bluuebunny/crossref_metadata_2025 huggingface dataset:
Suspended Sediment Particles Inside Gills and Spleens of Juvenile Pacific Salmon (Oncorhynchus spp.)
Authors: Martens Dennis W. , Servizi James A.
Published: August 2008

Intracellular sediment particles were observed in the gills of underyearling coho salmon (Oncorhynchus kisutch) and pink salmon (O. gorbuscha) following laboratory exposure to Fraser River sediment. Gills of underyearling sockeye salmon (O. nerka), chinook salmon (O. tshawytscha), and coho exposed to a natural suspended sediment in Cultus Lake hatchery water also contained intracellular mineral particles. Mineral particles were seen in both epithelial and underlying gill filamental cells, and it is believed that these particles were phagocytosed by the former. Intracellular sediment particles were also observed in spleens of some sediment-exposed fish. Electron microscopy was used to measure gill particle sizes and X-ray diffraction analysis to identify eight minerals and one metal in the gills of sockeye previously exposed to suspended sediment.
Nutritional Condition of the Pacific Lamprey (Lampetra tridentata) Deprived of Food for Periods of Up to Two Years
Authors: Whyte John N. C. , Beamish Richard J. , Ginther Norma G. , Neville Chrys-Ellen
Published: August 2008

The anadromous parasitic Pacific lamprey (Lampetra tridentata) does not feed during metamorphosis or its spawning migration. To assess the utilization of body reserves, we compared the compositions of an adult lamprey held for 2 yr without food, recently metamorphosed lampreys, and lampreys starved for 6 mo. Moisture was higher and soluble ash and lipid levels were lower in tissue of the 2-yr-starved than in metamorphosed lampreys (2.67 and 3.39 kj∙g−1, respectively). Fatty acid profiles of 2-yr-starved and metamorphosed lampreys were qualitatively similar except for the presence of 15:0 in the latter. Substantially lower levels of 14:0 and 16:1 n7 and higher levels of polyunsaturated fatty acids occurred in starved lampreys. Changes in composition of lampreys starved for 6 mo were similar to changes between the 2-yr-starved and metamorphosed lampreys. Maintenance energy in a normalized 1-g lamprey starved for 6 mo was derived from catabolism of 71% lipid and 29% protein; total loss was 2.56 kJ or 49% of the original energy. The ability to survive extended periods on endogenous reserves, which may have allowed L. tridentata to survive past environmental catastrophes, allows it to migrate considerable distances to spawning areas in the headwaters of rivers.
Estimating Crayfish Density in Lakes Using Quadrats: Maximizing Precision and Efficiency
Authors: Lamontagne S. , Rasmussen J. B.
Published: August 2008

We provide a method to estimate the number of quadrat samples needed to obtain precise crayfish densities at a site or transect for two quadrat sizes (1 and 10 m2). We based the analysis on data from a survey of 61 depth-transects from 31 lakes representing a gradient in crayfish density. There was no significant difference between density estimates obtained with different quadrat sizes for six transects where both quadrats were used. Fewer samples were needed with the large quadrat, but it was more efficient to use a 1-m2 quadrat at densities above 0.3 crayfish∙m−2 because less effort (i.e. diving time) was required to collect the requisite number of samples. There was a linear relationship between density estimates by quadrat and timed counts (a more rapid method to estimate crayfish density), but timed counts were less accurate.
Impact Assessment Using the Before-After-Control-Impact (BACI) Model: Concerns and Comments
Authors: Smith Eric P. , Orvos David R. , Cairns Jr. John
Published: August 2008

The effect of a change in an ecosystem can often be assessed through the use of a statistical model that incorporates the change. A sensible approach for assessing the effects of an industrial or power plant on the aquatic environment is to sample the environment both before and after the plant starts operation and test for a change in some biologically relevant parameter. To improve sensitivity, samples may be taken at a control site as well as at sites receiving the plant effluent. While this provides a powerful means for assessing effects, the implementation of the design is important and subsequent analysis of the collected data depends on proper implementation. Problems such as trends in the measurements, failure to meet the assumptions of the model, irregular sampling, confounding factors, and changes in the habitat can influence results, as we illustrate using a long-term impact assessment of a power plant on fish populations. In long-term studies, it may be difficult to separate effects due to the plant from effects due to other sources. Sound design requires both a good statistical model and an understanding of the underlying biological processes (what to measure) and careful planning (how to measure it well).
Fatty Acid Composition of Lipids in the Eggs and Alevins from Wild and Cultured Chinook Salmon (Oncorhynchus tshawytscha)
Authors: Ashton H. J. , Farkvam D. O. , March B. E.
Published: August 2008

The fatty acid profiles of lipids extracted from eggs and alevins of cultured chinook salmon (Oncorhynchus tshawytscha) were significantly different than those from eggs and alevins of wild fish of the same stock. The mean total concentrations of n3 fatty acids in the total lipid of eggs from wild and cultured broodstock were 40.2 and 29.4% and in the polar lipid 45.5 and 38.7% respectively. The mean concentrations of n3 fatty acids in the total lipid of alevins from wild and cultured broodstock were 35.4% and 23.2% and in the polar lipid 43.0 and 38.2%, respectively. The ratios of n3:n6 fatty acids were lower in both the neutral and polar lipids of eggs and of alevins from the cultured fish than in those of wild fish. The higher n3:n6 fatty acid ratios in the eggs and progeny of wild fish reflected the higher ratios in lipids of components of the natural marine food chain.
Methods for Nonlethal Gill Biopsy and Measurement of Na+, K+-ATPase Activity
Authors: McCormick Stephen D.
Published: August 2008

A gill biopsy, in which a small portion of gill tissue was removed from anesthetized fish, was shown to have no detrimental effect on subsequent survival, growth, and salinity tolerance of juvenile Atlantic salmon (Salmo salar). A method for measurement of Na+, K+ -ATPase activity in this small amount of gill tissue is presented. These methods are useful for nonlethal monitoring of physiological smolt characteristics in salmonids and may have applications in the study of disease, toxicology, and physiological ecology of many fish species.
Mirror-Elicited Agonistic Behaviour and Body Morphology as Predictors of Dominance Status in Juvenile Coho Salmon (Oncorhynchus kisutch)
Authors: Holtby L. Blair , Swain Douglas P. , Allan G. Michael
Published: August 2008

We tested whether body morphology and aggressive behaviour, measured through mirror image stimulation (MIS), could predict the eventual dominance status of juvenile coho salmon (Oncorhynchus kisutch) tested in paired contests and in stream tank interactions with several individuals. Dominance in paired contests was predicted by MIS behaviour on the fifth observation day using newly emerged juveniles and by MSS behaviour on the first observation day using 7-wk-old juveniles. In both.w420020 dstrials, deeper bodied fish tended to be dominant. In the stream tank tests, the MIS behaviour SAM (swim-against-mirror) and fork length were the best predictors of dominance. Large fish with high levels of SAM tended to be dominant. After removing the effects of fish size, neither body depth nor fin size consistently predicted dominance ability. SAM was positively correlated with overt aggressive behaviours in stream tanks but not with lateral displays, juvenile coho salmon appeared to react to conspecifics and to their own mirror images in a quantitatively similar way, and both MIS behaviour and body morphology were significant predictors of the outcome of agonistic interactions among individuals.
Biochemical aspects of pigment variation in the spider Enoplognatha ovata (Clerck) (Araneae:Theridiidae)
Authors: Seligy V. L.
Published: August 2008

Enoplognatha ovata (Cl.) exists as three varieties distinguished by their dorsal opisthosomal patterns. The pigments responsible for the coloration of these patterns closely resemble the two redox states of xanthomatin.
The life cycle of Trypanosoma chrysemydis
Authors: Woo Patrick T. K.
Published: August 2008

Trypanosoma chrysemydis of Chrysemys picta marginata reached the infective stage in 22 days in the crop and caeca of Placobdella parasitica and P. rugosa kept at 22–24 °C; this period was shortened to 14 days at 31 °C. Metacyclic stages were found in the crop. Leeches deprived of food for prolonged periods lost infections. Metacyclic forms reverted to epimastigotes and started to divide in leeches given a second blood meal. Leeches in nature probably retain infections throughout their lives if they get regular blood meals.Painted (Chrysemys picta marginata), snapping (Chelydra serpentina), and map (Graptemys geographica) turtles were infected by inoculation of metacyclic forms from leeches or cultures, and by bites of infected leeches. Turtles that ate infected leeches did not become infected. Amphibians could not be infected. The number of trypanosomes in the peripheral blood of naturally infected turtles was always low and only low parasitaemias were found in experimentally infected turtles, apparently because this trypanosome rarely divides in the vertebrate host.
The pH tolerance of Daphnia pulex (Leydig, emend., Richard)
Authors: Davis P. , Ozburn G. W.
Published: August 2008

The survival time and reproduction of female Daphnia pulex in solutions varying in pH have been observed. Dilute sodium hydroxide or sulfuric acid solutions were added to four different diluent waters: distilled water, aerated tap water, aerated and filtered tap water from an aquarium containing dace minnows, and McIntyre River water. D. pulex (initially up to 72 hours old) survived for the duration of the experiment (32 hours) in river water within a pH range of 6.1–10.3; in aquarium water within a pH range of 4.3–10.4; only at pH 6.4 and pH 7.6 in distilled water; and in none of the solutions using aerated tap water. The dissolved oxygen content was measured at the beginning and end of every experiment and was found never to fall below 6.2 p.p.m. Those individuals which survived were cultured in the laboratory and parthenogenesis was observed at pH values between 7.0 and 8.7.
The locomotor activity of Cryptolestes ferrugineus (Stephens) (Coleoptera:Cucujidae) in wheat
Authors: Watters F. L.
Published: August 2008

Moisture content was the factor that most affected locomotor activity of Cryptolestes ferrugineus in wheat at 15°, 22°, and 28 °C. More insects emigrated from dry than from damp wheat; accelerated emigration from damp wheat after 4 days at 28° was attributed to the growth of storage fungi, primarily Aspergillus spp. and Penicillium spp. Emigration was not different at insect densities ranging from 5 to 50 insects per 98 g of wheat.C. ferrugineus was positively geotactic except in wheat which had been previously infested. Emigration was stimulated in daylight and by continuous illumination, but was depressed in darkness.Starved insects were less active than unstarved insects in dry wheat, but both groups were equally active in damp wheat. Insects were more active in dry than in damp wheat, but activity did not differ when both wheats were cracked to provide more accessible feeding sites. Locomotor activity in moldy wheat was related to preconditioning; more insects preconditioned for 3 days in dry wheat remained in moldy wheat than did those preconditioned for 3 days on damp wheat.The results suggest that insects concentrate in damp or cracked wheat because they can feed, oviposit, and develop more readily than is possible in dry wheat. Thus, in grain bulks C. ferrugineus tends to disperse in dry regions and to concentrate in moister regions.
Male accessory gland substance: an egg-laying stimulant in Melanoplus sanguinipes (F.) (Orthoptera:Acrididae)
Authors: Pickford R. , Ewen Al B. , Gillott C.
Published: August 2008

The rate of egg deposition by mature virgin females of the migratory grasshopper, Melanoplus sanguinipes (F.), increased markedly after implantation of accessory glands from mature males. Implants consisting of one-half of a complete set of glands, or of the 10 short hyaline glands alone, were about equally effective in increasing the rate of egg deposition. However, in each case the oviposition rate was less than that of normally mated females of the same age. Implanting only the white glands of the accessory gland complex had a lesser effect on egg-laying and implants of the long hyaline gland or of the seminal vesicle had little or no effect.Our results indicate that the physical act of mating per se or the presence of sperm probably do not provide the primary stimulus to egg-laying. The abdominal location of the implanted accessory gland does, however, suggest that some diffusible chemical substance is responsible for increasing egg deposition in these virgin females.
Morphology of the pineal body of wild house sparrows (Passer domesticus) in relation to reproduction and age
Authors: Ralph C. L. , Lane Karen B.
Published: August 2008

The pineal bodies of wild English or house sparrows (Passer domesticus) were examined histologically for evidence of morphological changes with respect to seasonal reproductivity, sexual maturation, and age. No correlation of changes in the appearance of the pineal of either sex was found with time of year or with size of gonads. However, it was observed that the pineal changed during the bird's first 90 days from a loose, highly folliculated body to a compact, more solid-appearing structure. Area measurements of median sections indicated that the size of the pineal body tended to decrease with an increase in age from 30 to 180 days.
Immigration and emigration as contributory regulators of populations through social disruption
Authors: Bailey E. D.
Published: August 2008

Previously isolated mate laboratory mice were placed into groups of 16 mice per cage. Each day for 10 days, one animal was exchanged for another between two of the groups in a simulated balanced emigration–immigration. The animals in the third groups served as controls. Stress indicator organs were weighed to determine the effect of the balanced movement and the ensuing social disruption. Splenic and adrenal hypertrophy was greater in the mice exposed to movement than in the controls. Variance of hypertrophy followed the same pattern. Testicular development and size of seminal vesicles was greatly inhibited in the mice exposed to movement. Reproductive potential may be influenced by immigration and emigration through social disruption alone, with no change in actual available space, food, and other factors on a per animal basis.
Macroinvertebrate colonization of the marginal zone of a small impoundment in Eastern Canada
Authors: Paterson C. G. , Fernando C. H.
Published: August 2008

Colonization of the marginal macroinvertebrate fauna of Laurel Creek Reservoir was followed from the time of first filling in the spring of 1967 until the reservoir was drained in mid-October of the same year. Of the 55 taxa found during this period 34 (61.8%) were facultative species which had maintained populations in the lotic environment before impoundment. Colonization was an active process which accelerated as the water temperature increased. Passive colonization by species swept into the reservoir by flooding of the creek and the resultant rapid filling of the reservoir was negligible. For the first 3 months after subsequent filling in the spring of 1968 the marginal fauna was very similar to that of the previous year although colonization was more rapid as a result of overwintering of many limnophilic species in various refugia in the reservoir basin. Colonization of the marginal zone appeared to approach completion, with respect to the prevailing environmental conditions, during the first summer period of the reservoir's existence.
The respiratory importance of vascularization of the tadpole operculum in Rana catesbeiana Shaw
Authors: Gradwell Norman
Published: August 2008

Capillary densities in the opercular membrane of the bullfrog tadpole are consistent with the postulate that this membrane has the respiratory function of increasing the surface area for blood ventilation. The arteries and veins of the opercular membrane are mapped and identified for the first time in an anuran tadpole.
Ergasilus luciopercarum males in an unusual collection from Newfoundland
Authors: Davis Charles C.
Published: August 2008

A plankton sample obtained from the lake (Barachois Pond) at Barachois Pond Provincial Park, near Stephenville in southwestern Newfoundland, was dominated by males of Ergasilus luciopercarum, along with a few free-swimming females and juveniles. Henderson's original description of the male was based upon a single specimen. Because his account differed in some respects from the Barachois Pond material, the male is redescribed in some detail.
Studies of Late Cretaceous vertebrates. III. A triconodont mammal from Alberta
Authors: Fox Richard C.
Published: August 2008

Alticonodon lindoei, new gen. and sp., a triconodont mammal from the early Campanian Upper Milk River Formation, Alberta, is the first known triconodont of Late Cretaceous age, and only the second recorded from post-Jurassic rocks. Progressive specializations in Alticonodon suggest a more highly developed shearing of the postcanine dentition than in geologically older members of the order.
Nematodes of the family Neotylenchidae (Tylenchida:Nematoda) from the Canadian high Arctic
Authors: Mulvey R. H.
Published: August 2008

Six species of nematodes in the family Neotylenchidae, including two new species, are reported from the Canadian high Arctic for the first time. Hadrodenus n. gen. is established for species similar to Deladenus Thorne, 1941, but with a more anterior vulva and a postuterine sac. Deladenus saccatus Andrássy, 1954 is transferred to this genus. H. megacondylus n. sp. and Nothotylenchus attenuatus n. sp. are described and illustrated. Measurements and illustrations of the known species N. acris, N. acutus, N. danubialis, and Stictylus mucronatus, and a taxonomic key to the nominal species of these genera, are provided.
The courtship behavior of the male brook stickleback, Culaea inconstans (Kirtland)
Authors: McKenzie Joseph A.
Published: August 2008

The courtship behavior of a population of Culaea inconstans from London, Ontario, has been described in detail. Sequential analysis of the courtship of eight males for 77 half-hour periods shows that there is a sequence of behavior elements which go from pummeling to leading to showing to quivering and to fertilizing. During courtship the male shows aggressive and nest-building elements of behavior which are described as displacement activities. The courtship elements of behavior of this population differed from those described for another population from the state of New York. The differences probably represent postglacial evolution in this species.
Comparative breeding behavior of the red-legged frog (Rana aurora aurora) and the western spotted frog (Rana pretiosa pretiosa) in southwestern British Columbia
Authors: Licht Lawrence E.
Published: August 2008

The breeding behavior of Rana aurora aurora and R. pretiosa pretiosa from an area of sympatry in southwestern British Columbia is described and compared. A 7-ac field near White Rock, B.C., was closely observed during the 1968 and 1969 breeding seasons.Both species arrived at breeding sites and began breeding activities within 2 weeks after emergence from hibernation in February and March. They both used the same temporary pond and slow-moving stream, and breeding occurred simultaneously.Male pretiosa gather into small groups with individuals vocalizing within inches of each other. The mating call is given in air as the frogs float on the surface of water only a few inches deep at the margins of the pond and river. Male aurora call several feet apart while completely submerged in 2 ft or more of water, and 3 ft or more from the pond and river edges. Descriptions of the mating calls of both species, as well as a call peculiar to amplectic male aurora, are given.Female pretiosa spawn mainly during daylight and the eggs are placed on top of, or immediately adjacent to, the first mass present. As many as 26 separate masses were laid on top of one another in the same place, unattached to vegetation in only a few inches of water. Female aurora spawn only at night and deposit their eggs attached to submerged vegetation in a minimum of 12 in. of water, and at least 3 ft from the pond and river shore; masses are several feet apart. The eggs of both species are laid in those areas where conspecific males vocalize.Peculiar aspects of both species' breeding behaviors are discussed, as well as those factors leading to successful reproductive isolation. Observations of breeding aurora in allopatry indicate no major differences from those on aurora sympatric with pretiosa.
Topography and vascularization of brown fat in a hibernator (little brown bat, Myotis lucifugus)
Authors: Rauch Josefine C. , Hayward J. S.
Published: August 2008

Thirteen identifiable deposits of brown fat occur in the little brown bat, Myotis lucifugus. Drawings of these deposits and their vascular supply are presented. Blood vessels were distinguished during dissection by filling the circulatory system with methyl methacrylate. The findings demonstrate the potential of brown fat to transfer heat efficiently to the blood during arousal from hibernation, thereby providing further evidence in support of a thermogenic role for this tissue.
Blood volume in the African migratory locust
Authors: Loughton B. G. , Tobe S. S.
Published: August 2008

The blood volumes of locusts were determined by the 14C-carboxyl inulin dilution technique. In each of the last two larval instars the blood volume was low at first, increased sharply at midstage, and remained high until after ecdysis, when it suddenly decreased. In the young adult the blood volume was low until the 8th day, when a gradual rise became evident.Mature locusts generally possessed higher blood volumes than the immature adults. No sign of a diurnal change in blood volume was detected.The isotope gradually disappeared from the blood and became concentrated in the fat body and gonads. No evidence of excretion or metabolism of the 14C-carboxyl inulin was obtained.
Deformation of developing embryos of sea urchins with changes in the ionic environment
Authors: Wolfson N.
Published: August 2008

Embryos of Paracentrotus lividus, deprived of their fertilization membranes and exposed for periods of 10–120 min to cold buffered isotonic NaCl at various cleavage stages, will often exhibit pseudopodial extensions of the external surface of blastomeres still in embryonic association. Similarly treated embryos allowed to develop for 1–2 days in seawater will often fuse to produce large monsters with continuous blastocoels. Photographs of living embryos displaying blastomeric pseudopods and multiembryonic fusion are presented. The exposure of embryos to artificial saline may promote losses of calcium, of hyaline layer, and perhaps of other superficial components, some of which are reversible losses and others not, after return to seawater.
Two new host records for Nematodirus species
Authors: Webster W. A , MacKay R. R.
Published: August 2008

Nematodirus spathiger (Railliet, 1896) Railliet and Henry, 1909 from a horse, and Nematodirus odocoilei Becklund and Walker, 1967 from the white-tailed deer Odocoileus virginianus, constitute new host–parasite records.
The bearing of Phoxinus (Cyprinidae) hybridity on the classification of its North American species
Authors: Legendre Pierre
Published: August 2008

Three populations of Phoxinus eos × P. neogaeus were found to form single Mendelian populations, by comparison with the parental species through a discriminant function. The hybrids of one of these populations were found to be fertile. A fourth hybrid collection, studied by three discriminant functions, was found to contain Semotilus margarita, P. eos × P. neogaeus, and hybrids of S. margarita with at least P. eos, but possibly P. eos × P. neogaeus. The presence of this hybrid, when related to the chromosome number of the species concerned, suggests the transfer of S. margarita to the genus Phoxinus.
Predator–prey relationships and predation rates for crustacean zooplankters from some lakes in western Canada
Authors: Anderson R. Stewart
Published: August 2008

Experimental studies on Diaptoimus shoshone, D. arcticus, D. nevadensis, Cyclops bicuspidatus thomasi, C. vernalis, and Branckinecta gigas show that these predatory species can capture and eat many prey species of various sizes. B. gigas probably combines raptorial with filter feeding and can eat 150 or more smaller crustaceans per day. Adult D. shoshone, D. arcticus, and D. nevadensis eat up to 12 or more cyclopoids or diaptomids per day. Rotifers are also preferred prey. Predation rates are inversely proportional to prey size. Cannibalism probably causes the uniformity in body size and instar of predaceous diaptomids in some populations, C. vernalis and C. b. thomasi can eat six or more prey animals daily, depending on the size of the prey. Predaceous diaptomids and cyclopoids will eat the same prey species at rates which are influenced more by hunger than by abundance of prey. Furthermore, each species is a potential predator on the other, where the role of predator or prey is determined by the relative size or instar of the two groups. Hence, codominance of the zooplankton by predaceous diaptomid and cyclopoid species is unlikely.
Erythropoiesis through clone cell formation in peripheral blood of the white sucker, Catostomus commersoni, studied after labeling with 3H-thymidine for various exposure intervals
Authors: Deutsch Maurice , Engelbert Vibeke E.
Published: August 2008

A process of erythropoiesis, in which new red blood cells (clone cells) originate from preexisting young mature red blood cells as sac-like protuberations or nuclear blebs in the peripheral blood of the white sucker, is demonstrated. These protuberations, called the clone cells, which became labeled on exposure to 3H-thymidine and which stain positively for deoxyribonucleic acid (DNA), eventually condense, producing margins of cytoplasm which surround discrete nuclei. This cytoplasm is shown to contain ribonucleic acid (RNA) and, later, the appearance of hemoglobin can be demonstrated with the acridine orange fluorescence method. Clone cells make up about 10% of the cells of the peripheral blood of the white sucker. Both clone cells and their mother cells became labeled on exposure to 3H-thymidine: from 25% to 38% of the young mature red blood cells had mean grain counts which varied from 18.2 to 21.1 grains per cell; from 13.1% to 18.3% of the stage II clone cells gave mean grain counts of 235 to 301 grains per cell. Greatest uptake of 3H-thymidine was observed about the 48th h and the fifth day. This investigation shows that clone cell formation, in the peripheral blood of teleost fish, is identical with the one demonstrated earlier for birds and for reptiles. This is the first time, however, that grain counts of mother nuclei and clone cell nuclei have been reported and compared to one another.
The biology of Gammarus (Crustacea, Amphipoda) in the northwestern Atlantic. IV. Gammarus lawrencianus Bousfield
Authors: Steele D. H. , Steele V. J.
Published: August 2008

Gammarus lawrencianus is an endemic estuarine species of the northwestern Atlantic, found from Labrador south to the Gulf of Maine. Fifty percent maturity for the females occurs at 5.25 mm at Holyrood, Newfoundland, and at 4.4 mm at St. Andrews, N.B. In Newfoundland, females produce a series of broods between March and October, at which time they enter the resting stage. The oogonia begin to enlarge in January but are not released into the brood pouch until March. The young hatched in the spring mature during the summer and may produce several broods before October. The older generation disappears in the summer. The population rises quickly to a peak in August or September in the river water but declines rapidly in early winter. Only in the bottom of pools and in the barrachois pond do specimens apparently survive until spring.
Taenia macrocystis (Diesing, 1850), its occurrence in Eastern Canada and Maine, U.S.A., and its life cycle in wild felines (Lynx rufus and L. canadensis) and hares (Lepus americanus)
Authors: Bursey Carl C. , Burt Michael D. B.
Published: August 2008

Examination of 129 bobcats (Lynx rufus) from New Brunswick, Nova Scotia, and Maine and 14 lynx (Lynx canadensis) from Newfoundland revealed the presence of adult Taenia macrocystis (Diesing 1850) in 86% of the bobcats and in all the lynx. Concurrent examination of snowshoe hares (Lepus americanus) showed that a high proportion of adult hares were infected with cestode larvae of the strobilocercus type. Scolices of these larvae were identical with scolices of T. macrocystis adults recovered from wild cats.Experimental infection of domestic cats with fresh larvae from hares yielded adult taeniids, within 42 days, which were identical with the adult T. macrocystis found in wild cats.Experimental infection of laboratory-reared snowshoe hares with eggs of these cestodes produced fully developed, infective strobilocercus larvae within 14 weeks, thus establishing that Lepus americanus acts as an intermediate host in the life cycle of T. macrocystis in northeastern North America.
The effect of age on the thermal preference of white mice (Mus musculus) and gerbils (Meriones unguiculatus)
Authors: Eedy J. W. , Ogilvie D. M.
Published: August 2008

Selected temperatures were determined for white mice and gerbils of various ages tested in a horizontal thermogradient chamber. Although the temperature preference of both species was initially high, it decreased at different rates, and reached the adult level at about 5 weeks of age in white mice, and 12 weeks in gerbils. These ages correspond closely with the reported time of attainment of sexual maturity in both species. In addition, determination of metabolic rates for white mice of various ages suggested that adult heat production and the adult level of selected temperature were reached at about the same age.
Observations on the opisthonephric kidney of the sea lamprey of the Great Lakes, Petromyzon marinus L., at various stages during the life cycle
Authors: Youson John H.
Published: August 2008

The kidneys at all stages consist of renal corpuscles, tubules, and an archinephric duct. The kidney of the ammocoete does not contribute to the formation of the adult kidney for at transformation a new kidney is formed. Degeneration of kidney tissue occurs at four stages: in the anterior regions throughout larval life; in the entire ammocoete kidney at transformation; in the anterior regions throughout adult life; in the entire kidney during the spawning migration. Large quantities of amorphous material appear in the interstitium during anterior degeneration of the adult. The other stages involve necrosis followed by the invasion of phagocytes.
Effect of pituitary homotransplants on peripheral target organs in intact threespine sticklebacks, Gasterosteus aculeatus L. form trachurus
Authors: Leatherland John F.
Published: August 2008

The activity of pituitary homotransplants in the anadromous form (trachurus) of the threespine stickleback, Gasterosteus aculeatus L. was investigated by examining the structure of the thyroid, interrenal, gonad, and in situ pituitary; the melanophore index was also measured.The thyroid gland was markedly more active and the in situ thyrotrophs more granulated in the recipient fish when compared with the sham-operated animals. Similarly, the interrenal nuclear index was slightly (but significantly) larger in the recipient fish and there was a concomitant partial regression of the in situ pituitary corticotrophs.There was no difference between the structure of the gonads in the two groups although the in situ gonadotrophs were apparently smaller and less well granulated in the recipient fish.The melanophore index was significantly lower in recipient sticklebacks.In situ prolactin-secreting cells, somatotrophs, and neurointermediate lobes were similar in recipient and sham-operated animals.
Studies on the band-tailed pigeon (Columba fasciata) in British Columbia. 1. Seasonal changes in gonadal development and crop gland activity
Authors: March G. L. , Sadleir R. M. F. S.
Published: August 2008

Band-tailed pigeons ovulate in British Columbia from May through July although apparently not all females do so early in the breeding season. Males are in breeding condition when they arrive after the northward migration in April and remain so until late July. Evidence suggests that two clutches (one egg each) may be produced during the breeding season. The female's ability to ovulate white crop feeding the squab provides additional evidence of two clutches. Four stages of crop gland development are described in detail and the usefulness of this gland to indicate breeding status is demonstrated. Many birds had active crops when shot during the hunting season indicating a potentially reduced recruitment of the squabs being fed at this time.
The geographical distribution of ice worms (O1igochaeta:Enchytraeidae)
Authors: Tynen Michael J.
Published: August 2008

Ice worms (Mesenchytraeus solifugus (Emery 1898)) have been found on the western coastal glaciers of North America, from the Bagley Icefield in Alaska, to Mt. Rainier, in Washington State. They are absent from the western interior and from the Central Alaska Ranges. It is speculated that their southern limit is north of the Columbia River, since this area represents the probable southern limit of Cordilleran ice.
The diurnal vertical migration of some Cumacea (Crustacea, Pericarida) in Kames Bay, Isle of Cumbrae, Scotland
Authors: Corey S.
Published: August 2008

The occurrence of a diurnal vertical migration was recorded for two sublittoral cumaceans, Pseudocuma longicornis and Iphinöe trispinosa, in the sublittoral region of Kames Bay, Isle of Cumbrae, Scotland. Three 24-h surveys carried out in January, June, and July showed that both species performed a diurnal migration with greatest numbers appearing at the surface just after sunset and before sunrise. The swimming appendages and relative densities of these cumaceans were also noted.
A preliminary study of factors influencing the number of oocytes present in newly emerged blackflies (Diptera: Simuliidae) in Ontario
Authors: Chutter F. M.
Published: August 2008

The number of oocytes and size (length of a wing vein) were measured at emergence in adults of seven blackfly species reared from natural preimaginal populations whose density was assessed. Oocyte counts were often greatest in females from intermediate preimaginal populations. In Simulium vittatum Zetter-stedt size, number of oocytes and nutrient reserves (indirectly measured as the proportion of oocytes present at emergence which later matured in starved females) were positively correlated. In S. decorum Walker and Cnephia dacotensis (Dyar and Shannon) size and oocyte counts were positively correlated. Formulae for the regressions of oocyte counts on size are given for these three species. It is concluded that the number of oocytes present at emergence is related mainly to nutrition and temperature during the larval stage and not to larval density.
Small chamber tests of insecticidal fumigants
Authors: Dixon R. K. , Morrison F. O.
Published: August 2008

A technique is described for small chamber testing of both high and low volatility insecticidal fumigants against stored products' pests. The method has potential for both field and laboratory use. The susceptibilities of Oryzaephilus and Sitophilus to methyl bromide have been established in that order of ascendancy. The susceptibility of Sitophilus can be altered either way by feeding different pre- and post-exposure diets under different relative humidities, which in turn makes the diets more or less available to the insect.At 25 ± 1 °C, methyl bromide is 1.40, 1.30, and 1.10 times as toxic to Oryzaephilus, Tribolium, and Sitophilus respectively as it is at 20 + 1 °C. The sensitivity, indicated by the smallness of the difference constantly detected between two susceptibility levels, and the reliability with which results can be reproduced, attest to the suitability of this technique for determining susceptibility levels of species and strains of stored products' pests to fumigants.
A simple manoeuver to prevent loss of sections for performic acid–Victoria blue technique and a comparison of various neurosecretory stains
Authors: Ganagarajah M. , Saleuddin A. S. M.
Published: August 2008

It is shown that whole brains of migratory locusts can be oxidized with performic acid and that paraffin sections of these can be successfully stained with Victoria blue. Either performic acid or acid permanganate oxidants can be used for Victoria blue and aldehyde fuchsin staining techniques thus allowing crisscross comparisons.
Phagostimulatory effects of lipids and related substances on the prairie grain wireworm, Ctenicera destructor Brown
Authors: Davis G. R. F.
Published: August 2008

Larvae of Ctenicera destructor Brown bit spots treated with C18 unsaturated fatty acids more often than those treated with other lipids or related substances. They also bit spots treated with 5% solutions of these substances more often than those treated with 1% solutions. The relatively high response recorded for triolein-treated spots may have reflected a metabolic requirement for oleic acid. When spots were treated with mixtures of fatty acids, the larvae bit most frequently those treated with palmitic, oleic, and linoleic acids. These observations support the hypothesis that a phagostimulatory response by insects is not dependent upon the presence of any single substance.
Weight and histological studies of growth and regression in the bursa of Fabricius in the mallard, Anas platyrhynchos
Authors: Ward J. G. , Middleton A. L. A.
Published: August 2008

A weight and histological study of growth and regression of the bursa of Fabricius in captive and wild mallards was made between May 1967 and May 1968. Mean bursal weight reached a maximum by 8 weeks in males and 6 weeks in females, and decreased steadily after 12 weeks in males and 16 weeks in females. During growth of the bursa there was a general enlargement of the bursal follicles, but the trabeculae between the follicles remained thin. During bursal regression the follicular size decreased, and trabeculae thickened. Ultimately the follicles and bursal lumen disappeared leaving connective tissue and blood vessels. A classification was erected to describe the phases of bursal growth and regression.
Freshwater ostracodes of Canada. Part V. Families Limnocytheridae, Loxoconchidae
Authors: Delorme L. D.
Published: August 2008

The family Limnocytheridae is represented in Canada by 22 species belonging to the genus Limnocythere and subgenus Limnocytherina. The following are described as new: Limnocythere (Limnocytherina) paraornata, Limnocythere (Limnocytherina) parascutariense, Limnocythere platyforma. The family Loxoconchidae is represented by the marine-brackish water form Cytheromorpha fuscata.
Helminths from the Weddell seal, Leptonychotes weddelli (Lesson, 1826), in the Antarctic
Authors: Beverley-Burton Mary
Published: August 2008

The alimentary tracts of seven Weddell seals taken at McMurdo Sound, Antarctica, were examined for helminth parasites. Two species of trematodes, three of cestodes, and one of nematodes were recovered. Numerical data on incidence and intensity of infection are given for each species. Heavy infections of diphyllobothriid plerocercoids were also recorded.
Fine structure of degenerating and regenerating flight muscles in a bark beetle, Ips confusus. II. Regeneration
Authors: Bhakthan N. M. G. , Nair K. K. , Borden J. H.
Published: August 2008

The flight muscles of the bark beetle Ips confusus regenerate by two means, by formation and differentiation of new myoblasts, and by the regeneration of the old flight muscle itself. Mononucleated myoblasts appear in beetles which have been in the inner bark of ponderosa pine logs for 5 days. These cells apparently fuse with other myoblasts to form multinucleated cells. By the end of the ninth day of regeneration the myofilaments become attached to an incoherent Z line. By the 11th day of regeneration these differentiating myoblasts appear very much like the fibers of the regenerating old flight muscle.Simultaneously the fibers of the old degenerate muscles show signs of regeneration. On the sixth day after the beetles entered the bark, rearrangement of the existing degenerate myofilaments takes place. The incoherent and diffused Z line shows some degree of reorganization. Numerous ribosomes are present between the filaments. Between the 7th to 11th days of regeneration the mitochondria appear to fuse to form giant mitochondria up to five sarcomeres in length. These mitochondria by subsequent divisions give rise to numerous mitochondria. Almost invariably the line of mitochondrial fission is aligned with the Z line. The presence of numerous ribosomes and polysomes in the fibers indicate a high protein synthetic activity. By the end of the 13th day regeneration of the flight muscle appears complete and the beetles are now ready to reemerge. These results further confirm our earlier observation (Bhakthan et al. 1970) that flight muscle degeneration in I. confusus is a reversible process.
Functional morphology of the thysanopteran pretarsus
Authors: Heming B. S.
Published: August 2008

The functional morphology of the unique pretarsal mechanism of adult Thysanoptera is described. The components of each pretarsus are homologous with those of other insects, but changes in their relative sizes and shapes have arisen through modifications in their function. Among these are the enlargement of the arolium into a protrusible bladder; the reduction of the ungues into spoon-shaped, laterally ensheathing plates; the development of a tibial gland opening to the surface of the arolium through three fine ducts; and the evolution of two elastic "restraining" tendons each inserting into the "head" of the unguitractor apodeme and originating laterally on the walls of the distal end of the tibia.The contraction of the pretarsal depressor muscle causes the ungues to rotate outward on the unguifer and blood pressure, increased by abdominal contraction, everts the arolium. When the depressor muscle relaxes, the restraining tendons contract and the arolium is withdrawn between the closing ungues by sclerites and filaments associated with each. The adults of species in all five families of the order have this mechanism.
The life cycle and seasonal variation of Davainea tetraoensis Fuhrmann 1919, a cestode parasite of ruffed grouse, Bonasa umbellus (L.)
Authors: Dick Terry A. , Burt Michael D. B.
Published: August 2008

Ruffed grouse (Bonasa umbellus) were collected from August 26, 1965, to August 25, 1966, and examined for cestodes. Two morphological variations of Davainea tetraoensis were found, fully developed mature worms being recovered during the summer months and poorly developed winter forms with no mature prolottides being recovered during the winter months. Various causes are considered and investigated experimentally. Changes in diet and changes in photoperiodicity do not seem to effect any change from one form to the other; changes in temperature, however, seem to be closely related to the transition from summer forms to winter forms, this transition occurring at around 0C. The change back to mature forms may be linked to gonad development in the host or to those environmental factors which influence gonad development. Cysticercoids from experimentally infected molluscs are described and compared. The rate of development of cysticercoids in Zonitoides arboreus under different conditions is investigated showing that full development, from oncospheres, can occur within 12 days in small individuals (2 mm) but takes at least 19 days in larger individuals (4.5 mm). Examination of grouse and chickens after experimental infection with up to 450 cysticercoids showed no apparent ill effects, or damage of any kind, to the hosts.
The effect of hypophysectomy on physiological color change in Fundulus heteroclitus
Authors: Abbott F. S. , Favreau M. B.
Published: August 2008

Thirty-eight Fundulus heteroclitus were tested for ability to adapt to white and black backgrounds. They were then hypophysectomized and distributed individually to white and black containers. Their ability to adapt to background was determined for periods up to 2 weeks. Sixteen operated fish retained their preoperative ability to adapt; 8 became dark temporarily; 14 became persistently dark. Histological examination confirmed the result of the operation. In the third group of fish the persistent darkness was not associated with damage to specific areas of the brain although damage was more widespread in this group. It is concluded that hypophysectomy does not interfere with physiological color change in F. heteroclitus. The location of the central relays in the melanophore system could not be determined.
Variations in the photoperiodic reaction controlling diapause induction in Lucilia caesar L. (Diptera: Calliphoridae)
Authors: Ring R. A.
Published: August 2008

Two strains of the blowfly Lucilia caesar L. were established in the laboratory, one producing a low incidence and the other a high incidence of diapause under the normally diapause-preventing conditions of long photoperiod. Crossbreeding was carried out between the strains, with the resulting hybrids having diapause performances intermediate between those of the parents. Little or no filial segregation occurred in two hybrid generations, indicating the multiple-gene condition of diapause inheritance. The genetic influence on diapause control is apparently enhanced by sexual characteristics since the male enters diapause more readily than the female in this species.
Embryotoxic effects of tissue-specific antiserum in the chick embryo
Authors: McCallion D. J.
Published: August 2008

Antiserum against adult chicken brain was obtained in rabbits. The antiserum was absorbed on chicken kidney and serum. Subsequently the gamma-globulins were precipitated with half-saturated ammonium sulfate and resuspended in distilled water. At least three neural-specific antibodies were present in the solution. Chick embryos of 33–36 h of incubation were exposed in ovo to this solution and to the same preparation of normal rabbit serum. Control embryos were normal. The neural-specific antibodies had specific cytotoxic effects on the neural epithelium of embryos. All other tissues were normal and healthy.