bluuebunny/crossref_metadata_2025 huggingface dataset:
Factors influencing the emergence of a northern population of Eastern Ribbon Snakes (Thamnophis sauritus) from artificial hibernacula
Authors: Todd J. , Amiel J. , Wassersug R.
Published: December 2009

We investigated whether Eastern Ribbon Snakes ( Thamnophis sauritus (L., 1766)) use a rise in water level as a cue for emergence from hibernation. We also examined the hypotheses that snakes use temperature gradients or endogenous signals as emergence cues. Twelve artificial hibernacula were used to house 15 Ribbon Snakes. Water level and temperature were regulated. Four Ribbon Snakes emerged from hibernation without any manipulation of water level or temperature. Eight snakes emerged after thermal conditions in their hibernacula changed. Of these, one emerged after the hibernaculum was made warmer on the surface than at depth, four emerged after the room temperature was increased to 9 °C, and three emerged after incandescent lights were shone on the surface of each hibernaculum. Three snakes died during hibernation. Eight snakes chose to hibernate fully submerged in water. Although the sample size is too small to draw conclusions that are statistically significant at α = 0.05, our observations collectively suggest that Ribbon Snakes do not use a rise in water level as a cue to emerge. While water-level rise does not appear to be an emergence cue, hibernation below the water table may lead to increased survivorship by decreased metabolism and elimination of the risk of desiccation.
Winter use of montane forests by porcupines in southwestern Alberta: preferences, density effects, and temporal changes
Authors: Harder Lawrence D.
Published: December 2009

The pattern of winter use of montane forest by porcupines (Erethizon dorsatum) during a 40-year period was examined on two areas in southwestern Alberta. Of the three available coniferous communities, porcupines fed in relatively more trees in pure stands of Douglas fir (Pseudotsuga menziesii) in leeward situations. Douglas fir, limber pine (Pinus flexilis), and hybrid spruce (Picea glauca × P. engelmannii) were used with equivalent frequency when found in the same community. The number of porcupines that used both areas peaked and declined in relation to the average ages of the forests. Trees in low density stands (< 11 trees/100 m2) were fed in during more years than those in denser stands and the use of dense stands was more frequent during years when porcupines were most abundant. Differences between the study areas in repeated feeding in leeward Douglas fir and in the relative proportions of trees used in low and high density stands are attributed to differences in the abundance of porcupines.
Ontogeny of feeding behaviour in hatchery-reared rainbow trout, Salmo gairdneri Richardson
Authors: MacCrimmon Hugh R. , Twongo Timothy K.
Published: December 2009

Development of feeding behaviour in young rainbow trout, Salmo gairdneri, from "swim-up" to day 57 after hatch at 8.5 °C is described relative to food type (live Artemia salina or dry trout ration) and water flow (current or no current). Earliest signs of feeding behaviour appear during the process of swim-up at days 27 to 29, with the movement of the eyes to fixate particles and the beginning of a snap response which intensifies within 2 days. Initially the alevins are nonselective between food and inert targets, but by about day 25 at the test temperature they have become able to discriminate food from nonfood items, and show a marked increase in exogenous feeding activity. The timing, which will differ at different rearing temperatures, coincides approximately with final absorption of the visible yolk sac and follows disappearance of the oesophageal plug by about 10 days. This would seem to be the best time to initiate artificial feeding of hatchery-reared alevins, with the fish showing a preference for ingestion of live food (shrimp nauplii) over dry rations. Despite evident behavioural differences in current and no-current conditions this factor had little effect on timing or ultimate success of first feeding. Failure of some alevins to begin feeding, or feed adequately for survival, is associated with the agonistic behaviour of more aggressive siblings.
Incorporation of L-α-glycerophosphate and acyl-S-CoA into lipids by microsomes of Galleria mellonella
Authors: Barlow J. S. , Thompson S. N. , Martini J.
Published: December 2009

Microsomal preparations from the wax moth, Galleria mellonella, rapidly incorporated L-α-glycerophosphate and the acyl components of palmitoyl and stearoyl coenzyme A into glycerides. The rate of incorporation increased with pH at least up to pH 9.0 but so did enzyme inactivation; therefore a pH of 7.5 at 30 °C was adopted for the study.The incorporation of glycerophosphate did not proceed in the absence of added acyl-S-coenzyme A, but the amount of acylation required for the observed incorporation of glycerophosphate was of a greater order of magnitude than the amount of acyl-S-CoA added to the reaction mixture. It appears that the added acyl-S-CoA was acting as a positive effector for the release of endogenous acyl groups which also served as substrate for acylation.There was also evidence of an amount of endogenous acyl acceptor.The intervention of various amounts of endogenous substrates must confuse attempts to determine transacylase specificity by measuring relative rates of incorporation of exogenous substrates in microsomal preparations from the wax moth.
Avian Haemoproteidae. 13. The haemoproteids of the ducks and geese (Anatidae)
Authors: Williams Norman A. , Bennett Gordon F.
Published: December 2009

The haemoproteids of ducks and geese, family Anatidae, are reviewed. Haemoproteus nettionis (Johnston and Cleland 1909), Coatney 1936 is redescribed. Haemoproteus anatis Haiba 1947 and H. hermani Haiba 1948 are declared synonyms; H. netti Johnston and Cleland 1910, a lapsus calami; and H. vilhenai Travassos Santos Dias 1953, a nomen dubium. The hosts and zoogeographic distribution are summarized.
The blunting of Occam's Razor, or to hell with parsimony
Authors: Dunbar M. J.
Published: December 2009

The Principle of Parsimony, and the apparently related matter of the supposed inadmissibility of untestable hypotheses, are examined in the light of certain examples taken from the history of science. It is urged that many important new ideas would not have occurred had their authors not disregarded both principles entirely. Illustrations are drawn from the manner in which 18th century biologists dealt with the problem of organizing a rapidly growing body of knowledge, from the history of the type concept in zoology, and from the 18th and 19th century controversies on the history of the earth and on biogeography.
Revision of the milliped genus Pleuroloma (Polydesmida: Xystodesmidae)
Authors: Shelley Rowland M.
Published: December 2009

The rhysodesmine xystodesmid milliped genus, Pleuroloma, is unique to the family in its great age, extensive range, high ecological adaptability, and aggregating and migrating behavior. Four species are recognized, two of which, P. pinicola, in coastal North and South Carolina, and P. plana, ranging from piedmont South Carolina to the Gulf Coast of north Florida, are described herein. Of the 12 nominal species in Pleuroloma today, 10 are synonyms of the type species, P. flavipes Rafinesque, which occurs from the eastern Atlantic Coast of the United States to the central Great Plains. The fourth species, P. cala (Chamberlin), occurs in peninsular Florida south of the Suwannee River. Specific differences in Pleuroloma are subtle, and characters useful in making determinations include segmental profile, configuration and degree of pubescence of the sterna, and aspects of the male gonopods. Identifications are most reliable when based on characters in combination. The tendency to aggregate in masses and migrate is important behavior for Pleuroloma, especially P. flavipes, and appears to at least partly explain its great range. The other three species appear to have arisen from two successful penetrations of the southeastern Coastal Plain by P. flavipes during the Pliocene and early Pleistocene. Generically Pleuroloma appears most closely related to Cherokia, but their distinctly different gonopods suggest an early dichotomy.
Croissance, nutrition et reproduction des ouaouarons Rana catesbeiana Shaw (Amphibia Anura) des Laurentides au nord de Montréal
Authors: Bruneau Marcel , Magnin Etienne
Published: December 2009

About 2600 bullfrogs have been captured in three small lakes of the Laurentian region and 1863 among them have been marked and released. The study of the body length growth has been made by three methods (age lecture on pterygoïds, body length histograms, mark–recapture), which give concordant results: 59 mm at 1 year, 81 mm at 2 years, 108 mm at 3 years, 125 mm at 4 years, 137 mm at 5 years, 143 mm at 6 years. The biggest, measuring 162 mm, might have been 8 or 9 years old. The growth rate is the most important between 2 and 3 years, when bullfrogs reach sexual maturity. The body weight is 18 g at 1 year and 40 g at 2 years. At 3 years, the females weigh 101 g and the males 96 g. and at 5 years, the weights are respectively 215 and 194 g. Bullfrogs between 45 and 65 mm eat mostly in sects and the biggest ones eat mostly frogs, tadpoles, fish, and crayfish. The mating calls were heard by the end of May and the spawning occurs between the 20th of June and the 10th of July. The number of eggs (3 826 to 23 540) depends on the size of the individual. Sexual maturity is generally reached at 3 years when bullfrogs measure between 95 and 110 mm. However, some individuals reach sexual maturity at 2 years and some others at 4 years. Our results were compared with those of the literature.
Phenetic variation between some species in the family Phytoseiidae (Acarina: Gamasida)
Authors: Chant D. A. , Hansell R. I. C. , Rowell H. J.
Published: December 2009

Examination of differences in phenetic variation between a number of closely related species of mites of the family Phytoseiidae from four widely different environments in North America, ranging from subarctic to subtropical, was undertaken. Phenetic variation was measured by (1) determining the numbers of taxa recorded in given areas as a measure of the richness of species and genera; (2) determining interspecific morphological diversity using multivariate techniques based on frequency distributions of the taxonomic distances between pairs of species; and (3) by using phenogram analyses to determine the species groups in a given area.The results show a consistent trend in the degree of diversity. The more northerly communities have fewer taxa and these show little phenetic diversity, whereas the more southern communities have more taxa and they show greater phenetic diversity.
Taxonomic variability and criteria for distinguishing metamorphosing larval and juvenile stages of Limanda ferruginea and Hippoglossoides platessoides (Pisces: Pleuronectidae) from the Scotian Shelf
Authors: Guelpen Louis Van
Published: December 2009

Metamorphosing larval and juvenile Limanda ferruginea and Hippoglossoides platessoides from the Scotian Shelf were examined to characterize their taxonomic variability and to establish the reliability of criteria for their identification. The species were found to be separable using several characters. Limanda ferruginea had 11 to 12 precaudal and 41 to 44 total vertebrae, 38 to 41 total myomeres, 51 to 67 anal fin rays and usually metamorphosed at less than 16 mm standard length (SL). Hippoglossoides platessoides had 13 to 14 precaudal and 45 to 48 total vertebrae, 44 to 47 total myomeres, 62 to 76 anal fin rays, and usually metamorphosed at greater than 25 mm SL. Anal fin ray counts and size at metamorphosis were of limited diagnostic value only. In addition, stage IV L. ferruginea usually had dark gut pigment and a visible modified first anal pterygiophore (anal spine), whereas H. platessoides had light gut pigment and no visible anal spine. Dark gut pigment also was diagnostic for juvenile L. ferruginea still possessing this character.
Cytochemical and cytopathological observations in robins (Turdus migratorius) infected with Leucocytozoon dubreuili
Authors: Wong T. C. Steve , Desser Sherwin S.
Published: December 2009

Pathological alterations in hepatocytes and proximal renal tubular cells of the American robin (Turdus migratorius) harbouring schizonts of Leucocytozoon dubreuili consisted primarily of nuclear hypertrophy and the reduction and disruption of cytoplasmic organelles such as endoplasmic reticulum and mitochondria. Other changes included the accumulation of lipofuscin-like bodies and the reduction and disorganization of microvilli.Neither glycogen nor acid or alkaline phosphatase activities were detected in the parasite while these occurred in the parasitized cells and adjacent uninfected cells. The significance of these observations is discussed in relation to studies on other malaria-like parasites.
Reproductive responses of northern orioles to a changing food supply
Authors: Sealy Spencer G.
Published: December 2009

The response of the northern oriole (Icterus galbula) to an outbreak of the forest tent caterpillar (Malacosoma disstria) on the Delta Beach Ridge, Manitoba, was studied. Orioles responded in 1976 to the increased food supply by feeding on all life stages of the insect and by feeding late instar larvae and pupae to their young. The nesting density doubled in 1977, the 2nd year of the 2-year outbreak, but the caterpillar larvae died off before the orioles' chick-rearing period. The 1978 breeding density was back down to the level of 1976. Clutch sizes and body weights did not change despite the increase and eventual reduction in both food abundance and nesting density. Productivity was lower, and hatching failure and nestling death were higher, at the higher nesting density.
The effect of stress on the parasitism of mallard ducklings by Echinuria uncinata (Nematoda: Spirurida)
Authors: Ould P. , Welch H. E.
Published: December 2009

Mallard ducklings given a standardized inoculum of Echinuria uncinata and stressed by crowding or by injecting with cortisone retained greater numbers and larger nematodes at necropsy than infected nontreated controls. Stressed ducklings exhibited signs of the General Adaptation Syndrome; namely, involution of the bursae of Fabricius and thymus glands, hypertrophy of the adrenal glands (except in those birds injected with cortisone), and retardation of growth. Numerous eosinophils normally infiltrate granulomas in response to the nematode infection. Stress inhibited this reaction and may have contributed to the retention of larger nematode burdens. Bursectomy within 2 days of hatching failed to prevent antibody production in mallard ducklings infected with E. uncinata.
The effect of superparasitism by Aphidius smithi (Hymenoptera: Aphidiidae) on the food budget of the pea aphid, Acyrthosiphon pisum (Homoptera: Aphididae)
Authors: Cloutier Conrad , Mackauer Manfred
Published: December 2009

The food budget of diet-fed, second-instar pea aphids when superparasitized by Aphidius smithi was similar to that of single-parasitized aphids. Aphids containing two parasite eggs or embryos consumed less diet and grew at a slower rate than did healthy controls. Feeding, assimilation, and growth increased significantly after the parasite larva(e) had hatched from the trophamnion. During the late stages of parasite larval development, host growth was increased by 133% and honeydew excretion by 146% over control values. During the same period, parasitized aphids converted ingested and digested food, respectively, with 66% and 86% greater efficiency than did controls. These increases were higher than in single-parasitized aphids, perhaps as a result of the larger number of teratocytes present in superparasitized hosts.
Fine structure of the retinal pigment epithelium in the mud minnow (Umbra limi)
Authors: Braekevelt C. R.
Published: December 2009

The fine structure of the retinal pigment epithelial layer and associated regions has been studied by electron microscopy in the adult mud minnow Umbra limi. The pigment epithelium is composed of a single layer of large columnar cells. Each epithelial cell has abundant small mitochondria, much smooth endoplasmic reticulum (often in highly organized arrays), myeloid bodies, phagosomes and pigment granules. Rough endoplasmic reticulum and ribosomes are scarce. The scleral or basal border of the epithelial cells is but minimally infolded whereas the vitreal or apical surface displays numerous elongated processes which surround the inner and outer segments of the photoreceptors. Unattached, presumably phagocytic cells are a constant feature both between the retinal epithelial cells and within Bruch's membrane. Bruch's membrane lacks a central elastic layer and is composed only of three layers. The endothelial wall of the choriocapillaris bordering Bruch's membrane is typically very thin with a few fenestrations. This region of the mud minnow eye is morphologically similar to that described in other teleost species but differs from that described in most mammals.
Stygobromus canadensis, a new subterranean amphipod crustacean (Crangonyctidae) from Canada, with remarks on Wisconsin refugia
Authors: Holsinger John R.
Published: December 2009

Stygobromus canadensis, new species, is described from Castleguard Cave, a large alpine cave located in the Canadian Rockies of Alberta. This is the first subterranean amphipod crustacean reported from Canada and the ninth member of the genus found north of the southern limits of Pleistocene glaciation. Considering the evidence against postglacial dispersal (e.g., endemicity and lack of close affinity with species living farther south), and the presence of a subterranean isopod in the same cave, it is hypothesized that these small aquatic crustaceans survived the Wisconsin glaciers in deep, groundwater refugia under the ice. There is some evidence to suggest that Castleguard Cave, itself, could have served as such a refugium.
On the occurrence of Corynosoma spp. (Acanthocephala) in ringed seals (Pusa hispida) in the Bothnian Bay, Finland
Authors: Helle Eero , Valtonen E. Tellervo
Published: December 2009

The occurrence, location, sex ratio, growth, and development of Corynosoma strumosum and Corynosoma semerme were studied in 29 Baltic ringed seals, Pusa hispida botnica, in October–November 1977. The prevalence of infection was 96.5% for both species, the intensity of infection being 68(1 to 324) per infected seal in C. strumosum and 140 (1 to 1230) in C. semerme. Of the C. strumosum, 99% were in the small intestine; the remainder, together with 97% of the C. semerme, were distributed from the caecum to the rectum. The numbers of C. strumosum increased along the small intestine, and although the sex ratio remained constant, young females were more numerous in the anterior part of the intestine and gravid females more numerous distally. Factors affecting the numbers and proportions of the Corynosoma species are discussed with reference to their development and the progress of infection in the intestine of the ringed seal.
Rare sighting of a right whale (Eubalaena glacialis) in Hawaii
Authors: Rowntree V. , Darling J. , Silber G. , Ferrari M.
Published: December 2009

The presence of a right whale (Eubalaena glacialis) in the Hawaiian waters on March 25, 1979 was documented by photographs which allow individual recognition. The sighting is significant because right whales have not been reported in these waters since 1851 and because the North Pacific population has been estimated to number only 100–200 individuals even though the killing of right whales has been banned since 1937.
Inhibition of flight muscle degeneration by precocene II in the spruce bark beetle, Dendroctonus rufipennis (Kirby) (Coleoptera: Scolytidae)
Authors: Sahota T. S. , Farris S. H.
Published: December 2009

Attack on the new host material by the adult bark beetles initiates reproductive processes and degeneration of flight muscles. Application of precocene II to adult female Dendroctonus rufipennis caused a temporary inhibition of flight muscle degeneration, as revealed by serial sections. This observation extends our knowledge of the effectiveness of precocene II to inhibiting an additional juvenile hormone-dependent process. The results also provide a confirmation of the role of juvenile hormone in the reproduction-associated degeneration of flight muscles.
Description of Gordius attoni sp.n. (Nematomorpha, Gordiidae) from Northern Canada
Authors: Redlich A.
Published: December 2009

Gordius attoni sp.n. (Nematomorpha, Gordiidae) is described using a scanning electron microscope (SEM) and conventional methods. The presence of white spots, the postcloacal crescent on the male caudal end, and the shallow interareolar furrows devoid of pores and bristles as seen in SEM are characteristic of the genus Gordius. The species is characterized by its spindle shape and well defined polygonal areoles, which completely cover the body surface. Spinules, sparsely distributed mainly on the periphery of the areoles, are apparent in SEM. Adults have been found north of 51.5° extending beyond the Arctic circle from the Western Yukon to Chesterfield Inlet of Hudson's Bay.
Aspects of the biology of a gutless species of Solemya (Bivalvia: Protobranchia)
Authors: Reid Robert G. B.
Published: December 2009

A new species of Solemya is found to lack a gut. It has no provision for the collection of food particles. The ciliation of the mantle cavity functions only to cleanse and irrigate the mantle cavity. Assay of glandular tissues and histochemistry reveal no digestive enzymological apparatus. It is inferred that this species obtains nutriment in the form of dissolved organic molecules. The ctenidia provide a large surface area for such a function, and the lamellae are well supplied with blood. This benthic species, which is most common in the vicinity of pulp mills, lives in a U-shaped burrow in soft mud. The burrow is lined with mucus which is secreted by the large pedal gland. The organism is capable of sustained swimming by repeated adduction of the valves, which causes jets of water to issue from the posterior exhalant opening.
Female mating frequency and progeny production in singly and doubly mated house and field crickets
Authors: Sakaluk Scott K. , Cade William H.
Published: December 2009

Many female insects mate more than once although the adaptive significance is often unclear. We studied the frequency of mating, the fate of the spermatophore, and progeny production of individual females as a function of single or double matings in the house cricket, Acheta domesticus, and the field cricket, Gryllus integer. Females of both species may mate repeatedly and often eat the externally attached spermatophore. In A. domesticus, doubly mated females produced significantly more offspring than did single maters, the difference resulting largely from the failure of 12.5% of the single maters to leave progeny. Singly and doubly mated G. integer did not differ regarding nymph production, but 50% of the singly mated females did not reproduce. Remating by female crickets partly functions in offsetting the probability of a failed initial mating. Nymph production increased significantly with the time the spermatophore was attached in singly mated A. domesticus. Spermatophore consumption by the female was not affected by male "guarding" behaviour, and the interval between mating and eating of the spermatophore may often be shorter than the time required for maximum insemination. It is suggested that acquisition of nutrition may be an additional function of female repeated matings.
Sexual dimorphism in two savannah sparrow populations
Authors: Weatherhead Patrick J.
Published: December 2009

Contrary to predictions, a monogamous, mainland population of savannah sparrows was found to be more sexually dimorphic than a polygynous, insular population. When only trophic characters were considered, the insular population fit the prediction of greater sexual dimorphism. Several explanations for increased sexual selection or decreased stabilizing selection in the more dimorphic population are considered. While none of the explanations seem readily applicable from the available evidence, further avenues of investigation are suggested.
Selective predation and the species composition of arctic ponds
Authors: Hebert Paul D. N. , Loaring Jaimie M.
Published: December 2009

The zooplankton species composition of 135 ponds in the Churchill, Manitoba, area was determined. The predaceous copepod Heterocope septentrionalis was present in 99 of these habitats. Several species of calanoid copepod, but only a single morph of Daphnia middendorffiana, coexisted with this predator. Two additional species of Daphnia and a second morph of D. middendorffiana were found in ponds lacking the predator. Experiments showed that these latter species were much more vulnerable to predation than the Daphnia morph that coexisted with Heterocope.
Skein cells in lamprey epidermis
Authors: Lane E. B. , Whitear M.
Published: December 2009

The fine structure of the so-called club cells in lamprey skin shows that they are modified basal layer epidermal cells and therefore are not homologous with the club cells of teleost skin which are unicellular secretory elements. It is proposed that the cell type in lampreys be renamed "skein cell"; this term is indicative of the structure. It is noted that tonofilaments in bundles are united into a meshwork by apparent adhesion between individual filaments, so enhancing their efficiency as a cytoskeleton. The function of the skein cells may be to provide support against distortion in the soft mucigenic epidermis and to protect the germinative cells.
Pineal control of the circadian rhythm of colour change in the killifish (Fundulus heteroclitus)
Authors: Kavaliers Martin , Firth Bruce T. , Ralph Charles L.
Published: December 2009

The killifish, Fundulus heteroclitus, displays a circadian rhythm of colour change (pigment aggregation and dispersion) under constant light and temperature conditions. Pinealectomy eliminates the circadian rhythm of colour change but does not affect physiological colour change and background adaptation. Pineal control of the rhythm of colour change is interpreted as arising from the pineal's involvement in determining circadian organization.
Observations on social behaviour of Atlantic walruses (Odobenus rosmarus (L.)) during terrestrial haul-out
Authors: Salter R. E.
Published: December 2009

Social interactions in walrus herds of mixed sex and age composition were recorded at a haul-out site on the east coast of Bathurst Island, N.W.T., during July–August 1977. Most walruses maintained body contact with at least one other walrus while hauled out on land; herds were usually circular in shape. Adult males, adult females, and immatures all displaced other walruses, and thus entered herds, by jabbing with the tusks. Dominance during agonistic interactions was related to relative tusk length and sex and age of interactants. Behaviour of walruses on land suggested an energetic advantage in mutual body contact, which would be maximized by occupation of interior positions within herds.
Indirect determination of ungulate foot area
Authors: Kelsall John P. , Telfer Edmund S. , Simpson Keith
Published: December 2009

The possibility of using an index calculated from (hoof width × foot length) for an estimation of foot area was investigated using data from moose, wapiti, white-tailed deer, and bison. No significant differences in measurements were found between males and females for any species (p > 0.10). Correlation coefficients between (hoof width × foot length) against measured foot area were high for all species (p < 0.001) and use of the mean of values for one fore foot and one hind foot per animal was as satisfactory as the use of the means of all four feet. The technique can be used in the field to facilitate collection of foot area data for calculation of foot loading of various sex and age classes of ungulates during studies of adaption to snow.
Blackbird damage to ripening field corn in Ontario
Authors: Tyler B. M. J. , Kannenberg L. W.
Published: December 2009

Blackbird damage to ripening field corn is widespread throughout Ontario. On a grain corn basis, the total losses to blackbirds in Ontario were in the order of 39 200 tonnes, which is equivalent to a 0.7% reduction in yield. Percentage reductions in yield for each county and losses in fields with damage in previous years also were determined. The reductions in yield on a provincial and county basis do not reflect the high levels of damage by blackbirds that were sustained in some areas.
Some factors influencing the diet of coexisting, benthic, algal grazing Naididae (Oligochaeta)
Authors: McElhone M. J.
Published: December 2009

A population of Chaetogaster diastrophus which lived in the periphyton on the surface of slates in the shallow, littoral zone of Llyn Llygeirian ingested longer diatom cells than those found in the periphyton and in the gut of the co-occurring naid, Nais pseudobtusa. Chaetogaster diastrophus preferentially ingested diatom cells with large volumes. Seasonal changes in the volume of Cymbella cells in the periphyton influenced whether C. diastrophus ingested greater numbers of either Cymbella or Navicula cells.In the spring of 1976, as the population density of C. diastrophus and N. pseudobtusa increased, the number of diatom cells in the gut of both species decreased and the number of individuals of C. diastrophus with empty guts increased. Chaetogaster diastrophus also ingested a larger number of green unicellular algae cells in response to an increase in density of the corresponding cells in the periphyton. The proportion of detritus and mineral particles in the gut was greater at high densities of C. diastrophusPopulations of C. diastrophus and N. pardalis in Llyn Coron reached peak densities of 5800 m−2 and 10 000 m−2 respectively in the summer of 1975. At low worm population densities in February, C. diastrophus ingested large numbers of Navicula cells, whereas the gut contents of N. pardalis consisted mainly of detritus and diatoms. In June when population densities were higher, the guts of both species were empty.
Further observations on spermiogenesis in the shrimp, Crangon septemspinosa. A mechanism for cytoplasmic reduction
Authors: Arsenault A. L. , Clattenburg R. E. , Odense P. H.
Published: December 2009

In the shrimp (Crangon septemspinosa), spermatid production and storage occur within an extensive syncytium. Reduction of this syncytium results from the reorganization of syncytial materials into elaborate tubuloreticular and lamellar membrane profiles which enclose granular inclusions and mitochondria. In this study, these configurations are referred to as cytoplasmic reduction complexes (CRC) and are present throughout the region of the testes undergoing stage 4 of spermiogenesis. The vacuolated appearance of this segment of the testes is the result of CRC formation. Further reduction of the syncytium and syncytial complexes proceeds according to their relationship with nurse cells. The tubuloreticulum of complexes located near nurse cells is transformed into multilaminate membrane whorls which, subsequently, are phagocytosed by nurse cells. In contrast, the complexes and associated vacuoles not related spatially to nurse cells are further reduced to irregular membrane profiles and paracrystalline lattices. The possible functional significance of these membranous inclusions is discussed.
Studies on the parasites of Pacific herring (Clupea harengus pallasi Valenciennes): a preliminary evaluation of parasites as indicators of geographical origin for spawning herring
Authors: Arthur J. R. , Arai H. P.
Published: December 2009

A preliminary analysis of parasites as biological indicators for spawning stocks of Pacific herring (Clupea harengus pallasi Valenciennes) occurring in coastal waters of British Columbia and adjacent areas of Washington and Alaska was conducted using the techniques of pattern recognition. Separation of stocks based on three parasites which best served as category separators (Thynnascaris adunca (Rudolphi, 1802) larva; Anisakis simplex (Rudolphi, 1809) larva; and bucephalid metacercariae) using multicategory linear discriminant analysis and k-nearest neighbor analysis revealed good separation for only one locality (Port Gamble, Washington). Re-analysis using three subsets of collections based on geographical area (northern, central, and southern) gave substantially improved classification. Although reliable separation of adjacent stocks of spawning herring could not be accomplished, parasites may be useful in characterizing certain stocks of herring or for separation of stocks taken from more divergent geographical areas.
A seasonal study of the parasites of the red-winged blackbird (Agelaius phoeniceus L.) in Manitoba and Arkansas
Authors: Hood Deborah E. , Welch H. E.
Published: December 2009

Examination of 223 red-winged blackbirds revealed seven trematodes of which Zonorchis petiolatum, Leucochloridium macrostomum, Tanaisia (Tamerlania) zarudnyi, and Tanaisia (Tanaisia) fedtschenkoi are new host records; three cestodes of which Anomotaenia sp. is a new host record; and six nematodes of which Dispharynx nasuta, Diplotriaena bargusinica, and Tetrameres sp. are new host records. Only one acanthocephalan, Mediorhynchus grandis, and three blood protozoa were found. Two protozoa, Parahaemoproteus (= Haemoproteus) orizivora and Plasmodium vaughani, are new host records. The 12 ectoparasites included two new host records, Ceratophyllus garei and Sternostoma tracheacolum. Four nonparasitic organisms were recovered, none of which have been reported associated with this bird.The most common parasites were the trematode Plagiorchis noblei, the louse Brüelia sp., and the feather mite Proctophyllodes egglestoni. Each showed a characteristic seasonal pattern. Ectoparasites were most abundant prior to host breeding, and endoparasites during the host breeding period. Ten species of parasites were ubiquitous according to Dogiel's classification, nine were breeding-site or northern parasites, three were probably migratory, and eight were wintering or southern parasites. Eight other species were tentatively classified according to Dogiel's system, and one species could not be classified.The highest intake of animal food by the host coincided with the peak of endoparasitism.
Multilaminar aggregates of sarcoplasmic reticulum in caudal muscle cells of an ascidian larva
Authors: Cavey Michael J.
Published: December 2009

The sarcoplasmic reticulum (SR) in caudal muscle cells of the larva of the polycitorid ascidian Distaplia occidentalis consists of perifibrillar cisternae and coextensive cisternal aggregates. The multilaminar aggregates resemble the interdigitated collars of perifibrillar SR which embrace the sarcomeric H-bands of the cross-striated myofibrils. Cisternae of the coextensive sarcoplasmic reticulum neither envelop the contractile myofilaments nor couple to the sarcolemma. Ultra-structural evidence is suggestive that the coextensive multilaminar aggregates are transient elements of the sarcoplasmic reticulum.
Trypanosomes of small mammals in southern Ontario
Authors: Woo P. T. K. , Grant D. R. , McLean L.
Published: December 2009

Using the haematocrit centrifuge technique, 53 of 619 small mammals from seven areas in southern Ontario were found to be infected with three species of trypanosomes. Trypanosoma microti was found in 10 of 374 (2.7%) Microtus pennsylvanicus examined from two of five locations. Thirty-five of 102 (34%) of Tamias striatus from one area were infected with Trypanosoma tamiasi and over 94% (33 of 35) of the infected animals were juveniles. This would indicate that the trypanosome is primarily a parasite of juveniles. A trypanosome which was tentatively identified as Trypanosoma soricis was found in 8 of 36 (22%) Blarina brevicauda; it was recorded from two of four areas where the shrews were caught. A detailed description of the trypanosome was given because the original description was inadequate. No trypanosome was found in 74 Peromyscus maniculatus, 31 Mus musculus, and 2 Zapus hudsonius examined.
Influence du parasite Sacculina carcini Thompson au début de son développement sur les fractions hémolymphatiques et épidermiques du crabe Carcinus maenas Linné
Authors: Herberts Charmaine , Andrieux Nicole , Frescheville Jacques De
Published: December 2009

The seric and epidermic proteins of parasitized Carcinus maenas were analyzed by immunochemical methods before the exit of the Sacculina. Four groups were observed in healthy crabs. Some proteins showed variations during the moulting cycle. Except for stages close to exuviation, these variations are generally the same in both tissues. Hemolymphatic and epidermic specific proteins were found and the latter appear to be implicated in elaboration processes of the new cuticle. The fraction characteristic of crabs parasitized with external Sacculina was revealed in the hemolymph of the host when the parasite was still internal, and in the corresponding epidermic extracts.
Variations in measurements among white pelican eggs and their use as a hatch date predictor
Authors: O'Malley J. Brian E. , Evans Roger M.
Published: December 2009

Incubated bird eggs tend to lose weight linearly, and it is therefore possible to predict hatch dates from egg measurements taken during incubation. From 30 white pelican eggs measured in the laboratory, we found that egg volume (V) was estimated by V = 0.500 LB2 (L = length, B = maximum width). Specific gravity (SG) was then obtained as W/V (W = weight in air). A regression line of SG against days of incubation based on values for naturally incubated eggs was used to predict hatch dates for additional samples of 10 eggs from each of 55 subcolonies on five islands in Manitoba in 1978. Mean SG of 21 freshly laid eggs was 1.1009 ± 0.0033 g∙cm−3. The regression line for naturally incubated eggs was SG = 1.1081 g∙cm−3 – (0.0042 g∙cm−3∙egg−1∙day−1∙days). Actual hatch dates of 17 subcolonies were strongly correlated with predicted dates (r = 0.95). Hatch synchrony was independent of subcolony size. Mean error for subcolony predictions was 0.4 days, but was 2.8 days for individual eggs.Only width and consequently volume differed significantly among the colonies. Within subcolonies, variability in linear dimensions was mainly due to interclutch differences.Observations of vocalizations and pipping of eggs during visits are also useful for predicting hatch dates.
Positioning changes of mayfly nymphs due to behavioral regulation of oxygen consumption
Authors: Wiley Michael J. , Kohler Steven L.
Published: December 2009

Experimental investigations in a small artificial stream showed that the positioning of mayfly nymphs (Ephemeroptera) on stones varied with dissolved oxygen concentration (DO). At low DO levels nymphs moved to current-exposed positions, presumably to increase the renewal rate of oxygen at respiratory exchange surfaces. The expected magnitude of positioning changes under field conditions was determined and suggests that behavioral regulation of oxygen consumption may commonly influence both habitat distribution and diel behavioral patterns. The implications of these results to drift studies are also discussed.
A multiple mark and recapture estimate applied to polar bears
Authors: DeMaster Douglas P. , Kingsley Michael C. S. , Stirling Ian
Published: December 2009

The mark–recapture technique described in this paper estimates polar bear (Ursus maritimus) populations for all sample periods except the first sample period, incorporates an open population model, and is supported by ecological data from ringed seals and polar bears. The estimation procedure requires that survival rates are either known or estimated independently as part of the research program. Reasonably precise estimates will be produced if 10 to 20% of the population can be marked and sample sizes of 150 bears can be handled at any given sample period.
The raptorial siphonal apparatus of the carnivorous septibranch Cardiomya planetica Dall (Mollusca:Bivalvia), with notes on feeding and digestion
Authors: Reid Robert G. B. , Crosby Suzin Porteous
Published: December 2009

Cardiomya planetica Dall is a carnivorous septibranch bivalve. The food-capturing organ is the inhalant siphon, which can be rapidly extended by a surge of blood. The increase in blood pressure is brought about by the contraction of the septum. The sensory mechanism is constituted by seven siphonal tentacles with mechanoreceptors at their tips. The mechanoreceptors are composed of clumps of clubbed cilia in apical pits lined with microvilli. The activity of the septum, inhalant siphon, and pallial valve is coordinated with the sensory input through a large siphonal ganglion. Food consists largely of ostracods and digestion appears to be periodic.
Clinostomum complanatum or Clinostomum marginatum? (Trematoda: Clinostomatidae). A problem of priority and synonymy
Authors: Dowsett J. A. , Lubinsky G.
Published: December 2009

The description of Clinostomum complanatum (Rudolphi) is dated by various authors as 1809, 1814, 1819, and 1899, that of Clinostomum marginatum (Rudolphi) as 1809 and 1819. Though some of these datings are based on misprints, of special importance is the fact that Rudolphi has described his Distoma complanatum as a new species twice, in 1814 and again in 1819. His D. marginatum was described in 1819. The authors agree with Baer that Clinostomum marginatum is a junior synonym of Clinostomum complanatum, but point out that this is a priority of years, and not of pages.
Food habits and caching behavior of urban grey squirrels
Authors: Thompson D. C. , Thompson P. S.
Published: December 2009

Grey squirrels are basically conservative in their choice of diet, selecting items closely resembling those used in habitats containing native vegetation. There is a strong seasonality in the use of various foods. The period of late spring appears to be the most critical for food supply; however, food did not appear to be a proximate limiting factor for this population. Food-caching and recovery behaviors show a strong seasonality. Food caching starts with the maturation of husked nuts and terminates with the onset of winter. Food recovery begins with cessation of food caching and terminates with the appearance of spring foods. Large numbers of nuts are cached and a large proportion (84.6%) of these are recovered. Cached food contributes significantly to the winter diet. The caching of food by an individual squirrel is beneficial to the general population and possibly to tree reproduction.
Uptake and clearance of petroleum hydrocarbons by the glaucous-winged gull (Laras glaucescens) and the mallard duck (Anas platyrhynchos)
Authors: McEwan E. H. , Whitehead P. M.
Published: December 2009

Glaucous-winged gull (Larus glaucescens) and mallard duck (Anas platyrhynchos), fed tritiated crude oils, showed a rapid uptake of labelled hydrocarbons into tissues and plasma. About 45% of the ingested oil was excreted. After 24 h, tritiated hydrocarbon concentrations in the plasma and tissues declined to background level except for bunker-C-fed birds and stressed, oil-fed gulls.
Two new species of the genus Strandesia Vavra, 1895 (Ostracoda–Crustacea) from Kerala, southern India
Authors: Victor Reginald , Paul M. A. , Fernando C. H.
Published: December 2009

Two new species of the genus Strandesia Vavra, 1895 are described from southern India and compared with related species. In Strandesia hartmanni n. sp. both males and females were found and are described. Strandesia trichurensis n. sp. is described only from females. Both species are readily diagnosed by the valve characteristics and spine configuration.
Formation des reliefs externes de l'œuf de Micropteryx calthella L. (Lepidoptera: Micropterigidae)
Authors: Chauvin J. T. , Chauvin G.
Published: December 2009

The external sculpturing of the egg of Micropteryx calthella L. appears after the egg has been laid. Immediately after oviposition, the external surface of the egg is smooth, being covered with a viscous material. During the hour following oviposition, this material is locally raised up, forming club-like structures that remain perpendicular to the egg surface. These club-like structures result from exudation of a substance produced by the oocyte. The external layers of the egg and their ornamentations do not constitute a true chorion because they are not secreted by the follicle cells.
Respiratory patterns and antipredator responses in the central mudminnow, Umbra limi, a continuous, facultative, air-breathing fish
Authors: Gee John H.
Published: December 2009

The central mudminnow. Umbra limi, is a continuous facultative air breather whose respiration is primarily aquatic in normoxic water and primarily aerial in hypoxic water. Under these conditions the frequency of respiration (air breaths; branchial breaths) by the primary mode increases with temperature. In hypoxic water, fish exposed to simulated predator disturbance breathed air in synchrony where a breath by one fish was immediately followed by breaths from one or more other fish. Undisturbed fish breathed air at random times with respect to other individuals. The level of dissolved O2 at which fish switch from primarily aquatic to primarily aerial respiration during progressive hypoxia was positively related to temperature. When fish were exposed to progressive hypoxia in groups (n = 10) the transition to air breathing in terms of dissolved O2 concentration was unaffected by acclimation to hypoxia and by simulated predator disturbance. When held alone (isolated) and disturbed, fish became very active and switched to aerial respiration at a higher level of dissolved O2 than either fish held alone and undisturbed or fish held in a group of 10. During progressive hypoxia without access to air, mudminnows maintained both a high level or activity and frequency of branchial breathing down to 15 Torr (1 Torr = 133.322 Pa). Acclimation to hypoxia did not greatly increase resistance to hypoxia in fish without access to air.
Karyotypes of side-necked turtles (Testudines: Pleurodira)
Authors: Bull James J. , Legler John M.
Published: December 2009

Karyotypes are presented for 13 of the 14 genera of side-necked turtles (suborder Pleurodira, families Pelomedusidae and Chelidae). Pelomedusids have low diploid numbers and few microchromosomes (2n = 26–36); the five largest chromosomes are homologous in the three genera. Chelids have high diploid numbers and many microchromosomes (2n = 50–64) and are similar in this respect to cryptodires (2n = 50–66). The pelomedusid karyotype is regarded as derived, probably from an ancestral condition like that seen in chelids. Gross karyotypic differences are slight or nil within genera and among closely related pleurodiran genera. Triploidy probably occurs in Platemys platycephala (family Chelidae) which has 96 chromosomes. No sex chromosome heteromorphism was observed.
Spatial interrelationships of bivalves and nonbivalve benthos in a small reservoir in New Brunswick, Canada
Authors: Sephton T. W. , Paterson C. G. , Fernando C. H.
Published: December 2009

Quantitative sampling of macrobenthos in Morice Lake, New Brunswick, showed that the numerical abundance of chironomid larvae and other nonbivalve detritivore species was significantly increased in the vicinity of bivalve molluscs. Experimentally, increased bivalve numbers in tanks led to an aggregated distribution of nonbivalve benthos. Numerical abundance near bivalves was increased, probably due to a behavioral response of the detritivores to an increased food source.