bluuebunny/crossref_metadata_2025 huggingface dataset:
Ontogeny of phonotaxis in Orchelimum gladiator (Orthoptera: Tettigoniidae: Conocephalinae)
Authors: Morris Glenn K. , Kerr Gordon E. , Gwynne Darryl T.
Published: August 2008

The ontogeny of phonotaxis in female Orchelimum gladiator was monitored in a circular arena using attraction to tape-recorded conspecific male song as the response criterion. Parasite-free females became responsive on day 5 or 6 after the final molt. Response appeared to wane after the 9th day. Mating on the 15th day extinguished responsiveness. Nematomorph-parasitized females were generally less responsive to song and none mated even when placed with a male.
Notes on tidal anticipation and migration in Gammarus duebeni Lilljeborg
Authors: Nuttall Peter M.
Published: August 2008

Hourly samples of Gammarus duebeni, taken upstream of a concrete obstruction to active invertebrate movement from the tidal reach of a river, indicated that the species undergoes tidal migration. Before a change in the tide, G. duebeni began migration in anticipation of a rapid increase in the conductivity of the river.
Note on the biology of Hydrophitrema gigantica Sandars, 1960 (Trematoda: Hemiuridae) from the lung of sea snakes (Hydrophis cyanocinctus)
Authors: Ko Ronald C. , Lance Valentine , Duggan R. T.
Published: August 2008

Of 183 Hydrophis cyanocinctus caught in Hong Kong, 180 were infected with Hydrophitrema gigantica. The intensity of infection per snake varied from 1 to 126 worms. The size composition of the parasite populations in winter and summer was studied on the basis of the measurements of 2404 worms. The histopathology of the infection is described and the taxonomic characters of the species are briefly discussed.
Relationship of body surface area to weight in fishes
Authors: Niimi A. J.
Published: August 2008

The relationship of body surface area to weight in fishes can be expressed by the equation S = KWb. The values of K and b can vary among species as well as during the different life stages of a species. For the species examined in this study, the values of K ranged from 5.8 to 10.8, and b from 0.64 to 0.74.
The reproductive season of Newfoundland caribou
Authors: Bergerud A. T.
Published: August 2008

The length of estrus, length of the estrous cycle, dates of breeding and calving, and length of gestation were investigated for Newfoundland caribou (Rangifer tarandus). The length of heat was about 48 h and the length of the estrous cycle was thought to be 10–12 days. Breeding observed during 5 years occurred between October 9 and October 19. In 6 years of observations, 90% of the calves were born in about a 12-day period, usually between May 24 and June 5. Information is provided on the weight of calves at birth. The gestation for four wild females with adequate winter diet was 229 days.
Differences in copulatory behavior as partial isolating mechanisms in the poeciliid fish Gambusia
Authors: Peden Alex E.
Published: August 2008

Differences between species were found in the direction of gonopodial thrust of male Gambusia during copulation. Males of species such as G. heterochir, G. marshi, and G. regani direct their gonopodia posteriorly in the same direction as the orientation of their female's urogenital sinus. Males of G. affinis and G. gaigei direct their gonopodia anteriorly, as would be expected from the morphology of their conspecific female's urogenital opening. G. vittata males adopt a precopulatory posture oriented at a much larger angle in relation to the female than is that of other species of Gambusia. This precopulatory angle probably allows male G. vittata to direct their gonopodia posteriorly rather than anteriorly during copulation.Because species of male Gambusia are known to court heterospecific females and produce hybrids in nature, ethological prefertilization mechanisms preventing this wasted effort are obviously inefficient. Since copulatory behavior and genital morphology are apparently adapted for efficient sperm transfer during conspecific copulation, the differences in copulatory behavior found in Gambusia could provide a partial prefertilization mechanism subject to reinforcement.
The breeding habitat of the ringed seal (Phoca hispida). The birth lair and associated structures
Authors: Smith Thomas G. , Stirling Ian
Published: August 2008

The subnivean lairs of the ringed seal (Phoca hispida) were studied in the Amundsen Gulf and Prince Albert Sound areas from 1971 through 1974. The structure of several different types of lairs are described. The existence of a birth-lair complex consisting of several closely adjacent lairs appears likely. The spacial distribution of lairs and lair types found on refrozen leads and in pressure ridges is described. Lairs were more abundant in inshore ice than in offshore ice. The function of subnivean lairs appears to be to provide thermal shelter, especially for neonate seals, and protection from predation by arctic foxes (Alopex lagopus) and polar bears (Ursus maritimus).
Studies on the bionomics of mermithid nematode parasites of blackflies in Newfoundland
Authors: Ebsary Barry A. , Bennett Gordon F.
Published: August 2008

Neomesomermis flumenalis is a univoltine nematode infecting the simuliids Prosimulium fuscum/mixtum during the winter months and the first (early spring) generations of the summer simuliids, primarily Simulium venustum, in May and early June. Infection of simuliid larvae occurred when water temperatures were 4–12 °C. Data extrapolated from late-instar larvae and pupae indicated that less than 0.03% and 0.06% of the P. fuscum/mixtum and S. venustum adults, respectively, were infected with this parasite, which is primarily a parasite of larval simuliids. Adult simuliids were not considered to be the source of the next generation of mermithids. The apparent host specificity of N. flumenalis is attributed to the close synchronization of the parasite life cycle with the life cycle of those simuliid species which overwinter in the larval stage and develop at temperatures less than 12 °C; temperatures above this level tend to be lethal to the preparasitic mermithids and simuliid species developing in the summer are thus not infected by this species. Male mermithids were more numerous than females in the Prosimulium populations but females outnumbered male mermithids in the S. venustum populations. When only a single mermithid parasitized a simuliid larva, the nematode was always a female; when more than one nematode parasitized a single larva, the nematodes were usually males.
Patterns of hibernation in the arctic ground squirrel
Authors: Morrison Peter , Galster William
Published: August 2008

Cyclic patterns were defined in subspecies of arctic ground squirrels (Citellus undulatus) from the Brooks and Alaskan Ranges. In the annual cycle a heterothermal (hibernation) season with entry, maintenance, and emergence stages was distinguished from a homeothermal (active) season with reproductive, recovery/growth, maintenance, and fattening stages. The heterothermal season consisted of a series of short hibernation cycles in which heterothermal (hibernation) periods with reentry, refractory, and irritable phases were distinguished from homeothermal (active) periods with arousal, maintenance, and preparation phases. Squirrels in which exposure to darkness at 5 °C was delayed (Nov. vs. Sept.) showed a lesser response but emerged synchronously with the normal group. Entry was attenuated with a normal light cycle at 5 °C (8 vs. 3 weeks). Juveniles showed a 2- to 4-week delay in entry as compared to adults.
Evidence for multiple insemination in the common garter snake, Thamnophis sirtalis
Authors: Gibson A. Ralph , Falls J. Bruce
Published: August 2008

Morph frequencies in litters of naturally mated female Thamnophis sirtalis from populations containing a recessive allele for melanism were found to deviate significantly from simple Mendelian values. These deviations are attributed to multiple male parentage. It is argued that multiple insemination and the resultant sperm competition are viewed most profitably together with copulatory plugs, hemipenal morphology, and aspects of male and female reproductive behavior as consequences of intense intrasexual selection among males.
The effect of physiological salines on the crop–gizzard of the earthworm, Lumbricus terrestris
Authors: Divers Fred C. , Pax Ralph A.
Published: August 2008

Isolated earthworm crop–gizzards bathed in Pantin's saline show rhythmic contractions at a rate of about 3/min. The contraction rate increases when intralumenal pressure is increased. However, when isolated crop–gizzards are bathed in a new saline developed by Drewes and Pax (1974) no spontaneous contractions occur.In situ experiments show that the activity for the crop–gizzard consists of irregularly spaced contractions at an average rate of only 0.7/min. This activity is altered by Pantin's saline, but not by the new saline.
Population performance of Microtus pennsylvanicus confined to woodland habitat, and a model of habitat occupancy
Authors: Grant P. R.
Published: August 2008

Enclosure experiments were conducted to investigate short-term population performance of the meadow vole, Microtus pennsylvanicus, when confined to woodland. Animals survived in summer and winter, and reproduced but with generally low success. A large variety of plants was eaten, many of which do not occur in grassland habitat. These results demonstrate that the usual avoidance of woodland is not due to the inability of that habitat to meet the minimum requirements of Microtus. Coexistence for several weeks was demonstrated with Clethrionomys gapperi, a potential competitor species, but at low density. In one experiment an interaction between Microtus and Clethrionomys was indicated by spatial segregation.Performance of Microtus populations was distinctly poorer in woodland than in grassland habitat. Maximum density was much lower in woodland, primarily as a result of lower average adult survival in summer and lower reproductive success, secondarily to lower initial densities. Survival of young which were trapped was about the same in the two habitats, and maximum longevity was actually higher in the woodland.A model is developed which relates the use of grassland and woodland by M. pennsylvanicus to differences in habitat carrying capacities and the presence of competitors. Three hypotheses generated from it are outlined. The model poses the question of what determines the threshold density at which movement from a habitat is induced.
Reduced activity in transmitter-carrying voles
Authors: Hamley J. M. , Falls J. B.
Published: August 2008

Transmitter-carrying meadow voles (Microtus pennsylvanicus) behaved normally as judged by casual observation and live-trapping, but showed reduced activity in exercise wheels for several days.
Transferrin polymorphism in blueback herring, Alosa aestivalis (Mitchill)
Authors: McKenzie Joseph A. , Martin Christina
Published: August 2008

Using vertical polyacrylamide electrophoresis and autoradiography we have shown that blueback herring, (Alosa aestivalis), is polymorphic for transferrins found in the plasma. Assuming a three-allele, one-locus system, the frequencies of the transferrin bands agree with the Hardy-Weinberg model. Of the four samples analyzed, two were similar in transferrin frequencies but these were different from the other two. We conclude that transferrin is of limited suitability as a population marker in the case of blueback herring resident in the St. John River, New Brunswick.
An ultrastructural study of the enigmatic "rodlet cells" in the white sucker, Catostomus commersoni (Lacépède) (Pisces: Catostomidae)
Authors: Desser Sherwin S. , Lester Robert
Published: August 2008

The cytology of immature and mature stages of a peculiar and widespread cell, the "rodlet cell" is described from the epithelium of the operculum and gill raker of the white sucker, Catostomus commersoni. Immature stages were observed in the intermediate and basal zones of the epithelium. They were spherical to ovoid in shape and surrounded by a limiting membrane, beneath which were numerous microfilaments arranged in parallel. The cytoplasm of immature rodlet cells contained a prominent "active" Golgi complex, peripherally arranged mitochondria, numerous free ribosomes, and an extensive network of distended cisternae of granular endoplasmic reticulum. Mature rodlet cells were usually observed along the epithelial surface. These fusiform cells were surrounded by a thick wall which contained circumferentially arranged microfilaments. A nucleus, a spherical inclusion, and a Golgi complex were observed in the basal region of the cell. The cytoplasm contained many closely packed vesicles. Numerous mitochondria were aggregated in the apical region of the cell, which terminated in three or more microvillus-like processes. While the nature and function of the rodlet cells is not elucidated, it is postulated that they are not protozoan parasites.
Acid and alkaline phosphatase activity in relation to egg-laying and aging in Callosobruchus analis (Fab.) (Coleoptera: Bruchidae)
Authors: Dhand R. K. , Rastogi S. C.
Published: August 2008

Acid and alkaline phosphatase (EC 3.1.3.2 and EC 3.1.3.1) activities have been studied during aging of male and female Callosobruchus analis (Fab.). Acid phosphatase activity was found to be much higher than alkaline phosphatase activity in both sexes throughout adult life. Both the enzymes demonstrate two peaks of activity, one on the 3rd day and the other on the 10th day of the adult life. The first peak coincides with egg-laying activity in the female, where the egg production is found to be at a maximum until the 3rd day. The peak for both enzymes on the 10th day may be responsible for mobilizing of metabolites before the death of insects.
A gynandromorph cricket, Gryllus bimaculatus (Grylloptera: Gryllidae)
Authors: Johnstone D. E.
Published: August 2008

A nearly completely bilateral gynandromorph cricket, Gryllus bimaculatus (DeGeer), from a laboratory-reared culture is reported and described. Gynandromorphs and intersexes, and probable genetic development of these forms, are discussed.
Meloidogyne microtyla sp. nov. from southwestern Ontario, Canada
Authors: Mulvey R. H. , Townshend J. L. , Potter J. W.
Published: August 2008

A new root-knot nematode, Meloidogyne microtyla, infecting grass roots is described and illustrated. M. microtyla differs from its closest relative M. incognita in spicular and stylet length of the male, structures of the female lip region and head, and in the production of very small galls on tomato roots versus large galls by M. incognita. The perineal pattern is remarkably similar to M. incognita; the identification of species of Meloidogyne is discussed with regard to this similarity. Its host range and distribution in Ontario are included. This new root-knot nematode is the second species found occurring in the field. The northern root-knot nematode M. hapla is commonly found in the field.
Development of the giant kidney worm, Dioctophyma renale (Goeze, 1782) (Nematoda: Dioctophymatoidea)
Authors: Mace T. F. , Anderson R. C.
Published: August 2008

Dioctophyma renale was found in the right kidney of 48% of mink (Mustela vison) trapped in late fall and winter in the Black River area of Ontario. Eggs embryonated at temperatures from 14 C to 30 C. Eggs hatched in the intestine of the aquatic oligochaete Lumbriculus variegatus, and first-stage larvae migrated to the ventral blood vessel where development took place. The first molt occurred about 50 days after infection in oligochaetes kept at 20 C; the second molt occurred about 100 days after infection. Third-stage larvae removed from oligochaetes produced infection in a mink. Larvae given to frogs (i.e. Rana clamitans, melanota and R. pipiens) became encapsulated in the stomach wall or abdominal muscles. A mink was infected with larvae removed from frogs experimentally infected 25 days earlier. A mink was also infected with larvae found in a naturally infected bullhead (Ictalurus nebulosus). Infective larvae of D. renale were found in wild Rana catesbeiana (6.2%), R. septentrionalis (9.6%), and R. clamitans melanota (0.7%) in an area enzootic for dioctophymiasis. It is suggested frogs as well as bullheads are important natural paratenic hosts for D. renale. The various larval stages of D. renale are described and its third-stage larva is distinguished from that of Eustrongylides spp. which may also be found in frogs.
Ultrastructure of the esophageal procorpus in the plant parasitic nematode, Tylenchorhynchus dubius, and functional aspects in relation to feeding
Authors: Anderson R. V. , Byers J. R.
Published: August 2008

The ultrastructure of the procorpal region of the esophagus in the plant parasitic nematode, Tylenchorhynchus dubius, is described and interpreted in terms of function. The anterior procorpus has a small central core comprising attenuated processes of the esophageal cells that subtend the procorpal lumen and an outer sleeve comprising portions of the protractor muscle and marginal cells that are associated with the stylet base. Retractor muscles are absent, but fine filaments extending back from the posterior edge of the stylet knobs may play a role in retraction. Longitudinally oriented bundles of microtubules within both the marginal and, to a lesser extent, the muscle cells of the outer sleeve are a prominent feature of the anterior procorpus. Their function is unknown. The cytoplasmic extension ("dorsal duct") of the dorsal esophageal gland cell contains microtubules which lie parallel to the long axis of the extension and may participate in the transport of the secretory granules. The valvular end-apparatus of the terminal duct of the dorsal gland extension is described and a mechanism of its action is proposed. Structures filled with small vesicles resembling neurosecretory packets, which appear to be expanded nerve endings, are intimately associated with the ampulla of the dorsal gland extension.
Social behavior in a non-pupping colony of Steller sea lions (Eumetopias jubata)
Authors: Harestad A. S. , Fisher H. D.
Published: August 2008

An ethogram of 22 behavior patterns is described. Larger and older sea lions (Eumetopias jubata) are dominant to smaller and younger ones. Males are more socially involved, and their behavior becomes more complex than that of females.Adult male and female behavior is less vigorous than that of subadult males. Territories where adult males and females are concentrated are more tranquil than areas where subadult males aggregate. Since females avoid areas of activity and harassment by sexually mature subadult males, they group in territories which act as refuges. This contributes to the spacial organization of the colony.The behavior of subadult males results in social disruption, whereas social stability is accommodated by adult males and females who are more stationary and so maintain prolonged social relationships.Non-pupping colonies are spacially organized similar to pupping colonies except for the relative proportion of age–sex classes. Socially, non-pupping colonies are less organized than pupping colonies. Social organization in E. jubata is promoted by the tranquil or energy-conserving behavior and ability of adults and inhibited by the behavior of subadult males.
Response of the ovenbird (Aves: Parulidae) to an outbreak of the spruce budworm
Authors: Zach Reto , Falls J. Bruce
Published: August 2008

The response of the ovenbird (Seiurus aurocapillus) to an outbreak of the spruce budworm (Choristoneura fumiferana) was investigated in Algonquin Park, Ontario. Ovenbirds exhibited a functional response involving an unusual method of foraging for this species. The numerical response was based on smaller, more tightly packed territories and probably also on larger first and subsequent clutches. It is suggested that the great variability in clutch size of certain wood warblers (Parulidae) may indicate a tendency to lay successive clutches under conditions of food abundance.
Seasonal changes in the biochemical composition and nutritional state of the immigrant triclad Dugesia polychroa (Platyhelminthes: Turbellaria) in Toronto Harbour, Canada
Authors: Boddington M. J. , Mettrick D. F.
Published: August 2008

The biochemical components of a population of Dugesia polychroa from Toronto Harbour showed, with the exception of total nitrogen, statistically significant variations over the time period studied (May 1971 through January 1972). The variation in biochemical composition was not totally correlated to changes in percentage biomass (mean individual weight), although the latter was itself indicative of events occurring in the population.Fluctuations in carbohydrate, lipid, and caloric content were highly correlated to changes occurring in percentage biomass during the period of reproduction and subsequent recruitment to the population. During this period a maximum in stored food reserves and energy content was observed. Before the winter these fractions increased to a second peak but at a disproportionately higher rate than that for percentage biomass. In both cases the caloric values were lower than the maximum physiological energy values.The changing nutritional state of Dugesia polychroa strongly supports the thesis that triclad population numbers are controlled by intraspecific competition for food, and, specifically shows that Dugesia polychroa exists, at least in Canada, in a state of relative starvation over the whole year.
Individual recognition by song in white-throated sparrows. III. Song features used in individual recognition
Authors: Brooks Ronald J. , Falls J. Bruce
Published: August 2008

We investigated features of song important in recognition of neighbors by playing natural and altered songs to territorial male white-throated sparrows (Zonotrichia albicollis). The major pattern (ascending or descending) of notes in a song provided insufficient information for recognition, since strange songs were responded to as such, whether or not they resembled neighbors' songs in this respect. Songs consisting of only the first three notes permitted neighbor–stranger discrimination. Neighbors' songs were altered in various ways, though never beyond the normal range of variation for the population. We assumed that if features important for recognition of neighbors' songs were altered sufficiently, the birds would respond to neighbors' songs as though they were strange songs. We found that a change of more than 5 to 10% in pitch of the song, pitch of the first note, and possibly pitch change between the first and second notes interfered with recognition of a neighbor's song. In contrast, changes as great as 15% in duration of a song or of the first note had no effect on recognition. Reliance on pitch for recognition is consistent with present knowledge of natural variation in songs of individual white-throated sparrows and of auditory discrimination of birds. Features of song used in species and individual recognition are compared.
Demographic consequences of artificial selection at the LAP locus in voles (Microtus townsendii)
Authors: LeDuc Janice , Krebs Charles J.
Published: August 2008

A number of studies on small mammals have shown that changes in the frequency of alleles at polymorphic loci are correlated with population fluctuations. To determine whether the genetic composition of a population affected its density changes, we altered gene frequencies in two field populations of the vole Microtus townsendii. The fast allele, LAPF, was present in a control population at a frequency of about 35% from July 1971 to July 1973. By removing homozygous LAPS/LAPS voles from one experimental population we maintained an LAPF frequency of about 75%. Removal of LAPF/LAPF homozygotes from a second population resulted in an LAPF frequency of about 25%. We monitored demographic variables of the populations while the selection was being applied. The populations went through increasing and peak phases and then declined sharply during the spring of 1973. Different genotypes had an advantage in survival and reproduction during different phases of population density on the control area, and the selection that maintained the polymorphism on the control area could be correlated with population density. The altered allelic frequencies on the experimental areas did not produce any consistent effects on demography.
Paratylenchus neoprojectus n. sp. (Paratylenchinae: Nematoda) from alfalfa fields in Alberta, Canada
Authors: Wu Liang-Yu , Hawn E. J.
Published: August 2008

Paratylenchus neoprojectus n. sp. was found with P. projectus in soil around alfalfa collected from Breton, Alberta. The diagnostic characters established for P. neoprojectus were determined by studies of a population reared from a single larva. It has a spear 28 to 31 μ long. Lip region round, in some cases faintly truncate. Excretory pore usually is at the level of the basal esophageal bulb, 72 to 88 μ from the anterior end. Ovary prominently developed. Tail generally conically rounded, in some cases broadly or narrowly rounded.
Variations in the pituitary–interrenal axis and the abundance of circulating blood-cell types in juvenile coho salmon, Oncorhynchus kisutch, during stream residence
Authors: McLeay D. J.
Published: August 2008

According to histological and histometric indices, the pituitary–interrenal axis of juvenile coho salmon residing in a natural stream was inactive in postalevin fry sampled in the spring, and in summer and fall samples of fingerlings, compared with a December sample or with smolts captured the next spring. Interrenal nuclear diameters, interrenal cell size, and epsilon (adrenocorticotropin) cell nuclear diameters were highly positively correlated.The numbers of circulating small lymphocytes and thrombocytes were highest in summer samples. Numbers of circulating large lymphocytes and neutrophils (per thousand cells of all types) were small and did not differ from sample to sample.Histometric indices of pituitary–interrenal axis activity were negatively correlated with numbers of circulating small lymphocytes but were unrelated to thrombocyte counts. Water temperature during sampling was highly negatively correlated with interrenal number and cell size and epsilon-cell nuclear diameters, and positively correlated with small lymphocyte and thrombocyte counts.It was concluded that the pituitary–interrenal axis in juvenile coho salmon was activated by both cold-temperature acclimation and smoltification. Unlike thrombocytes, the seasonal variations in numbers of circulating small lymphocytes were attributed to adrenocortical secretory activity.
A 7-year life cycle for two Chironomus species in arctic Alaskan tundra ponds (Diptera: Chironomidae)
Authors: Butler Malcolm G.
Published: August 2008

The life cycles of two sibling Chironomus species inhabiting tundra ponds on the arctic coast of Alaska are interpreted from larval and adult data collected over 3 years. Emergence of adults was highly synchronous within each species, and the two emergence periods were always discrete. Larvae of the two species could not be separated morphologically and were treated as a single population through most of the life cycle. Analysis of larval size and development toward pupation indicated that seven cohorts coexist on nearly all sampling dates. A 7-year developmental period for each cohort is hypothesized and is supported by larval growth rates observed in the habitat and by the rates at which apparent cohorts progressed through the larval stages. Ten cohorts observed during the study period showed very similar schedules of growth and development, but cohort abundances varied considerably.This life cycle is among the longest reported for an arctic insect. It results from slow growth during an annual open-water season of about 90 days, though neither food nor temperature limitation could be definitely implicated in causing such slow growth. Coexistence of up to seven cohorts in each species stabilized Chironomus production and standing stock and may be important to benthic-feeding waterfowl which use these ponds.
Influence of forced renesting, seasonal date of laying, and female characteristics on clutch size and egg traits in captive American Kestrels
Authors: Bird David M. , Laguë Paul C.
Published: August 2008

Of 78 nesting attempts by captive American Kestrels (Falco sparverius) between 1974 and 1977, 95% successfully renested after removal of the first clutch. Replacement clutches had fewer eggs, longer eggs, and eggs with thicker shells than first clutches. Clutch size, egg length, eggshell thickness, and fresh egg weight declined seasonally. Renesting intervals were shorter in older, experienced layers and clutch size increased by 0.20 eggs with each additional year of age.
Description of Longidorus diadecturus n. sp. (Nematoda: Longidoridae), a vector of the peach rosette mosaic virus in peach orchards in southwestern Ontario, Canada
Authors: Eveleigh Eldon S. , Allen W. R.
Published: August 2008

Longidorus diadecturus n. sp., a virus vector found in peach orchards in southwestern Ontario, is described and illustrated. The most distinguishing feature of the species is the posterior position of the stylet guiding ring (50–64 μm posterior to head apex). It differs from closely related species with a posterior stylet guiding ring by the shape and length of the corpal mucro (sagittate, 1–2 μm), the length of the odontophore (55–66 μm), the expanded, set-off head, and the anteriorly located vulva (44–48%). The body lengths and the tail shapes and sizes are also diagnostic for larval stages.
The in vivo and in vitro development of Trypanosoma andersoni Reilly and Woo, 1982 and Trypanosoma grylli Nigrelli, 1944 (Kinetoplastida)
Authors: Reilly Brian O. , Woo P. T. K.
Published: August 2008

Trypanosoma andersoni Reilly and Woo multiplied in Hyla versicolor LeConte by binary fission as sphaeromastigotes and epimastigotes in the liver. Some experimentally infected frogs developed ascites and dividing T. andersoni and mononuclear macrophages were observed in the peritoneal fluid. Trypanosoma grylli Nigrelli multiplied by binary or multiple fission as sphaeromastigotes, epimastigotes, and rarely as trypomastigotes in the peripheral blood. In H. versicolor, no dividing T. andersoni was found in 50 days at 10 °C but dividing forms were seen at 22 and 30 °C. Dividing T. grylli were found for 10 days in frogs kept at 22 °C and for 50 days at 10 °C. However, no dividing form was seen at 30 °C.Trypanosoma andersoni and T. grylli were successfully cultured in a diphasic blood–agar medium. Trypanosoma andersoni blood trypomastigotes initially rounded up into primary sphaeromastigotes in slide cultures. Secondary sphaeromastigotes, epimastigotes, and metatrypanosomes were later formed in culture. All culture forms of T. andersoni except rounding trypomastigotes divided by binary fission. Trypanosoma grylli also formed sphaeromastigotes, epimastigotes, and metatrypanosomes in cultures. Multiple fission forms were common for this species. Cultures of both species of trypanosomes were cryopreserved and were infective to laboratory-raised H. versicolor 6 months later.
Cycles de développement de Skistodiaptomus oregonensis, Tropocyclops prasinus et Cyclops scutifer dans la zone limnétique du lac Cromwell, Saint-Hippolyte, Québec
Authors: Paquette Michèle , Pinel-Alloul Bernadette
Published: August 2008

A study of the life history of the three principal copepods (Skistodiaptomus oregonensis, Tropocyclops prasinus, Cyclops scutifer) in Lake Cromwell, Québec, demonstrated that these species are multivoltine. Skistodiaptomus oregonensis and T. prasinus have analogous life cycle strategies with two cohorts produced annually and active winter diapause as instar CV and adult; however, their reproductive periods are 2 months apart (May and July). Cyclops scutifer has two summer cohorts and a winter cohort without active diapause. The development times of cohorts are strongly related to water temperature but food availability and water oxygenation could also be of decisive importance for the development of summer cohorts.
Two new species of Paractinolaimus Meyl, 1957 (Nematoda: Paractinolaimidae) from the Mackenzie and Porcupine river systems, Northwest Territories, Canada
Authors: Eveleigh Eldon S.
Published: August 2008

Two new species of dorylaim nematodes, Paractinolaimus spanithelus n. sp. and Paractinolaimus longidrilus n. sp., from aquatic habitats are described and illustrated. The main differential characteristics of P. spanithelus are the small number of widely spaced supplements (12), length of sperms (9–10 μm), bluntly rounded convex–conoid shape of the male tail, and the number of pairs of caudal papillae in both sexes. Paractinolaimus longidrilus is distinguishable from closely related species by the spicule length (83 μm), the heavily cuticularized lateral guiding pieces that are broadly rounded distally, the number of pairs of caudal papillae (11) in the male, and the number of submedian ventral papillae (13) in the male.
Hirschmanniella pisquidensis n. sp. (Nematoda: Pratylenchidae) from roots of wild rice in Prince Edward Island, Canada
Authors: Ebsary B. A. , Pharoah G.
Published: August 2008

A new species, Hirschmanniella pisquidensis n. sp., is described and illustrated from wild rice growing in Prince Edward Island, Canada. The new species differs from H. mucronata and H. behningi, the most closely related species, by the shorter stylet, absence of spermatheca, sperm, and males, more anterior phasmid position, and complete areolation of the lateral field.
The genus Capillospirura Skrjabin, 1924 (Nematoda: Cystidicolidae) of sturgeons
Authors: Appy R. G. , Anderson R. C.
Published: August 2008

Capillospirura Skrjabin, 1924 (Nematoda: Cystidicolidae) is redefined on the basis of a study of specimens from old world sturgeons. It can be distinguished from the closely related Ascarophis van Beneden, 1870 by a bidentate plate-like structure which arises from the anterolateral wall of the buccal cavity. Capillospirura is also characterized by narrow pseudolabia with a ridge-like apex, submedian labia, and sublabia in subdorsal and subventral quadrants of the oral opening. Three species are assigned to Capillospirura: C. ovotrichuria Skrjabin, 1924 and C. argumentosa (Skrjabina, 1966) n. comb. (= Ascarophis argumentosus) from old world sturgeons and C. pseudoargumentosa (Appy and Dadswell, 1978) n. comb. (= Caballeronema pseudoargumentosus) from a new world sturgeon. The value of cephalic structure in cystidicolid taxonomy is discussed.
Life-history characteristics of a stream population of the freshwater clam Sphaerium striatinum Lamarck (Bivalvia: Pisidiidae)
Authors: Hornbach Daniel J. , Wissing Thomas E. , Burky Albert J.
Published: August 2008

Life-history characteristics of a population of Sphaerium striatinum in Little Four Mile Creek, OH, were studied from August 1977 to April 1980. Two generations of clams were produced each year, with major recruitment occurring in April – early July and August–October. Individuals born during either birth period lived for about 1 year. Minimum size at birth was 4.0 mm, and only adults with a shell length > 10.0 mm contributed to recruitment in the population. Examination of seasonal size distributions of embryos revealed an average embryonic development rate of 0.32 mm∙week−1 during April–October; the rate was lower during other times of the year. The annual selection ratio (average number of young born per adult) was 10.49:1 (7.68:1, April–July; 3.81:1, August–October); embryonic mortality was 97.5%. These results are compared with published values for a lake population of S. striatinum and indicate that the differences observed in life history characteristics for these populations apparently do not conform to expectations based on r- and K- selection theory. Instead the differences can best be explained by a "bet-hedging" theory dependent on stochastic rather than deterministic processes. Life-history characteristics of other pisidiid clams are compared with results from this study and discussed in relation to the adaptive plasticity of freshwater molluscs.
Water permeability in the developing embryo of the zebrafish, Brachydanio rerio
Authors: Harvey Brian , Chamberlain J. Blake
Published: August 2008

The water permeability of developing embryos of the zebrafish, Brachydanio rerio, is measured indirectly by noting the time taken for the embryos to fall through deuterated water. Stages between early high blastula and one-half epiboly were judged to be most permeable to water; we suggest that the change in the ratio of surface area to volume that accompanies decreasing cell size may increase overall permeability.
Cyatholaimidae (Nematoda) from the Canadian Pacific coast
Authors: Sharma J. , Vincx M.
Published: August 2008

Four species of Cyatholaimidae, represented in a study of free-living marine nematodes from Vancouver, Canada, are discussed. This paper includes the description of Marylynnia hopperi sp. nov., Paracyatholaimus vancouverensis sp. nov., and Propomponema websteri sp. nov., as well as the redescription of Paracyatholaimus pugettensis Wieser and Hopper, 1967.
Cytological studies of sibling species of Simulium tuberosum (Lundström) (Diptera: Simuliidae)
Authors: Mason G. F.
Published: August 2008

This paper extends the known geographic distribution of S. tuberosum siblings recorded in 1962 by R. Landau by analyzing the polytene chromosomes in the larva. Her seven basic IIS arrangements are augmented by the addition of four new types. These were St/A, A/A; CDE-2/CDE, CDE/CDE; Y2/AB, AB/AB; and FGI. These new siblings, like the originals, have fixed differences in chromosome arm IIS. One of these, FGI, distinguished by a high degree of polymorphism, and the presence of fixed differences from the tuberosum standard in arms IS, IL, and IIIL, occurred both in Alaska and Norway. A comparison of the standard tuberosum, the S. venustum, and the FGI sibling chromosome pattern revealed the FGI sibling to be much closer to the venustum standard than any other tuberosum sibling. A second new sibling (Y2/AB) from Norway differed from the standard in the Y chromosome by multiple rearrangements in IIS and two tandem inversions in IIL. The fixed changes on arms other than IIS in the FGI siblings and the Y2/AB sibling are the first to be detected in this complex. There were a number of shared inversions in the populations studied indicating a common ancestor and (or) introgression.
Description of Helicotylenchus amplius n. sp. and a key to the Canadian species of the genus (Nematoda: Hoplolaimidae)
Authors: Anderson R. V. , Eveleigh E. S.
Published: August 2008

Helicotylenchus amplius n. sp., a parthenogenetic plant-parasitic spiral nematode in Canada, is described and illustrated. The distinguishing characters are a thick, digitate ventral tail projection with a terminal mucro, fine annulations on the tail end and open-ended lateral field, a conical head, stylet length of 26–29 μm, and a deep vulval atrium and large uterus which occupies most of the body width. A key is provided to aid in the identification of the Canadian species of Helicotylenchus Steiner, 1945.
Stomach contents of immature lobsters (Homarus americanus) from Placentia Bay, Newfoundland
Authors: Carter J. A. , Steele D. H.
Published: August 2008

Stomachs of immature lobsters (Homarus americanus) from Placentia Bay, Newfoundland, were examined to determine natural diet. The most frequently occurring prey were sea urchins, mussels, rock crabs, polynoid and nereid polychaetes, and brittlestars. There was high incidence of lobster exuviae during the moulting period in late summer. Rock crabs, brittlestars, and mussels were dominant (in terms of relative volumes of hard parts in each stomach) more often than other food items. Sea urchins, periwinkles, chitons, rock crabs, and polynoids were consumed more frequently in late summer compared with other seasons. Stomach contents constituted approximately 1% of the wet weight of individual lobsters. There were no significant seasonal differences in stomach fullness during the period June to November.The residencies of natural prey hard parts in immature lobster stomachs were estimated. Some items remained in stomachs for up to 180 days. Measures of stomach fullness of lobsters 3 days after ad libitum feeding on rock crabs, mussels, and sea urchins were similar. Linear selection indices indicated relatively high selection by immature lobsters for hard parts of rock crabs and mussels and positive selection for nereids, polynoids, and brittlestars. Immature lobsters showed negative selection for hard parts of sea urchins, starfish, and periwinkles.
Isolation and characterization of antifreeze glycoproteins from the frostfish, Microgadus tomcod
Authors: Fletcher Garth L. , Hew Choy L. , Joshi Shashikant B.
Published: August 2008

The antifreeze proteins were isolated from frostfish (Microgadus tomcod) using gel filtration and ion exchange chromatography and characterized by high-performance liquid chromatography. The antifreeze proteins were glycoproteins which appeared to consist of at least six components with molecular weights ranging from 2 550 to 32 200. Chemical analysis of the larger components showed a predominance of alanine, threonine, and galactosamine. The smaller peptides contained proline and arginine in addition to alanine and threonine. The amino acid sequence of the smallest glycopeptides (molecular weight 2 550) was found to be Ala-Ala-Thr-Ala-Ala-Thr-[Formula: see text]-Ala-Thr-Ala-Ala-Thr-Pro-Ala-[Formula: see text]-Ala-Ala.These glycopeptides are very similar in amino acid and carbohydrate composition to those isolated from the Antarctic nototheniids and several northern gadoids. The sequence of the first 14 amino acids of smaller glycopeptides from the frostfish is identical to comparable peptides found in the nototheniids and the saffron cod. To date arginine has only been observed in the glycopeptide antifreezes of the frostfish and the saffron cod.
A redescription of Acanthocephalus bufonis (Shipley, 1903) Southwell and Macfie, 1925 (Acanthocephala: Echinorhynchidae) from the black-spotted toad, Bufo melanostictus, from Bogor, Indonesia
Authors: Kennedy Murray J.
Published: August 2008

Acanthocephalus bufonis (Shipley, 1903) Southwell and Macfie, 1925 is redescribed on the basis of specimens collected from the black-spotted toad, Bufo melanostictus Schneider, 1799, from Indonesia. The material collected by Southwell and Macfie in 1925 and by Petrochenko in 1953 is not considered conspecific with that collected by Shipley in 1903. The species described by Petrochenko is given the name Acanthocephalus breviprostatus nom. nov.; that of Southwell and Macfie is unnamed until a more adequate description is produced.
The demography of low-litter-size populations of Microtus californicus
Authors: Krohne David T.
Published: August 2008

Densities of populations of Microtus californicus inhabiting North Coastal perennial grasslands were found to be consistently less than 60 per acre over a 5-year period. There is no evidence of multiyear cyclicity in the fluctuations of this population. Another unusual feature of the population is the extremely low level of recruitment. Adults in this habitat appear to weigh more than similar animals in cycling populations in annual grasslands. Smaller litter sizes in perennial grasslands and perhaps higher juvenile mortality are thought to contribute to the low recruitment rates and the absence of cycling.
Foraging in bumblebees: rule of departure from an inflorescence
Authors: Pyke Graham H.
Published: August 2008

Most aspects of the bumblebees' rule of departure from an inflorescence of Aconitum columbianum are qualitatively what would be expected if the bumblebees maximize their net rate of energy gain. Flower revisitation increases with increases in the number of flowers already probed on an inflorescence and with decreases in the number of flowers available. Nectar volume per flower tends to decrease with increasing relative flower height and there is a positive correlation between nectar volumes of flowers from the same inflorescence. Consequently the bumblebees should be increasingly likely to leave an inflorescence with increases in either the number of flowers already probed or the relative height of the last flower and with decreases in either the number of flowers available or the nectar volume obtained at the last flower. The bumblebees showed all these trends.
Evaluating the sterile male method on Red-winged Blackbirds: clinical evaluation of thiotepa as a sterilant
Authors: Potvin Normand , Bergeron Jean-Marie , Norman Mark , Cyr André
Published: August 2008

Before attempting a small-scale field trial of the sterile male method to reduce blackbird population levels, laboratory studies were undertaken, in 1978 and 1979, to evaluate the efficiency of thiotepa as a bird sterilant. The LD50 of thiotepa was determined (6.2 mg/kg of body weight), as well as the applicable dose to produce sterility (4.32 mg/kg of body weight) without causing mortality, following a treatment beginning on April 25, 1979. This dose inhibited testicular growth for about 1 month. During this period, testes weight of treated redwings was only 10% of normal weight. Identical doses to those administered to male redwings produced the same effects on testicular development of grackles and cowbirds. No effects were noted on the testes weight of male Red-winged Blackbirds 1 year after treatment with thiotepa. Results indicated that the sterile male approach may have potential to reduce blackbird populations causing crop damage.
A collection of zooplankton from Tuktoyaktuk Harbour, Northwest Territories
Authors: Sutherland Ian
Published: August 2008

Forty-seven taxa of zooplankton were identified from collections taken during larval fish tows in the Tuktoyaktuk region. The zooplankton fauna consists of three components: a small number of common species characteristic of brackish water and a large number of rare species of either freshwater or marine affinities. Eurytemora gracilicauda Akatova l949, E. raboti Richard 1897, and E. richingsi Heron &Damkaer 1976 are newly recorded from Canada.
The occurrence of cartilage canals in shark vertebrae
Authors: Hoenig John M. , Walsh Alexander H.
Published: August 2008

Cartilage canals were found in the vertebrae of 16 species of sharks from five families. The canals variously contain blood vessels, lymph-like material, clumps of immature chondrocytes, unidentified amorphous material, or appear empty. Of 10 species examined in the family Carcharhinidae, only the dogfish, Mustelus canis, was devoid of canals. No canals were seen in the two batoid fish examined. The presence of canals may depend on the phylogenetic position or the maximum size attained by the species.
Phocanema decipiens (Nematoda: Anisakinae): experimental infections in marine copepods
Authors: McClelland Gary
Published: August 2008

Gravid female Phocanema decipiens were recovered from the stomachs of freshly killed harbour (Phoca vitulina) and grey seals (Halichoerus grypus). Ova dissected from the nematodes were incubated in seawater and the mean time to hatch varied from 8 days at 20 °C to 52 days at 5 °C. Posthatch survival of ensheathed larvae in seawater varied from 48 h at 20 °C to 140 days at 5 °C. Fifteen species of copepods collected from the North West Arm, Halifax, N.S., were exposed to freshly hatched larvae of P. decipiens. Exsheathed larvae of the parasite were subsequently detected in the haemocoel of 12 harpacticoid species including Danielsennia typica, Tisbe furcata, Ameira longipes, Enhydrosoma curticauda, and various undescribed species of the genera Halectinosoma, Tisbe, Alteutha, and Phyllothallestris and the family Diosaccidae. Phocanema decipiens also occurred in a cyclopoid copepod (Paracyclopina sp.) but calanoid copepods (Eurytemora sp. and Pseudocalanus sp.) did not become infected. The heaviest infections occurred in mature female copepods and prevalence and intensity of infection varied with host species. Adult male copepods and fifth copepodite females were lightly infected. Infected copepods survived for 3–7 days at 15 °C, 10–15 days at 10 °C, and 20–35 days at 5 °C. During the course of infection, larval P. decipiens grew an average of 60% and maximum of 130% in length but underwent little or no morphological change.