zinc could be removed by dialyzing with 10−2M histidine.The specificity of the plasma proteins for binding zinc was studied by introducing the following cations: Cu2+, Cd2+, Ca2+, Mg2+, Co2+, Mn2+, Hg2+, Fe2+, Cr2+, and Ni2+. Only Cu2+ competed significantly with the binding of zinc to the plasma. This competitive effect was diminished in the presence of Tris buffer.Studies in the presence of EDTA indicated that the EDTA had a greater effect on the zinc binding than would be predicted from its theoretical binding capacity for zinc.
Intramembrane particle densities in freeze-fractured sarcoplasmic reticulum
Authors: Bray D. F. , Rayns D. G. , Wagenaar E. B.
Published: August 2008

The particle densities over various regions of the sarcoplasmic reticulum (SR) have been analyzed in freeze-etched replicas of the chicken posterior latissimus dorsi muscle. A-band, I-band, and terminal-cisternae portions of the SR are shown to possess particle densities of 3465/μm2, 3467/μm2, and 3689/μm2 respectively, indicating that there is a homogeneous distribution of (Ca2+, Mg2+)-ATPases over the entire nonjunctional SR membrane. These results are discussed in terms of the current theory that calcium is accumulated by the longitudinal SR elements and then transferred to the terminal cisternae for storage.
Relationships between size of stream insects and current velocity
Authors: Kovalak William P.
Published: August 2008

Size frequency distributions and dry weight – head width relationships for six insect species from two habitats with differing current velocities in the Pigeon River, Michigan, were compared. Early in their growth cycles, Ephemerella subvaria, Ephemerella lata, Rhithrogena jejuna, and Glossosoma nigrior generally were larger at the slow station, but near the end of the growth cycles they generally were larger at the fast station. For Paraleptophlebia mollis, early in the growth cycle size differences between stations were small but near the end of the growth cycles nymphs were larger at the fast station, whereas nymphs of Ephemerella deficiens were slightly larger at the slow station throughout the growth cycle. Larger size at the slow station probably was due to differential growth whereas larger size at the fast station probably was due to differential habitat selection controlled by oxygen requirements.There were no significant differences in dry weight – head width relationships between habitats or between sexes. Sex ratios generally were similar at the two stations and did not deviate appreciably from 50:50.The life history of each species is briefly described.
Division of labour by song sparrows feeding fledged young
Authors: Smith James N. M.
Published: August 2008

Parental feeding of nestlings and fledglings is described in an individually marked population of song sparrows. Thirty-five broods of nestlings were observed in 1976 and 68 broods of fledglings in 1977. On leaving the nest, individual young dispersed to separate locations in the breeding territory where, at 13 days of age, a single parent fed each young. In broods with even numbers of young, male and female parents divided the young equally in most cases. With odd numbers of young, either male or female could feed the extra young, but females did so more often. Older young were more mobile and harder to observe, but there was some evidence that family division persisted. Male parents played a larger role in feeding older young than younger ones. Feeding rates of 13-day-old young were 44% higher than those of 7- to 8-day-old nestlings, suggesting that energy demands of young and investment of parents are maximal after young leave the nest. I suggest that division of labour helps parents to locate young and regulate their parental feeding efficiently.
Uncertainty analyses of the behaviour of the Carolina locust, Dissosteira Carolina (Orthoptera: Acrididae)
Authors: Kerr Gordon E.
Published: August 2008

Uncertainty analyses of sequences of actions by wild Dissosteira Carolina gave average uncertainties (Ĥ) of 2.4 male and 1.9 female bits/act in all contexts. Noninteracting males show low diversity and insignificant between-act predictability (log-likelihood approximation). Males interacting with males or females had higher uncertainties and significant between-act predictabilities. In male–male interactions, approaching and responding animals were nearly equivalent and Ĥ(I) was 2.02 bits/act for both. Three-way analysis showed that the effect of an animal's last act was slightly lower than that of the other animal's last act with some overlap. Bidirectional-communication and character analyses were also performed. Male–male interactions are neither stationary nor Markov processes. In male–female interactions, males had much higher uncertainties than females (2.25 versus 0.83 bits/act) and interanimal information transmission was very low.
Haemocytes associated with basement membrane of sex pheromone gland of Trichoplusia ni (Lepidoptera: Noctuidae). Ultrastructural observations
Authors: Percy Jean
Published: August 2008

In female Trichoplusia ni, granular haemocytes are observed near the basement membrane of developing sex pheromone gland cells while plasmatocytes are observed near the basement membrane of unmodified epidermal cells. The basement membrane underlying gland cells is clearly different from that of other epidermal cells. There is a thin amorphous layer (layer 1) which is also present beneath unmodified cells, and a second layer (layer 2) apposing the haemocytes. Layer 2 is distinctly banded which results from tubules similar in dimensions and structural appearance to those observed within granules of the granular haemocytes. The observations indicate that the granules participate in the formation of layer 2 by emptying their contents into the haemocoel next to layer 1.
Aspects of raccoon (Procyon lotor) social organization
Authors: Fritzell Erik K.
Published: August 2008

Spatial and temporal relationships among members of a raccoon (Procyon lotor) population were studied during spring and summer in east-central North Dakota during 1973–1975. Radio telemetry was used to locate 48 raccoons 6443 times. Livetrapping results and other observations suggested that most raccoons in the area were radio equipped; densities were estimated to be 0.5–1.0 resident/km2. Adult males maintained large areas relatively exclusive of other adult males; they seldom were located within 3 km of each other even though their home ranges abutted. One adult male responded to the death of an adjacent adult male by shifting movements into the dead male's former home range. Two or more parous or pregnant females resided within the home ranges of a single adult male. All yearling males showed signs of dispersal in May, June, or July; some occupied exclusive areas as adults in the following year. Parous or pregnant females (six adults, one yearling) occupied extensively overlapping home ranges but were never located with other adult or yearling raccoons. Nulliparous yearling females did not disperse and tolerated other raccoons. Territoriality is indicated among adult males probably in response to competition for access to females.
The effects of crude oil and the dispersant, Oilsperse 43, on respiration and coughing rates in Atlantic salmon (Salmo salar)
Authors: Barnett John , Toews Dan
Published: August 2008

Emulsions of Venezuelan crude oil and the dispersant, Oilsperse 43, in both unweathered and artificially weathered forms, increased the coughing rate of post smolt Atlantic salmon (Salmo salar L.) in fresh water at sublethal concentrations ranging from 0.01 to 0.7 toxic units in 12-h tests. Coughing rates increased significantly in what appeared to be a concentration- and time-related basis while respiration rates declined at the higher sublethal levels. At most concentrations tested, there were no significant differences between the physiological responses in either unweathered or artificially weathered emulsions.
Muscle sensitivity differences in two avian species to anatoxin-a produced by the freshwater cyanophyte Anabaena flos-aquae NRC-44-1
Authors: Carmichael Wayne W. , Biggs David F.
Published: August 2008

An example of species sensitivity differences between mallard ducks and ring-necked pheasants was found for the toxin (anatoxin-a) produced by the freshwater cyanophyte Anabaena flos-aquae NRC-44-1. The oral LD90 (dose required to kill 90% of animals) for pheasants was found to be 2.4 times the oral LD90 for ducks. The sensitivity of a gastrocnemius muscle sciatic nerve preparation in pheasants was about three times less than that of the duck. Comparison of muscle sensitivity with decamethonium bromide did not show this species difference. The species difference was also observed in the intraperitoneal LD90 which was 50 mg/kg body weight for ducks and 120 mg/kg body weight for pheasants. This is used as evidence for an example of species sensitivity variation to the toxin at its site of action and indicates one way in which animal losses due to field poisonings by these toxic blooms can differ.
Melanophore distribution within the integumentary tissues of two teleost species, Pseudopleuronectes americanus and Gasterosteus aculeatus form leiurus
Authors: Burton Derek
Published: August 2008

In winter flounder, dermal melanophores are prominent chromatic components in the skin of the entire upper surface, and their arrangement is affected by imbrication of the ctenoid scales. Epidermal melanophores are also prominent over most of the body upper skin, scale imbrication having relatively little effect on their arrangement. Epidermal melanophores occur only sparsely on the fins and head skin, and are virtually absent from white spots of flounder disruptive patterns. In stickleback, epidermal melanophores were not observed. Melanophores with thin processes form a superficial dermal layer in the dorsal skin of the head and body of stickleback, and along the fin dermal supports. Melanophores with broad, wedge-like, processes form an extensive and continuous deep dermal layer in most of the body skin, which lacks scales, and on the operculum. Imbrication of the small number of lateral bony plates behind the operculum in leiurus sticklebacks does not greatly affect the melanophore arrangement. The skin structure of both species shows sexual dimorphism, but the respective melanophore layers are strongly developed in each sex.
Underwater acoustic signals of the narwhal (Monodon monoceros)
Authors: Ford John K. B. , Fisher H. Dean
Published: August 2008

Underwater sound recordings of the narwhal from northern Baffin Island are analyzed and described. Frequency ranges of pulsed and pure tone vocalizations are found to be somewhat greater than previously observed. An earlier report that narwhals generate exclusively narrowband sounds is confirmed. Narwhal pulses appear to have a potential function as both orientation and communication signals. Pulse series having irregular repetition rates resemble the echolocation clicks of captive delphinids, and it is suggested that they serve a similar purpose. Pulse series having regular changes in repetition rate and distinct aural tones probably serve as social signals. The regular recurrence of a number of recognizably distinct pulsed tones suggests that the narwhal has 'signature' calls similar to several other odontocetes.
Effect of ambient salinity on ionic and osmotic regulation of eggs, larvae, and alevins of rainbow trout (Salmo gairdneri)
Authors: Shen A. C. Y. , Leatherland J. F.
Published: August 2008

The osmotic concentration of the perivitelline fluid in eggs of rainbow trout (Salmo gairdneri) was lower in eggs maintained in distilled water than in eggs maintained in dilute artificial sea water (11‰ and 13‰). The water content of eggs, larvae, and alevins in distilled water was significantly higher than in comparable developmental stages in dilute sea water. Similarly, differences were found in the tissue Na+, K+, and Na+:K+ ratios of eggs, larvae, and alevins reared in the different ambient salinities. These data suggest that the early developmental stages of rainbow trout possess a limited capacity for osmotic or ionic regulation. Larvae appear to regulate tissue Na+ content by increasing the Na+ concentration of the perivitelline space and alevins tolerate an increase in tissue K+ content and a small decrease in tissue water content.
Elevation of copper and nickel levels in primaries from black and mallard ducks collected in the Sudbury district, Ontario
Authors: Ranta W. B. , Tomassini F. D. , Nieboer E.
Published: August 2008

Black and mallard duck wings were collected from northern Ontario and northern Saskatchewan during the fall of 1975, and primary flight feathers were analyzed for Cu, Ni, and Zn by X-ray fluorescence spectrometry. Correlations between area sampled and mean metal concentrations in a population were investigated. Zinc concentrations did not vary with the population sampled, while mean levels of Cu and Ni were highest near Sudbury, Ontario, reflecting the known particulate fallout. Elevated Ni contents characterized the Sudbury collection site. No obvious trends in levels of the three metals were apparent with species, sex, age, or the choice of wing analyzed.
Structure and function of the male copulatory apparatus of the nematodes Capillaria hepatica and Trichuris muris
Authors: Wright K. A.
Published: August 2008

The anatomy of the terminal male reproductive system was studied by light microscopy and by scanning and transmission electron microscopy. In C. hepatica a common muscle sphincter surrounds the vas deferens and intestine at their point of juncture. The cloaca is divisible into proximal and distal portions. The spicule is formed in a short ventral spicule pouch but lies mainly in the distal cloaca. The spicule is retracted in C. hepatica by a paired retractor muscle and in T. muris by a single retractor muscle. Protraction of the spicule occurs by contraction of longitudinal muscles surrounding the distal cloaca. This results in the surface layers of the cloacal cuticle being everted as the spicule sheath. The spicule is tubular with a cellular core including multiple sensory receptors at its tip. The spicule is probably solely a chemosensory organ. Mechanical stimulation in the region of the distal cloaca resulted in activation of the spicule and spicule sheath. Response to mechanical stimulus is age dependent.
Comparative observations on the ecology of four species of ostracods living in a temporary freshwater puddle
Authors: McLay C. L.
Published: August 2008

The population biologies of Cyprinotus carolinensis, Herpetocypris reptans, Cypricercus reticulatus, and Candona decora in a spring-fed, temporary, winter puddle in Vancouver, Canada, were studied during 1967–1969. All species emerged at the same time in the fall, when the puddle filled, and competed to reach maturity. The order of maturation was Candona, Cyprinotus, Cypricercus, and Herpetocypris. Abundance was positively related to adult size of each species. Survivorship and fecundity patterns are given for Herpetocypris and Cyprinotus. Survivorship is closest to the type-I kind.All species have similar feeding appendages and ate grass detritus and its microinhabitants. They differed in their spatial distribution, each species being most abundant along a section of the rut. They also differed in their mobility and foraging patterns. The presence of grass was effective in restricting dispersal. Distribution and abundance of these species may be accounted for either in terms of competitive interactions or in terms of adaptation to physical differences in the environment.
Positive phototaxis of the brine shrimp Artemia salina to monochromatic light
Authors: Aiken Ronald B. , Hailman Jack P.
Published: August 2008

The brine shrimp Artemia salina was photopositive in response to monochromatic light of approximately equal quantum intensity of two absolute levels. At the higher level (about 3 × 1014 quanta s−1 cm−2), the spectral response was bimodal with peaks near 560 and 700 THz frequency (about 535 and 430 nm wavelength, respectively), with an antimode at about 640 THz (465 nm). Response at the lower level (about 2 × 1014) was slightly lower and the midspectrum peak was shifted to higher frequencies (shorter wavelengths) and depressed relative to the high-frequency peak near 700 THz. The results suggest that positive phototaxis is mediated by two visual pigments, the high-frequency (short-wavelength) pigment being activated at lower illuminations than the midspectrum pigment. A similar bimodal response is known from a crab larva, but this appears to be the first anostracan crustacean to have been tested.