bluuebunny/crossref_metadata_2025 huggingface dataset:
New marine hosts for Parorchis acanthus, Cryptocotyle lingua, Maritrema megametrios, and Maritrema gratiosum, trematodes of birds from British Columbia, Canada
Authors: Ching Hilda Lei
Published: August 2008

New molluscan, crustacean, and avian hosts were found for four species of digenetic trematodes in Vancouver, British Columbia, from 1973 to 1977. The rediae and cercariae of Parorchis acanthus (Nicoll) were discovered in Nucella lamellosa (Gmelin). Adults were recovered after 19 days from experimental feedings of the metacercariae to a newly hatched domestic chick. The cercariae of Cryptocotyle lingua (Creplin) from the snail Littorina scutulata Gould were used to infect young fish, Leptocottus armatus Girard, Oligocottus maculosus Girard, and Platichthys stellatus (Pallas). These fish, infected with the metacercariae, were fed to newly hatched gulls, Larus glaucescens Naumann, and mature worms were found in the anterior half of the intestine after 14 and 21 days. The metacercariae of Maritrema megametrios Deblock and Rausch, found in Orchestia traskiana Stimpson and Gnorimosphaeroma oregonense (Dana), became ovigerous in Locke's solution at 40 °C at 48 h. Natural infections were found in Larus Philadelphia (Ord). The metacercariae of Maritrema gratiosum Nicoll, found in Balanus glandula Darwin, also became ovigerous in vitro. Adults were found with two other microphallid species in the intestine of one Bucephala islandica (Gmelin).
Hormonal control of chloride transport across locust rectum
Authors: Spring J. , Hanrahan J. , Phillips J.
Published: August 2008

Rates of ion transport across locust recta were monitored in vitro by following fluxes of 22Na+ and 36Cl−, short-circuit current (Isc), and open-circuit electropotential difference (PD) across this epithelium for several hours. Corpora cardiaca (CC) homogenates, cAMP, theophylline, and hemolymph of recently fed locusts all stimulate electrogenic transport of Cl− across locust rectum, as indicated by a two- to three-fold increase in 36Cl− net flux, Isc, and PD. Cyclic AMP caused a Cl-dependent increase in PD across the lumen-facing but not the hemocoel-facing plasma membrane of the epithelial cells. We propose that a blood-borne factor, possibly from the CC, causes an elevation in cAMP levels in rectal tissue and that this second messenger acts by increasing Cl− entry into the cell from the rectal lumen. Additional fluid absorption accompanies the resulting increase in transport of NaCl, leading to an increase in the hemolymph volume of previously dehydrated locusts.
The morphology of the attachment and probable feeding site of the nematode Trichuris muris (Schrank, 1788) Hall, 1916
Authors: Lee T. D. G. , Wright K. A.
Published: August 2008

The 'tunnel' within which the nematode Trichuris muris is contained was examined by light, scanning, and transmission electron microscopy. The amount of worm covered by the tunnel varied with age. Young larval worms were completely embedded in the host's intestinal mucosa whereas older larvae and adults had part, if not all, of the posterior region protruding into the lumen. All worms were found to have heads embedded in the tissue and in no cases were whole worms found free in the lumen.The 'tunnel' was shown to be a syncytial protoplasmic mass with recognizable cellular elements such as nuclei, lipid droplets, mitrochondria, and mucous droplets anteriorly whereas more distal to the head these elements became increasingly scarce and degenerated. The syncytium is bordered apically, laterally, and basally by cell membrane. The basal lamina can be identified beneath the basal membrane of the syncytium indicating that syncytium formation occurs in the epithelial sheet only and does not extend into the lamina propria. Evidence suggests that the nematode initially induces a syncytium about its head, feeds on the syncytial cytoplasm, and then moves on to initiate extension of the syncytium. The result of this movement is a 'tunnel' snaking across the caecum and colon.
The transverse tubular (T) system of rat cardiac muscle fibers as demonstrated by tannic acid mordanting
Authors: Leeson T. S.
Published: August 2008

T-tubules and subsarcolemmal caveolae in rat cardiac muscle fibres have been studied using the tannic acid mordanting technique. While T-tubules form an extensive and relatively regular meshwork with triads at Z-lines in ventricular fibers, in atrial fibers the tubules are often absent, or very sparse and with an irregular distribution. There appears to be a relation to fiber size, the meshwork being more extensive in fibers of larger diameter, and an inverse relationship to the number of couplings found between sarcoplasmic reticulum and plasmalemma. In larger atrial fibers, while the T-tubule meshwork was extensive, it did not show the regularity of distribution found in ventricular fibers. T-tubule continuity with the extracellular space was visualized clearly, both directly and indirectly via subsarcolemmal caveolae.
Seasonal variation in ash and calorific content of Idotea baltica (Pallas) (Crustacea:Isopoda)
Authors: Strong Kim W. , Daborn Graham R.
Published: August 2008

Ash, calorific, and carbonate contents were determined monthly for Idotea baltica from Cape Blomidon, N.S. Although changes in calories per gram dry weight (1 cal = 4.1868 J) were correlated with reproductive effort, variations in the ash-free calorific value were difficult to interpret because of considerable changes in ash content. In mature animals, variation in percent ash was apparently associated with gametogenesis but ash variation in immature animals could not be explained. The importance of adequate carbonate corrections in bomb calorimetry is emphasized.
Influence of weathered crude oil on liver enzyme metabolism of testosterone in gulls
Authors: McEwan E. H. , Whitehead P. M.
Published: August 2008

Experiments were conducted with glaucous-winged gulls, Larus glaucescens, to evaluate the effect of petroleum hydrocarbons on testosterone metabolism by liver enzymes, using an assay which measured the metabolism of [4-14C]testosterone. Diets containing 100 and 500 mg of weathered crude oil per day had no significant effect on testosterone metabolism.
Reactions of some great plains fishes to progressive hypoxia
Authors: Gee John H. , Tallman Ross F. , Smart Heather J.
Published: August 2008

Twenty-six species from eight families of great plains fishes were examined in progressive hypoxia to see if the use of dissolved O2 in the surface film was common when subsurface waters became hypoxic. Only the Salmonidae (three species) and Stizostedion vitreum did not move to the surface and breathe the surface film. The concentration of dissolved O2 at which this reaction occurred was found to be strongly temperature dependent in Pimephales promelas. During progressive hypoxia all fishes exhibited a similar sequence of behavioural events. Particular points in this sequence were used to estimate incipient limiting and lethal levels of dissolved O2.
Biosystematics of the genus Euxoa (Lepidoptera: Noctuidae). XI. Mating discrimination between three closely related species of the declarata group
Authors: Byers J. R. , Hinks C. F.
Published: August 2008

The sibling species Euxoa declarata, Euxoa campestris, and Euxoa rockburnei will, in the laboratory, produce vigorous and fertile hybrid progeny from all interspecific combinations. Although interspecific matings occur readily under no-choice conditions there is a significant reduction, compared with intraspecific levels, in both the proportion of females mated and the occurrence of multiple mating. Tests for mating discrimination using the male-choice method show that ethological premating isolation between the three species is strong. In nature the ethological barriers in combination with other factors such as slight differences in seasonal flight period and habitat preference probably ensure complete reproductive isolation between the three species.
Crenosoma spp. (Nematoda: Metastrongyloidea) from black bears, Ursus americanus, of central Ontario
Authors: Addison Edward M.
Published: August 2008

Crenosoma vulpis (Dujardin 1844) Railliet 1915, Crenosoma petrowi Morozov 1939, and Crenosoma potos Buckley 1930 are redescribed from the lungs of black bear, Ursus americanus, of central Ontario. A telamon is described in each species for the first time. The relationship between C. petrowi and Crenosoma schulzi Gagarin 1958 is discussed.
Howling at two Minnesota wolf pack summer homesites
Authors: Harrington Fred H. , Mech L. David
Published: August 2008

Howling sessions were monitored at two Minnesota wolf pack homesites for 2255 h between 29 April and 3 August 1973. All sessions recorded occurred from dusk through early morning, with an evening peak for one pack. Within a night, multiple sessions were grouped temporally, most occurring within an hour of one another. Howling rates for both packs increased throughout the homesite season, with the larger pack howling twice as frequently. The role of howling in both intrapack and interpack contexts was considered. Much of the howling seemed to be involved in the coordination of pack activities. Further, the low frequency and clumped temporal distribution of sessions suggest that howling plays a secondary role in interpack contexts to other modes such as scent marking during the homesite season, but may increase in relative importance once homesites are abandoned and pack travel becomes nomadic.
Overripe eggs and postovulatory corpora lutea in the threespine stickleback, Gasterosteus aculeatus L., form trachurus
Authors: Lam T. J. , Nagahama Y. , Chan K. , Hoar W. S.
Published: August 2008

Threespine sticklebacks (Gasterosteus aculeatus L., form trachurus) with overripe, ovulated eggs have a hard 'berried' abdomen, easily distinguishable from the soft, smoothly distended abdomen of fish with normal ovulated eggs. The 'berried' fish weigh less and have a smaller GSI than 'nonberried' ovulated fish but the percentage water of their whole ovaries is the same. In contrast with 'nonberried' fish, 'berried' fish do not respond to male courtship. Overripe eggs are typical of those in other species with aggregation of cytoplasm and oil droplets at the animal pole. However, in contrast with normal ovulated eggs, they are larger, more transparent, and have a higher percentage water content although surrounded by much less fluid within the ovarian cavity. Overripe eggs do not appear to form a perivitelline space in fresh water. In 'berried' fish both the postovulatory corpora lutea (follicles) and ovarian epithelium (lining of the ovarian cavity) show histological signs of regression, in contrast with the histologically active condition of these tissues in fish with normal ovulated eggs. It is suggested that postovulatory corpora lutea play a role in maintenance of ovulated eggs in the ovarian cavity through secretion of steroid(s) which in turn stimulate the ovarian epithelium to secrete the bathing fluid of the eggs.
Field studies of growth, reproduction, and mortality in the burrowing wolf spider Geolycosa domifex (Hancock)
Authors: McQueen Donald J.
Published: August 2008

A population of burrowing wolf spiders (Geolycosa domifex (Hancock)) was studied near Toronto, Canada, from 1974 to 1977. By following the life history of individuals in marked burrows, it was found that females produce one brood when they are 3 years old. Juveniles leave their mothers during July and August, after which they search for suitable burrow sites, establish burrows, and overwinter. During this period approximately 85% of the juveniles die and the average burrow diameter increases from 1 mm in August to 2–3 mm in October. In the second summer approximately 9% of the original cohort die and the average burrow diameter is 7 mm when the remaining individuals overwinter. In the third summer 4–5% of the original cohort die and burrow diameters average 13 mm when the remaining individuals overwinter. In the fourth summer the remaining 1 or 2% of the original cohort reproduce and more than 99% of these are killed by acrocerid flies (Pterodontia flavipes Grey) and pompilid wasps (Anoplius relativus (Fox)). Because < 0.008% of the original cohort survive to reproduce in their 4th year of life, three separate cohorts occupy the same habitat with little (< 1%) gene flow between them.
Descriptions of the larvae of four species of Procladius from Great Slave Lake (Chironomidae:Diptera)
Authors: Moore J. W. , Moore I. A.
Published: August 2008

Descriptions of larvae of Procladius denticulatus, Procladius culiciformis, Procladius freemani, and Procladius bellus collected from Yellowknife Bay (lat., 62°25′; long., 114°20′) are given. Procladius denticulatus was separated from the other species by its large size, a character which always proved distinctive. Procladius culiciformis and P. freemani were separated from one another through several measurements including those of the basal antennal segment and the basal palpal segment. Almost all characters of the head were useful in distinguishing the much smaller P. bellus from the other species.
Relationship between nest sites of common terns and vegetation on the Eastern Headland, Toronto Outer Harbour
Authors: Blokpoel H. , Catling P. M. , Haymes G. T.
Published: August 2008

The distribution of common tern (Sterna hirundo) nests relative to vegetation and objects (rocks and sticks) was studied on the Eastern Headland of the Toronto Outer Harbour in 1977. The vegetative cover in one study plot ranged from 0–10% to 91–100%, with a mean of 16%. In that plot the vegetative cover near nests ranged from 0–10% to 81–90%, with a mean of 44%. In the second study plot where plants were widely scattered, the great majority of the nests were situated next to plants or objects. Possible advantages and disadvantages of this behaviour are briefly discussed.
Longevity of Trypanosoma murmanensis in the marine leech, Johanssonia sp.
Authors: Khan R. A.
Published: August 2008

A study was carried out to ascertain the longevity of trypanosome infections in leeches, Johanssonia sp. The latter were fed initially on Atlantic cod (Gadus morhua) harbouring trypanosomes and then refed at intervals on uninfected fish following digestion of each blood meal. The results indicate that infections in some leeches can persist through five to six feedings, i.e. 542–749 days after the initial blood meal, provided the fasting periods do not exceed about 5 months. Survival is attributed to residual stages in the proboscis.
Bivariate normal song territories in ovenbirds
Authors: Zach Reto , Falls J. Bruce
Published: August 2008

Song perches of each of nine male ovenbirds were bivariate normal in spatial distribution. Thus, song territories had no fixed boundaries. Song territories were elliptical rather than circular in shape, presumably due to environmental heterogeneity. Eighty-five percent equal frequency ellipses, which contain about 85% of the song perches of a given bird, corresponded approximately in area to the more conventional 95% song territory. Similarly, 90% equal frequency ellipses had about the same area as total song territories. However, all area estimates yielded closely correlated results. Distances between song centers and nest locations were highly variable. The distribution of nests was similar to that of song perches.
Ciliation and function of the food-collecting and waste-rejecting organs of lophophorates
Authors: Gilmour T. H. J.
Published: August 2008

Experiments with mixtures of colloidal graphite, stained Sephadex particles, and algae; observations by stroboscopic interference contrast optics; and scanning and transmission electron microscopy suggest that phoronids, brachiopods, and bryozoans can simultaneously reject waste material by an impingement mechanism and accept edible particles by a filtration mechanism without the ciliary reversals suggested in previous models of suspension feeding in lophophorates. Specialized laterofrontal cilia, which may detect heavy inedible particles, are found on the tentacles of all three phyla of lophophorates. In phoronids and bryozoans edible material is carried towards the esophagus by components of water currents created by the lateral cilia of the tentacles of the lophophore while inedible particles are rejected by the frontal cilia of the tentacles. The passage of food material to the mouths of brachiopods is assisted by frontal cilia located in grooves on alternate tentacles while the frontal cilia of ungrooved tentacles reject inedible material. The epistomes of lophophorates are also involved in the simultaneous acceptance of food and rejection of solid waste material and allow the escape of excess water travelling towards the mouth with food particles. This finding of a functional significance for the epistome suggests that lophophorates deserve reassessment as possible ancestors of chordates.
Freshwater Oligochaeta in Canada
Authors: Brinkhurst R. O.
Published: August 2008

Seventy-nine of the total 136 American species of aquatic oligochaetes found in fresh water have been reported from Canada. Specaria fraseri and Ilyodrilus mastix are species new to science. Other species are recorded for the first time in Canada or in British Columbia. The Canadian species are listed by province.
The internal morphology of sensilla on the abdominal gills of Thaumatoperla alpina (Plecoptera: Eustheniidae; subfamily: Thaumatoperlinae)
Authors: Kapoor N. N. , Zachariah K.
Published: August 2008

Light and electron microscopic studies of abdominal gills of the plecopteran nymph Thaumatoperla alpina Tillyard showed remarkable bulbous structures on the surface, each protected by fingerlike, cuticular processes. Some structural details of these gill organs are described.
Using sizes of unovulated follicles to estimate the laying rate of the brown-headed cowbird
Authors: Scott D. M.
Published: August 2008

Most female brown-headed cowbirds (Molothrus ater) collected at the peak of the breeding season have three large ovarian follicles. The largest, about 8 mm in diameter, is designated as an a follicle. A bird with an a follicle would ovulate the next day, but one without an a follicle would not. Thus, one can identify birds that will terminate or begin a clutch on a particular day. The proportion of such birds is used to estimate the clutch size and the interval (number of days without laying) between clutches.The clutch size is the reciprocal of the proportion of laying birds (those with an oviducal egg) that lack an a follicle. The interval is the reciprocal of the proportion of nonlaying birds (those in breeding condition but without an oviducal egg) that have an a follicle. The average daily laying rate equals the clutch size divided by the sum of the clutch size and the interval. This rate, based on a heterogeneous sample, is about 0.66 eggs.I present a technique for testing the hypothesis that there is no differential vulnerability to collecting between laying and nonlaying birds.
Comments on Calverley and Boag's (1977) hypothesis on displaced ducks and an evolutionary alternative
Authors: Nudds Thomas D.
Published: August 2008

Calverley and Boag's (1977. Can. J. Zool. 55: 1242–1251) analysis of reproductive potential in parkland- and arctic-nesting mallards and pintails does not support their conclusion that parkland-displaced birds breed in the arctic with reduced reproductive output. The different clutch sizes in the two areas may result from selection for a smaller clutch at higher latitudes because of the greater energy expense of travel; however, individual fitness may be similar in parkland- and arctic-nesting populations if the advantage of a large clutch at lower latitudes is offset by higher levels of competition and predation.
The use of Seralute® and Tetralute® for measurement of plasma triiodothyronine and thyroxine in salmonid fishes
Authors: Milne R. S. , Leatherland J. F.
Published: August 2008

There was found to be a marked effect of sample volume on the measured and calculated (i.e. corrected for volume size) levels of thyroxine (T4) and triiodothyronine (T3) in trout plasma when using the Ames Tetralute® and Seralute® assay kits. Freezing and thawing caused a significant (p < 0.001) increase in plasma T4 levels and a significant decrease (p < 0.01) in plasma T3 levels. Further freezing and thawing and plasma storage at – 30 °C for 1 month had no significant effect on measured hormone levels.
A survey of the ecology and composition of submerged aquatic snail–plant communities
Authors: Pip Eva
Published: August 2008

A total of 305 sites were surveyed in southern Manitoba and adjacent areas for the presence of aquatic gastropods and submerged macrophytes with respect to eight water chemistry parameters. Many of the 41 gastropod species found within the study area showed significant preferences for certain parameters. Chi-square tests revealed 68 significant positive and 4 negative interspecific gastropod associations, many of which could not be correlated with net similarities or dissimilarities in significant preferences for the environmental parameters examined. The most common species did not form the most highly significant associations. Members of possible species pairs were compared with respect to their similarities in significant positive associations with other gastropods. The major groupings that emerged reflected characteristics of the habitats within which the species occurred most frequently.Chi-square tests were also conducted for possible snail–plant pairs, resulting in 161 significant positive and 31 negative associations. Many of these could not be correlated with environmental preferences. Members of possible gastropod pairs were compared with respect to their similarities in significant associations with macrophytes. The major grouping that emerged consisted of gastropods which also formed the most highly significant positive associations with macrophytes.
Urogonimus macrostomus (Rudolphi, 1803) (Digenea): its taxonomy and morphology as revealed by light and scanning electron microscopy
Authors: Bakke Tor A.
Published: August 2008

The surface microtopography of adult Urogonimus macrostomus (Rudolphi) recorded in Sturnus vulgaris L. from southwest Norway is revealed by scanning electron microscopy and compared with Norwegian specimens of Leucochloridium variae McIntosh. The morphometric information from U. macrostomus in Norwegian starlings is compared with similar data on other U. macrostomus identified samples (U. macrostomus (sensu Witenberg) (= U. witenbergiella Kagan), U. macrostomus (sensu Schmidt), U. macrostomus (sensu Rutkowska)), and the present knowledge of morphological total range of the species is given. This result is further compared with other Urogonimus-related species, and the following species are regarded to be synonymous with U. macrostomus: U. cordis (Yamaguti), U. dryobatae (McIntosh), U. icteri (McIntosh), U. mniotiltae (McIntosh), and U. tetrastae (Oliger). The following are regarded as species inquirendae: U. mesostomus (Rudolphi), Urogonimus sp. (Lutz), Urogonimus sp. (Witenberg) (= L. witenbergi Skrjabin), U. seiuri (McIntosh), and U. vireonis (McIntosh). Four species are regarded from the present knowledge of their morphological variability, and that of U. macrostomus, as separate species within genus Urogonimus Monticelli: U. macrostomus (type species), U. caryocatactis (Zeder) (= D. caudale Rudolphi and D. caudale sensu Mueller), U. certhiae (McIntosh), and U. indicum (Singh).
The morphology and lactate dehydrogenase patterns of the sound muscle of the haddock (Melanogrammus aeglefinnus)
Authors: Odense Paul H. , Morrison Carol M. , Rombough Peter
Published: August 2008

The proportion of sarcoplasm to myofibrils in the muscle fibers of the sound muscle of haddock is lowest in immature females and highest in mature males. Some mature females have a higher ratio than immature females, and immature males usually have a higher ratio than females. The myofibrils form convoluted patterns in the muscle fibers of mature males, resulting in a large area of contact between the myofibrils and the numerous mitochondria in the sarcoplasm. Bundles of parallel axons give rise to groups of circumscribed nerve endings on the sarcolemma. This arrangement may be associated with the fast twitch function of the sound muscle.The lactate dehydrogenase activity is predominately of the B type in immature fish, but that of the mature fish shows more A and C type activity. This change is correlated with an increase in muscle size with maturity and alteration from an aerobic to a more anaerobic metabolism. Some sexual dimorphism is present.
Limb regeneration in Amphiuma tridactylum (Amphibia, Urodela)
Authors: Scadding Steven R.
Published: August 2008

This paper reports a histological study of the response of Amphiuma to simple limb amputation. The results of simple limb amputation in this species are variable. Some limbs undergo wound healing only, others regress, resulting in complete loss of the limb except for a residual rudiment embedded in the body wall, and still others produce heteromorphic limb regenerates of size comparable with the amputated limb. Heteromorphic limb regeneration when it occurs in Amphiuma is a very slow process compared with other urodeles. After 7.5 months (longest observed specimens in this study), the process was still not complete.
Hypocalcemic action of eel Stannius corpuscle in rats
Authors: Leung E. , Fenwick James C.
Published: August 2008

The intravenous injection of crude saline extracts of Stannius corpuscles from American eels, Anguilla rostrata, elicited a dose-dependent hypocalcemic response in young male rats with Kenny's (Endocrinology, 89: 1005–1013, 1971) bioassay for calcitonin. Extracts of Stannius corpuscles from the brown bullhead, Ictalurus nebulosus, and extracts of eel muscle and eel kidney had no calcium lowering activity.
Caractéristiques ultrastructurales du cortex somatique et buccal du cilié Colpidium campylum (Oligohymenophora, Tetrahymenina) quant à la position systématique de Turaniella
Authors: Lynn Denis H. , Didier Pierre
Published: August 2008

Colpidium campylum shows ultrastructural similarities in its somatic and buccal cortex to other tetrahymenine ciliates. The somatic kinetids are composed of single kinetosomes, radial transverse and postciliary fibres, a short kinetodesmal fibril, and a small supplementary tractus. The stichodyad and polykinetids are typically tetrahymenine.The assignment of the genus Turaniella to the hymenostome suborder Peniculina has recently been questioned. Turaniella shares morphological and stomatogenic characteristics with the hymenostome suborder Tetrahymenina and specifically with the genus Colpidium. The present study demonstrates ultrastructural similarities between these two genera. It is concluded tentatively that the genus Turaniella be placed in the hymenostome suborder Tetrahymenina, especially if the ultrastructure of the stichodyad is discovered to be tetrahymenine.
Development of longitudinal mucosal folds in the intestine of the anadromous sea lamprey, Petromyzon marinus L., during metamorphosis
Authors: Youson John H. , Connelly Kerry L.
Published: August 2008

During metamorphosis of the anadromous sea lamprey, Petromyzon marinus L., the larval intestine develops numerous longitudinal folds. The initiation of this event is marked by a decrease in diameter of the intestine and in the height of the typhlosole and is followed by an increase in numbers of cells undergoing DNA synthesis, first in the anterior intestine and later in the posterior intestine. Foci of proliferating cells along the epithelial walls of both regions result in the development of longitudinal folds which seem to elongate by further proliferation of the epithelial cells at their bases and by evagination of the underlying connective tissue and muscle. Slight variations in the mode of development of folds in the anterior and posterior intestines likely reflect the different functions of these regions in the adult. Metamorphosis of the lamprey provides an opportunity to study intestinal development in a vertebrate during a late stage of ontogeny.
Caractérisation écologique des milieux humides à larves de moustiques (Culicides) de la région subarctique continentale d'Opinaca (territoire de la Baie de James, Québec)
Authors: Mailhot Yves , Maire Alain
Published: August 2008

Twenty mosquito species were collected in a low-subarctic area located between Eastmain River and Petit-Opinaca Lake, Quebec (52°15′ N, 76°38′ W). Qualitative and quantitative analyses of larval mosquito populations identified 20 ecological units that served as larval breeding sites. The data revealed typical larval associations such as Aedes canadensis – Aedes decticus, characteristic of the open bog series, Aedes communis – Aedes pionips of alder–willow groves (Salix planifolia – Alnus rugosa), Aedes intrudens and Aedes cinereus in flooded riparian areas. The ecology of species with summer larvae is also described: Culex restuans, Culex territans, Culiseta alaskaensis, and Culiseta impatiens.
Daily cycles in serum cortisol levels in the goldfish: effects of photoperiod, temperature, and sexual condition
Authors: Peter R. E. , Hontela A. , Cook A. F. , Paulencu C. R.
Published: August 2008

The daily fluctuations in serum cortisol levels, measured by radioimmunoassay, in goldfish were examined. Male and female goldfish with regressed or immature gonads ('regressed' fish), female goldfish undergoing ovarian recrudescence ('maturing' females), and female goldfish with oocytes that had completed vitellogenesis ('mature' females) were exposed to environmental conditions of either 16 h light 8 h dark (16 L:8 D) and 12 °C, 16 L:8 D, 21 °C, 8 L:16 D, 21 °C, or 8 L:16 D, 12 °C. Blood samples were taken from individual fish in the groups and a 24-h cycle in serum cortisol levels, based on 4-h intervals, constructed. Significant daily fluctuations were found under most environmental conditions at each sexual condition, most commonly with one daily peak, but in some cases with 2 or 3 daily peaks. The 'mature' females tended to have the lowest levels of serum cortisol and fluctuations of the smallest magnitude. The 'maturing' females tended to have the highest levels and fluctuations of the greatest magnitude. The 'regressed' fish had levels similar to the 'maturing' females under warm conditions and had low levels with relatively little fluctuation under cold conditions.
Helminths in the great horned owl, Bubo virginianus, and snowy owl, Nyctea scandiaca, of Alberta
Authors: Ramalingam S. , Samuel W. M.
Published: August 2008

A total of 69 great horned owls (Bubo virginianus) and 16 snowy owls (Nyctea scandiaca) collected in Alberta from 1971 to 1974 were examined for helminths. Fourteen and four species of helminths were found in the host species, respectively. Echinoparyphium recurvatum, Echinostoma revolutum, Notocotylus attenuatus, Hysteromorpha sp., Capillaria falconis, and Cyrnea americanum are new records for great horned owls; Cyrnea longispicula is new for snowy owls. Many of the species recovered were probably acquired on the nonoverlapping summer ranges of each host.
Is benthic activity of stream invertebrates related to behavioural drift?
Authors: Corkum Lynda D.
Published: August 2008

Although benthic activity and drift have been found to occur within the same light phase, the correlation between these variables is poor. It is hypothesized that the ratio of mean activity among stream invertebrates in the dark to that in the light is inversely related to seasonally increased photoperiods.
An emendation of the genus Teratorhabditis (Osche, 1952) Dougherty, 1953 and description of Teratorhabditis stiannula n.sp. (Rhabditidae:Nematoda)
Authors: Anderson R. V.
Published: August 2008

A new bisexual species of Teratorhabditis, Teratorhabditis stiannula n.sp., from Canada is described and illustrated. The female is monodelphic, the cuticle composed externally of minute plaques, metarhabdions vary in form and have a verrucose or crenulate margin, and the tail is conoid-attenuate. Main characters of the male are a large, protuberant precloacal lip containing a copulatory cement gland duct, a peloderan bursa with u 2 () 4 + 1 + 3 arrangement of genital papillae, of which 7 open al the margin, and linear spicules, 40–48 μm long, which are fused distally along a fifth of their length. A duct-like canal opening on the anterior surface of the basal esophageal bulb is reported for the first lime. The generic diagnosis of Teratorhabditis is emended to include new characters that clarify relation ships of six recognized species and Teratorhabditis rovinjensis Sudhaus. 1974 is proposed as a new combination for Rhabditis (Teratorhabditis) rovinjensis Sudhaus, 1974.
Studies on the hymenolepid cestodes of waterfowl from New Brunswick, Canada
Authors: McLaughlin J. Daniel , Burt Michael D. B.
Published: August 2008

Twenty-one species of hymenolepid cestodes found in 12 species of waterfowl collected in New Brunswick, Canada, are identified and described in the following order: Aploparaksis furcigera (Nitzsch in Rudolphi, 1819); Diorchis bulbodes Mayhew, 1929; D. microcirrosa Mayhew, 1929; Cloacotaenia megalops (Nitzsch, 1829); Dicranotaenia coronula (Dujardin, 1845); Drepanidotaenia lanceolata (Bloch, 1782); Echinocotyle rosseteri Blanchard, 1891; Hymenolepis abortiva (von Linstow, 1904); H. collaris (Batsch, 1786); H. hopkinsi Schiller, 1951; H. paracompressa Czaplinski, 1956; H. parvula Kowalewski, 1904; H. rauschi Schiller, 1950; H. spinocirrosa Podesta and Holmes, 1970; H. tuvensis (Spasskaya and Spasskii, 1961); Retinometra macracanthos (von Linstow, 1877); Sobolevicanthus filumferens (Brock, 1942); S. gracilis (Zeder, 1803); Wardium creplini (Krabbe, 1869); Fimbriaria fasciolaris (Pallas, 1781); Diploposthe laevis (Bloch, 1782). The descriptions are supported by text figures and tables. A summary of the previous descriptions of each species is given.Dicranotaenia mergi (Yamaguti, 1940), Dicranotaenia anceps (Linton, 1927), Dicranotaenia sacciperium (Mayhew, 1925), and Dicranotaenia kutassi Matevosian, 1945, previously considered synonyms of Dicranotaenia coronula, are considered valid species. Hymenolepis compressa of Beverley-Burton (1964) nec (Linton, 1892) and Hymenolepis compressa of Bezubik (1956) nec (Linton, 1892) are considered synonyms of Hymenolepis paracompressa. Kowalewskius yoshidai Yamaguti, 1956 is a synonym of Hymenolepis parvula Kowalewski, 1904. Wardium aequabilis of Spasskaya 1961 nec (Rud., 1810) is considered a synonym of Wardium creplini and Diploposthe mathevossianae Ryšavý (1961) is considered a synonym of Diploposthe laevis.
Remarks on display functions of the snout of the grey seal, Halichoerus grypus (Fab.), with comparative notes
Authors: Miller E. H. , Boness D. J.
Published: August 2008

Adult males of the grey seal, Halichoerus grypus (Fab.) (Phocidae), display the large snout conspicuously in threats. The male's snout has probably evolved through sexual selection as a visual display organ, as in some other extant phocids: the hooded seal, Cystophora cristata (Nilsson) and the two species of elephant seals, Mirounga (Gray). This may also be true of the extinct desmatophocid Allodesmus Kellogg. Cephalic display organs in the form of long tusks have also evolved twice in the Odobenidae (walruses). Comparable display structures do not occur in the Otariidae (fur seals and sea lions). However, the massive neck of adult male otariids is important in undirected static-optical threat displays, especially at long range, and in some kinds of short-range threats. Also, adult otariids show sexual dimorphism in facial appearance, which varies interspecifically.Pinniped species in which large mature males have prominent, constant-growing cephalic display structures show fluid spacing among rutting males, and much agonistic communication at the water surface and on land or ice. This correlation may reflect selective pressures on males to affirm social status repeatedly, through displays which communicate their age (hence strength and experience), and their resource-accruing abilities.
Uptake of sodium and chloride by freshwater mussels
Authors: Dietz Thomas H.
Published: August 2008

Ion transport rates were measured in six species representing the four families of freshwater bivalves in North America. Sodium and chloride transport systems function independently in all of the species. The unionid steady-state influx of Na and Cl was about 1 μ equiv/g dry tissue per hour. Margaritifera hembeli Na influx was about 5 μ equiv/g dry tissue per hour and they were in a positive Na balance. Chloride influx by M. hembeli was similar to the unionids. The Sphaeriacea transport Na and Cl at significantly higher rates than Unionacea. Corbicula manilensis Na and Cl influx was about 9 μ equiv/g dry tissue per hour. Sphaerium transversum Cl influx was similar to C. manilensis; however, Na influx was twice as high. The higher transport rates of the Sphaeriacea are similar to brackish-water animals. Sodium, Ca, and Cl are major ions in the blood of all species. Bicarbonate is a major anion (19–12 mM/L) in all species except C. manilensis (4 mM/L).
Aspects ultrastructuraux des mécanismes de la rudimentation rétinienne chez l'Anoptichthys adulte, forme cavernicole aveugle de l'Astyanax mexicanus (Characidae, Pisces)
Authors: Durand Jacques P.
Published: August 2008

Degeneration of the retina and retinal pigment epithelium operates by necrosis, phagocytosis, and also by vacuolization, the processes causing the retinal layers to shorten. The residual cells are transferred in a necrotic center that probably represents the persistance of a transitory event in normal eye development.In this case, the lack of vascularization cannot be the cause of rudimentation. The progressive degeneration of the outer segment of the photoreceptor can eventually be explained by an inhibition of the proteic synthesis or by another cytological disturbance. When the cell degenerates the renewal process slows and stops, the shedding and the phagocytosis of the pigment epithelium continues, and the outer segment gradually disappears. The comparison of the eyes of adult animals reared in darkness or light indicates only that the light effects are not long detectable as aging and degeneration progresses.The cytological characteristics of the main occular rudimentation mechanisms indicate that retinal rudimentation of blind cave Astyanax (or Anoptichthys) obeys previously described rules of occular degeneration as defined for other cave vertebrates.
Browsing and grazing by cladoceran filter feeders
Authors: Horton P. A. , Rowan M. , Webster K. E. , Peters R. H.
Published: August 2008

If different Cladocera have similar minimum requirements for suspended food, the capacity to utilize sedimented material would shift the competitive advantage to facultative bottom foragers in ponds, shallow lakes, and laboratory cultures with fluctuating levels of planktonic food. In laboratory cultures, Daphnia pulex browses or forages on the bottom of its culture vessel when suspended food concentration is too low to support reproduction or high rates or ingestion. Suspension feeding or grazing is the primary feeding mechanism only above the incipient limiting food concentration when ingestion rate is maximal, although a proportion of the animal's time is spent swimming (and therefore suspension feeding) at all food concentrations. Limited evidence suggests that different species of Cladocera have similar food levels at which reproduction is zero, yet not all are facultative browsers. Daphnia magna exhibits a similar behaviour to D. pulex but D. galeata and Ceriodaphnia quadrangula do not. These results show that the switch from grazing to browsing may be a determinant of competitive success among Cladocera.
The distribution of fat in larval, metamorphosing, and young adult anadromous sea lampreys, Petromyzon marinus L.
Authors: Youson J. H. , Lee J. , Potter I. C.
Published: August 2008

A histological study using Sudan Black B has been made of the distribution and relative density of fat in the various regions of the body of larval (ammocoete), metamorphosing, and young adult stages of the anadromous sea lamprey, Petromyzon marinus L., caught in New Brunswick. The principal sites of fat storage are located in and around the fat column, lateral to the notochord, between the notochord and either the cardinal or caudal veins, surrounding the body cavity, beneath the skin, and in the myosepta and the nephric fold. Dense but more restricted sites are present lateral to the nerve cord, between the bundles of muscle fibres, and surrounding the pharyngeal cavity. Fat is most abundant in large ammocoetes captured in May and June and in those displaying the very earliest stages of metamorphosis in July. The amount of fat declines during metamorphosis, but is still abundant in November just prior to the time when the sea lamprey can commence parasitic feeding. Fat was undetectable, however, in nearly every site in those animals in which feeding was delayed until the following May. This study shows that sea lampreys accumulate large amounts of fat at the end of larval life by employing a wide variety of different storage sites. It also demonstrates that the fat in virtually all of these sites may be exhausted when the nontrophic period following the initiation of metamorphosis is of a very long duration.
Field observations on the reproductive behaviour of the cunner, Tautogolabrus adspersus (Walbaum), in Newfoundland
Authors: Pottle Robert A. , Green John M.
Published: August 2008

Courtship behaviour and pair spawning of the cunner, Tautogolabrus adspersus (Walbaum) were observed in Conception Bay, Newfoundland, during midsummer of 1977 and 1978. Courtship displays were recorded between 0600 and 2100 hours and spawns between 1300 and 2100 hours. The frequency of both courtship behaviour and spawns varied with the time of day. Spawning, but not courtship, is correlated with the tidal cycle. Spawns occur most often during the mid flood to high-tide phase of the eye le. Fish of both sexes are capable of multiple spawns per day. Both territorial and non territorial males acquire nuptial colouration between emergence from overwintering torpor and the start of the spawning season. Nonterritorial males are vigorously excluded from territories by the resident males and appear to contribute little to the reproductive effort of the population. Courtship and spawning occur only within male's territories. Group spawning was not observed. Sexual dichromatism and reproductive behaviour in the cunner are discussed with reference to other labrid species.
Comparative studies of Giardia spp. in small mammals in southern Ontario. III. Duration and cyst production in natural and experimental infections
Authors: Grant David R. , Woo Patrick T. K.
Published: August 2008

Experimental infections of Giardia-free laboratory rats and mice with their respective parasites (Giardia simoni in rats and Giardia muris in mice) demonstrated that the infections persisted for the duration of the study period (4 months). Similarly, naturally infected meadow voles (with Giardia microti) and deer mice (with Giardia peromysci) retained their infections during their captivity (6 months). Rigorous precautions were taken to prevent contamination and coprophagy. The relative numbers of cysts in consecutive faecal samples varied considerably and there were periods when the numbers of cysts were extremely low. The excretions of cysts were cyclical and there were periods of 7 and 8 days between peaks in laboratory rats and mice infected with G. simoni and G. muris respectively.
The blood leukocytes of Bufo alvarius: a light, phase-contrast, and histochemical study
Authors: Cannon M. Samuel , Cannon A. M.
Published: August 2008

Blood leukocytes of Bufo alvarius were studied by light and phase-contrast microscopy and histochemical techniques for the localization of glycogen and several hydrolytic enzymes, i.e., acid and alkaline phosphatases, nonspecific esterase, beta-glucuronidase, aryl-sulfatase, and myeloperoxidase (peroxidase). Neutrophils were the only leukocytes to demonstrate alkaline phosphatase activity, while beta-glucuronidase and aryl-sulfatase were not observed in any leukocytes. Periodic acid – Schiff (PAS) positive granules and granules containing hydrolytic enzymes occurred in varying amounts in leukocytes. In eosinophils, most glycogen was associated with smaller granules, while the larger refractile granules were PAS negative. Small lymphocytes were myeloperoxidase (peroxidase) negative. The present study agrees with previous investigations in mammals which indicate that specific granules in granulocytes may be PAS positive as well as contain one or more hydrolytic enzymes. In small lymphocytes of B. alvarius, PAS positive and acid phosphatase positive granules correspond to neutral red granules seen in supravital films. Furthermore, the appearance and histochemical reactivity of acid phosphatase granules in mature neutrophils, metamyelocytes, and late myelocytes correspond closely with the appearance and number of specific neutrophilic granules seen in Wright–Giemsa preparations and with PAS positive granules.
Detection of substrate vibrations by salamanders: eighth cranial nerve activity
Authors: Ross R. J. , Smith J. J. B.
Published: August 2008

Eighth cranial nerve activity was recorded from supine and prostrate juvenile and adult Notophthalmus viridescens while vibrations were applied to either the dorsal or ventral surfaces. Increases in activity were obtained over a vibration frequency range from 20 to 650 Hz. Responses were produced over a maximum amplitude range from 0.018 to 30 μm peak-to-peak displacement, but the range limits varied at different frequencies. Eighth cranial nerve activity increased with vibration amplitude above an apparent threshold. The threshold varied with stimulus frequency, being lowest between 150 and 350 Hz. Responses to a steady-slate vibration were partially adapting or nonadapting. At higher amplitudes of vibration multiunit responses tended to be dominated by nonadapting activity. Some, but not all, activity was synchronized with the stimulus wave form, either at the same or double the frequency of the stimulus. The important features of the responses to vibration were due to afferent rather than efferent activity. The results show that the salamander ear is capable of transmitting considerable information about substrate vibrations to the central nervous system.
Growth dynamics in natural populations of Sphaeriidae clams (Sphaerium, Musculium, Pisidium)
Authors: Mackie G. L.
Published: August 2008

Analyses of life history samples of five species of sphaeriid clams collected at least monthly for 1 year from 10 different habitats show that growth of all larval stages stops when parents cease to grow. During the logarithmic phase of growth larvae grow slower than parents in temporary and permanent pond populations of Musculium lacustre, Pisidium casertanum, and Pisidium variabile, as fast as parents in a river population of Sphaerium fabale, and as fast or faster than parents in five populations of Musculium securis. Species with slow larval growth rates are usually semelparous and univoltine but can be iteroparous by precocious birth of larvae and multivoltine by accelerated growth of semelparous individuals. Species with rapid larval growth rates are usually iteroparous because larvae grow faster than parents and (or) there is precocious birth of larvae. There is greater mortality of larvae during early stages than during later stages of larval development. The greatest numbers of larvae per parent usually occur in early winter and (or) late spring; winter and summer 'kills' often result in small litter sizes.