bluuebunny/crossref_metadata_2025 huggingface dataset:
Morphology and behaviour of the benthic larva of Arenicola cristata (Polychaeta)
Authors: Marsden Joan R. , Lacalli T.
Published: August 2008

The structure of the three-setiger larva of Arenicola cristata is described with emphasis on the ultrastructure of the apical region, particularly the nervous and muscular systems, and ciliated and glandular cells. At least one population of well-differentiated nerve cell bodies can be identified in the cerebral ganglia, and these are filled with dense-cored vesicles. Processes apparently derived from these cells, containing both dense-cored and clear vesicles, are found throughout the cerebral commissure and circumesophageal connectives. Nerve terminals are restricted to a single small region along each of the two ventrolateral longitudinal muscles. Most of the terminals contain predominantly one or the other of the two vesicle types, but some terminals appear to contain both. Normal behaviour involves control of both muscular and ciliary activities. Experiments with drugs indicate a muscarinic cholinergic innervation of muscle, but we have found neither pharmacological nor structural evidence for a mechanism controlling ciliary activity. Preliminary observations suggest the presence of biogenic amines exhibiting specific fluorescence and a relationship between serotonin and the secretion of mucus.
Vertebral variation in zebrafish (Brachydanio rerio) related to the prefertilization temperature history of their parents
Authors: Dentry W. , Lindsey C. C.
Published: August 2008

Four breeding pairs of zebrafish were maintained at a low temperature (21, 22, or 24 °C), and their eggs placed immediately after laying at one of a variety of temperatures (ranging between 21 and 33 °C). in which they were reared until vertebral count was determined. The same breeding pairs were at another lime maintained at a high temperature (29 or 30 °C), and eggs were similarly placed for rearing at one of a variety of temperatures. Vertebral counts were compared between sets of samples reared at the same temperature and originating from the same parents but laid during periods with different parental holding temperatures. In the three cases where differences between such pairs were statistically significant, vertebral counts were higher in the sample originating from the higher parental holding temperature. If meristic characters are in fact partly dependent on temperature history of the parents before fertilization, many published experimental and racial studies may need to be reinterpreted.
Diductor muscles of brachiopods: activation and very slow contraction
Authors: Wilkens Jerrel L.
Published: August 2008

The diductor muscles of brachiopods run from the ventral valve to an insertion posterior to the hinge on the dorsal valve: thus they serve to open the shell. Spontaneous electrical activity is recorded from the muscles when they are contracted, i.e., the shell is open. A burst of impulses is recorded shortly after the antagonist smooth adductor muscles begin to contract to close the shell. A second burst may occur at the time the valves begin to reopen.The diductors contract spontaneously and open the shell in 1–5 min. The rate of isotonic contraction is in marked contrast with the very low rate of isometric development of tension which may require as long as 186 min. If the contracted diductors are stretched the tension holding ability abruptly drops to near zero, then begins to redevelop immediately at a low rate. This sudden compliance is termed 'slip.' The burst of impulses recorded during shell closure is seen to follow slip and may serve to reactivate the diductor muscles. Slip is induced by stretch and by vibration and also occurs spontaneously from high levels of tension. It is suggested that the phenomenon of slip represents a sudden breakage of all cross bridges in this slowly contracting muscle.The diductor muscles do not appear to possess a 'catch' mechanism as found in molluscan muscles, but rather appear to exist in a tonically contracted active state.
Some effects of Mermis nigrescens on the hemolymph of Schistocerca gregaria
Authors: Rutherford T. A. , Webster J. M.
Published: August 2008

The sugar, free amino acid, and lipid fatty acid components of the hemolymph of adult Schistocerca gregaria parasitized by the larvae of the entomophilic nematode Mermis nigrescens were examined at intervals during the 4-week infection period. Glucose levels remained low, relative to trehalose, and at no time during the infection was there a significant difference in the glucose concentrations of controls and parasitized locusts. Trehalose was maintained at high levels (75–80 mM) in controls but fell to less than 25 mM between 7 and 10 days after parasitization and continued at a low level until day 17, when it began to rise in the parasitized group. Total free amino acid levels doubled in the parasitized group by day 21. By day 7 the concentration of methionine doubled, by day 14 both methionine and ornithine were at high levels, and by day 21, 13 of the 21 ninhydrin-positive substances were different from controls. There was no significant difference in the relative lipid fatty acid composition at day 14 between parasitized and control locusts.It is suggested that the nematode modifies its host's metabolism to favour production of small molecules such as glucose and amino acids from carbohydrate and protein reserves and it is also suggested that the host cell's ability to sequester nutrients is impaired during parasitism.
Age composition of some vespertilionid bats as determined by dental annuli
Authors: Schowalter David B. , Harder Lawrence D. , Treichel Bruce H.
Published: August 2008

Determination of age of several species of vespertilionid bats by counting incremental lines in dentine, cementum, and peridontal bone is described. The technique was most effective for aging Eptesicus fuscus and Lasionycteris noctivagans and less so for Myotis lucifugus. Incremental lines in specimens of Lasiurus cinereus and Lasiurus borealis were clearly defined, while those in a Myotis californicus were not. Longevity of E. fuscus and longevity and apparent age structure of M. lucifugus agree with the findings of published banding studies.
Natural selection by predators on the defensive apparatus of the three-spined stickleback, Gasterosteus aculeatus L.
Authors: Gross Harm P.
Published: August 2008

Three-spined sticklebacks (Gasterosteus aculeatus L.) can receive considerable protection against predators from characteristic dorsal and pelvic spines. The size and structure of this defensive apparatus were examined in marine and freshwater populations located throughout the European distribution of this species and exposed to differing predatory species and levels of predation pressure. Marine populations appear to experience the greatest predation pressure and have the largest defensive apparatus. Predation in freshwater appears to decline towards both the northern and southern distributional extremes of Gasterosteus, a result attributable to the differential distributions of major piscine predators, especially pike and perch; and this pattern produces arched clines in the morphometrics of defensive structures. Local differences in central latitudes can also be attributed to site-specific differences in predation pressure. Evidence is given for both hereditary and environmental determination of variation in dorsal spine number.
An examination of some Hexarthra species (Rotatoria) from western Canada and Nepal
Authors: Dumont Henri J. , Coussement Marc , Anderson R. Stewart
Published: August 2008

Four species of Hexarthra are reported from ponds and lakes in western Canada. Two Rocky Mountain forms are described as new subspecies: Hexarthra bulgarica canadensis n.subsp., at high altitudes, and Hexarthra polyodonta jasperina n.subsp. The nominate subspecies of the latter is known only from saline Lake Van, Turkey. Hexarthra polyodonta jasperina occurs in low salinity lakes and differs morphologically from the nominate subspecies in having a moderately developed ventro-anterior lip. Hexarthra bulgarica bulgarica is a true high-mountain rotifer known from the Rila Mountains, Bulgaria (nominate subspecies), from the Himalayas (H. bulgarica nepalensis n.subsp.), and from the Rocky Mountains (H. bulgarica canadensis n.subsp.). The Nepalese subspecies differs from the nominate subspecies and from H. bulgarica canadensis in having a well developed ventro-anterior lip. Hexarthra bulgarica canadensis differs from the nominate subspecies in having more teeth on the unci, more spines on the ventral arm, and more filaments on all arms. The pair of spines on the dorsolateral arm is the main diagnostic character of the H. bulgarica group. Hexarthra mira (Hudson) occurred at intermediate and lower altitudes, and Hexarthra fennica (Levander) was identified from a saline lake in Saskatchewan where specimens were unusually large, but otherwise typical.
Inventaire aérien de la faune dans le Moyen Nord québécois
Authors: Legendre Pierre , Long Francine , Bergeron Raymond , Levasseur Jean-Marc
Published: August 2008

An aerial survey of animal tracks has been carried out by helicopter in March 1976 in northwestern Quebec, along a transect of 1368 km between latitudes 49° and 55° N. Five hundred and eighty-four animal tracks or winter grounds have been observed in seven of the bioclimatic regions denned on this territory. Vegetation and drainage data have been collected during the survey, and all this data has been correlated with the descriptors of the previously completed geomorphological map. Analysis of this data showed three main faunal zones in the survey, corresponding to established bioclimatic gradients. The north is characterized by the willow ptarmigan, and in general an impoverished fauna. The southeastern part of the survey is characterized by abundant hares and lynx, and in the southwest the marten is characteristic, together with hares. Tracks of 16 species have been observed during the survey, and the niche of 10 of them is described. The six other species were not abundant enough to warrant this exercise. Besides the previously mentioned associations of hares with lynx and with martens, the survey has also shown a tendency for the fox and lynx to exclude each other.
The ultrastructure of the liver of the rainbow trout: normal structure and modifications after chronic administration of a polychlorinated biphenyl Aroclor 1254
Authors: Hacking M. A. , Budd Joan , Hodson K.
Published: August 2008

Rainbow trout (Salmo gairdneri) were fed dietary levels of 0-, 1-, 10-, and 100-ppm Aroclor 1254 for 229 to 330 days. The ultrastructural features of control livers were similar to those of other animals, but rainbow trout liver differed from mammalian liver in an apparent absence of Kupffer cells. Also small dense duct-type cells were present that formed a transition zone, combining with hepatocytes to form canaliculi; alone they formed preductules and in combination with cells of lower density they formed ductules. Microtubules were found in the vicinity of canaliculi and less frequently adjacent to the plasma membrane of other cell surfaces. They were not seen at the sinusoidal border as they are in mammalian liver. Peroxisomes lacked nucleoids. There were no ultrastructural liver changes in the 1-ppm group. The most frequently encountered alterations in both the 10- and 100-ppm groups were those involving the nucleus. These included irregular and bizarre nuclear outlines, separation of nucleolar components, and large nuclear pseudoinclusions. Other frequently encountered changes were slight increases in smooth endoplasmic reticulum, altered rough endoplasmic reticulum, increased lysosomes, reduced and altered glycogen, increased lipid, and hypoxic vacuoles. Seen also were concentric membrane arrays, myelin figures in intercellular spaces and Golgi cisternae, and bundles of fine tubules throughout the cytoplasm.
The effect of temperature and body size on electron transport system activity in freshwater zooplankton
Authors: Borgmann Uwe
Published: August 2008

Electron transport system (ETS) activity in Mysis relicta, Limnocalanus macrurus, and surface zooplankton was measured by following the rate of reduction of cytochrome c in the presence of NADH, succinate, or NADPH. The steady-state kinetics indicate that NADPH is oxidized by a different ETS from NADH and succinate, and more than one system may exist for the oxidation of NADH and succinate in surface zooplankton. The NADPH requiring ETS which, because of its higher Km, presumably does not reduce cytochrome c in vivo, is probably equivalent to the microsomal NADPH requiring ETS from vertebrates and insects used in the detoxification of organic compounds. ETS activity is affected by both environmental temperature and size of the organism, with environmental temperature affecting both the total activity of the enthalpy of activation of the system. Larger organisms have a lower activity per unit weight compared with smaller animals. Because the effects of temperature and size are roughly similar for NADPH oxidation and NADH or succinate oxidation, the ratio of NADPH to either NADH or succinate oxidation may be a useful indicator of exposure to toxic organic compounds.
Measurements and weights of eggs of the Canada goose, Branta canadensis, analyzed and compared with those of other species
Authors: Manning T. H.
Published: August 2008

The length and breadth of 334 eggs (82 clutches) of Branta canadensis interior were measured and 125 eggs (30 clutches) were weighed. Published and unpublished data for eggs of Branta canadensis maxima, hutchinsi, moffitti, and minima were also used and comparisons made with published data on 31 other species from seven ordersMeasurements of full clutches rather than of one egg per clutch proved advantageous. The means for length (L) and breadth (B) were 83.87 ± 0.366 mm and 56.60 ± 0.126 mm; those for the indices of volume (LB2), shape (100B/L), and density (100W/LB2), 268.98 ± 1.897 cm3, 67.34 ± 0.248, and 55.21 ± 0.190; that for weight (W), an estimated 1.5 days after the commencement of incubation, 150.02 ± 1.718. The clutch variances were significant and accounted for about half the total variance. The lightest egg weighed 68% of the heaviest and the coefficients of variation varied from 2.48 (breadth) to 7.17 (weight). The last eggs were significantly lighter and smaller than earlier eggs, owing to their lesser breadth. Correlations between egg size and clutch size were not constant. Correlations between length and breadth were generally positive, those between volume and shape generally negative. The mean true density of the eggs was estimated to be 1.085, the mean true volume 137.74 cm3, the mean fresh weight 150.95 g, and the mean of the factor k for the correction of the ellipsoidal volume, 0.9780. All differences between the five races for length, breadth, and volume were significant. Joint non-overlaps varied from 64 to 100%.
Some kinetic properties of skeletal muscle pyruvate kinase from air-breathing and water-breathing fish of the Amazon
Authors: Fields J. H. A. , Driedzic W. R. , French C. J. , Hochachka P. W.
Published: August 2008

The kinetic properties of pyruvate kinase from skeletal muscle were studied in two species of air-breathing fish, Hoplerythrinus unitaeniatus and Arapaima gigas, and two species of water-breathing fish, Hoplias malabaricus and Osteoglossum bicirrhosum. It was found that the enzymes from Hoplias and Hoplerythrinus showed hyperbolic saturation kinetics for all substrates, were activated slightly by fructose 1,6-diphosphate, and were inhibited by phosphocreatine and citrate. The enzyme from Hoplias was inhibited by alanine, whereas the enzyme from Hoplerythrinus was not. The enzymes from Arapaima and Osteoglossum showed hyperbolic saturation kinetics for adenosine diphosphate, but the saturation kinetics for phusphoenol-pyruvate were sigmoidal. These enzymes were strongly activated by fructose 1,6-diphosphate and strongly inhibited by alanine, the former completely reversing the inhibition by the latter. Phosphocreatine and citrate were also found to be inhibitors of these enzymes, but the inhibition by phosphocreatine was not reversed by additions of fructose 1,6-diphosphate. The enzymes from the water-breathing fish were more sensitive to inhibition by alanine than were those from the air-breathing fish, but in other respects the enzymes were very similar.
Metabolic biochemistry of water- vs. air-breathing osteoglossids: heart enzymes and ultrastructure
Authors: Hochachka P. W. , Guppy M. , Guderley H. , Storey K. B. , Hulbert W. C.
Published: August 2008

The ultrastructure of the inner myocardium of aruana, an osteoglossid water breather, and Arapaima, an air-breathing Amazon relative, was compared. The aruana heart was laden with glycogen granules while Arapaima heart was fat loaded. Associated with air breathing in Arapaima, the ultrastructure of the inner myocardium displayed abundant mitochondria, clearly differentiated into myofibrillar and peripheral populations. As many of the mitochondrial characteristics of Arapaima resembled those in the mammalian heart, it was postulated that the inner myofibrillar mitochondria are probably specialized for oxidative metabolism as is the case also in the mammalian heart, while subsarcolemmal mitochondria were specialized for the exchange of materials with the blood. In contrast with the heart of the air breather, in aruana the inner myocardium contained two cell types. Type I cells like those in Arapaima myocardium were specialized for aerobic metabolism, displaying abundant mitochondria mostly myofibrillar in location and ample glycogen granules as a potential substrate source. Type II cells by comparison contained fewer mitochondria, but were rich in glycogen granules, and appeared specialized for anaerobic metabolism.
Gill phospholipids of Amazon fishes
Authors: Phleger Charles F.
Published: August 2008

Gill phospholipid composition was quantitatively determined for four Amazon fishes. The fishes included Hoplias malabaricus (obligate water breather), Hoplerythrinus unitaeniatus and Erythrinus erythrinus (facultative air breathers), and Arapaima gigas (obligate air breather). Phosphatidylcholine and phosphatidylethanolamine were the principal gill phospholipids (49–64% and 12–27% of the total phospholipids, respectively). Other phospholipids present included sphingomyelin (5–16%), phosphatidylserine(1–13%), lysophosphatidylcholine (0–6%), phosphatidylinositol (0–5%), and diphosphatidylglycerol (0–3%). The gill phospholipid composition was similarfor these four species of fish.
Kinetic properties of glutamate dehydrogenase from the gills of Arapaima gigas and Osteoglossum bicirrhosum
Authors: Fields J. H. A. , Driedzic W. R. , French C. J. , Hochachka P. W.
Published: August 2008

Glutamate dehydrogenase was isolated from the gills of Arapaima gigas and Osteoglossum bicirrhosum and kinetically characterized, in order to determine whether there was any alteration in the ability of the gills to generate ammonia associated with the development of an air-breathing life-style. The catalytic and regulatory properties of both enzymes were found to be very similar. They were activated by leucine, adenosine monophosphate, and adenosine diphosphate, and inhibited by guanosine triphosphate, guanosine diphosphate, and adenosine triphosphate. Inhibition by nicotinamide adenine dinucleotide and reduced nicotinamide adenine dinucleotide was strong in both cases. It was concluded that both enzymes were regulated by a combination of the energy charge of the cell and the redox potential. There is no evidence for any qualitative alteration of the gills to produce ammonia from amino acids in the air breather, Arapaima gigas, as compared with the water breather, Osteoglossum bicirrhosum.
The erythrinid gill: correlations of structure, function, and metabolism
Authors: Hulbert W. C. , Moon T. W. , Hochachka P. W.
Published: August 2008

Gill cellular and metabolic organization were compared in two erythrinid Amazon fishes, Hoplias being a water breather, Hoplerythrinus, a facultative air breather. The gill of the water breather was larger and displayed a higher abundance of chloride cells. Enzymes selected to represent different metabolic functions, including glycolysis, gluconeogenesis, the Krebs cycle, hydrogen shuttling, and ammoniagenesis were found in significant activities in the gills of both species. The gills in the two species differed most in the levels of enzymes in oxidative metabolism, enzymes such as citrate synthase, aspartate aminotransferase, and glutamate dehydrogenase occurring in higher activities in Hoplias gill. The relative enzyme activities correlate well with the higher abundance of chloride cells in the Hoplias gill, and are presumably involved in the generation of energy for ion-pumping work of these mitochondria-rich cells. In both Hoplias and Hoplerythrinus the total activities of Na+/K+-ATPase and Ca2+-ATPase in the gill greatly exceed total kidney activities, implying that in both species the gill is charged with a much larger fraction of overall ion regulation. These results contrast sharply with parallel studies of obligate water-breathing and obligate air-breathing osteoglossids.
The osmotic fragility and critical hemolytic volume of red blood cells of Amazon fishes
Authors: Kim Hyun Dju , Isaacks R. E.
Published: August 2008

The osmotic fragility and critical hemolytic volume were determined in red cells obtained from common Amazon fishes including the arawana (Osteoglossum bicirrhosum), the armored catfish (Pterygoplichthys), the electric eel (Electrophorus electrocus), the pirarucu (Arapaima gigas), and the lungfish (Lepidosiren paradoxa). The red cells of the pirarucu and the electric eel displayed the osmotic fragility profile remarkedly akin to human red cells, whereas the red cells of the armored catfish were considerably more resistant to hemolysis than human cells. The arawana cells exhibited a broad shoulder in the region of 120 mM to 70 mM followed by a complete hemolysis near 40 mM NaCl as in other fishes. Unexpectedly, the lungfish red cells were found to be extraordinarily resistant to hemolysis. A 15-min and a 1-h exposure of the lungfish cells to distilled water resulted in hemolysis of 55 and 80%, respectively. The critical hemolytic volume of Amazon fish red cells thus far examined was of the order of 1.83–2.03, except the pirarucu red cells which had a low value of 1.25.
Inorganic ions and pH in the body fluids of Amazon animals
Authors: Mangum C. P. , Haswell M. S. , Johansen K. , Towle D. W.
Published: August 2008

In all but 3 of 16 species of Amazon crustaceans and fishes, the activities of inorganic ions in the blood are 15–27% lower than expected. In most of the fishes, blood pH is higher than expected. In two of the fishes both departures are reversed by adding NaCl or KCl, but not H+, to the medium. Ammonia excretion varies inversely with blood and water salinity, and changes in blood ammonia induced by experimental exposure to air or high salinity can explain the changes in blood pH. Preliminary data suggest that the (Na+ + K+)-ATPase prepared from the gill of one teleost has a higher affinity for NH4+ than K+. It is suggested that at least some of the Na+ absorbed from the medium is exchanged for NH4+, and that binding to the ammonia molecule is responsible for at least some of the reduction of H+ activity in the blood.
Air-breathing mechanics in two Amazonian teleosts, Arapaima gigas and Hoplerythrinus unitaeniatus
Authors: Farrell A. P. , Randall D. J.
Published: August 2008

The mechanics of air breathing in pirarucu, Arapaima gigas, and jeju, Hoplerythrinus unitaeniatus, were studied by simultaneous monitoring of air bladder gas pressure and buccal pressure. Also the effect of alterations in air bladder gas tensions on air-breathing patterns was examined by a gas replacement technique. Pirarucu surface every 4.2 min to make a single ventilation of the air bladder, whilst jeju usually make two or three ventilations at an air breath every 3.0 min. Pirarucu exhale first, then inhale, but in jeju buccal filling occurred before lung emptying. Inhalation in pirarucu is a result of air bladder aspiration combined with the action of a buccal pump; however, lung filling in jeju is achieved by a buccal pump only. The significance of aspiration breathing in pirarucu is discussed. Both fish respond similarly to alterations in air bladder gas tensions. Hyperoxia prolongs the interval between air breaths and hypercapnia reduces this interval.
Carbon dioxide excretion in the jeju, Hoplerythrinus unitaeniatus, a facultative air-breathing teleost
Authors: Randall D. J. , Farrell A. P. , Haswell M. S.
Published: August 2008

The facultative air breather Hoplerythrinus unitaeniatus utilizes a modified swim bladder as an accessory breathing organ. Dorsal aortic blood and bladder [Formula: see text] and [Formula: see text], and blood pH values were measured while in water, after 20 min air exposure, and 20 min after returning the fish to water. In water the dorsal aortic [Formula: see text] is 31 mmHg(1 mmHg = 133.322 Pa), [Formula: see text] is 11 mmHg, and pH is 7.81. After 20 min air exposure both pH and [Formula: see text] fell, [Formula: see text] increased, and the bladder gas exchange ratio, R, 0.21 in water, increased to 0.40. In water there is no difference between mean [Formula: see text] levels in blood and bladder; however, upon air exposure [Formula: see text] levels increase and large differences develop between the blood and lung. Carbonic anhydrase infusion reduces these differences and also increases the R value for the bladder. In water carbonic anhydrase infusion is without effect on CO2 levels in the blood or the bladder. The results are consistent with the hypothesis that CO2 excretion into the air bladder during air exposure is limited by the velocity of the plasma bicarbonate dehydration reaction.
The partitioning of oxygen uptake from air and from water by the large obligate air-breathing teleost pirarucu (Arapaima gigas)
Authors: Stevens E. Don , Holeton George F.
Published: August 2008

Pirarucu, weighing 2 to 3 kg, ventilated their gills 16 to 24 times per minute and ventilated their lungs every 1 to 2 min. Average oxygen uptake from water was 23 mg∙h−1∙kg−1; average oxygen uptake from air was 80 mg∙h−1∙kg−1. That is, in normoxic water they obtain about 75% of their oxygen from air, and never less than 50% from air. In hypoxic water the fraction from air increases, ultimately to 100% in anoxic water.
Carbon dioxide excretion in the pirarucu (Arapaima gigas), an obligate air-breathing fish
Authors: Randall D. J. , Farrell A. P. , Haswell M. S.
Published: August 2008

The obligate air-breathing fish Arapaima gigas has a reduced gill area and utilises a modified swim bladder as a lung. Dorsal aorta blood and lung [Formula: see text] and [Formula: see text] in addition to blood pH were measured between air breaths. The mean lung gas exchange ratio, R, was 0.45 with the majority of lung gas transfer occurring in the 1st min of the 4-min breath hold. The blood [Formula: see text] was 39 mmHg (1 mmHg = 133.322 Pa), [Formula: see text] was 26 mmHg and pH was 7.58, none of which vary significantly between air beaths. The blood [Formula: see text] was often less than lung gas [Formula: see text]. Carbonic anhydrase infusion had no effect on blood pH and [Formula: see text], nor lung [Formula: see text], [Formula: see text], and R value. However carbonic anhydrase infusion increased blood [Formula: see text] to a level that was always higher than lung gas [Formula: see text]. It is concluded that oxygen uptake and removal of molecular CO2 at the gills is limited by the reduced gill area. Furthermore, most of the CO2 excreted at the gills originates from plasma bicarbonate, whilst molecular CO2 is excreted at the lungs. This situation is consistent with the hypothesis that the blood CO2:HCO3− system is normally in a state of non-equilibrium between the gills and lung. Pirarucu blood shows a marked Bohr shift and a small Root shift which facilitate O2 uptake at the lung.
Développement postnatal de l'activité motrice chez Microtus pennsylvanicus
Authors: Pépin François-Marie , Baron Georg
Published: August 2008

Three litters of Microtus pennsylvanicus were observed in an artificial tunnel system from birth to 21 days of age. Isolated movements, positions and rotations of the body, and linear locomotion were recorded. Movements could be classified into three stages or five periods based on their first appearance. 'Nest' stage (0–7 days) with period I (0–2 days) in which most isolated movements and rotations occurred and period II (3–7 days) which was characterized by 'crawling'; the 'transitional' stage (8–10 days) or period III in which the pups left the nest for the first time; the 'outside of nest' stage (11–21 days) which included period IV (11–12 days), characterized by coordinated walking and frequent visits to the tunnels, and period V (from 13 days on) in which the animals visited the surface and mastered the basic locomotory repertoire found in adults. Development of rotation movements could also be divided into four distinct periods based on the relative frequencies of their occurrence. Although they are based on different criteria, the two types of developmental sequences give basically the same temporal distribution.
A cytological description of sibling species of Simulium venustum and S. verecundum with standard maps for the subgenus Simulium Davies (Diptera)
Authors: Rothfels Klaus , Feraday Ray , Kaneps Aina
Published: August 2008

The paper proposes standard polytene chromosome maps for species groups in the subgenus Simulium. In the S. venustum/verecundum complex we distinguish by their chromosomes a minimum of seven sibling species designated by their IIS sequences, as follows: EFG/C (S. truncatum?) holarctic; EFG, Germany; CC (S. venustum?) North America (with probably CC 1 a separate sibling); A/C venustum, New Hampshire (with AC(gB) venustum Newfoundland probably distinct); CC 2 Ontario, Newfoundland; AA verecundum Newfoundland (with possibly A/C verecundum, Ontario distinct); and ACD (S. verecundum? = sublacustre) holarctic. Three of these taxa (EFG/C, ACD, and CC) were probably recognized by taxonomists, though the circumpolar distribution of the first two was not reliably recorded. The remaining species were not previously resolved. The chromosomal characteristics of all species are described and notes are given on available details of their biology and distribution. Some broad aspects of the relationship between cytological and taxonomic methodology in the group are discussed.
Heart rates of white-tailed deer fawns in response to recorded wolf howls
Authors: Moen Aaron N. , DellaFera M. A. , Hiller A. L. , Buxton B. A.
Published: August 2008

Weekly measurements of heart rate responses of a hand-reared white-tailed deer fawn to recorded wolf howls were completed through the age of 87 days, with occasional measurements of the responses of three other fawns. Alarm bradycardia was a very predictable initial response to the first howl through 45 days of age. Increased heart rates were observed in response to a chorus of howls 35 s into the 62-s sequence. A most interesting characteristic of the response was a highly significant (sign test) relationship between the direction of the heart rate response at 1-s intervals from one test to another, and from one week to the next, until the fawn was 45 days old. Heart rates varied from 86 to 225 beats per minute during the tests, within the ranges observed for transient stimuli such as horses, rain, machines, and other deer. The fawn remained bedded during the tests. A hiding response and alarm bradycardia in the first few weeks of life seems to be good adaptive strategy as the neonate has little chance to escape from a predator by running.
The effect of crude oils on salt gland sodium secretion of orally imposed salt loads in glaucous-winged gulls, Larus glaucescens
Authors: McEwan E. H.
Published: August 2008

Oil had no effect on the salt gland secretion of seawater-adapted gulls loaded orally with 0.5 N NaCl.
Otolith comparison of Alosa pseudoharengus (Wilson) and Alosa aestivalis (Mitchill)
Authors: Price Wm. Stephen
Published: August 2008

Differences in the morphology of the otoliths of Alosa pseudoharengus (alewife) and Alosa aestivalis (blueback herring) have been found to be reliable criteria in distinguishing the two species.
Seasonal dynamics and spatial distribution of Cleidodiscus stentor Mueller 1937 and Ergasilus centrarchidarum Wright 1882, gill parasites of Ambloplites rupestris (Raf.)
Authors: Hanek George , Fernando C. H.
Published: August 2008

Seasonal dynamics and spatial distribution were determined for Cleidodiscus stentor Mueller 1937 and Ergasilus centrarchidarum Wright 1822, gill parasites of Ambloplites rupestris (Raf.).Twenty-five specimens of A. rupestris from eutrophic (West Lake) and 25 specimens from oligotrophic (Glenora) habitats were examined monthly between November 1971 and October 1972.The data were analysed using a two-factor ANOVA and Duncan's multiple range test.High abundance levels of C. stentor and E. centrarchidarum were recorded in the two localities throughout the sampling period.Cleidodiscus stentor, the dominant parasite of A. rupestris in West Lake, reached the peak during March 1972 in West Lake and during April 1972 in Glenora. Ergasilus centrarchidarum, the dominant parasite of A. rupestris in Glenora, reached the peak during August 1972 in both localities.The anterior side of hemibranchs, their medial sections, and gill arch two were preferred sites of infection (P < 0.001) for C. stentor.Ergasilus centrarchidarum exhibited clear preference (P < 0.001) for anterior sides of hemibranchs and their dorsal and ventral sections, while its distribution over the four gill arches was fairly even.
Song variation in a population of chestnut-sided warblers (Dendroica pensylvanica): its nature and suggested significance
Authors: Lein M. Ross
Published: August 2008

Song variation in a population of chestnut-sided warblers (Dendroica pensylvanica) was investigated during 1970–1972 in Hillsboro County, New Hampshire. Five song types, which appear to be shared by all males in the local population, are described and are used differentially by the birds. Two 'accented ending' song types are used primarily by undisturbed males located centrally on their territories. Two 'unaccented ending' song types are used in territorial encounters, or when a male is located peripherally on his territory. The fifth type, 'jumbled song,' is used almost exclusively during territorial encounters. There is no evidence of special association of any of the types with male–female interactions. It is suggested that the song types form a graded series of signals, increasing the efficiency of male–male communication by transmitting more precise messages than would be possible with only a single song type.
Mortality, recovery, and survival of larval Brachycentrus numerosus (Trichoptera) after exposure to the insecticide fenitrothion
Authors: Symons P. E. K. , Metcalfe Janice L.
Published: August 2008

The 72- and 96-h LC50's of the organophosphate insecticide fenitrothion to caddis larvae (Brachycentrus numerosus Say) at 5 °C were 20 and 11 ppm respectively. However, within 30 days of 24-h exposures to 0.076and 0.130 ppm fenitrothion, 66 and 100% of the larvae respectively were dead. Recovery of survivors from exposure to 0.076 ppm appeared complete within 19 days. The 24-h threshold concentration for case leaving and mortality lay between 0.055 and 0.076 ppm. The case-leaving response showed an increase with increasing concentrations, but the percentage leaving their cases varied in different experiments at similar concentrations. All larvae leaving their cases were incapacitated and died without signs of recovery. On the basis of the 72- and 96-h LC50's, B. numerosus was insensitive to fenitrothion compared with other species, but on the basis of 30-day tests, its margin of safety during current forest spraying with fenitrothion to control forest pests appeared low.
Parasites of Acipenser brevirostrum LeSueur and Acipenser oxyrhynchus Mitchill (Osteichthyes: Acipenseridae) in the Saint John River Estuary, N.B., with a description of Caballeronema pseudoargumentosus sp.n. (Nematoda: Spirurida)
Authors: Appy R. G. , Dadswell M. J.
Published: August 2008

Eleven species of helminth and arthropod parasites are reported from Acipenser brevirostrum and Acipenser oxyrhynchus in the Saint John River estuary, N.B., Canada. Diclybothrium armatum, Spirorchis sp., Fessesentis friedi, and Argulus alosa are new records from A. brevirostrum. Derogenes varicus, Truttaedacnitis sphaerocephala, Echinorhynchus gadi, and Dichelesthium oblongum are new records from A. oxyrhynchus. Truttaedacnitis sphaerocephala and D. oblongum are new locality records for North America. Caballeronema pseudtiargumentosus sp.n. is described from A. brevirostrum and differs from the similar spirurid Ascarophis argumentosus in length of spicules (110–138 μm and 492–598 μm versus 81–86 μm and 320–340 m), egg length (38–44 μm versus 29–35 μm), and number of egg filaments (4–10 versus 2). Details of the oral structure of C. pseudoargumentosus are described and its relationship to Ascarophis and Capillospirura discussed. Parasite fauna of adult A. oxyrhynchus, juvenile A. oxyrhynchus, and A. brevirostrum are distinct and reflect differing life histories and ecologies of the hosts.
Studies on Daphnia pulex Leydig in sewage oxidation ponds
Authors: Daborn Graham R. , Hayward John A. , Quinney Terry E.
Published: August 2008

Populations of Daphnia pulex Leydig inhabiting two aerated sewage treatment ponds at Canning, Nova Scotia, were studied from May to September 1975 and October 1976 to January 1977. Very large females (< 4.4-mm total length) present in May exhibited high fecundity, producing up to 70 parthenogenetic eggs per brood (average, 29.5). These nonephippial eggs hatched immediately, giving rise to population densities as high as 932 ℓ−1 in mid-June. Maximum body size and fecundity decreased during summer 1975 to 2.5 mm and two eggs per brood respectively. Two periods of parthenogenetic ephippial egg production were recorded, one in May to June and a second in September to October. Males were not found at any time. Seasonal changes in abundance, an inverse relationship between numerical abundance and oxygen saturation levels, and changes in fecundity are considered to indicate that the summer populations were at times food limited. During the winter, mean densities declined from 473 and 178 ℓ−1 in October 1976 to zero by 21 January 1977. A complete shift from nonephippial to ephippial egg production occurred in October, but less than 25% of ephippia collected in January contained eggs. The role of Daphnia in sewage oxidation ponds is discussed.
A reexamination of litter size in some North American microtines
Authors: Innes Duncan G. L.
Published: August 2008

Data from the literature on litter sizes of several species of Microtus and Clethrionomys were examined in relation to latitude and elevation by single and multiple correlation. Litter size in these genera was significantly correlated with latitude, as it was with latitude and elevation together. In Microtus, litter size within species was not significantly correlated with either of the independent variables. Litter size in Clethrionomys gapperi was significantly correlated with latitude and with latitude and elevation together. Multiple range tests revealed that some species which occur at the same latitudes and elevations have significantly different litter sizes from each other. Litter size may be species specific and not primarily determined by latitude and elevation.
Some effects of different Plantago species on feeding preference and egg laying in the flea beetle Dibolia borealis Chev. (Chrysomelidae)
Authors: Hawthorn Wayne R.
Published: August 2008

The differential feeding and egg-laying responses by overwintered adults of the North American chrysomelid beetle Dibolia borealis Chev. to native and introduced host plants of the genus Plantago were investigated. Adults exhibited a feeding preference for Plantago rugelii (native species) > Plantago major (introduced) > Plantago lanceolata (introduced). However, females fed P. rugelii and P. lanceolata laid fewer eggs than females fed P. major. In the field, D. borealis laid more eggs on P. major and more adults emerged from plants of this species than from P. rugelii. The ecological and evolutionary implications of feeding and egg laying on different food resources are discussed.
Behavioural strategies relevant to the energy economy of the red squirrel (Tamiasciurus hudsonicus)
Authors: Pauls Ronald W.
Published: August 2008

Amount and intensity of locomotor activity and time out of the nest were measured for a 1-year period on captive red squirrels (Tamiasciurus hudsonicus) under natural conditions. Daily and annual activity patterns and correlations between activity and meteorological variables were examined. A pronounced annual cycle, in phase with the annual temperature cycle, was found in all three aspects of activity. Daily amount of locomotor activity and time out of the nest were closely correlated with mean daily air temperature. Wind, photoperiod, and air temperature during the preceding week showed a weak but significant correlation with activity. Daily patterns of activity varied seasonally from a distinctly bimodal to a unimodal pattern, with a shift in winter to more midday activity. The relevance of these behavioural strategies to the energy economy of the red squirrel is discussed.
Rufous hummingbird feeding territoriality in a suboptimal habitat
Authors: Gass Clifton Lee
Published: August 2008

Postbreeding migratory female and immature rufous hummingbirds (Selasphorus rufus) establish feeding territories in dense meadows of several 'typical hummingbird plant species' and in individual Rhamnus purshiana shrubs. Resource utilization patterns and activity budgets of individuals in meadows are typical of territorial hummingbirds. Individuals in Rhamnus forage a high proportion of the time and are absent from their territories frequently and for long durations early and late in the day, and feed on other species during these absences. Rhamnus is marginally profitable to feed on and defend, but it may be the only available habitat for the individuals that utilize it.
Les groupements benthiques du fleuve Saint-Laurent près des centrales nucléaires de Gentilly (Québec)
Authors: Vincent B. , Vaillancourt G.
Published: August 2008

The structure and distribution of the macrobenthos were determined to evaluate the present state of the section of the St. Lawrence River which might be affected by the cooling waters of the Gentilly nuclear reactors. Ten groups were recognized, characterized by the presence of one to three constant and dominant species. In lentic conditions characterized by the presence of the gastropod Bithynia tentaculata the zonation is depth dependent. Three groups inhabit the littoral zone characterized by the Glossoscolecidae Sparganophilus tamesis. There are two groups in the sublittoral zone characterized by the Tubificidae Limnodrilus hoffmeisteri and two groups in the deep waters characterized by the Sphaeriidae Sphaerium striatinum. Bithynia tentaculata, a hydrobiid, seldom inhibits the lotic environment where the Tubificidae Limnodrilus hoffmeisteri is the only typical species.
The larval instars and population dynamics of five species of black flies (Diptera: Simuliidae) and their responses to selected environmental factors
Authors: Ross Douglas H. , Merritt Richard W.
Published: August 2008

The larval instars of four species of black flies were determined. Prosimulium fuscum Syme and Davies and Prosimulium mixtum Syme and Davies had seven instars; however, larvae of these Prosimulium spp. passed through only six instars when development occurred at warmer temperatures. Simulium vittatum Zetterstedt and Stegopterna mutata (Malloch) had seven and six larval instars, respectively. The instars of Cnephia dacotensis (Dyar and Shannon) could not be positively segregated.Stream temperature was the most important physical factor regulating larval black fly population dynamics, determining hatching time and developmental rates. Prosimulium mixtum/fuscum larvae required 240 D °C (day-degrees) above 0 °C for maturation, while St. mutata and C. dacotensis needed 250–275 and 475 D °C, respectively. Stream discharge also influenced the annual dynamics of simuliid populations, as spring floods produced second cohorts of some univoltine species which normally have one cohort of overwintering larvae per generation. Changes in discharge also affected estimates of larval densities by influencing the number of larvae colonizing artificial substrates.
Depth distributions determined with SCUBA, and associated studies of the freshwater unionid clams Elliptio complanata and Anodonta grandis in Lake Bernard, Ontario
Authors: Ghent Arthur W. , Singer Robert , Johnson-Singer Lucinda
Published: August 2008

Underwater circular-plot sampling showed Elliptio complanata to be confined to the hard-sand, wave-swept shallows, on which the heavy shell and narrow ventral angle of this species permit it to retain a footing. The E. complanata population lay shoreward of 4 m, mostly at depths of 2.5 m or less. A shoreward, low-density extension of the Anodonta grandis population overlaps that of E. complanata, but the A. grandis population extends lakeward to depths of 13–14 m, where its lightweight shell and wide ventral angle permit it to sit on the soft, unconsolidated silt substrate. A blanket of 10 cm or more of this soft substrate has accumulated in Lake Bernard at depths of 6 m or more, beyond the disturbance of surface waves. Specimens taken from these greater depths were markedly stunted, but such stunting was shown to be a progressive phenomenon, increasing with greater depth, rather than a sudden threshold effect at any particular depth. Regression relations among length, height, obesity, and weight of A. grandis shells were the same from all depths. The speculation is advanced that A. grandis may have evolved primarily as a deep-water species.
Morphology of the barren-ground caribou ovary
Authors: Dauphiné Jr. T. Charles
Published: August 2008

Reproductive tracts were collected from 532 female caribou (Rangifer tarandus groenlandicus) in northern Canada over a [Formula: see text]-year period. Ovaries were weighed and scrutinized by gross and histological techniques. Ovaries of nulliparous and nongravid, parous cows responded to follicular fluctuations by increasing in weight in summer and declining in winter. Weights of ovaries from calves, yearlings, and 2 year olds overlapped extensively. Formation of corpora lutea of pregnancy more than doubled ovary weight. During gestation ovary weight declined and then partially recovered; it increased with age in pregnant cows. The number and size of follicles [Formula: see text] diameter increased with age until puberty, reaching greatest development just before the autumn rut. After puberty the seasonal incidence of such follicles remained stable except during gestation, when it declined. Corpora lutea of pregnancy regressed to form apparently permanent scars composed of vascular and connective tissue remnants. Secondary corpora lutea developed in 35% of the cows at or before conception and upon regression produced scars which were not permanent. Regressing corpora lutea of estrus also disappeared into the ovarian stroma, apparently within 1 year. In individual cows one ovary, selected at random, dominated in the production of ova and corpora lutea.