bluuebunny/crossref_metadata_2025 huggingface dataset:
The energetic cost of predator avoidance in neonatal ungulates: hiding versus following
Authors: Carl Gary R. , Robbins Charles T.
Published: March 2009

Growth rates, milk intake, and activity patterns of neonatal mule deer (Odocoileus hemionus) and mountain goats (Oreamnos americanus) were compared, along with weight changes and activity patterns of their mothers, to determine (i) the energetic costs and trade-offs of following and hiding as strategies to reduce predation and (ii) whether any additional energy cost due to following is borne by the neonate, the mother, or both. Body weights of neonates at 1 and 9 weeks of age did not differ between species, but growth rates differed and changed with time. For the first 4 weeks postpartum, the deer fawns were less active and had a higher growth rate than the goat kids. Growth rates of fawns decreased after the 4th week while growth rates of the kids increased near the 7th week. Throughout the study, individual milk intakes were generally higher for singleton fawns than for twin fawns and single kids. Deer nursing single or twin fawns produced more milk (measured in grams or kilocalories) than did goats. Fawns nursed less frequently but in longer bouts, consuming more milk per bout than the goats. The lactating deer lost weight during early lactation while lactating goats maintained their weight. The energetic cost to goats of following was borne primarily by the neonate, with the additional costs directly associated with following being quite small.
Effect of incubation temperature on the development of five species of Pacific salmon (Oncorhynchus) embryos and alevins
Authors: Murray C. B. , McPhail J. D.
Published: March 2009

Embryo and alevin survival, time to hatching and emergence, and alevin and fry size of five species of Pacific salmon (Oncorhynchus) were observed at five incubation temperatures (2, 5, 8, 11, and 14 °C). No pink (Oncorhynchus gorbuscha) or chum (O. keta) salmon embryos survived to hatching at 2 °C. Coho (O. kisutch) and sockeye (O. nerka) salmon had higher embryo survival at 2 °C than chinook (O. tschawytscha) salmon. At 14 °C, chum, pink, and chinook salmon had higher embryo survival than coho or sockeye salmon. In all species, peaks of embryo mortality occurred at specific developmental stages (completion of epiboly, eye pigmentation, and hatching). Alevin survival to emergence was high for all species, except for coho and pink salmon at 14 °C. Hatching and emergence time varied inversely with incubation temperature, but coho salmon hatched and emerged sooner at all temperatures than the other species. Coho and sockeye salmon alevins were larger at 2 °C, pink, chum, and chinook salmon alevins were larger at 5 and 8 °C. Coho salmon fry were larger at 2 °C, chinook and chum salmon fry were larger at 5 °C, and sockeye and pink salmon fry were larger at 8 °C. High incubation temperatures reduced fry size in all species. Each species of Pacific salmon appears to be adapted to different spawning times and temperatures, and thus indirectly to specific incubation temperatures, to ensure maximum survival and size and to maintain emergence at the most favorable time each year.
Control of glycogenosis in rainbow trout muscle during exercise
Authors: Parkhouse W. S. , Dobson G. P. , Hochachka P. W.
Published: March 2009

The purpose of this study was to measure and compare the in vivo levels of glycolytic pathway intermediates during high-intensity, progressive exercise in rainbow trout red and white muscle. The mass action ratios of those reactions catalyzed by the enzymes hexokinase, phosphofructokinase, and pyruvate kinase appear to be displaced far from thermodynamic equilibrium (greater than log 2) under all experimental conditions in both tissue types. Furthermore, the near-equilibrium glyceral-dehyde 3-phosphate dehydrogenase – phosphoglycerate kinase complex deviated from thermodynamic equilibrium during the exhaustive swim for white muscle and for all exercise intensities in red muscle. The mass action ratio of the combined glyceraldehyde 3-phosphate dehydrogenase – phosphoglycerate kinase/lactate dehydrogenase demonstrated displacements from thermodynamic equilibrium similar to those of the glyceraldehyde 3-phosphate dehydrogenase complex. Potential control sites were identified as phosphorylase for white muscle and hexokinase and glyceraldehyde 3-phosphate dehydrogenase – phosphoglycerate kinase for red muscle. No alterations in potential control sites were found in white muscle with changing flux rates (sustained and burst swims) provided sufficient glycogen was available as precursor. Phosphofructokinase and glyceraldehyde 3-phosphate dehydrogenase only demonstrated potential control in this tissue when glycogen content and flux rates were low (exhaustive swim). These changes coincided with substrate depletion to low levels and large declines in the ATP/ADPf ratio. Therefore, it would appear that glycogen content is the primary factor regulating glycolytic flux and control sites via alterations in adenylate levels.
Cytologie et taxonomie d'une microsporidie du genre Unikaryon (Microspora, Unikaryonidae) parasite du Mylabris vestita (Coleoptera, Meloidae)
Authors: Toguebaye Bhen S. , Marchand Bernard
Published: March 2009

Unikaryon euzeti sp. nov. is a microsporidian parasite infesting the gut, adipose tissue, Malpighian tubules, and muscles of Mylabris vestita (Coleoptera, Meloidae). The meronts of U. euzeti are, in turn, uninucleate or binucleate and are surrounded by a single plasma membrane. The sporonts are also alternately uninucleate or binucleate but they are surrounded by a wall about 15 nm thick. The binucleate sporonts give rise to two uninucleate sporoblasts which turn into spores. Mature spores are uninucleate, ovoid, and measure 2.22 ± 0.11 × 1.38 ± 0.07 μm. Their polar filament describes seven to nine coils and their polaroplast is divided into an anterior lamellar part and a posterior granular one.
The cyphonautes larva of the marine bryozoan Membranipora membranacea. I. General morphology, body wall, and gut
Authors: Stricker Stephen A. , Reed Christopher G. , Zimmer Russel L.
Published: March 2009

The cyphonautes larva of Membranipora membranacea (phylum Bryozoa, order Cheilostomata) is a laterally compressed, planktotrophic larva covered by a triangular, bivalved shell. In this paper, the general morphology of the larva and the cytology of the body wall and gut are examined by light and electron microscopy. The outer part of the body wall underlying the shell consists of an essentially nonciliated layer, called the aboral epithelium. At the larval apex, the aboral epithelium forms a knob-shaped apical organ. The apical organ contains putative sensory cells, a basal nerve plexus, and a group of undifferentiated epithelial cells that probably corresponds to a blastema. The body wall at the base of the larva constitutes the larval locomotory organ or corona. The corona consists of two rows of multiciliated cells, which are flanked by myoepithelial cells and monociliated cells. A large mantle cavity, referred to as the vestibule, occupies the central region of the larva. The vestibule is partially divided into an anterior inhalant chamber and a posterior exhalant chamber by two ciliary ridges that run along the sides of the mantle cavity. At the base of the larva, the inhalant chamber is surrounded by a horseshoe-shaped flap of tissue, called the velum. Apically, the inhalant chamber forms a densely ciliated preoral funnel. Food particles filtered by the ciliary ridges are conveyed to the larval mouth by cilia in the preoral funnel. The mouth in turn leads into a tripartite gut consisting of an esophagus, stomach, and intestine. Two types of ciliated lining cells occur in the esophagus and stomach. The intestine appears to be lined by nonciliated epithelial cells and empties into the exhalant chamber by way of an anus. Morphological features of the cyphonautes larva are compared with those described for other bryozoan larvae in an attempt to define homologous structures among the various larvae of bryozoans.
The cyphonautes larva of the marine bryozoan Membranipora membranacea. II. Internal sac, musculature, and pyriform organ
Authors: Stricker Stephen A. , Reed Christopher G. , Zimmer Russel L.
Published: March 2009

The internal sac, muscles, and pyriform organ of the cyphonautes larva of Membranipora membranacea (phylum Bryozoa, order Cheilostomata) were examined by light and electron microscopy. The internal sac is an ovoid, tripartite organ that lies near the larval gut. The posterior and lateral parts of the sac are composed of nonglandular epithelial cells and are referred to as the roof and wall regions, respectively. The neck region occurring at the anterior end of the sac is packed with large secretory granules and is folded posteriorly into the lumen surrounded by the roof and wall regions. A previously undescribed network of ciliated cells, which may constitute part of an excretory organ, occurs between the internal sac and the gut. Four major sets of muscles are present in the larva: (i) a single adductor muscle that attaches to the two valves of the larval shell and contains non-striated myofibers with conspicuous dense bodies, (ii) a pair of nonstriated sac muscles that extend between the shell and the roof region of the internal sac, (iii) two sets of striated lateral muscles which originate near the center of the shell and ramify along the sides of the larva, and (iv) a median band of striated myofibers located along both the anterior and posterior margins of the larva. The pyriform organ is a large neuroglandular complex located at the anterior end of the larva. The organ consists of (i) a median ciliated groove with an anteriorly positioned tuft of long cilia, (ii) numerous glandular cells surrounding the ciliated groove, and (iii) several discrete tracts of nerves with accompanying muscles. The cytological features of the internal sac, larval muscles, and pyriform organ are compared with those described for other bryozoan larvae.
A study of Gyrodactylus colemanensis Mizelle and Kritsky, 1967 and Gyrodactylus salmonis (Yin and Sproston, 1948) (Monogenea) parasitizing captive salmonids in Nova Scotia
Authors: Cone D. K. , Cusack R.
Published: March 2009

Gyrodactylus colemanensis Mizelle and Kritsky, 1967 and Gyrodactylus salmonis (Yin and Sproston, 1948) parasitized Salvelinus fontinalis, Salmo gairdneri, and Salmo salar at a fish farm in Nova Scotia. Gyrodactylus colemanensis occurs on the edges of fins and clings delicately to the skin surface. Gyrodactylus salmonis embeds its marginal hooks deeply into the epidermis and occurs all over the body surface except on the fin edges. The parasites gain entrance to the hatchery on infected stocks arriving from other facilities and possibly through infected wild salmonids entering via the water supply. Brood stocks serve as reservoir hosts within the farm. Young-of-the-year S. fontinalis became infected within 8 weeks of transfer to the outside raceways, with hatchery buckets and nets likely serving as vehicles of transmission. Intensity of infection increased during winter to a spring peak followed by a decrease during the summer months. Intensity generally decreased with host age. Stocks were initially infected with mixed infections; subsequently, single species infections occurred which involved first G. salmonis, then G. colemanensis, and then G. salmonis. There were no clinical signs of disease associated with infections and the parasites did not harbor bacterial or viral pathogens.
Dorsal fin scars as indicators of age, sex, and social status in humpback whales (Megaptera novaeangliae)
Authors: Chu Kevin , Nieukirk Sharon
Published: March 2009

We compared the number of linear marks and the shapes of dorsal fins of different classes of humpback whales during the breeding season. Male humpbacks tend to have more marks than females. Such marks are probably scars resulting from physical contact during intrasexual competition for mates. Not all males have marks; therefore, an unmarked adult humpback could be a male or a female. An adult with many marks is likely a male, however. Differences in the dorsal fins of principal and secondary escorts in large groups of competing males suggest that not all escorts have the same chance of attaining principal escort status. Therefore, male – male competitions in large groups should not necessarily be viewed as contests between equals. Principal escorts showed significantly more of some types of marks than did lone escorts of cows with calves, suggesting that not all lone escorts may retain their position if challenged.
Intraspecifîc discrimination of amphipod prey by a freshwater leech through mechanoreception
Authors: Blinn Dean W. , Pinney Chris , Wagner Vincent T.
Published: March 2009

We recorded the vibrations produced by different age-classes of swimming amphipods (Hyalella montezuma). Adult H. montezuma produced a more continuous signal, while juveniles produced an intermittent signal (22 – 28 pulses/s). The leech Erpobdella montezuma demonstrated a significantly greater attack response for playback recordings of juvenile amphipod prey. Intermittent signals produced from an electronic generator were also attacked by E. montezuma at a significantly greater rate than more continuous electronic signals. This provides evidence that E. montezuma can distinguish between juvenile and adult H. montezuma prey by mechanoreception.
Behaviour and ecological importance of a mud snail (Ilyanassa obsoleta) population in a temperate macrotidal estuary
Authors: Cranford Peter J.
Published: March 2009

A population of Ilyanassa obsoleta was sampled during the 8-month period when they are present in the intertidal zone in the Southern Bight of Minas Basin, Bay of Fundy. Mud snails were first observed in April, and spawning took place in late May and early June. Flesh weight increased between May and November, with the highest growth rates recorded during August and September. During November the population returned to the subtidal zone, where energy reserves are partially utilized during winter. Clustering and differential habitat selection (salt marsh or mud flat) within size classes resulted in large spatial variations in density, standing stock, and production. Production by I. obsoleta averaged 1.1 g C∙m−2 during their stay in the intertidal zone. The supply of carbon from epibenthic microalgae is insufficient to meet the requirements of this population. Detritus derived from Spartina is believed to be an important additional source of carbon. Ilyanassa obsoleta is not a major prey item of any of the better known predators in this region. Their importance to the intertidal community results from the direct (predation) and indirect (competition, disturbance, nutrient regeneration, and bioturbation) influence of their presence on sedimentary microbial processes and the resident benthic flora and fauna.
A cellular basis for high levels of vitamin A in livers of polar bears (Ursus maritimus): the Ito cell
Authors: Leighton F. A. , Cattet M. , Norstrom R. , Trudeau S.
Published: March 2009

Numerous large perisinusoidal cells containing prominent cytoplasmic lipid droplets were observed in the livers of adult and subadult polar bears (Ursus maritimus). The cells were identified as Ito cells by histological, histochemical, and ultrastructural criteria. The ratio of Ito cell to hepatocyte numbers in three bears was 1:5.6, much higher than that reported in humans. Total liver retinol and retinol palmitate in three livers correlated well with mean Ito cell area (r = 0.98). We postulate that the large number and size of Ito cells in polar bear livers is an adaptation to high dietary levels of vitamin A.
Alteration of carbon cycling by beaver: methane evasion rates from boreal forest streams and rivers
Authors: Ford Tim E. , Naiman Robert J.
Published: March 2009

In boreal forest drainage networks, beaver (Castor canadensis) apparently influence the biogeochemical cycling of carbon by creating conditions for sediment accumulation in streams, providing anoxic conditions suitable for significant methanogenesis. To test this assumption we measured methane evasion rates in streams, ranging in size from first to sixth order, in the Matamek River drainage network, Quebec, Canada. Evasion rates varied between 0.04 and 4.41 g C (CH4)∙m−2∙year−1. There was no correlation between stream size or water temperature and evasion rate. However, methane evasion was 33-fold greater in beaver ponds than at other sites, representing 3.6% of the measured annual carbon output. In contrast, methane evasion accounted for only 0.05–0.5% of the annual carbon output from sites not modified by beaver.
Biology of the endangered black-footed ferret and the role of captive propagation in its conservation
Authors: Miller Brian J. , Anderson Stanley H. , DonCarlos Michael W. , Thorne E. Tom
Published: March 2009

The black-footed ferret (Mustela nigripes), one of the rarest mammals in the world, is apparently an obligate dependent on prairie dogs. Ferret numbers were probably reduced by habitat fragmentation. The last known wild colony, west of Meeteetse, Wyoming, was decimated by canine distemper in 1985. The few remaining ferrets exist in captivity. In this paper, we review aspects of the reproductive physiology and life history of the black-footed ferret with focus towards captive propagation and subsequent reintroduction of the species into natural habitat. We discuss the black-footed ferret in the context of small population biology and relate the value of captive propagation as a conservation tactic.
Population status, distribution, and movements of woodland caribou in west central Alberta
Authors: Edmonds E. Janet
Published: March 2009

Twenty-four woodland caribou (Rangifer tarandus caribou) in the mountains and foothills of west central Alberta were radio collared to obtain information on seasonal movements, location and extent of seasonal ranges, rutting and calving areas, and population status. The study was conducted from December 1979 to June 1984 (fall composition surveys continued to 1986). Two populations of woodland caribou resided in the foothills winter range: a migratory mountain variety that moved west to the mountains in spring and returned in fall, and a more sedentary woodland variety that remained year round in the forested foothills. Calving and rutting grounds of the two populations were widely separated (minimum of 60 km). The mountain population ranged over a much larger area (11 000 km2) than the woodland population (4000 km2). Woodland caribou were fewer (maximum estimate 50) than the mountain caribou (maximum estimate 200). Population sex–age structure of the mountain caribou population, based on six surveys during the rut (October), averaged 54 males: 100 females: 27 calves (15% calves). Annual minimum adult mortality was 22% for the mountain and woodland populations, and both populations appeared to be declining. Predation, primarily by wolves, was strongly implicated in adult mortality, but causes of calf mortality were not determined. Human-caused mortality was an additional factor. Intensive management is required to ensure the viability of these caribou populations in the face of increasing industrial and recreational development. A short-term wolf reduction program and long-term public education, law enforcement, and habitat protection programs are recommended.
Sustained exercise augments long-term starvation increases in plasma growth hormone in the steelhead trout, Salmo gairdneri
Authors: Barrett Bruce A. , McKeown Brian A.
Published: March 2009

During the increased locomotor activity of migration many salmonids do not actively feed and it is likely that metabolic alterations occur to facilitate the mobilization of stored reserves. The present laboratory study was designed to simulate the occurrence of exercise and starvation as natural parameters of migration and to assess the effects of such parameters on levels of plasma growth hormone, which might indicate alterations in metabolism during migration. Juvenile steelhead trout, Salmo gairdneri, were starved for a 30-day period. Starved individuals exhibited a marked increase in plasma growth hormone concentration (38.6 ± 6.7 ng/mL) compared with control individuals held on a normal feeding regime (6.4 ± 1.84 ng/mL). A subgroup of fish from the starved group were exercised by being forced to swim at 1.5 body lengths/s for a 24-h period. Exercised individuals exhibited plasma growth hormone levels in excess of 140 ng/mL. There was no significant difference between the plasma growth hormone levels of unexercised starved fish and exercised fed fish.
Peregrine falcon and merlin predation on small shorebirds and passerines in Alberta
Authors: Dekker Dick
Published: March 2009

This study describes and compares hunting techniques and predatory efficiency of peregrine falcon (Falco peregrinus) and merlin (Falco columbarius) preying on small shorebirds and passerines in open agricultural lands around Beaverhills Lake, Alberta, during spring and fall, 1965–1987. Hunting methods were divided into four categories: (i) surprise attacks with less than six swoops at prey initially on the ground, (ii) short pursuits with less than six swoops at flying prey, (iii) persistent, long-range pursuits with more than six swoops, and (iv) other or unknown methods. They made up, respectively, 73.9, 17.2, 2.5, and 6.4% of 647 hunts by peregrines, and 72.3, 16.1, 4.5, and 7.1 % of 354 hunts by merlins. Persistent pursuits of prey were significantly more successful than surprise attacks by merlins (62.5 vs. 9.4%, P < 0.00001), but not by peregrines (18.8 vs. 8.8%, P = 0.40). I postulate that peregrines and merlins employ persistent hunting techniques only if surprise attacks are unproductive because of (i) lack of expertise of the falcon, (ii) scarcity of prey, (iii) unsuitable habitat, and (iv) effective early warning by flocking prey. Peregrines captured 50 shorebirds of 11 species, and 3 passerines of 2 species. Merlins captured 28 shorebirds of 8 species, and 16 passerines of 5 species. Adult male merlins were significantly more successful than immatures and adult females combined (38.7 vs. 9.1%, P < 0.00001). Adult peregrines were not significantly more successful than either spring or fall immatures (9.2 vs. 7.2 and 4.9%, P = 0.21, P = 0.24, respectively). Merlins were significantly more successful than peregrines in hunting small passerines (12.2 vs. 3.8%, P = 0.04), but not significantly more successful in hunting small shorebirds (12.6 vs. 8.8%, P = 0.10).
Changes in lipid and protein reserves and in diet of breeding House Sparrows
Authors: Krementz David G. , Ankney C. Davison
Published: March 2009

We collected House Sparrows (Passer domesticus) around London, Ontario, weighed their protein and fat reserves, and determined their food habits and egg production to test the effects of reserve levels on the timing of egg formation and the control of clutch size. Although consumption of high-protein foods was apparently related to insect availability, females consumed more high-protein foods than did males, especially during the laying period. Before egg production began, protein and fat reserves of males declined but those of females were constant. After egg production began, reserves of males remained constant through postreproduction. Neither protein nor fat reserves were accumulated by females before egg formation began, suggesting that an elevated threshold level of nutrient reserves was not necessary to commence egg formation. Protein reserves of females did not decline during egg production; fat reserves increased just before the first ovulation and declined rapidly thereafter. Neither fat reserve levels on the first day of ovulation nor the decline in fat reserves thereafter were related to clutch size. Postlaying females had, on average, enough fat reserves to produce an additional egg. We conclude that although female House Sparrow use fat reserves during egg laying, their clutch size is not controlled thereby.
Adaptation, constraint, and the function of the gluconeogenic pathway
Authors: Moon Thomas W.
Published: March 2009

Gluconeogenesis is responsible for the de novo synthesis of glucose (and glycogen) from precursors including lactate, amino acids, glycerol, and fructose. This metabolic sequence is highly constrained by design features including enzyme composition and tissue localization, but demonstrates a variety of adaptive patterns which are critical to the maintenance of blood glucose levels optimal for animal function. This review identifies the adaptive responses of gluconeogenesis when glucose levels are challenged by changes in diet (both quality and quantity) and in activity level, and by environmental disturbances. Five adaptive patterns are identified: (i) quantitative changes in gluconeogenic enzyme activities and their subcellular distribution; (ii) alterations in tissue demand for glucose; (iii) existence of in situ skeletal muscle lactate cycling; (iv) quantity and type of gluconeogenic precursors; and (v) regulation of gluconeogenesis. The validity of the omnivorous mammalian model in our understanding of gluconeogenesis is discussed.
Low-temperature adaptation of oxidative energy production in cold-water fishes
Authors: Dunn J. F.
Published: March 2009

This paper addresses the possibility that oxidative energy production in fish muscle is limited by low temperatures. Data are used from species that seasonally acclimatize to low temperatures, and from animals that have adapted to low temperatures over an evolutionary period. It is likely that the inhibitory effect of declining temperatures on the potential rate of oxidative energy production is compensated for largely by increasing the volume of mitochondria in the cell (volume density). For fishes that acclimatize, this increase in mitochondrial volume density may offset diffusion limitations. This is less likely for species that have adapted to low temperatures, because these animals have also developed large-diameter muscle cells. It is suggested that the stimuli for increasing cellular mitochondrial volume density, be they diffusion limitations or catalytic limitations, have not totally been overcome by increased mitochondrial volume density. In addition, a further restriction is concurrently placed upon maximum rates of oxygen uptake by the cell because the increase in mitochondrial volume density occurs at the expense of myofibrillar volume. This has the effect of reducing the maximum rate at which ATP can be used by working muscle.
La nidification de la sauvagine dans le marécage de la Rivière-du-Sud et la zone agricole environnante
Authors: Masse Denis , Raymond Michel
Published: March 2009

Nesting of dabbling ducks was studied in 1983 and 1984 on a southern Quebec marsh. Nest locations were determined during the nesting period in all habitats of the marsh (926 ha) and in a sample representing 24.4% (284 ha) of the fields available for nesting in the neighbouring agricultural zone. A total of 115 nests were numbered, involving mainly Mallards (Anas platyrinchos) and Blue-winged Teals (Anas discors). In the agricultural zone, nesting grounds were used mainly by the teals. However, 62% of the nests were destroyed during the first haying. Although mallards usually nest on the ground in areas of dense grass, intense agricultural use of the land results in very few fields offering enough vegetation cover in the early spring for this early nesting bird. An important number of mallards are forced to nest in trees or on different substrates in the marsh. In that type of environment, flooded woodland is the most extensively used habitat, with a mean density of 5.5 nests/100 ha. Nesting success is higher in the marsh (44 and 34%, respectively, in 1983 and 1984) than in the agricultural zone (5%). In the marsh, the main cause of nest destruction is predation. Water level variation also influences nesting success.[Journal translation]
Factors affecting the density of populations of common snapping turtles (Chelydra serpentina serpentina)
Authors: Galbraith David A. , Bishop Christine A. , Brooks Ronald J. , Simser W. Len , Lampman Karen P.
Published: March 2009

Density, biomass, and sex ratio were measured in two populations of snapping turtles (Chelydra serpentina) in Ontario in 1984 and 1985. The more southern population inhabited a nutrient-enriched pond at an unusually high density and biomass density (66/ha, 340 kg/ha), and exhibited a significantly male-biased sex ratio (1.96:1) but no significant sexual dimorphism in adult size. The northern population inhabited dystrophic or oligotrophic ponds at a low density (2.4/ha, 16 kg/ha), did not show a significant bias in adult sex ratio, but did have a strong sexual dimorphism in adult size, males having approximately twice the mass of females. A comparison among several populations indicated that density was negatively correlated with latitude and with surface area of suitable habitat. Density and biomass density were significantly higher in habitats of relatively high primary productivity, which tended to be at relatively low latitudes. Therefore, important proximal factors affecting density of these turtles are likely to be primary productivity and recruitment history. Differences in sex ratio and sexual dimorphism in size between the two Ontario populations did not support the hypothesis that the latter is due to sexual selection.
Detection thresholds of a harbour seal to repeated underwater high-frequency, short-duration sinusoidal pulses
Authors: Terhune J. M.
Published: March 2009

Underwater hearing thresholds of a harbour seal (Phoca vitulina) were obtained from 1 to 64 kHz using sinusoidal pulses as short as 0.5 ms. The lowest threshold was 57 dB (re 1 μPa) at 8 kHz. Thresholds for 500- to 50-ms tones increased to about 70 dB (re 1 μPa) in the 1- to 4-kHz and 32-kHz ranges and to 111 dB (re 1 μPa) at 64 kHz. At 50 ms duration, thresholds were from 0 to 6 dB greater than the maximum sensitivity for each frequency tested. Thus, only very brief seal vocalizations are not as audible as longer (and equally loud) underwater calls. For pulses shorter than 400 cycles, the thresholds increased linearly with the logarithm of the number of cycles, independent of frequency (4–32 kHz). The total energy of the pulses at threshold was estimated. From 4 to 32 kHz, as the pulse durations shortened, the threshold energy value decreased and then began to increase. These findings bring into question the concept that when presented with high-frequency sound, the auditory system integrates energy for a specific time period.
Copper, nickel, and iron levels in pelage of red squirrels living near the ore smelters at Sudbury, Ontario, Canada
Authors: Lepage P. , Parker G. H.
Published: March 2009

Geographical and seasonal variabilities in pelage metal levels of the red squirrel (Tamiasciurus hudsonicus) were studied in wild populations subject to different degrees of contaminant fallout from the copper–nickel smelters at Sudbury, Ontario. Levels of copper and iron in recently emerged pelage (10–12 and 13–20 μg∙g−1, respectively) did not differ among animals from highly contaminated, moderately contaminated, and noncontaminated sites, thus indicating minimal metal loading via endogenous routes. Nickel levels were significantly elevated for animals at the two contaminated sites relative to the control group; however, such increases are believed to reflect external contamination from environmental sources and (or) cross-contamination between old and new pelage coats. Pelage in the premoult condition, having been subjected to exogenous influences during the pelage year, showed higher levels of all three metals at one or both of the contaminated sites but not at the control site. Relative increases of nickel, copper, and iron coincided with atmospheric loading ratios reported for the Sudbury smelters, thus confirming the latter as the source. Nickel gains conformed to a previously reported model in that pelage burdens varied as a simultaneous function of duration of exposure to the environment and reciprocal of distance from the pollution source. Element-specific variabilities are discussed in relation to the use of pelage and choice of elements in monitoring smelter emission fallout.
The millipeds of eastern Canada (Arthropoda: Diplopoda)
Authors: Shelley Rowland M.
Published: March 2009

The diplopod fauna of eastern Canada, an area containing all or parts of Ontario, Quebec, New Brunswick, Nova Scotia, Prince Edward Island, and Newfoundland, consists of 6 orders, 15 families, 28 genera, and 38 species. Eighteen species, 47% of the total fauna, are synanthropic forms introduced chiefly from Europe, and 11 additional millipeds, including another order and family, may occur there, particularly in southern Ontario. The sole Canadian records of Polyzonium mutabile Causey, Aniulus paludicolens Causey, Uroblaniulus stolidus Causey, Pseudopolydesmus branneri (Bollman), Scytonotus granulatus (Say), and Pleuroloma flavipes Rafinesque; the genera Cleidogona, Scytonotus, and Pleuroloma; and the family Cleidogonidae are from Ontario. Pleuroloma flavipes and Uroblaniulus stolidus, in Essex and Algoma counties, are newly recorded from Canada. Polyxenus lagurus (L.), Underwoodia iuloides (Harger), and Trichopetalum lunatum Harger are the only native diplopods in the Maritime Provinces, and Allajulus caeruleocinctus (Wood), a Palearctic introduction, is the only species known from New Brunswick and Prince Edward Island. The combination Polyzonium cryptocephalum (McNeill) is revived for the dominant eastern polyzoniid species, and Petaserpes rosalbus Cope and Polyzonium divaricatum Loomis are recognized as synonyms of it, the latter being new. Other new synonymies are Polyzonium borealis Loomis and P. quadricauda Loomis with P. mutabile Causey; Julus immaculatus Wood and Parajulus dux Chamberlin with Uroblaniulus canadensis (Newport); and Underwoodia polygama Cook and Collins with U. iuloides. Apheloria virginiensis (Drury), n.comb., is proposed as are subspecific statuses for the common eastern spirobolid millipeds. American species improbable for eastern Canada are identified, and a key to known and potential taxa and pertinent anatomical drawings are provided.
Within-basin variation in the shell morphology and growth rate of a freshwater mussel
Authors: Bailey Robert C. , Green Roger H.
Published: March 2009

We measured a correlation between the habitat of the freshwater mussel Lampsilis radiata siliquoidea (Barnes, 1823) from several sites in Inner Long Point Bay, Lake Erie, and its shell morphology and growth rate. Morphometric analysis revealed that mussels in more exposed areas of the bay (areas with more turbulence and sandier sediments) had thicker shells than those from less exposed areas (areas with little turbulence and muddier sediments). Two growth rate analyses showed that the mussels from high exposure areas also grew faster. The results demonstrate the importance of (i) a multivariate consideration of shell form (as opposed to the use of ratio variables) when assessing form–habitat correlations, (ii) quantitatively defining habitat variation in examining such relationships, and (iii) measuring form–habitat relationships among more than two sites in a given basin or stream reach.
Influence of photoperiod and temperature on timing of sexual maturity of pink salmon (Oncorhynchus gorbuscha)
Authors: Beacham Terry D. , Murray Clyde B.
Published: March 2009

The effect of two photoperiods and rearing at 10, 13, and 16 °C on the development of pink salmon (Oncorhynchus gorbuscha) maturity 12 to 13 months after fry emergence was examined. Highest rates of maturity for both males and females were observed in the 10 °C temperature regime with a normal first summer, short winter, and short second summer photoperiod. In any environment examined, males were more likely to have matured than females. Highest survival rates and fastest overall growth rates were also observed at 10 °C. The feasibility of transplanting genes from one pink salmon brood line to another is examined.
The ability of wood frog eggs to withstand prolonged terrestrial stranding: an empirical study
Authors: Forester Don C. , Lykens David V.
Published: March 2009

In Maryland, the wood frog, Rana sylvatica, oviposits in ephemeral ponds and pools during early spring. Seasonal precipitation is often unpredictable and egg masses may become exposed as ponds recede. The ability of wood frog eggs to withstand prolonged terrestrial exposure was tested in the laboratory. Egg mortality rate was exponential. Compared with a submerged control, 49% of the eggs died within 2 days, but 11% of the eggs were alive after 10 days and a few survived as long as 14 days. Wood frogs are thought to have evolved communal egg laying as a mechanism to minimize thermal stress during development. We suggest that this behavior also enabled egg masses to withstand terrestrial stranding. Today, advantages accrued through reduced thermal exposure and resistance to desiccation likely act in concert to stabilize communal egg-laying behavior.
Over-winter survival in a boreal population of the bank vole, Clethrionomys glareolus
Authors: Karlsson A. Fredric
Published: March 2009

What characteristics enhance the probability of individual bank voles (Clethrionomys glareolus) surviving the winter? Two hypotheses were tested in this paper: (i) over-winter survival is determined by an individual's nutritional condition, such that voles in poor condition succumb disproportionately often, and (ii) over-winter survival is determined by the quality of an individual's home range. The study was performed during two winters near Uppsala, Sweden. Body weight could not be used to predict over-winter survival in males or in females. The mean body weight of males decreased significantly from October through December. Females remaining within one home range throughout the winter and reproducing (P+) were, on average, heavier during all months from October to April than those not recaptured after the onset of breeding (P−), suggesting a difference in age rather than a difference in condition. Rocky areas are preferred as overwintering habitats. Persistent voles used the same rocky microhabitats before and after the onset of breeding. The difference between persistent and nonpersistent voles is interpreted in terms of individual differences in the success of establishment. A difference in micro-habitat use among P+ and P− females suggests a difference in microhabitat optima in different years. The difference between P+ and P− within years suggests a difference in individual status and fewer options for those individuals arriving later.
Electrophoretic differentiation among local populations of the long-finned pilot whale, Globicephala melaena, at the Faroe Islands
Authors: Andersen Liselotte Wesley
Published: March 2009

Enzyme variation within and between nine schools of long-finned pilot whales, Globicephala melaena, caught at the Faroe Islands, was examined by starch gel electrophoresis. Twenty-seven enzymes were investigated, representing 41 loci, of which three were polymorphic. The polymorphic enzymes were analyzed in either liver or muscle tissue from 628 specimens. No heterogeneity within the schools was observed, while significant differences in allele frequencies between schools were detected by a multilocus G-test. This result indicated some degree of reproductive isolation.
Immunoreactive thyroxine levels in the serum of thyroidectomized adult newts, Notophthalmus viridescens
Authors: Liversage Richard A. , Foty Ramsey A. , McLaughlin Danielle S.
Published: March 2009

The concentration of immunoreactive thyroxine was determined in blood serum samples from thyroidectomized adult newts (Notophthalmus viridescens) relative to levels found in samples of serum from intact and sham-thyroidectomized newts by means of radioimmunoassay. The results show a significant rate and degree of decline in the level of thyroxine from 24 h to 14 days post-thyroidectomy, followed by further reductions of the immunoreactive thyroxine levels between 14 and 35 days, as compared with levels in intact and sham-thyroidectomized controls.
Interactions of fish and pelagic coelenterates
Authors: Arai Mary Needler
Published: March 2009

Coelenterates may be predators or prey of fish, act as intermediate hosts for parasites, or provide shelter. At least 42 species of fish, including such commercially important species as the spiny dogfish, chum salmon, Atlantic mackerel, and various gadoids, include pelagic coelenterates in their diets. Coelenterates may represent a substantial proportion of the fish stomach contents and preliminary data on caloric content of coelenterates is available. However, in the absence of measured digestion rates it is not possible to calculate feeding rates or assess the dietary importance of coelenterates to fish. Similarly, although many instances of coelenterates eating larval fish are known, only a few measurements of predation rates based on feeding rates and abundances of predator and prey have yet been made. Recent studies with newer sampling methods indicate that the biomass of coelenterates, particularly large scyphomedusae, has been underestimated. Hence, much quantitative work needs to be done on the interactions of coelenterates with both fish and other marine groups to evaluate their trophic position and importance in pelagic ecosystems.
Detoxifying enzyme activity in worker honey bees: an adaptation for foraging in contaminated ecosystems
Authors: Smirle Michael J. , Winston Mark L.
Published: March 2009

The activities of two important groups of detoxifying enzymes, the glutathione S-transferases and the mixed-function oxidases, were assayed throughout the lifetimes of worker honey bees (Apis mellifera L.). Detoxification capacity decreased on a per insect basis in older workers and was associated with a dramatic loss of midgut protein. However, analysis of specific activity (enzyme activity per milligram protein) showed increasing activity levels as bees aged and began to forage. These results show that foraging worker honey bees compensate for protein loss by increasing the activity of important enzymes, suggesting a possible biochemical adaptation for foraging in contaminated ecosystems.
A fourth genus of unusually modified Ceratocanthinae (Coleoptera: Scarabaeidae) from South America
Authors: Howden H. F. , Gill B. D.
Published: March 2009

Ivieolus pseudoscutellatus n.gen., n.sp. from La Gran Sabana of Venezuela is described and figured. Ivieolus is placed in the Ceratocanthinae and shares several apomorphies with the recently described genus Xenocanthus Howden and Gill and other Ceratocanthinae.
On penguin porpoising
Authors: Blake R. W. , Smith M. D.
Published: March 2009

Speeds above which porpoising becomes energetically more economical than swimming are calculated from a hydro-mechanical model for Humboldt (Spheniscus humboldti) and emperor (Aptenodytes forsteri) penguins. Predicted minimum porpoising speeds for S. humboldti are significantly less than observed values. At low porpoising speeds time in air is low and may not be sufficient to permit efficient breathing. It is suggested that ventilatory requirements may set a practicable lower bound on porpoising speed. Other possible constraints on the lower limits to porpoising speed include the requirement of raising the centre of mass high enough for the animal to completely clear the surface and the influence of sea conditions.
Helminths of mountain lions (Felis concolor) from southwestern Texas, with a redescription of Cylicospirura subaequalis (Molin, 1860) Vevers, 1922
Authors: Waid Douglas D. , Pence Danny B.
Published: March 2009

Nine nematode and two cestode species were recovered from the viscera of 53 mountain lions (Felis concolor) collected from four counties in southwestern Texas. The distribution patterns of the common (> 20% prevalence) helminth species (Taenia omissa, Physaloptera praeputialis, Physaloptera rara, Cylicospirura subaequalis, Ancylostoma tubaeforme, Toxascaris leonina, Metathelazia californica, and Vogeloides felis) were overdispersed and did not change with host age or sex. Abundances of the common helminth species were examined relative to sex and age-groups of the lions. Significant differences were found for abundances of T. omissa, C. subaequalis, and T. leonina between host age-groups, and for T. omissa between host sexes. Only 2 of 29 species were shared among the helminth communities of mountain lions from Texas, Oregon, and Florida, indicating a basic disparity of species common to this host across its geographic range in North America. Taenia omissa is regarded as the single core species across this host's range in North America. New host records are reported for the occurrence of Taenia multiceps, P. rara, Gnathostoma procyonis, A. tubaeforme, and V. felis. Cylicospirura subaequalis is redescribed and compared with Cylicospirura felineus, a species commonly found in Felis lynx and Felis rufus. In addition to previously described bifid versus trifid teeth in C. subaequalis and C. felineus, respectively, differences were noted in the length of spicules in males and the location of the vulva in females.
Predation by American crows reduces overwintering European corn borer populations in southwestern Ontario
Authors: Quiring Dan T. , Timmins Peter R.
Published: March 2009

American crows (Corvus brachyrhynchos) overwintering in Canada's largest known crow roost near Essex, in southwestern Ontario, often forage during the day in surrounding fields of corn, Zea mays, where they perforate cornstalks and eat overwintering larvae of the European corn borer, Ostrinia nubilalis. Survival of overwintering larvae was ca. 50% less in uncaged than in caged plants in a field 26 km from the roost. Although crows perforated stalks in all fields < 25 km from the rookery that were sampled, the number of perforations per cornstalk was negatively correlated with the distance from the roost to the cornfields. In Essex county migratory crows do not arrive until October when most corn has been harvested and they leave in March, before corn is planted. Thus overwintering crows usually do not damage standing corn, increasing their importance as biological control agents.
The Simuliidae (Diptera) of Sri Lanka. Description of a new species of Simulium (Byssodon)
Authors: Davies D. M. , Györkös H.
Published: March 2009

This paper is the fourth in a series treating the Simuliidae of Sri Lanka and describes the larval, pupal, and adult stages of a new species, Simulium (Byssodon)languidum. Taxonomic comparisons are made with other members of the subgenus.
Gill histopathology of juvenile Oncorhynchus kisutch exposed to suspended wood debris
Authors: Magor Brad G.
Published: March 2009

Gill histopathology was examined in three groups of parr of coho salmn (Oncorhynchus kisutch (Walbaum)) maintained for 30 days in suspended wood debris (< 1.00 mm diameter; concentrations of 44–132 mg/L dry weight) collected from an estuarine log sorting site. Gills of fishes were examined by light microscopy following exposure, and histopathologic responses were indexed by percentage of gill filaments affected. Lamellar edema and telangiectasis each had statistically significant (P < 0.05) associations with exposure to the suspended debris, and the severity of these conditions was positively correlated with increased concentrations of debris. The severity of hyperplasia of the primary filament epithelium did not correlate with the concentration of debris. The total number of gill lesions in each fish (sum of hyperplasia, telangiectasis, and edema) was positively correlated with the concentration of debris to which the fish were exposed, and negatively correlated with the percent weight increment (((final weight – initial weight)/initial weight) × 100) of fishes over the experimental period.