bluuebunny/crossref_metadata_2025 huggingface dataset:
Observations on the ventilation cycle of the harbour porpoise Phocoena phocoena (L.) in coastal waters of the Bay of Fundy
Authors: Watson A. P. , Gaskin D. E.
Published: January 2010

The ventilation cycle of the harbour porpoise was studied through analysis of 700 dive sequences recorded in the Fish Harbour region of southern New Brunswick. Two basic ventilation patterns were recognized; one (pattern A) was exhibited by travelling animals and was characterized by short submergence periods (24.4 ± 1.6 s (SE)), the second (pattern B) by animals apparently feeding, and was characterized by restricted ventilation periods, between which the submergence periods averaged 1.44 ± 0.07 min. Submergences during pattern B behaviour ranged from 35 s to 4 min 4 s. One animal observed over an extended period took considerably more breaths (6.6 ± 0.4) after dives of above-average duration than after dives of less than average duration (3.6 ± 0.2). We found that the number of breaths per minute in each behaviour pattern were very similar (2.4 and 2.3, respectively), supporting statements by other workers that the energetic demands of diving in marine mammals may not be greater than that required for surface activity. In behaviour patterns A and B, respectively, harbour porpoises in this area were at the surface for only 7.2 and 7.5% of any observation period. The maximum to mean dive-time ratio in P. phocoena was noted as being almost identical to that observed in Orcinus orca; this may be a generalized relationship in all odontocetes.
An ultrastructural comparison of soft and hardened spermatophores from the crayfish Pacifastacus leniusculus Dana
Authors: Dudenhausen E. E. , Talbot P.
Published: January 2010

The spermatophore of the crayfish Pacifastacus leniusculus consists of two main parts: a sperm mass composed of sperm embedded in a dense fibrillar matrix and an acellular wall which surrounds the sperm mass and is formed from secretions produced in the vas deferens. Following extrusion from the male, the spermatophore wall, which is initially soft and sticky, undergoes a hardening process. In this study, the structure of the spermatophore walls of unextruded (soft) and hardened spermatophores were compared using light and electron microscopy. The wall of the unextruded spermatophore is composed of three concentric layers: a thin primary spermatophore layer which directly surrounds the sperm mass; a thick middle layer composed primarily of electron-dense, spherical granules; and a thick outer layer formed from a dense globular secretion. The primary spermatophore layer and outer globular layer are positive for carbohydrate with the periodic acid – Schiff method. Following extrusion and hardening, the walls of spermatophores showed several structural changes. These are (i) division of the middle granular layer into a compact inner region and a highly reticulated outer region; (ii) the loss of the outer globular layer; and (iii) the formation of a thickened ridge along one side of the spermatophore wall. The thickened ridge is fibrillar in structure and is believed to be derived from a structural modification of the outer globular layer. No structural modifications in the primary spermatophore layer were observed. We interpret these observations to indicate that the outer globular layer functions in attachment of the spermatophore to the female and the middle layer is involved in spermatophore hardening and sperm protection during storage.
Renesting in adult and yearling blue grouse
Authors: Sopuck Lennart G. , Zwickel Fred C.
Published: January 2010

Eight of 31 radio-tagged female blue grouse (Dendragapus obscurus) that had first nests terminated before hatch produced second clutches. Significantly more adult than yearling hens renested. All yearling hens that produced a second clutch had first nests terminated during laying or early incubation; but most yearlings did not renest. Adult females renested independently of the stage of incubation when nests were terminated. Average size of second clutches of adults are likely larger than those of yearlings and average size of second clutches of all females are likely smaller than those of first clutches. Most prenesting home ranges used during second nesting attempts were in the same general areas and of the same sizes as those used during initial nesting attempts.
Osteological and ocular anomalies in juvenile big brown bats (Eptesicus fuscus)
Authors: Kunz Thomas H. , Chase Julia
Published: January 2010

Osteological and ocular anomalies are reported from four wild-taken, juvenile (16–32 days old) big brown bats (Eptesicus fuscus) from eastern Massachusetts. Anomalies include polydactyly, deformed sacral and caudal vertebrae, underdeveloped radius and ulna, closed eyelids, unpigmented choroid layer, undifferentiated retina, and an underdeveloped lens. Bats with osteological anomalies showed no apparent ocular deformities and those with ocular deformities showed no evidence of bone anomalies. The combined incidence of anomalies represents 3.3% of the young bats born in this maternity colony in 1978.
The structure and hydration dynamics of trichopteran (Insecta) egg masses
Authors: Berté Stephen B. , Pritchard Gordon
Published: January 2010

Scanning electron microscopy techniques were used to compare the structure of the gelatinous egg masses of five species of caddisflies (Insecta: Trichoptera) and an aquatic snail (Gastropoda: Pulmonata). The structure of the matrix was different in each species and varied in complexity from amorphous to uniformly channeled to channeled with a cortex of larger channels than those found in the medullar area. In the limnephilid caddisfly Nemotaulius hostilis (Hagen) hydration–dehydration altered channel size and density of the matrix in a reversible manner, which is explained in terms of the molecular structure and hydration dynamics of gels. A direct relationship between the presence of a coarsely channeled cortex and desiccation resistance was observed. This study indicated that egg mass structure may provide information of taxonomic, phylogenetic, and ecological significance in the Trichoptera.
Redescription of Cucullanus elongatus Smedley, 1933 (Nematoda: Seuratoidea) from the lingcod Ophiodon elongatus Girard, 1854 from the Pacific coast of Canada
Authors: Berland Bjørn
Published: January 2010

Cucullanus elongatus Smedley, 1933, from the intestine of the lingcod Ophiodon elongatus Girard, 1854, caught off Vancouver Island, B.C., Canada, is redescribed and illustrated. The fine morphology of the head and pseudobuccal capsule is described and depicted in some detail, with functional considerations.
Comparative morphology of Gyrodactylus groenlandicus Levinsen, 1881, G. nainum Hanek and Threlfall, 1970, G. pleuronecti Cone, 1981, and G. adspersi sp. n. (Monogenea) from northwest Atlantic fishes
Authors: Cone D. K. , Wiles M.
Published: January 2010

Gyrodactylus groenlandicus from Myoxocephalus scorpius, G. nainum from Myoxocephalus quadricornis, G. pleuronecti from Pseudopleuronectes americanus, and Gyrodactylus adspersi sp. n. from Tautogolabrus adspersus, collected from the northwest Atlantic Ocean, are compared morphologically. Gyrodactylus groenlandicus has long hamuli (63–66 μm) and long marginal hooklets (35–36 μm). Gyrodactylus nainum and G. pleuronecti have intermediate-sized hamuli (56–58 and 55–59 μm, respectively); the marginal hooklets of G. nainum are 35–36 μm in length while those of G. pleuronecti are 28–29 μm. Gyrodactylus adspersi sp. n. has short hamuli (38–43 μm) and short marginal hooklets (24–27 μm). The four species differ subtly, but distinctly, in morphology of the marginal hooklet sickle. The study concludes with discussion of possible evolutionary relationships between the four species.
Sibling aggression in nestling ospreys in Nova Scotia
Authors: Jamieson Ian G. , Seymour Norman R. , Bancroft Robert P. , Sullivan Ron
Published: January 2010

Eighteen instances of sibling aggression were seen in six of eight osprey nests under intensive observation. Aggression primarily occurred during the last 3 weeks of the nestling period. Most encounters lasted 5–20 s and parents did not interfere. Eleven of 18 instances of aggression occurred during feeding and sometimes nestlings did not receive food because of interference by siblings. The same amount of fish were brought to nests with two as with three young but hostility occurred only in nests with three young. There was no hostility between the one incumbent chick and a foster chick which was placed in a nest. However, hostility did occur between a foster chick and two incumbents in another nest. Aggression may be more common in nests with larger broods where competition for food could be greater.
Evolutionary radiation in polychaete ovaries and vitellogenic mechanisms: their possible role in life history patterns
Authors: Eckelbarger Kevin J.
Published: January 2010

Two types of oogenesis have evolved in polychaetes: one (extraovarian) in which germ cells are ovulated into the coelomic cavity where they undergo vitellogenesis, and another (intraovarian) in which the germ cells are released from the ovary after or near the completion of vitellogenesis. There are many mechanisms of yolk synthesis and significant variation as to the sources of yolk precursors, their route of entry into developing oocytes, and the oocytic organelles involved in yolk synthesis. The evolution of the coelom and its role in nutrient storage and transfer, as well as the origin of germ cells, are intimately related to the evolution of vitellogenic mechanisms in polychaetes. Comparative studies have revealed a correlation between mechanisms of yolk synthesis and the breeding patterns of polychaetes with the rate and type of vitellogenesis being related to the frequency of breeding. Vitellogenic mechanisms in polychaetes are compared with those of other metazoans in an effort to better understand the evolution of this important process and to identify primitive and derived features of yolk synthesis within the Polychaeta.
The effect of respiratory mode and oxygen concentration on the risk of aerial predation in fishes
Authors: Kramer Donald L. , Manley David , Bourgeois Ray
Published: January 2010

Six bimodal and six water-breathing species of fish were exposed to predation by a green heron (Butorides striatus) in a laboratory experiment to examine the hypothesis that aerial predation selects against the evolution and use of air breathing. Tests were performed at 1.6 and 0.5 mg O2∙L−1 ([Formula: see text] and 9 Torr, respectively; 1 Torr = 133.322 Pa). Most water breathers avoided the surface at 1.6 mg∙L−1 but not at 0.5 mg∙L−1, where they performed aquatic surface respiration. Most bimodal species breathed air at both oxygen concentrations. The risk of capture increased with proximity to the surface. The prey species responded to the predator by increasing mean depth, decreasing the rate of air breathing or aquatic surface respiration, and avoiding the vicinity of the predator when surfacing. Despite these and other antipredator characteristics, all species were vulnerable to capture in the test situation. Overall, the survivorship of water-breathing fishes was significantly higher than that of bimodal species at 1.6 mg∙L−1 and similar to that of bimodal species at 0.5 mg∙L−1. Aerial predation pressure should favor water breathing over air breathing except at oxygen concentrations lower than 0.5 mg∙L−1.
Ultrastructure d'une glande sternale tubuleuse des mâles de Speonomus hydrophilus (Coleoptera, Bathysciinae)
Authors: Cazals Monique , Juberthie-Jupeau Lysiane
Published: January 2010

The tubular sternal glands of S. hydrophilus are tegumentary glands present only in the males and were until today unknown. They lie in the segments 6–8 and open between the 8th and 9th segment. They consist of a ramified epithelium made up of prismatic cells. The gland opening is composed of a porous plate connected to an internal cuticular complex. The porous plate itself consists of an epicuticular layer perforated by tiny pores, a mesocuticular layer with large pore canals reaching the pores, then a part with cuticular filaments. All around the porous plate, the mesocuticle makes up a cylindrical excrescence directed towards the secretory part, the free edge of which is prolonged by long mesocuticular plates called pseudomembranes; they are thin, parallel, and penetrate each of the gland cavities. Thus the tubular sternal glands appear as a ramified epidermal invagination; only the internal part of the cuticle is accompanying this invagination. The pseudomembranes might play the same role as an end apparatus for the secretory products. These glands may produce a sex pheromone which would allow the female to recognize the male.
Similar nucleus numbers among copepods
Authors: McLaren I. A. , Marcogliese D. J.
Published: January 2010

First nauplius stages (NI) of Pseudocalanus sp., Eurytemora herdmani, Calanus finmarchicus, and C. hyperboreas all have on average about 2000 nuclei. First copepodid stages (CI) of Acartia hudsonica, Pseudocalanus sp., E. herdmani, C. finmarchicus and C. glacialis have about 9600–13 000 nuclei. Body volumes among the same species differ ca. 8-fold in NI and 30-fold in CI. Larger species have much larger nuclei, but close correspondence of body size to nucleus size (amount of DNA) may only occur among closely related species. Nucleocytoplasmic ratios must also vary seasonally within species.
Testing the generic structure revealed by numerical methods in the family Phytoseiidae (Acarina: Mesostigmata)
Authors: Hansell R. I. C. , Gates M. A. , Eveleigh E. S. , Yarranton A. , Chant D. A.
Published: January 2010

There has been extreme divergence of opinion about the generic structure of the family Phytoseiidae. An objective evaluation of this structure, obtained by numerical taxonomy, was tested by the method of creating a neutral model based on species distributed at random in morphological space and sampled from hyperellipsoids having the same boundaries as the postulated genera. The numerical taxonomic solution is substantially supported by this test. Minor subjective taxonomic revisions of the numerical solution showed improvement of fit, indicating that the taxonomist's judgment remains an important part of the process of classification.
Trichopsyllopus oregonensis g.n., sp. n. (Acari, Acaridae), a new hypopus phoretic on a flea Trichopsylloides oregonensis, parasitic on the rodent Aplodontia rufa in the United States
Authors: Fain A. , Baker G. T.
Published: January 2010

Trichopsyllopus oregonensis g.n., sp. n. (Acari, Acaridae), a new hypopus phoretic on a flea Trichopsylloides oregonensis, parasitic on the primitive rodent Aplodontia rufa from the United States is described.
Nematocysts of stages in the life cycle of Stomolophus meleagris, with keys to scyphistomae and ephyrae of some western Atlantic Scyphozoa
Authors: Calder Dale R.
Published: January 2010

Nematocysts were examined in the planula, scyphistoma, ephyra, and medusa stages of the rhizostome scyphozoan Stomolophus meleagris from South Carolina, U.S.A. Two categories of nematocysts, holotrichous isorhizas and heterotrichous microbasic euryteles, were present in all four stages. Holotrichous isorhizas were of one morphological type (a-isorhizas) in the planula, ephyra, and medusa, and two types (a-isorhizas and α-isorhizas) in the scyphistoma. Several distinct varieties of heterotrichous microbasic euryteles were observed. Those of the planula were all small (5.7–7.0 × 3.9–4.8 μm), those of the scyphistoma and ephyra were either small (5.7–8.4 × 3.8–5.9 μm) or medium (7.5–9.8 × 6.0–7.6 μm), and those of the medusa were small (6.4–10.1 × 4.5–6.5 μm), medium–large (10.5–12.6 × 7.3–9.0 μm), or large (13.2–17.8 × 8.0–10.3 μm). The cnidom is compared with that of other scyphozoans, and identification keys to the scyphistomae and ephyrae of temperate western Atlantic semaeostome and rhizostome Scyphozoa are presented.
Habitat utilization by brook char (Salvelinus fontinalis) and rainbow trout (Salmo gairdneri) in Newfoundland streams
Authors: Cunjak Richard A. , Green John M.
Published: January 2010

Recent range extension of introduced salmonid species in insular Newfoundland has caused concern over their effects on native fish species. The present study was designed to investigate the stream habitat utilization of the exotic rainbow trout and the native brook char. Results of underwater field observations in a stream where the two species coexisted showed that brook char occupied positions with significantly lower water velocities and more cover than similar-sized rainbow trout. Brook char showed similar microhabitat preferences in a nearby stream where they were allopatric. The extent of species segregation was largely affected by local stream morphology, specifically the availability of preferred habitat. The implications for future introductions of exotic salmonids to native brook char streams are discussed.
The polytene chromosomes of species of Eusimulium (Hellichiella) (Diptera: Simuliidae)
Authors: Rothfels Klaus , Golini Victor I.
Published: January 2010

In an extension of Dunbar's work (R. W. Dunbar. 1967. Can. J. Zool. 45: 377–396) eight species in Hellichiella were examined cytologically on the basis of the banding pattern of salivary gland polytene chromosomes. Hellichiella congareenarum, H. innocens, and H. anatinum were restudied. It was concluded that the sibling distinction between congareenarum and congareenarum 'b' stipulated by Dunbar is not tenable and that anatinum differs from standard by only one inversion (IIS-1). Species studied for the first time are H. rendalense (from Norway), H. latipes (syn. subexcisum from Britain) and H. saccai (from Italy), and the undescribed "Opinaca" sp. (from James Bay, Quebec), and "sp. near dogieli" (from Norway). Diagnostic features are given for each taxon in terms of (i) fixed inversions from standard (congareenarum), (ii) specific sex differential segments, and (iii) inversion polymorphisms. These features are utilized in the construction of an unrooted cytophylogeny.
The extent of long-term temperature compensation for jumping distance in the frog, Rana pipiens, and the toad, Bufo americanus
Authors: Renaud J. M. , Stevens E. D.
Published: January 2010

The effects of acclimation to either 5 or 25 °C were studied on the longest jumping distances of Rana pipiens and Bufo americanus to estimate their capacity for long-term compensation. Animals were tested randomly at 5, 10, 15, 20, and 25 °C. Both Rana and Bufo jumped further at higher temperatures. For both species, acclimation temperature modified the effect of test temperature. At test temperatures of 20 and 25 °C, frogs acclimated to 25 °C jumped further than those acclimated to 5 °C. There was no evidence for thermal compensation in toads, but half of those acclimated to 25 °C would not jump when tested at 5 °C, whereas only 1 out of 16 cold-acclimated toads did not jump. We suggest that the acclimation effects on the jumping ability of R. pipiens at high temperatures are important in increasing their ability to escape predation and that this effect depends on an effect on the nervous system rather than the muscular system.
Cuticular changes and structural dynamics in the fourth-stage larvae and adults of Ascaris suum Goeze, 1782 (Nematoda: Ascaridoidea) developing in swine
Authors: O'Grady Richard T.
Published: January 2010

Fourth-stage larvae and adults of Ascaris suum recovered from pigs at 11 days after infection (DAI) to maturity were examined by light and scanning electron microscopy for changes in the cuticle. Allometric body growth in the larva affects the structure of the cuticle in three ways. First, there is increasing separation of the external striae and incomplete longitudinal ridges which closely follows the longitudinal and circumferential expansion of the body. Second, although the cuticle increases in absolute thickness, its thickness in relation to the midbody diameter decreases. Third, the spiral fibre system in the basal layer is elongated, causing a decrease in the spiral angle. All three of these changes are the reverse of that which occurs in the adult cuticle after the fourth moult at 22 DAI. An analysis of the structural dynamics of the larval cuticle shows the decreased spiral angle to be approaching the functional limit of a hydrostatic skeleton enclosed within an anisometric exoskeleton.
Geographic variation in the Indo-Pacific damselfish genus Lepidozygus (Pisces: Pomacentridae)
Authors: Emery Alan R.
Published: January 2010

The genus Lepidozygus Günther (Pomacentridae) is reviewed; Pomacentrus tapeinosoma Bleeker, Lepidozygus anthioides Smith, and Chromanthias exilis Whitley (incorrectly assigned to Anthiidae) are the only nominal species in the genus. A reexamination of the holotypes of each nominal species and multivariate (discriminant function) statistical analyses of the characteristics of individuals from populations over the range from eastern Africa to the central Pacific Ocean indicate the genus comprises a single species. The oldest name is Lepidozygus tapeinosoma; a lectotype is designated from Bleeker's syntypic material at the Rijksmuseum van Naturlijke Histoire at Leiden. The species is unique within the Pomacentridae, possessing heavy recurved teeth in the anterior part of each jaw, a row of fleshy papillae on the posterior margin of the eye and an extremely terete body (depth 30.5 to 38.8% of standard length). Maximum total length recorded was about 100 mm. Lepidozygus is a plankton-picker, feeding almost exclusively on copepods.
Fish predation on the macrobenthos of tidal salt marsh pools
Authors: Ward G. , FitzGerald G. J.
Published: January 2010

A combination predator inclusion–exclusion cage was used to examine predation by sticklebacks (Gasterosteidae) on the macrobenthos of tidal salt marsh pools. Although there were fewer oligochaetes found in plots with fish than in plots without fish, this result is interpreted as a cage-produced artifact. Caged sticklebacks fed much more than uncaged fish elsewhere in the marsh. We propose that the enclosed fish, unable to reproduce inside the cage, had more time available to feed than free-living fish. There was no evidence to support the hypothesis that fish predation plays a significant role in structuring the macrobenthic community in the salt marsh pools.
A simple device for field studies of animal activity
Authors: Stebbins Lucius , Daisley David
Published: January 2010

A reliable and simple device suitable for long-term recording of activity in natural environmental conditions is described. It is inexpensive to make, assembled with standard electronic components, and adaptable for a wide range of animal sizes. Instructions for assembly which can be interpreted with a minimum of electronics knowledge and parts lists with catalog numbers for a common Canadian electronics retailer are provided.
Pairing chronology and mate selection in the American wigeon (Anas americana)
Authors: Wishart Richard A.
Published: January 2010

The American wigeon (Anas americana) was studied during winter in southwestern British Columbia and on its breeding grounds in south-central Saskatchewan. Sex ratios ranged from 52.4 to 59.6% males. Wigeons courted in small groups but not all birds did so concurrently. However, by April all females were paired. Some winter pair bonds were temporary and observations of wild birds as well as a group of captives indicated that males and females exhibited mate preferences. Persistent aggression, dominance, mate attentiveness, and the performance of functional displays and aerial chases by males were important in acquiring a mate. Adult males in full alternate plumage tended to pair earliest. Those unable to obtain a mate were generally smaller and had lower protein and lipid reserves. These characteristics with which mate choice was correlated were also those which were important during nesting later on.
Postembryonic growth of Romanomermis culicivorax Ross and Smith, 1976: an example of accretionary growth in the Nematoda
Authors: Curran J. , Webster J. M.
Published: January 2010

The postembryonic development of Romanomermis culicivorax was studied in experimentally infected Aedes aegypti larvae. During its 7-day parasitic phase the nematode increased 8-fold in length and 10-fold in width, and the number of somatic nuclei increased 30-fold. Mitosis was observed in the hypodermal, trophosomal (intestinal), and muscle tissues. Body length and body width were correlated with number of somatic nuclei (r = +0.95, p < 0.001 and r = +0.91, p < 0.001 respectively). Growth in R. culicivorax is associated with extensive nuclear division, and this is believed to be the first report of accretionary growth in nematodes. The number of lateral hypodermal chord nuclei is variable in postparasitic juveniles and adults (mean, 1206 ± 536; range, 610–2475) and is correlated with body length (r = +0.84, p < 0.001). The lateral hypodermal chord nuclei do not undergo a fixed number of divisions.
Estimation of nuclear polyhedrosis virus produced in field populations of the European pine sawfly, Neodiprion sertifer (Geoff.) (Hymenoptera: Diprionidae)
Authors: Kaupp W. J.
Published: January 2010

The quantity of virus measured as the number of polyhedral inclusion bodies (PIBs) produced and liberated at death from two diseased European pine sawfly (Neodiprion sertifer (Geoff.)) populations was studied over a 3-year period in Britain. As high as 2.3 × 1015 PIBs/ha were produced as a resut of a natural epizootic in one of the populations. Subsequent years saw an appreciable reduction in the quantity of the virus produced, a direct result of the reduction in the number of sawfly larvae infesting each plot. Polyhedra persisting over winter in the host's environment were found to alter the nature of subsequent epizootics by causing virus infection to occur at an earlier stage of larval development than previously observed. This increased the percentage contribution of PIBs from the death of early instar larvae to the total amount of virus produced.
Oxygen consumption by largemouth bass under constant and fluctuating thermal regimes
Authors: Diana James S.
Published: January 2010

The metabolic rates of five largemouth bass (Micropterus salmoides) were measured in flow-through respirometers under constant warm (30 °C), constant cool (15 °C), and diel cycles of warm and cool (20 h at 15 °C, 4 h at 30 °C) conditions. Metabolic rate for each individual did not differ significantly when tested under a diel temperature cycle or under constant conditions at that temperature. The metabolic rates were also similar to those predicted for standard metabolic rate from an earlier study. These data are interpreted in light of energetic modeling and vertical migration studies to predict that bass under predictably fluctuating temperature regimes react metabolically similar to bass acclimated to constant conditions at that temperature, and models constructed on data from laboratory-acclimated fish would not be substantially in error when used for fish under variable thermal conditions.
Ultrastructure and host–parasite association of Blastocrithidia gerridis in the ventriculus of Gerris odontogaster (Gerridae: Hemiptera)
Authors: Tieszen K. , Heywood P. , Molyneux D. H.
Published: January 2010

Blastocrithidia gerridis the type species of the genus Blastocrithidia is parasitic in the gut of bugs of the genus Gerris. The ultrastructure and host–parasite relationship of the epimastigote stages of B. gerridis in the ventriculus of Gerris odontogaster are described. The ultrastructure is typical of other kinetoplastid flagellates but the elongated epimastigotes in the lumen of the ventriculus possess armlike protrusions of the plasma membrane. Intense infections are found in the ventriculus and masses of parallel orientated flagellates are attached to each other by their flagella and to the ventriculus epithelium by interdigitation with microvilli. Parasites and flagella are also wedged in folds of epithelium. Where the epithelium has lost microvilli junctional complexes between flagella and epithelial cell plasma membranes occur but no junctional complexes are observed between flagella and microvilli. A comparison is made between these mechanisms and those described previously for other trypanosomatid–insect or leech associations. The possibility of mixed infections of kinetoplastid flagellates in Gerris is discussed which reinforces the need for a study of the origin or source of promastigote and amastigote organisms found in Gerris species.
Prevalence of the kidney worm (Gnathostoma miyazakii) in river otters (Lutra canadensis) in Virginia
Authors: Whelan John , Anderson-Bledsoe Karen Lynn , Scanlon Patrick F.
Published: January 2010

The overall prevalence of Gnathostoma miyazakii Anderson, 1964 in 368 river otters (Lutra canadensis) from Virginia was 52.45%. Neither sex nor age of otters significantly affected prevalence of G. miyazakii. More (P < 0.005) otters were infected from saltwater areas than from freshwater areas of the state. Kidney weights of infected otters were significantly (P < 0.05) higher than those of noninfected otters.
Altitudinal adaptation of the life cycle in Allonemobius fasciatus DeGeer (Orthoptera: Gryllidae)
Authors: Tanaka Seiji , Brookes Victor J.
Published: January 2010

Allonemobius fasciatus DeGeer maintains a univoltine life cycle with an embryonic diapause over an altitudinal gradient of as large as 1100 m. Hatching time differs by more than 1.5 months between the highest and lowest altitudes studied. Little or no genetic difference was detected between populations from different altitudes when physiological traits such as diapause intensity, postdiapause development, and nymphal development were compared in the laboratory. Photoperiod influenced the duration of the nymphal stage and the number of instars, compensating for the shorter growing season at higher elevations. This photoperiodic regulation of nymphal development would also serve as a mechanism synchronizing adult emergence within a population of this species.
Parameters affecting survival of Weddell seal pups (Leptonychotes weddelli) to weaning
Authors: Thomas Jeanette A. , DeMaster Douglas P.
Published: January 2010

We examined birth dates, onset and duration of molt, spacing of females and pups, onset and date of weaning, and post-weaning dispersal of Weddell seal pups (Leptonychotes weddelli) in breeding colonies from 1976 to 1979. Survival of pups to weaning was most influenced by their date of birth, their ability at a very young age to haul out on the ice, and the stability of the fast ice during their weaning. The onset and duration of molt was variable; neither a long molt nor an early molt adversely affected pups. Pups born late in the season were not weaned at a younger age. Exclusive space for females and pups in the colony was most important immediately after a pup's birth. Pups born during the optimal pupping period and in years of stable fast ice had a high probability of survival.
A new species of Amphinema: Amphinema platyhedos n. sp. (Cnidaria, Hydrozoa, Pandeidae) from the Canadian West Coast
Authors: Arai Mary Needler , Brinckmann-Voss Anita
Published: January 2010

A new species of hydro medusa, Amphinema platyhedos n. sp. is described and illustrated. It is differentiated from all other species of the genus by broad marginal bulbs, nonfolded horseshoe-shaped gonads, and long tentaculae.
Distributional patterns of chaetognaths in the Bay of Fundy
Authors: Hurley P. C. F. , Corey S. , Iles T. D.
Published: January 2010

Nine species of chaetognaths were found in the Bay of Fundy: Sagitta elegans, S. tasmanica, Eukrohnia hamata, S. maxima, S. lyra, S. enflata, S. hexaptera, S. serratodentata, and Pterosagitta draco. Sagitta elegans was the dominant and only native species and maintained a centre of very high abundance in the study area. It is suggested that surface circulation carries young out of the Bay of Fundy and that the centre of abundance is maintained principally by immigration from outside the Bay and by interaction of adult specimens with the hydrographic conditions. Sagitta tasmanica was the second most abundant species and an immigrant carried into the Bay of Fundy by surface circulation. The distribution and abundance of E. hamata indicated a regular but variable inflow of slope water. The occurrence of S. maxima and S. lyra, and S. enflata, S. hexaptera, S. serratodentata, and P. draco indicated periodic inflow of oceanic boreal and (or) Gulf Stream waters.
Winter pelage colour in snowshoe hares (Lepus americanus) from the Pacific Northwest
Authors: Nagorsen David W.
Published: January 2010

Winter pelage colour was assessed in 207 museum study skins from California, Oregon, Washington, and southwestern British Columbia. Specimens were classified into two distinct colour morphs: brown or white. The brown morph inhabits the coastal lowlands and the Olympic Mountains; the white morph occupies the Sierra Nevada, Blue Mountains, northeastern Washington, and the interior of British Columbia. Except for the occurrences of the brown morph above the snow line in the Olympic Mountains, this distribution correlates with the presence or absence of continuous snow cover and reflects selection for cryptic colouration. The absence of the white morph from areas in the Olympics with snow cover may be the result of intense selection for brown hares in adjacent lowland areas coupled with gene flow or historical biogeographic factors in the Pacific Northwest. Both morphs occur in the Cascade Mountains and coexist at some localities. However, data are insufficient to evaluate the ecological distribution of brown and white hares in the Cascades.
Hypothalamic gonadotropin-releasing hormone and pituitary luteinizing hormone contents in the male vole (Microtus agrestis) in the field during the breeding and nonbreeding seasons
Authors: Charlton H. M. , Chiappa S. A. , Fink G. , Grocock C. A. , Versi E.
Published: January 2010

Pituitary luteinizing hormone (LH) and hypothalamic gonadotropin-releasing hormone (GnRH) contents were measured in male voles trapped in the field over a period of 5 years. Pituitary LH contents were positively correlated with testicular and seminal vesicle weights but hypothalamic GnRH contents showed no correlation with pituitary LH contents or organ weights. Pituitary LH contents and testicular and seminal vesicle weights increased between January to April, reached peak values during May to July, and fell from August to December. Hypothalamic GnRH contents were high for most of the year with low values during December and January. During July, August, and September two populations of males were studied; a group with large active testes and high pituitary LH levels and a group with small testes and low pituitary LH levels. With the exception of the group in July of animals with small testes, all males, both sexually active and inhibited, had high hypothalamic GnRH levels.
The taxonomy of Gyrodactylus (Monogenea) parasitizing certain salmonid fishes of North America, with a description of Gyrodactylus nerkae n. sp.
Authors: Cone D. K. , Beverley-Burton M. , Wiles M. , McDonald T. E.
Published: January 2010

Specimens of Gyrodactylus Nordmann, 1832, both newly collected and deposited type material, from cultured and wild salmonid fishes from various localities in North America, are compared and five species are recognized: G. salmonis Yin and Sproston, 1948 status emended, on Salmo clarki, S. salar, S. aguabonita, S. gairdneri, S. trutta, Salvelinus fontinalis, S. namaycush, and Oncorhynchus kisutch from several localities throughout the continent; Gyrodactylus nerkae n. sp. on O. nerka from Vancouver Island; G. colemanensis Mizelle and Kritsky, 1967 on Salmo gairdneri from California, Arkansas, and insular Newfoundland, S. fontinalis from Nova Scotia and Ontario, and S. trutta, S. namaycush, and S. fontinalis × S. namaycush from Ontario; G. avalonia Hanek and Threlfall, 1969 on S. gairdneri from Nova Scotia; and G. brevis Crane and Mizelle, 1967 on S. gairdneri from California. Gyrodactylus salmonis, G. nerkae, and G. colemanensis are considered specific to salmonid fishes, whereas G. avalonia and G. brevis are considered "accidental" infections, acquired from nonsalmonid fishes. A diagnostic key to the five species is provided and gyrodactyliasis, as a disease of cultured salmonids in North America, is discussed briefly.
What's going on in evolution? A brief guide to some new ideas in evolutionary theory
Authors: Brooks Daniel R.
Published: January 2010

Evolutionary theory is currently undergoing a healthy period of controversy and reexamination. Many issues are discussed by a relatively small number of specialists in particular fields. This paper attempts a brief outline of some of the major areas of contention, and indicates some current researchers, including a good number in Canadian institutions, who are contributing to the growing body of literature. The most contentious fields are (1) systematics, (2) biogeography, (3) paleontology, (4) community ecology, (5) molecular genetics, (6) development biology, (7) nonequilibrium thermodynamics, and (8) philosophy. Such widespread dissatisfaction with the current paradigm may presage the emergence of a new unified theory of evolution.
Seasonal dispersal in a seminatural population of Peromyscus maniculatus
Authors: King John A.
Published: January 2010

Social factors contributing to seasonal patterns of dispersal in Peromyscus maniculatus bairdi were tentatively identified by partial control of the initial demography, nutrition, predation, and competition. Populations consisting of eight mated pairs of adult mice were established in an open field artificially provided with favorable microhabitats during two springs, one summer, and two falls. The microhabitats were 32 aluminum cylinders 2 m in diameter arranged in 16 couplets on a square grid covering 1.4 ha. Each cylinder enclosed an area of 3.1 m2 containing nest boxes, food, water, and a single small exit to the surrounding fields. Nests were checked every 3rd day for marked individuals over a period of 10 weeks, after which the existing population was removed and a new one established. More individuals were lost from the population during spring and summer than in the fall. Local movements on the study area were not related to the disappearance of mice. Significantly more mothers moved nests between litters than remained. Family groups were most cohesive in fall and were rarely joined by nonrelatives. There was no evidence of agonistic behavior within families. Most mice left the population in the spring and summer when the juveniles were sexually maturing, in contrast to the fall when only the resident adults continued to breed. A sexual search hypothesis proposes that the rate of dispersal increases directly with the rate of recruitment of sexually maturing individuals.
Mortality patterns for a population of burrowing wolf spiders, Geolycosa domifex (Hancock), living in southern Ontario
Authors: McQueen D. J.
Published: January 2010

A population of burrowing wolf spiders, Geolycosa domifex (Hancock), was studied near Toronto, Ontario, between 1974 and 1979. Some preliminary life history and mortality information for this population has been published previously by D. J. McQueen. In the paper that follows, these results are updated and additional data pertaining to density-dependent mortality and the effects of the parasite Pterodontia flavipes Grey are presented. At the Uxbridge field site, the maximum life span for G. domifex was 3 years and they were semelparous. On average, the wasp Anoplius relativus (Fox) killed 18.7% of the population at age 24 months and >98% of the female spiders after they had reproduced at age 36 months. The acrocerid fly, P. flavipes killed 40.4% of the population at age 22 months and an average of 17.5% of the population at age 34 months (before reproduction). Younger spiders were not killed by either A. relativus or P. flavipes. An analysis of survivorship with respect to burrow spacing suggested that there was no density-dependent mortality.
Sibling species of the blackfly Prosimulium onychodactylum (Simuliidae, Diptera): a salivary gland chromosome study
Authors: Newman Lester J.
Published: January 2010

Larvae of the morphospecies Prosimulium onychodactylum collected from two streams in northern Oregon are divided into 11 sibling species based on fixed and polymorphic inversions. The sibling species have differentiated sex chromosomes; each sibling species falls into one of two groups based on the chromosome arm which carries the sex chromosome markers. Males exhibit lack of homologous pairing or inversion heterzygosity and females have complete chromosome pairing or inversion homozygosity. There is a succession of sibling species which mature in the streams from January through September. Mature larvae of each sibling species are present for about 6 weeks; some are synchronic while others are allochronic. Some of the sibling species occur in the same stream and others are in different streams. Sibling species which are both synchronic and sympatric appear to be reproductively isolated. Reproductive isolation may not be complete for sibling species which are normally allopatric or allochronic; small numbers of F1 and backcross hybrids were found between some of these sibling species. The division of the morphospecies into sibling species was also observed in collections from Washington through northern California.
Nutrient content of four rosaceous hosts and their effects on development and fecundity of the eastern tent caterpillar, Malacosoma americanum (Fab.) (Lepidoptera: Lasiocampidae)
Authors: Segarra-Carmona A. , Barbosa P.
Published: January 2010

Eastern tent caterpillar, Malacosoma americanum (Fab.), larvae reared on four rosaceous hosts differed in development time and survival under laboratory conditions. Fecundity and pupal weight were also affected by diet. Levels of nitrogen, carbohydrates, and fatty acids in host foliage as well as water content and caloric values were determined. No direct relationship was found between nutrient or caloric levels and developmental parameters.
MAXIMAL PLURISUBHARMONIC MODELS
Authors: TOMASSINI GIUSEPPE , VENTURINI SERGIO
Published: December 2009

An analytic pair of dimension n and center V is a pair (V, M) where M is a complex manifold of (complex) dimension n and V ⊂ M is a closed totally real analytic submanifold of dimension n. To an analytic pair (V, M) we associate the class [Formula: see text] of the functions u : M → [0, π/4] which are plurisubharmonic in M and such that u(p) = 0 for each p ∈ V. If [Formula: see text] admits a maximal function u, the triple (V, M, u) is said to be a maximal plurisubharmonic model. After defining a pseudo-metric EV, M on the center V of an analytic pair (V, M) we prove (see Theorem 4.1, Theorem 5.1) that maximal plurisubharmonic models provide a natural generalization of the Monge–Ampère models introduced by Lempert and Szöke in [18].
ON TWO CONJECTURES FOR CURVES ON K3 SURFACES
Authors: KNUTSEN ANDREAS LEOPOLD
Published: December 2009

We prove that the gonality among the smooth curves in a complete linear system on a K3 surface is constant except for the Donagi–Morrison example. This was proved by Ciliberto and Pareschi under the additional condition that the linear system is ample. The constancy was originally conjectured by Harris and Mumford.

As a consequence we prove that exceptional curves on K3 surfaces satisfy the Eisenbud–Lange–Martens–Schreyer conjecture and explicitly describe such curves. They turn out to be natural extensions of the Eisenbud–Lange–Martens–Schreyer examples of exceptional curves on K3 surfaces.
PRICING GEOMETRIC TRANSPORTATION NETWORKS
Authors: CARDINAL JEAN , LABBÉ MARTINE , LANGERMAN STEFAN , PALOP BELÉN
Published: January 2010

We propose algorithms for pricing a transportation network in such a way that the profit generated by the customers is maximized. We model the transportation network as a subset of the plane and take into account the fact that the customers minimize their own transportation cost. The underlying theory is a two-player game model called Stackelberg games. We propose algorithms for the cases where the fare does and does not depend on the distance traveled, in the L1 or L2 metrics. In particular, we propose an O(n log n) algorithm for optimal pricing of a highway under the L2 metric, and an O(nk log n log 3 k) algorithm for orthogonally convex networks of complexity O(k) under the L1 metric.
Shear Bands in Matter with Granularity
Authors: Schall Peter , van Hecke Martin
Published: January 2010

Shear bands, localized regions where shear flows concentrate, form in many complex fluids under a wide range of circumstances. In this review, we outline the main mechanisms that cause shear banding in complex fluids with granularity: foams, emulsions, colloidal suspensions, and granular matter. Apart from shear bands caused by continuum-scale mechanisms such as stress inhomogeneities and flow instabilities, we discuss a range of shear-banding phenomena for which the particle scale plays a crucial role.
Turbidity Currents and Their Deposits
Authors: Meiburg Eckart , Kneller Ben
Published: January 2010

The article surveys the current state of our understanding of turbidity currents, with an emphasis on their fluid mechanics. It highlights the significant role these currents play within the global sediment cycle, and their importance in environmental processes and in the formation of hydrocarbon reservoirs. Events and mechanisms governing the initiation of turbidity currents are reviewed, along with experimental observations and findings from field studies regarding their internal velocity and density structure. As turbidity currents propagate over the seafloor, they can trigger the evolution of a host of topographical features through the processes of deposition and erosion, such as channels, levees, and sediment waves. Potential linear instability mechanisms are discussed that may determine the spatial scales of these features. Finally, the hierarchy of available theoretical models for analyzing the dynamics of turbidity currents is outlined, ranging from dimensional analysis and integral models to both depth-averaged and depth-resolving simulation approaches.