bluuebunny/crossref_metadata_2025 huggingface dataset:
The influence of salinity on the cuticular permeability of Cenocorixa bifida hungerfordi Lansbury (Hemiptera: Corixidae)
Authors: Cannings S. G.
Published: April 2009

The cuticular permeabilities of individual Cenocorixa bifida hungerfordi Lansbury collected over a wide range of salinities were determined. Corixids from low salinity water (0–2000 μmhos∙cm−1 surface conductivity at 25 °C) exhibited low cuticular permeability, whereas those from moderately saline water bodies (7000 – 11 000 μmhos∙cm−1) were much more permeable. However, at higher salinities cuticular permeability was again low; corixids from a lake with a surface conductivity of 16 000 μmhos∙cm−1 (approximately half that of seawater) had cuticular permeabilities comparable with those of corixids from freshwater lakes. This phenomenon was shown to be acclimatory, since permeability decreased over time when corixids from moderately saline lakes were placed into distilled water. The biological reasons for these results are not clear, but it appears that cuticular permeability of C. bifida increases as problems of ion regulation diminish, and then begins to decrease, seemingly at the salinity at which it becomes difficult for the corixid to maintain a constant haemolymph osmotic pressure. The biological implications of this phenomenon are discussed.
Toxicity of environmental acid to the rainbow trout: interactions of water hardness, acid type, and exercise
Authors: Graham Mark S. , Wood Chris M.
Published: April 2009

Classical 7-day lethality tests were used to establish the influence of water hardness [Formula: see text], acid type (HCl versus H2SO4) and activity level (rest versus exhaustive exercise) on acid toxicity to fingerling rainbow trout (Salmo gairdneri) at 15 °C. Seven-day mean lethal concentration (LC50) pH's ranged from 4.1 to 4.5. Hardness reduced H2SO4 toxicity at all pH levels during both rest and exericise, but reduced HCl toxicity only at very low pH levels. Hardness increased HCl toxicity at pH's > 3.8. H2SO4 was generally less toxic than HCl, except at pH's > 3.8 in soft water. Exchaustive exercise markedly potentiated H2SO4 toxicity in both hard and soft water except at very low pH levels. Below pH = 4.4–4.6, critical swimming speed declined linearly by about 4% per 0.1 pH unit. Possible physiological mechanisms responsible for these modifying influences and their ecological significance are discussed.
A test of three hypotheses for latitudinal segregation of the sexes in wintering birds
Authors: Myers J. P.
Published: April 2009

Three hypotheses have been proposed to explain sexual differences in wintering latitude for different bird species: (1) intersexual behavioral dominance leads the subordinate sex to migrate farther to avoid competition; (2) intrasexual selection favors those individuals of one sex that arrive earlier and thus selects for wintering closer to the breeding ground; and (3) sexual differences in physiological tolerance allow the larger sex to survive harsher climates. Using sex, age, date, and location data from specimens collected south of the breeding range in the western hemisphere, I tested predictions of these hypotheses for two scolopacid shorebirds showing reverse sexual size dimorphism, the red phalarope, Phalaropus fulicarius, and the sanderling, Calidris alba.Neither red phalaropes nor adult sanderlings showed any sexual difference in wintering latitude. First-winter male sanderlings tended to winter farther south than first-winter females. Combined with comparative data from other species of shorebirds and passerines, these results are consistent only with hypothesis 2.
The impact of predation by red-winged blackbirds on European corn borer populations
Authors: Bendell Barry E. , Weatherhead Patrick J. , Stewart Robin K.
Published: April 2009

Population estimates of the European corn borer (Ostrinia nubilalis Lepidoptera: Pyralidae) were significantly positively correlated with distance from a blackbird roost near Beauharnois, Quebec. Gullet contents of male red-winged blackbirds (Agelaius phoeniceus) indicated that corn borers were consumed, particularly in the late fall. This predation appears to be responsible for lowering corn borer populations in standing corn the following year. It was estimated that the benefit provided by red-winged blackbirds through predation on com borers compensated for approximately 20% of the damage the birds did to standing corn.
Food-collecting and waste-rejecting mechanisms in Glottidia pyramidata and the persistence of lingulacean inarticulate brachiopods in the fossil record
Authors: Gilmour T. H. J.
Published: April 2009

Potentially inedible particles entering the mantle cavity of Glottidia pyramidata impinge on the frontal surfaces of ungrooved outer tentacles and are removed very efficiently by frontal cilia beating directly towards the exhalent aperture. Particles which settle out of the inhalent current are resuspended by cilia on the mantle ampullae. Edible material passing between the outer tentacles is captured by the combined action of laterofrontal cilia beating into the grooves and frontal cilia beating towards the bases of the inner grooved tentacles of the spirolophous lophophore. The arrangement of the tentacles and their cilia on the spirolophe of G. pyramidata is contrasted with the plectolophous condition in the articulate brachiopod Laqueus californianus in which heavy potentially inedible particles penetrate deeply into the lophophore before being trapped by ungrooved tentacles which, because of differences between the developmental patterns of articulates and inarticulates, lie within the grooved tentacles. Furthermore, the immobile laterofrontal cilia on both sets of tentacles of L. californianus detect waste particles. It is suggested that the exterior position of the waste-rejecting tentacles and the involvement of the laterofrontal cilia in food collection in lingulacean inarticulates may have contributed to their ability to compete successfully with bivalve molluscs in turbid habitats and their persistence in the fossil record.
Elimination marking behavior in feral horses
Authors: Turner Jr. J. W. , Perkins A. , Kirkpatrick J. F.
Published: April 2009

It was the goal of this study to develop a reliable behavioral endpoint for use in studying patterns of reproduction and methods for regulating reproduction in feral horses. Several characteristic stallion behavior patterns associated with harem activities were examined. The only behavior which occurred with high frequency and was readily observable and quantifiable was stallion elimination marking behavior in which stallions marked eliminations (urinations–defecations) of other horses with their own urine and feces. Elimination marking behavior was not exhibited by mares or immature animals and stallions rarely marked eliminations made by immatures. Stallion response to eliminations by mature mares varied markedly with time of year, averaging 93% and 89% in May and June, the peak of the breeding season, and 1% from November through February. Thus, seasonal changes in elimination marking behavior were well correlated with the breeding season. The completeness of the behavior pattern showed an annual pattern similar to that for frequency. The possible significance of this behavior in relation to feral horse social organization and its use as a behavioral correlate in studying reproductive patterns is discussed.
Longevity of cross-fostered honey bee workers (Apis mellifera) of European and Africanized races
Authors: Winston Mark L. , Katz Susan J.
Published: April 2009

Longevities of two races of honey bee workers, European and Africanized, were compared both within colonies of their own races and within colonies of the other race. Differences in longevity were found which were likely due to inherited differences between workers of the two races. The age at which workers began foraging was one factor important in determining longevity. These results may provide a partial explanation for the success and impact of Africanized bees in South America, and also suggest that the northerly spread of these bees could be limited by worker life spans.
Dualistic spawning behaviour of the cunner, Tautogolabrus adspersus (Pisces: Labridae), in Bonne Bay, Newfoundland
Authors: Pottle Robert A. , Green John M. , Martel Guy
Published: April 2009

Group spawning and pair spawning cunners, Tautogolabrus adspersus, were studied at Bonne Bay, Newfoundland. This is the first recorded occurrence of both types of spawning behaviour of this species at a single location. Group spawning occurred within aggregations of 30 to > 150 fish. Cunners in group spawning aggregations ranged in length from 80 to 180 mm. Those with brown phase colouration outnumbered those with male nuptial (blue phase) colouration by at least 3:1. All courtship was initiated by males with nuptial colouration, but some brown-phase males participated in group spawnings. Pair spawning involved territorial males and was observed within 5 m of an aggregation in which group spawning was occurring. Territorial males were larger than 200 mm and had nuptial colouration. They were not observed where small (< 180 mm) cunners were most abundant. Group spawning occurred in the afternoon, being most frequent between 1800 and 1900 hours.
The migrations of anadromous cisco (Coregonus artedii) and lake whitefish (C. clupeaformis) in estuaries of eastern James Bay
Authors: Morin Roderick , Dodson Julian J. , Power Geoffrey
Published: April 2009

Experimental gill-netting and tagging programs were undertaken in the Eastmain and La Grande rivers of James Bay to determine the migratory patterns of anadromous cisco (Coregonus artedii) and lake whitefish (C. clupeaformis). Cisco and whitefish were found to differ in the distribution of juveniles during summer, in the upriver migration of mature fish, and in the selection of overwintering sites. Models are presented to illustrate the general life cycles of anadromous cisco and lake whitefish in James Bay.
Evidence for dissolved glucose uptake from seawater by Neocalanus plumchrus (Arthropoda, Copepoda)
Authors: Chapman Peter M.
Published: April 2009

Autoradiographic techniques indicate that Neocalanus plumchrus is capable of removing labelled glucose from seawater at concentrations as low as 2.3 × 10−9 M. Uptake is via dermal glands and midgut. Consequent glucose transfer occurs through haemocoel to muscles and germinal tissue.
Occurrence of Sarcocystis Lankester, 1882, in wild geese in Saskatchewan
Authors: Wobeser G. , Leighton F. A. , Cawthorn R. J.
Published: April 2009

Skeletal and cardiac muscle from wild geese dead of avian cholera was examined for Sarcocystis sp. infection. Microscopic cysts of Sarcocystis sp. were found in skeletal muscle of 42 of 88 Lesser Snow Geese, Anser caerulescens caerulescens, 1 of 7 Ross Geese, Anser rossi, and 1 of 3 Canada Geese, Branta canadensis, collected during April and May in central Saskatchewan. Two types of microcysts were present in skeletal muscle; one type had finger-like protrusions on the primary cyst wall; the other had a relatively smooth primary cyst wall. Both types were found in one Lesser Snow Goose. Microscopic cysts were found in the heart of 8 of 150 Lesser Snow Geese and 3 of 35 Ross Geese. All cysts in the myocardium had a smooth primary cyst wall.
Underwater observations on a rare Caribbean fish, Labrisomus filamentosus (Labrisomidae) in Barbados, W.I.
Authors: Emery Alan R. , Labelle Marc
Published: April 2009

Labrisomus filamentosus Springer, 1959 was previously known from the holotype and three specimens, and considered to be a deep-dwelling species (35–100 m). Observations were made in Barbados at much shallower depths (12–16 m) of large adults which were territorial and which used the elongate anterior portion of the dorsal fin in signalling other species of fish. Habitat was on or near sand interstices and interconnecting coral caves amongst large boulder-shaped live corals on isolated pinnacle or barrier reefs.
Colonization by nearshore fish on small artificial reefs in Barkley Sound, British Columbia
Authors: Gascon Dominique , Miller Roberta A.
Published: April 2009

We investigated the structure of a temperate nearshore fish community by examining the development of fish assemblages on small artificial reefs of concrete blocks constructed in two series 6 months apart. In each series, a species equilibrium, of approximately six species, was rapidly reached within 6 months. Eight of the 30 species which had colonized the reefs from the surrounding rocky habitats were common on the reefs. Both juveniles and adults of all species were present, except for the rockfishes (Sebastes spp.) which were represented only by young individuals (1 to 3 years of age). Tagging indicated that the bottom-dwelling species (Gobiidae, Cottidae) remained permanently on the reefs, whereas a seasonal turnover in rockfish occurred.The communities inhabiting the reefs usually did not differ from each other within each series, whereas significant differences occurred between series. This difference was attributed to the differential colonizing ability of species. No evidence of interspecific competition was apparent among the species inhabiting the reefs.The results are discussed in light of some current models of coral reef fish community structure. Some possible factors affecting the differences observed between tropical and temperate waters are also discussed.
Birds and mammals as vectors of the chestnut blight fungus (Endothia parasitica)
Authors: Scharf Craig S. , DePalma Nancy K.
Published: April 2009

This study investigated the potential of birds and mammals to vector the chestnut blight fungus in today's mixed hardwood forests. Animals were shot or trapped in established woodland plots in southern Connecticut where densities of American chestnut sprouts were high, brought back to the laboratory, and examined for the presence of Endothia parasitica. Results showed that birds and mammals can transport virulent and hypovirulent-like strains of E. parasitica in today's forest community. Two birds, a mouse, and a shrew were identified as carriers of the blight fungus; the shrew harbored a hypovirulent-like strain introduced onto the plot 2 years earlier.
Snake tongue-flicking: transfer mechanics to Jacobson's organ
Authors: Gillingham James C. , Clark David L.
Published: April 2009

Cinematographic analysis of the open-mouthed tongue flick of rat snakes (Elaphe) revealed elevation of the anterior processes following tongue retraction into the lingual sheath. The ventral surface of the tongue makes contact with these processes on each retraction and these processes are directly aligned with Jacobson's (vomeronasal) organ in the roof of the mouth. Scanning electron microscopic examination of the anterior process surface reveals an increased surface area through oblique ridges. Experimental removal of these structures prevents open-field detection of food odors in garter snakes (Thamnophis). These data indicate that this structure is the vehicle for transfer of substances to Jacobson's organ during snake chemosensation.
Ecology of the fourspine stickleback, Apeltes quadracus, with respect to a polymorphism for dorsal spine number
Authors: Blouw D. M. , Hagen D. W.
Published: April 2009

The subject of our research is the ecological genetics of a polymorphism for dorsal spine number in Apeltes quadracus. Here we present information on its ecology and on dorsal spine variation, as background for subsequent publications.Estimating age from otoliths is subject to several serious errors, and spine sections are questionable. We have estimated generation time at about 1 year using length frequency distributions. Dorsal spine number varies from one to seven, but the four-and five-spined morphs predominate. The polymorphism is ubiquitous; where samples are available for comparisons over time, morph frequencies have remained relatively constant for at least 50 years. Sex ratio is highly variable among sites and among samples at particular sites. However, morph frequencies are independent of sex and age. Morph frequencies are homogeneous among samples taken at differing times of day, tide levels, months within a year, and among years. They are also homogeneous among microhabitats we sampled in an estuary. The relevance of these results to our subsequent publications is the following: (1) we take 1 year as the generation time, (2) sexes and ages can be pooled to estimate morph frequencies, and (3) since morph frequencies remain relatively constant, at least within the time period of our survey, comparisons of morph frequencies among sites to detect geographical and ecological patterns of variation seems valid.
Vertical distributions and zooplankton predation in a small temperate pond
Authors: Melville Guy E. , Maly Edward J.
Published: April 2009

Depth-specific sampling in a small Quebec pond between April and October 1977 revealed that instars of Daphnia pulex less than 1.41 mm in length and instars of Diaptomus leptopus greater than 0.64 mm in length consistently had vertical distributions which were different from those of late instars of their predator Chaoborus americanus. Experiments were done to determine to what extent these distributions affected the rate of predation by Chaoborus. Vertical and horizontal 25-L enclosures, 1.4 m long, and 2.5-L enclosures, all containing Chaoborus–prey pairs, were introduced into a pond for 3-day periods weekly from July to September. Predation rates in vertical enclosures were considerably lower than those in small and horizontal enclosures. These results suggest that distributions of Diaptomus and Daphnia in vertical enclosures significantly reduce predation on them by Chaoborus. In horizontal and small enclosures where overlap of predator and prey was increased, predation rate of Chaoborus was higher. Results are discussed in relation to the impact of invertebrate predation on zooplankton and the structure of zooplankton communities.
Distribution of certain Arctic and Subarctic Cumacea in Canadian waters
Authors: Corey S.
Published: April 2009

Eleven species of cumaceans are recorded from collections made in the Canadian Arctic and Subarctic from 1947 through 1962. Platyaspis typica is recorded here for the first time from Canadian waters. The distribution of each species is discussed and compared with previous findings.
The ecology, role of the killer trait, and interactions of five species of the Paramecium aurelia complex inhabiting the littoral zone
Authors: Landis Wayne G.
Published: April 2009

The field work was carried out over a 3-year period. Extensive sampling of two ponds in the Bloomington, Indiana, area was conducted using a 0.5-m2 grid to ensure the precise determination of the location, patchiness, and size of the populations of the five species of the Paramecium aurelia complex found in central Indiana. The number of killer paramecia in each collection was also determined. Competition experiments were performed with killers and sensitives at densities observed in nature.It was discovered that density-independent factors regulated the population size of paramecia in nature. Paramecia generally exist in small, clumped, and temporary resource patches. Several species often inhabit the same patch yet statistical analysis does not demonstrate that competitive exclusion occurs. The spatial and temporal heterogeneity of the environment is the likely factor allowing the very similar species to co-exist. The exception may be the species of P. tetraurelia, which exhibits the killer trait. Paramecium tetraurelia may successfully exploit specific resource patches that enable the species to reach particularly high densities compared with those in which other species of paramecia are found. Paramecium tetraurelia killers, as shown by the laboratory experiments, can outcompete sensitives. They are also rarely found with sensitive paramecia. Field collections also indicate that killers rarely have an opportunity to mate. An analysis of the genetics of the killer trait demonstrates that only infection due to cytoplasmic exchange or natural selection can maintain the killer trait in a population. Therefore, only natural selection could be responsible for the continued existence of killer paramecia in nature.
Spatial relationships and behavior of polar bears (Ursus maritimus Phipps) concentrated on land during the ice-free season of Hudson Bay
Authors: Latour Paul B.
Published: April 2009

I observed polar bears (Ursus maritimus Phipps) at Cape Churchill, Manitoba, a site where polar bears congregate during the autumn when Hudson Bay is ice free. Adult males, subadult males, and subadult females were spatially segregated to a degree that depended primarily on density. The higher the density, the greater the degree of segregation. Adult males showed the closest intraclass association. Subadult females spent more time in activity than did either adult or subadult males; this may be due to subadult females being approached more by other subadults. Much of an individual's social behavior occurred with members of its own age–sex class, perhaps as a result of spatial segregation. In the noncompetitive situation of this study, polar bears aggregated and were more social than when hunting on the sea ice. This study provides further evidence for the flexibility of carnivore social systems, not only between populations of the same species, but also within a single population.
Northern Canadian mayflies (Insecta; Ephemeroptera), records and descriptions
Authors: Harper Françoise , Harper P. P.
Published: April 2009

Sixty-eight species are recorded from the northern regions, tundra and open boreal forest, of Canada. The Eurasian Ephemerella mucronata (Bengtsson) is reported for the first time from North America and Caenis Candida n.sp. is described from the James Bay drainage in Quebec. The mayfly fauna of Northern Canada is composed of a distinctive tundra element (five species, three of which are holarctic), a north boreal element containing a few characteristic but not exclusive species, together with the most tolerant species of the eastern and, to a limited extent, western temperate faunas. Eighty-two species are now reported from Canada north of the closed boreal forest, roughly one fourth of the known Canadian fauna of mayflies.
Factors influencing growth of juvenile spruce grouse
Authors: Quinn Norman W. S. , Keppie Daniel M.
Published: April 2009

The influences of date of hatch, and age and prelaying body weight of brood female on the growth rate of juvenile spruce grouse (Canachites canadensis) were studied in central New Brunswick in 1977 and 1978. Because of differential timing of hatch of broods of adult and yearling females, it was not clear whether a difference in juvenile growth rates during 5–14 days of age in 1977 was related to date of hatch, age of brood female, or both. Differences in juvenile growth rates within and between years apparently were not influenced by body weight of brood females prior to egg laying. Results suggest that posthatch factors are more important in determining growth rate than a prehatch or "maternal" influence.
Oocyst production of four species of murine coccidia
Authors: Tilahun G. , Stockdale P. H. G.
Published: April 2009

Oocyst output and the reproductive potential of the four species of murine coccidia, Eimeria falciformis, E. ferrisi, E. papillata, and E. vermiformis were examined. Graded infections were produced by inoculating either 10, 102, 103, 104, or 105 sporulated oocysts to groups of mice. Oocyst production was estimated by examining all the feces passed. oocyst output was influenced by the size of the dose of oocysts. Maximum oocyst production per mouse was observed in groups of mice infected with 103 to 104 sporulated oocysts, after which, decline in oocyst output was observed despite increasing the dose of oocysts. The reproductive potential per oocyst given in each of the four species of Eimeria decreased as the dose of oocysts was increased. Mortality at rates of 60 and 40%, respectively, occurred in groups of mice infected with 105 sporulated oocysts of E. vermiformis and E. ferrisi.
Food abundance and territory size in juvenile coho salmon (Oncorhynchus kisutch)
Authors: Dill Lawrence M. , Ydenberg Ronald C. , Fraser Alex H. G.
Published: April 2009

Feeding territory size and potential food abundance were measured simultaneously in a field population of juvenile (40–50 mm) coho salmon. Territory size was inversely related to the density of benthic food on the territory, as predicted from an energy-based model of territoriality. The relationship between the abundance of drift food and territory size was in the predicted direction, but was not significant. Territories were also smaller where intruder pressure was higher, but intrusion rate and food abundance were not directly correlated. Therefore, the effect of food abundance on territory size was not caused indirectly by attraction of nonterritorial fish to areas where food was abundant. In the laboratory, the distance from which a resident coho attacked an approaching model intruder increased asymptotically with hunger. The fish therefore appear to possess an appropriate behavioural mechanism (tactic) to adjust territory size to local food abundance.
Actinocleidus oculatus (Mueller, 1934) and A. recurvatus Mizelle and Donahue, 1944 (Monogenea: Ancyrocephalinae) from Lepomis gibbosus L. (Pisces: Centrarchidae) in Ontario, Canada: anatomy and systematic position
Authors: Beverley-Burton M.
Published: April 2009

Actinocleidus oculatus (Mueller, 1934), the type species of Actinocleidus Mueller, 1937, and A. recurvatus Mizelle and Donahue, 1944 (Monogenea: Ancyrocephalinae) from the gills of Lepomis gibbosus L. (pumpkinseed) in Ontario, Canada, are redescribed with details of their internal anatomy as well as the sclerotized components of the haptor and copulatory complex. A revised generic diagnosis incorporating features of the reproductive system is presented.
A second new subterranean amphipod crustacean of the genus Stygobromus (Crangonyctidae) from Alberta, Canada
Authors: Bousfield E. L. , Holsinger John R.
Published: April 2009

Stygobromus secundus n.sp. is described from a spring 24 km southwest of Rocky Mountain House, Alberta. This is the second hypogean amphipod crustacean recorded for Canada. Its occurrence well north of the southern limits of Pleistocene glaciation may further support the hypothesis that small peracaridan crustaceans survived Wisconsin glaciation in groundwater refugia.
A revision of species of the genus Haematoloechus Looss, 1899 (Trematoda: Haematoloechidae) from Canada and the United States
Authors: Kennedy Murray J.
Published: April 2009

Previous experimental and field studies have shown that variations within the genus Haematoloechus may result from differences in age and degree of maturity, extent of crowding, species of host, and other factors.Based on these observations, only 6 of the 15 previously known species from Canada and the United States are considered valid. The valid species and their synonyms are as follows: Haematoloechus longiplexus Stafford, 1902; H. breviplexus Stafford, 1902; H. varioplexus Stafford, 1902 (= H. parviplexus, = H. buttensis, = H. similiplexus, = H. floedae, and H. uniplexus); H. kernensis Ingles, 1932 (= H. tumidus); H. medioplexus Stafford, 1902; and H. complexus (Seely, 1906) (= H. coloradensis, = H. confusus, = H. oxyorchis).The existence of three species groups is hypothesized. Haematoloechus longiplexus and H. breviplexus constitute one group, characterized by little geographical variation and a narrow host range. They are typically parasites of Rana catesbeiana and R. clamitans. Haematoloechus varioplexus and H. kernensis constitute the second group. These species have a wider host range and greater variation in characters purported to be specific differences. The third group includes those lung flukes which do not contain extracaecal loops (H. medioplexus and H. complexus). Of these, only H. medioplexus had little geographical variation and was found to occur in a single frog host.
Pallisentis nagpurensis (Bhalerao, 1931) (Acanthocephala: Quadrigyridae) from the gabus, Ophiocephalus striatus, from Depok, Indonesia
Authors: Kennedy Murray J.
Published: April 2009

Pallisentis nagpurensis (Bhalerao, 1931) Baylis, 1933 from the small intestine of the gabus, Ophiocephalus striatus, from Depok, Indonesia, is redescribed. Additional data are given for the males, and for females for which previous descriptions were either inadequate or absent. The relationship between P. nagpurensis (Bhalerao, 1931) Baylis, 1933 and Pallisentis gaboes (MacCallum, 1918) Van Cleave, 1928 is clarified.
The population structure of Simulium vittatum (Zett.): the IIIL-1 and IS-7 sibling species
Authors: Rothfels Klaus , Featherston David
Published: April 2009

This paper describes two sibling species in Simulium vittatum (Zett.) on the basis of their salivary gland chromosomes. The IIIL-1 sibling is characterized by a Y chromosome carrying the IIIL-1 inversion; the IS-7 sibling is characterized by the IS-7 X chromosome. The basic banding sequences are identical in the two sibling species. The siblings differ however in the relative frequencies of standard and inverted sequences for a number of autosomal polymorphisms that they share. Standard sequences are predominant in the IIIL-1 sibling and inverted sequences in the IS-7 type. The IIIL-1 sibling is distributed from the Atlantic, south to the Gulf of Mexico and west to the Saskatchewan–Alberta border. The IS-7 sibling ranges from the Atlantic to Alaska, but so far has not been found south of Pennsylvania. The sibling species are sympatric over a wide zone extending through parts of Quebec, Ontario, and northeastern United States via Michigan, Wisconsin, and Minnesota to Saskatchewan and Alberta. It is argued that the two sibling species originated in the region of the present sympatry. Evidence for this conclusion derives from the geographic pattern of sex chromosome and autosome polymorphism in North America and from cytological characteristics of certain extraterritorial populations (Iceland).
The haemocyte of the holothurian Eupentacta quinquesemita: ultrastructure and maturation
Authors: Fontaine A. R. , Hall B. D.
Published: April 2009

The ultrastructure of the haemocyte (erythrocyte) is described. A full complement of functional organelles is retained for the cell's lifespan. Sequences in haemocyte maturation are identified. Organelle abundance and metabolic activity appear to peak during maturation. Cell size increases and shape transforms from spheroid to ellipsoid, reverting to spheroid at full maturation; these are accompanied by changes in the configuration of the microtubule cytoskeleton (marginal band). The adaptive significance of haemocyte shape is discussed. Lymphocytes do not appear to be prohaemocytes (stem cells). Very immature haemocytes have protrusions that suggest recent detachment from an epithelial surface. The high frequency of maturing stages, variability of volume, and variability of cell population suggest a frequent turnover of perivisceral coelomic fluid correlated with the species' proneness to evisceration.
Metazoan parasites as indicators of movements of anadromous brook charr (Salvelinus fontinalis) to sea
Authors: Black Geoff A.
Published: April 2009

Changes in the numbers of metazoan parasites of anadromous brook charr, Salvelinus fontinalis, during the summer 1980 were determined by examining 220 fish at different times and localities in the Moisie River, Quebec. The marine trematode Brachyphallus crenatus remained in brook charr during their movements into fresh water. Differences in the prevalence of this parasite between sampling localities in late July indicated that some charr which undergo smoltification do not go to sea although others do. Also, infection with B. crenatus enabled an estimate to be made of the percentage of charr that had been to sea entering a tributary in late August. Brook charr were also infected with Crepidostomum cooperi, Diplostomum spathaceum, Eubothrium salvelini, Proteocephalus sp., Metechinorhynchus lateralis, Echinorhynchus gadi complex, Cystidicoloides tenuissima, Hysterothylacium sp., Anisakis simplex, Acuarioidea: Seuratiinae gen. sp., Salmincola edwardsii, and glochidia larvae.
Redescription of Cosmocephalus obvelatus (Creplin, 1825) (Nematoda: Acuarioidea) from Larus delawarensis Ord (Laridae)
Authors: Anderson R. C. , Wong P. L.
Published: April 2009

Cosmocephalus obvelatus (Creplin, 1825) Seurat, 1919 is redescribed on the basis of specimens from the oesophagus of Larus delawarensis Ord from Lake Ontario. The specimens were compared with Creplin's (1825) types of C. obvelatus and the following synonyms of obvelatus are recognized: Cosmocephalus diesingi Molin, 1858; Spiroptera adunca Stossich, 1892 (not Creplin, 1846); Cosmocephalus aduncus Yorke and Maplestone, 1926 (not Creplin, 1846); Cosmocephalus faridi Khalil, 1931; Cosmocephalus firlottei Rao, 1951; Cosmocephalus tanakai Rodrigues and Vicente, 1963. Creplin's types of Cosmocephalus adunca (Creplin, 1846) Yorke and Maplestone, 1926 were examined and shown to belong to the genus Paracuaria resulting in the new combination Paracuaria adunca (Creplin, 1846) n.comb. Cosmocephalus asturis Yorke and Maplestone, 1926 is transferred to the genus Synhimantus, i.e. S. asturis (Yorke and Maplestone, 1926) n.comb. Besides C. obvelatus, the genus Cosmocephalus apparently contains only C. capellae Yamaguti, 1935; C. imperialis Morishita, 1930; and C. jaenschi Johnston and Mawson, 1941.
Development of vocalizations in the American Coot
Authors: Cosens Susan E.
Published: April 2009

Vocal development was followed in laboratory-reared American Coots (Fulica americana). Four call types were observed in young chicks: twitter, wit-ou, squawk, and yeow. During the first month all calls showed changes in pitch. Call duration showed no change in the twitter and yeow calls, but showed an increase in both the wit-ou and squawk calls. Twitters were dropped from the repertoire after 30 days of age, whereas yeow calls were dropped after about 2 months of age. When approximately 2 months old, juveniles used three calls, one derived from the squawk, and two derived from the wit-ou. Sexual dimorphism also developed when birds were about 2 months old. By 3 months of age, juvenile calls resembled those of adult coots.
Physical and reproductive characteristics of an expanding woodland caribou population (Rangifer tarandus caribou) in northern Labrador
Authors: Parker G. R.
Published: April 2009

One hundred and fifty-nine caribou (Rangifer tarandus caribou) were collected from the area of precalving distribution of the George River population in northern Labrador between April 3 and 15, 1980. The sample revealed that caribou of northern Labrador reach physical and reproductive maturity earlier than most other free-ranging caribou populations in North America. Females attained mature values for lean body weight and shoulder height by 34 months and for total body length, heart girth, and mandible length by 46 months. Pregnancy rates for females 22, 34, and 46 months and older were 43, 90, and 95%, respectively. Measurements of fat reserves showed George River females to be in superior physical condition during spring migration than caribou on mainland Northwest Territories. Fat reserves, however, were substantially less than comparable values for females collected from the same population in March, 1976. The calf: pregnant female ratio was 42:100, suggesting a 1st year rate of mortality of approximately 58%. The most common internal parasites were Cysticercus tenuicollis and Fascioloides magna. It is concluded that the recent growth of the George River population has resulted from early female physical and reproductive maturity, low adult mortality, and high survival of calves.
The surface topography of Benedenia sp. (Monogenea: Capsalidae)
Authors: Cone D. K. , Beverley-Burton M.
Published: April 2009

The tegumental surface of Benedenia sp. (Monogenea: Capsalidae), a skin-dwelling parasite of Haemulon sciurus (blue-striped grunt) from coastal waters of Bermuda, was examined using scanning electron microscopy. The dorsal surface of the body and haptor is covered with comparatively long, flexible microvilli (2 to 3 μm in length; density 5/μm2), and the ventral surface of the body is covered with short, stubby microvilli (0.5 μm in length; density 10/μm2). The surface of the two anterior adhesive discs has three transverse zones which differ morphologically: the anterior region has a reticulate texture with uniciliated structures arising from some of the elevated ridges; the middle zone has a dense mat of short microvilli with scattered uniciliated structures, each of which is surrounded by a collar of shorter protuberances; the posterior zone is smooth and lacks ciliated structures. The ventral surface of the haptor is also smooth with the bare extremities of the accessory sclerites and the anterior and posterior hamuli protruding. The surface topography of Benedenia sp. is compared with that of other monogeneans.
The digestive enzymes of detritus-feeding stonefly nymphs (Plecoptera; Pteronarcyidae)
Authors: Martin M. M. , Martin J. S. , Kukor J. J. , Merritt R. W.
Published: April 2009

Proteolytic activity in the midguts of immature stages of the two detritus-feeding stoneflies, Pteronarcys pictetii Hagen and P. californica (Newport) is very high, and is comparable with levels recorded in other aquatic detritivores. Conditions close to neutrality prevail in the midguts of both species, a situation which is in contrast with the highly alkaline conditions typical of some detritus-feeding Diptera and of many foliage-feeding insects which possess digestive systems presumed to be adapted for the digestion of protein which is bound to polyphenols. The digestive systems of both P. pictetii and P. californica are poorly adapted for the digestion of the major polysaccharides present in detritus. Under natural conditions, polysaccharide digestion is probably restricted to α-1,4-glucans, the chief storage polysaccharides of higher plants, algae, fungi, and animals, and β-1,3-glucans, which are present in algae and fungi. Low or negligible enzymatic activity was detected toward the major structural polysaccharides of higher plants.
The buccal capsule of Caenorhabditis elegans (Nematoda: Rhabditoidea): an ultrastructural study
Authors: Wright K. A. , Thomson J. N.
Published: April 2009

The buccal capsule of the free-living nematode Caenorhabditis elegans has been analysed by serial section electron microscopy. Whereas the regions classically identified in the rhabditid buccal capsule can be distinguished, the cuticle lining does not constitute separate cuticular plates, but rather, structural–functional differentiations within a cuticle continuous with that of the esophagus. Only the lip region (cheilostom) is lined by body wall cuticle. The prostom cuticle is underlain by two rings of syncytial arcade cytoplasm connected to nine cell bodies. The mesostom cuticle is underlain by the nonmuscular epithelial cells of the esophagus, whereas the cuticle of the metastom and telostom is underlain by esophageal muscle cells m1 and m2. During moulting, buccal cuticle is produced later than body cuticle and its formation is characterized by accumulation of dense granules in both arcade and esophageal cytoplasm. It is concluded that the buccal capsule should be considered as "astomatous" in the terminology of K. A. Wright.
Production and reproduction in Hymenolepis diminuta (Platyhelminthes: Cestoda)
Authors: Boddington M. J. , Mettrick D. F.
Published: April 2009

The productive and reproductive capacities of the tapeworm Hymenolepis diminuta were examined at five densities of infection, in two strains of rat host, bred and weaned in two facilities and maintained on two different diets.Density of worm infection and host diet significantly affected worm growth. Total egg production by the worms increased with density of infection, but decreased for individual worms. Reduced egg production was a function of both reduced worm proglottid production and a decrease in eggs per proglottid. Energy content increased from the immature through the gravid regions of the worms.Total net worm production increased with density of infection with a matching decrease in individual production. Approximately 80% of net production was put into reproduction. Biomass turnover rate remained relatively constant over all levels of infection.Comparison with similar data from free-living helminths indicates that the enormous differential in egg production rates of individual worms can largely be accounted for by the differences in relative body and egg sizes.
Eutylenchus excretorius n. sp. (Nematoda: Atylenchidae) from Quebec, Canada
Authors: Ebsary B. A. , Eveleigh E. S.
Published: April 2009

Eutylenchus excretorius n. sp. is described and illustrated from Quebec, Canada. The new species differs from E. vitiensis by having stylet lengths of 20–22 μm, a more posterior excretory pore (94–105 μm from head) located posterior to the hemizonid in the posterior half of the isthmus, and by the presence of an elevated disc-like vulval area. A key to the genera and species of Atylenchidae is also provided.
Age determination in the arctic fox (Alopex lagopus)
Authors: Bradley J. A. , Secord D. , Prins L.
Published: April 2009

Canine teeth from foxes (Alopex lagopus) trapped in the Canadian arctic were aged by counting annular layers in the cementum. Of 513 teeth examined by this method, 448 were from foxes <1 year of age. Only 11% of those caught in February of their first year had a developing incremental line, compared with 77% in foxes >1 year. Simple linear measurement of the anteroposterior width of the pulp cavity was found to be an accurate method of aging 80% of juveniles.
Activity of moose and white-tailed deer at mineral springs
Authors: Fraser D. , Hristienko H.
Published: April 2009

Activity of moose (Alces alces) and white-tailed deer (Odocoileus virginianus) was studied at two natural mineral springs (licks) in Ontario during the springtime and summer of 1977 to 1980. Most adult moose appeared to use a lick during a single 1- to 5-day period in a year; some returned at intervals during the season; and all seemed drawn principally by the mineral-rich water. Some young moose remained in the lick vicinity for 3 weeks or more, and often wandered in and out of the licks, grazing herbage as well as drinking. This suggested a social as well as a nutritional attraction for young moose. Activity of both moose and deer increased after leaf flush. Adult male moose used licks most heavily in late May and early June, adult females in middle and late June. Use by young animals was more variable, but all moose activity declined in late June when aquatic feeding became common. Deer continued to use licks heavily until mid-July. Evidently the Na hunger that motivates lick use is related to spring phenology and wanes during the summer. Social and other behaviour seen at licks is described.
Metorchis conjunctus (Cobbold, 1860) Looss, 1899 (Trematoda: Opisthorchiidae): isolation of metacercariae from fish hosts
Authors: Watson Thomas G.
Published: April 2009

After 40 years Lac Edouard, Québec (46°45′ N, 72°55′ W), remains a focus of Metorchis conjunctus. Prevalence of infection differs for species of fish: Catostomus commersoni (100.0%), C. catostomus (81.8%), Semotilus corporalis (78.3%), and Salvelinus fontinalis (71.4%). All cysts isolated from S. fontinalis had a dense calcium coat.Many metacercariae, recovered after digestion of the fish in acid–pepsin solution, were viable and infective to domestic cats. Viability apparently depended on time of collection since more encysted larvae were found to be viable in October (32.4%) than in May (19.6%). Metacercariae of M. conjunctus were distributed in C. commersoni in an anterior–posterior density gradient. Anterior regions of the fish were more likely to be penetrated by the cercariae, based on both density and percent of metacercariae recovered. It is concluded, as a result of this study, that fish swim into clouds of cercariae which actively penetrate into the musculature of the fish.
Modifications ultrastructurales des parois végétales dans le tube digestif d'une larve xylophage Oryctes nasicornis (Coleoptera, Scarabaeidae): rôle des bactéries
Authors: Bayon Colette
Published: April 2009

The ultrastructural modifications of plant cell walls have been studied in the food and gut contents from the xylophagous larvae of Oryctes nasicornis. Before ingestion the natural food undergoes a large amount of degradation by fungus-rich microflora of the soil. The break-down of α-cellulose, and amorphous and crystalline cellulose of the secondary walls occurs in the mesenteron and later in the proctodeal dilation where it is greatest. The role of bacteria is recognised and the successive stages of degradation are characterised.
Cyclomorphosis in Bosmina and copepod predation
Authors: Wong C. Kim
Published: April 2009

In Pinks Lake, Quebec, individuals of the cladoceran Bosmina longirostris underwent an increase in mucro length during the summer at a time when adults of the predaceous copepod Epischura lacustris appeared. Predation experiments demonstrated that Bosmina with enlarged mucrones were less susceptible to Epischura predation than similar sized prey without the adaptation. The results support S. I. Dodson's hypothesis that cyclomorphosis is an adaptation against size-selective invertebrate predators.
Interspecific nest parasitism by redheads on islands in southeastern Alberta
Authors: Giroux Jean-François
Published: April 2009

I studied interspecific nest parasitism by redheads (Aythya americana) from 1976 to 1978 in a population of upland nesting ducks on artificial islands in southeastern Alberta. Of 685 duck nests, 19% were parasitized by redheads with a mean of 2.68 parasitic eggs per host nest. The proportion of nests parasitized increased with the density of host nests on the islands. There is also some evidence that the rate of parasitism was influenced by the nesting density of redheads. Mallards (Anas platyrhynchos) had the greatest percentage of nests parasitized by redheads whereas lesser scaup (Aythya affinis) had the largest number of parasitic eggs per nest. Redhead parasitism affected reproductive output of hosts by increasing nest desertion. Finally, the parasitic activity of redheads was reduced during a season characterized by drought conditions.
Pseudophoxinus persidis, a new cyprinid fish from Fars, southern Iran
Authors: Coad Brian W.
Published: April 2009

A new cyprinid, Pseudophoxinus persidis, is described from the province of Fars, southern Iran. It is distinguished from other members of the genus by a two-rowed pharyngeal tooth formula (modally 1, 5–4, 1), a complete lateral line with 35–43 scales, III, 7 dorsal fin rays, and III, 7–9 anal fin rays. The new species is found in endorheic and Persian Gulf drainages, in springs, qanats, streams and large rivers.
Relegation of Hatschekia acuta Barnard, 1948, to synonymy with Hatschekia conifera Yamaguti, 1939 (Copepoda: Siphonostomatoida)
Authors: Kabata Z.
Published: April 2009

Specimens of Hatschekia (Copepoda: Siphonostomatoida), taken from the gills of Brama japonicus (Pisces: Teleostei) in the eastern North Pacific, are described, illustrated, and identified as conspecific with Hatschekia acuta Barnard, 1948, originally recorded from South Africa. Comparison of that species with Hatschekia conifera Yamaguti, 1939, shows that they are also conspecific. A proposal is put forward to relegate H. acuta to synonymy with H. conifera. Host-dependent size differences are discussed.
Two species of Kudoa (Myxosporea: Multivalvulida) parasitic in the flesh of Merluccius productus (Ayres, 1855) (Pisces: Teleostei) in the Canadian Pacific
Authors: Kabata Z. , Whitaker D. J.
Published: April 2009

Two samples of hake, Merluccius productus (Ayres, 1855), one taken SW off Vancouver Island, the other in the Strait of Georgia, were examined for muscle parasites. The offshore hake is infected with two species of Kudoa Meglitsch, 1947 (Myxosporea): K. thyrsitis (Gilchrist, 1924) and K. paniformis sp.nov. Only K. thyrsitis occurs in the Strait of Georgia. The new species is described and illustrated. Host–parasite relationships of both species are discussed and reasons for their differences in this respect are speculated upon.