bluuebunny/crossref_metadata_2025 huggingface dataset:
The effects of temperature on growth and development of water strider species (Heteroptera: Gerridae) of central British Columbia and implications for species packing
Authors: Spence J. R. , Spence D. Hughes , Scudder G. G. E.
Published: December 2009

The duration of life-cycle stages and the effects of temperature on development were assessed with laboratory rearing studies for six species of water striders which occur sympatrically in British Columbia. Larval production and development are strongly temperature dependent in all species studied. Temperature thresholds for development differ, both among species and often among stages of particular species. Instars of Gerris species showed distinct optimum temperatures for laboratory survival which varied with developmental threshold. Low thresholds calculated for G. pingreensis lead to significant growth advantages for this species during early spring. Threshold differences between species and instars appear to be adaptations to seasonal temperature regimes and to usual habitats occupied by gerrids. These relationships lead to temporal separation of species and help explain the patterns of habitat occupation observed in the study area.
Response of red-winged blackbirds to nests of long-billed marsh wrens
Authors: Picman Jaroslav
Published: December 2009

The response of female red-winged blackbirds to nests of long-billed marsh wrens was studied by placing wren courtship nests near redwing nests. Agitated redwings frequently approached experimental nests; some landed on the nests and examined them, but only two females pecked at them. Because redwings respond specifically to wren nests (as opposed to a strange object), it is proposed that redwings associate wren nests with marsh wrens. This, and independent evidence that marsh wrens destroy redwing nests, suggest that redwings go to wren nests to search for marsh wrens.The response of redwings to wren nests is influenced by their previous experience with marsh wrens. This is supported by two observations: (1) individuals become more responsive through the breeding season; and (2) banded (experienced) females are more responsive than unbanded (mostly inexperienced) females. Redwing response to wren nests also increases with increasing wren density and decreasing redwing–wren internest distance. Examination of marsh wren nests by redwings and redwing aggression towards marsh wrens probably play a role in reducing the nesting success of marsh wrens.
Coastal populations of brook trout, Salvelinus fontinalis, in Lac Guillaume-Delisle (Richmond Gulf) Québec
Authors: Dutil J. D. , Power G.
Published: December 2009

Brook trout grow slowly in coastal streams and resident fish average only 15.6 cm during their fourth summer. Anadromous fish move into brackish water at approximately 20 cm fork length. In the gulf, the modal age is 4+ and age groups 3+ to 6+ account for 80–90% of the catch. Fish rapidly attain lengths of 35–40 cm, instantaneous growth in weight decreases from 1.27 for 2- to 3-year-old fish to 0.35 for 5- to 6-year-old fish. Dispersal from river mouths may be restricted to a distance of only 5–6 km. Late in July and throughout August, maturing fish of both sexes enter fresh water where ripening occurs. Movements at sea and duration of residence are controlled by salinity and temperature as influenced by maturation.
Transmission of Dirofilaria ursi Yamaguti, 1941 (Nematoda: Onchocercidae) of black bears (Ursus americanus) by blackflies (Simuliidae)
Authors: Addison Edward M.
Published: December 2009

Microfilariae of Dirofilaria ursi Yamaguti, 1941 from black bears (Ursus americanus) developed to the third stage in Simulium venustum Say and perhaps other simuliids but not in culicids, tabanids, and ceratopogonids. Malpighian tubules were the only site which supported development to the third stage. In blackflies held at 27 and 23 °C, D. ursi reached the third stage in 5 and 9 days respectively. At 18 °C larvae did not reach the third stage in blackflies held for 16 days.The effects of temperature (18, 23, and 27 °C) on growth of D. ursi in the vector are described. Morphological changes in larvae during development to the infective stage at 23 °C are reported. The prepatent period of D. ursi in black bears is 210–271 days.
Studies on locust rectum. III. Stimulation of electrogenic chloride transport by hemolymph
Authors: Spring J. H. , Phillips J. E.
Published: December 2009

Hemolymph was collected from recently fed desert locusts either by adsorption onto filter paper, or by centrifugation and methanol extraction. Whole hemolymph caused both the short-circuit current (Isc) and open-circuit transepithelial electropotential difference (PD) across locust recta mounted in Ussing-type chambers to double during the steady-state period. Methanol extracts of hemolymph caused similar but smaller increases in Isc. The transepithelial resistance (R) did not change. Simultaneous measurements of 36Cl− fluxes indicated that all of the increase in Isc following stimulation could be accounted for by a parallel increase in net Cl− absorption from the lumen side. With the exception of an initial small biphasic fluctuation in Isc, stimulation by hemolymph exhibited identical characteristics to those produced by submaximal dosages of corpora cardiaca (CC). Cardiatectomy drastically reduced the stimulatory activity of hemolymph, suggesting that this neuroendocrine organ is the source of the active factor (chloride transport stimulating hormone (CTSH)) in hemolymph.
The effects of glyphosate herbicide on chicken egg hatchability
Authors: Batt Bruce D. J. , Black James A. , Cowan Wayne F.
Published: December 2009

Hatchability and time to hatch of chicken eggs were found to be unaffected by application of glyphosate herbicide at three different concentrations and at four different embryo ages. We concluded that the use of the chemical as a weed control agent in zero tillage farming should not negatively affect the hatchability of the eggs of upland nesting birds.
A scanning electron microscope study of the structure and fertilization of an ascidian egg, Ciona intestinalis
Authors: Bates William R.
Published: December 2009

Fertilization of the ascidian egg, Ciona intestinalis, is complicated by extravitelline accessory structures. This report describes morphological aspects of these accessory structures, in particular the follicle cell layer, using the scanning electron microscope. It is suggested that interfollicular clefts exist between adjacent follicle cells thereby facilitating the species-specific binding reaction between sperm cells and the chorion.
Cercaricidal activity of phenylheptatriyne and α-terthienyl, naturally occurring compounds in species of Asteraceae (Compositae)
Authors: Graham K. , Graham E. A. , Towers G. H. N.
Published: December 2009

The susceptibility of some digenetic trematode cercariae to the polyacetylene phenylheptatriyne (PHT), from leaves of Bidens pilosa L. (Compositae), and the thiophene α-terthienyl (α-t), from roots of Tagetes patula L. (Compositae), with and without ultraviolet (UV) activation, was examined. In darkness the lethal concentration for 100% (LC100) for both substances was 0.3 ppm. Under UV irradiation of 300–400 nm and incident intensity of 6 W/m2, the LC100 for PHT was not markedly lowered, but for α -t it was reduced by a factor of 30 (to 0.01 ppm). A cercaricidally effective aqueous infusion (1:1000) of Tagetes roots protected the snail hosts Physa occidentalis Tyron (Physidae) from bacterially complicated death but did not reduce cercarial production or predispose the emerging cercariae to subsequent UV injury.
Key to the Geotrupini of Mexico and Central America, with the description of a new species (Scarabaeidae, Geotrupinae)
Authors: Howden H. F.
Published: December 2009

Geotrupes reddelli n.sp. from Puebla, Mexico, is described and figured. The key of the Mexican and Central American Geotrupini includes 3 species in the genus Ceratotrupes and 18 species and subspecies in the genus Geotrupes.
Capricious mountain weather: a driving variable in hummingbird territorial dynamics
Authors: Gass Clifton Lee , Lertzman Kenneth P.
Published: December 2009

A violent summer hailstorm destroyed a large proportion of flowers in one of several meadows in a small mountain basin. This decimation of the resource base resulted in a dramatic decrease in the number of fall migrant rufous hummingbirds holding territories there, supporting the hypothesis that hummingbird populations closely track their food supplies. We found no evidence that the individuals displaced by the hailstorm established territories in neighboring meadows, and we therefore concluded that these individuals were forced into suboptimal habitats nearby or emigrated from the basin.
Johnston's organ of the black fly Simulium vittatum Zett.
Authors: Boo K. S. , Davies D. M.
Published: December 2009

Ultrastructure of the Johnston's organ was similar in both sexes of the black fly Simulium vittatum. Three types of scolopidia were found: types A, B, and C. Type A and B scolopidia are amphinematic and type C scolopidia are mononematic. Males had slightly wider pedicels than females and bore about 30 type A, 150 type B, and 4 type C scolopidia. Females had about 20 type A, 105 type B, and 5 type C scolopidia. The basic structure and location of each type are similar to, although less well organized than, these types in the adult mosquito. The number of type A and B scolopidia, while much lower than that found in mosquitoes, is similar to the number in other insects. Each amphinematic scolopidium has either two (type A) or three (type B) sensory cells, as well as three sheath cells and a long cuticular cap. A mononematic type C scolopidium has two sensory cells, a sheath cell, a short cap, and a microtubular cap cell. The structure of the Johnston's organ complements previous behavioural observations indicating that sound detection is absent or minimal in the black fly, even in the mate-seeking males. The probable function of each scolopidial type is discussed as it may relate to flying and wind detection.
Aerial respiration in the catfish, Corydoras aeneus (Callichthyidae)
Authors: Kramer Donald L. , McClure Martha
Published: December 2009

Corydoras aeneus uses the posterior intestine for aerial respiration. Ventilation takes place in a rapid dash to the surface. Air is inspired during the 0.06–0.07 s that the mouth is exposed; expiration occurs via the anus as the fish begins to dive. Air breathing occurs at all dissolved oxygen partial pressures [Formula: see text] from 0 Torr (1 Torr = 133.322 Pa) to at least 140 Torr, but frequency, ranging from 1–45 breaths∙h−1, is negatively correlated with [Formula: see text]. Corydoras aeneus survive at least 9 days without air breathing under normoxic conditions [Formula: see text] but below 15 Torr, only fish able to reach the surface survive. Air-breathing rates are significantly influenced by variations in depth between 10–120 cm but the pattern of response depends on [Formula: see text] and involves changes in activity.
Helminth parasites of squirrels (Sciuridae) in Saskatchewan
Authors: McGee Steven G.
Published: December 2009

During the period March 1976 to November 1977, 377 mammals of the family Sciuridae (Rodentia) were collected in Saskatchewan and examined for helminths. Species and numbers of each were as follows: Spermophilus richardsonii (Sabine), 209; Spermophilus franklinii (Sabine), 46; Spermophilus tridecemlineatus (Mitchill), 31; Tamiasciurus hudsonicus (A. H. Howell), 64; Glaucomys sabrinus (Shaw), 12; Eutamias minimus (J. A. Allen), 11; and Marmota monax (Erxleben), 4.Ten species of cestodes, 2 species of trematodes, 11 species of nematodes, and 1 acanthocephalan were represented in the collections made. New host records and (or) geographic range extensions were indicated for 10 species of helminths.In addition to taxonomic considerations of the helminths, attention has been given to parasite–host relationships involving ground squirrels. In general, male Spermophilus spp. were significantly more commonly infected than were females, and older squirrels were significantly more commonly infected than were younger ones. However, adult squirrels did not have significantly more worms than did juveniles.
Water balance of the eggs of a desert lizard (Callisaurus draconoides)
Authors: Packard Mary J. , Packard Gary C. , Boardman Thomas J.
Published: December 2009

Eggs of a desert lizard (Callisaurus draconoides) were incubated under hydric conditions simulating those of natural nests. Eggs increased in mass during the first half of incubation owing to a net uptake of water, and declined in mass during the second half of incubation owing to a net loss of water. Patterns of net water exchange were related to water potential of substrates on which eggs were incubated, and could be modified by increasing the proportion of each eggshell contacting the substrate. Hatching success was high among eggs associated with wetter substrates but very low for eggs incubated on drier substrates. Eggs associated with wetter substrates also had longer periods of incubation and gave rise to larger hatchlings than eggs exposed to drier substrates. These findings indicate that nest-site selection by females is an important determinant of reproductive success, for selection of appropriate nesting sites increases the probability of high hatching success and of young lizards attaining large size prior to hatching.
Optical metamorphosis of the eye of Salamandra salamandra
Authors: Sivak J. G. , Warburg M. R.
Published: December 2009

Ocular structure before, after, and during metamorphosis of Salamandra salamandra was monitored by means of a freeze-sectioning technique. Attention was directed toward the shape and relative position of the lens, corneal curvature, and the angle formed by the geometrical axes of the two eyes. The larval eye is aquatic in form; i.e. the lens is spherical and in close proximity to the relatively flat cornea. In stages during metamorphosis the lens assumes a flattened shape, corneal curvature becomes more pronounced, and the lens moves relatively closer to the retina. The angle between the two eyes decreases as well. Furthermore, these changes continue through the juvenile stage into the adult. Retinoscopic measurements of refractive state indicate that both the larvae and juveniles are more or less free of refractive error in water and air, respectively.
Nomenclature of Aulactinia (= Bunodactis), with description of Aulactinia incubans n.sp. (Coelenterata: Actiniaria), an internally brooding sea anemone from Puget Sound
Authors: Dunn Daphne Fautin , Chia Fu-Shiang , Levine Regina
Published: December 2009

Aulactinia incubans n.sp. is an internally brooding actinian known from the San Juan Archipelago, Washington, U.S.A., and from Torch Bay, Alaska, U.S.A. Found in sheltered intertidal habitats, this sea anemone averages 25–30 mm in pedal disc diameter and has fewer than 65 tentacles. Females, hermaphrodites, sexually undifferentiated, and possibly male individuals are known. Aulactinia incubans releases its brooded young through the pore at the tip of each tentacle; the young are tentaculate at the time of release. This species fits genus Bunodactis in all respects except that the outer tentacles of some individuals contain atrichous nematocysts. We believe that this feature alone, which is not apparent in all specimens of the species, does not require naming a new genus. Rather, we broaden the definition of genus Aulactinia, a name that has priority over Bunodactis, to include this character.
Observations on the biology of Mansonia perturbans (Walker) (Diptera: Culicidae) in the Nova Scotia–New Brunswick border region
Authors: Lewis David J. , Bennett Gordon F.
Published: December 2009

Aerial sweep netting of mosquitoes in the Nova Scotia – New Brunswick border region during the summers of 1973–1975 revealed that Mansonia perturbons (Walker) is the most abundant species in this region. This mosquito is univoltine; adult emergence commences in late June; peak abundance occurs about mid-July; peak activity of blood-seeking females occurs at or near darkness. Observations were made of swarming adults, and the immature stages were associated with at least seven species of aquatic plants. Mansonia perturbans appears to have become a relatively recent pest in this region.
Morphological variation in the hydromedusa genus Polyorchis on the west coast of North America
Authors: Rees John T. , Larson R. J.
Published: December 2009

Morphological variation in the hydromedusan genus Polyorchis on the west coast of North America is analyzed in relation to gonad number, tentacle number, and radial canal diverticula number relative to the height of the bell. In specimens of Polyorchis examined, it is concluded that P. penicillatus (Eschscholtz, 1829) is highly variable morphologically over its known geographic range from Alaska to Baja California. Polyorchis montereyensis Skogsberg, 1948 is considered a synonym of P. penicillatus, and P. haplus Skogsberg, 1948, is retained as a valid species.
Similarity of dispersal among sibling male spruce grouse
Authors: Keppie Daniel M.
Published: December 2009

Distances of dispersal between brood range and winter range were analyzed for 38 male juvenile spruce grouse (Canachites canadensis) in 16 broods in southwest Alberta, 1970–1972. Variability in distances among siblings was significantly less than for juveniles among different broods.
Effect of photoperiod on fat accumulation in juvenile Citellus lateralis born in captivity
Authors: Phillips John A. , Jameson Jr. E. W.
Published: December 2009

Gravid female golden-mantled ground squirrels, Citellus lateralis, were kept at 7 °C in 6 h light (L): 18 h dark (D) and 18 h L: 6 h D regimes. Young born and raised under these conditions were sacrificed at 5 months of age. Total ether-soluble lipids were significantly greater and basic weights (fat-free, water-free weights) were significantly less for young raised in the 6 h L: 18 h D regime. Live weights of the two groups did not differ. The adult females did not appear to respond to the different light schedules, with no significant differences noted in either the basic weights or lipid indices. It is suggested that (1) shortened days promote fat deposition and thereby could influence the time of onset of hibernation in young of this species, and (2) the adiposity of an animal is not necessarily correlated to the live weight.
A circadian rhythm of behavioural thermoregulation in a freshwater gastropod, Helisoma trivolis
Authors: Kavaliers Martin
Published: December 2009

The behaviour of the aquatic gastropod Helisoma trivolis was examined in a thermal gradient. Under a 12 h light: 12 h dark cycle gastropods displayed a diel rhythm of preferred temperature selection. Maximum temperatures (21–22 °C) were selected during the dark phase and minimum temperatures (17–18 °C) were selected during the light phase of the light–dark cycle. Under constant darkness temperature selection continued as an endogenous free-running circadian rhythm of behavioural thermoregulation.
Observations of a newborn Ross seal pup (Ommatophoca rossi) near the Antarctic Peninsula
Authors: Thomas J. , DeMaster D. , Stone S. , Andriashek D.
Published: December 2009

A Ross seal mother and male pup (Ommatophoca rossi) were sighted on 14 November 1978 in Dallmann Bay near the Antarctic Peninsula. This is believed to be the first documented observation of a newborn Ross seal. Behavioral observations and standard measurements taken from this pup enhance the small amount of information known about the early life of the species.
Effect of spring removal experiments on the spacing behavior of female snowshoe hares
Authors: Boutin Stan
Published: December 2009

On an area in the southern Yukon, four adult female snowshoe hares were removed in May 1979, 10 days before birth of the first litter. For the next 35 days, movements of the surrounding females were monitored by livetrapping and telemetry, and compared with those of females on a control area. The experiment was repeated in June 1979 by removing six more females. Animals adjacent to the removal areas did not shift their home ranges to cover the vacated area, nor did immigrants come in from further outside. Females did spend significantly more time on that portion of their range nearest the removal areas. Females use their home range in a manner that would be expected to avoid interaction. Spacing behavior following first litter conception did not limit breeding density.
An investigation of the ecology of the map turtle, Graptemys geographica (Le Sueur), in the northern part of its range
Authors: Gordon David M. , MacCulloch Ross D.
Published: December 2009

Data obtained during the course of a 3-year study on a population of map turtles, Graptemys geographica, in Lac des Deux Montagnes, Quebec, Canada, suggest that the population size is approximately 351 turtles, that the sex composition is biased in favour of males, and that juveniles compose at least 8% of the total population. Map turtles emerge soon after ice breakup. During the prenesting period, males exhibit less movement over shorter distances than do females. In mid-May, female turtles start to move into the two bays used for nesting. The nesting season is about 2 weeks in duration, commencing in mid-June. The mean size of three clutches was 12. After nesting there appears to be a marked dispersal of both male and female turtles, with females moving more frequently and greater distances than males. By September the turtles have returned to the bays in the study area and remain until freeze-up. Bay utilization by the turtles is discussed in terms of food resources and human recreational use.
The ovotestis of Aplysia californica: anatomy and egg release
Authors: Dudek F. Edward , Injeyan Hampik S. , Soutar Bonnie , Weir Greg , Tobe Stephen S.
Published: December 2009

Egg release from the ovotestis of Aplysia californica has been studied using ovotestis fragments and bag cell extracts. Light and scanning electron microscopy showed clusters of follicles surrounded by muscle cells. Mature oocytes observed in egg masses and those released from ovotestis fragments were 90 μm in diameter. The number of mature releasable oocytes was relatively constant throughout the ovotestis, although a gradual reduction occurred with increasing distance from the small hermaphroditic duct.Bag cell induced egg release was detectable in vitro within 30 min and was complete by 180 min. The time course of egg release was similar under conditions of either continuous exposure or a 30-min pulse of bag cell extract. Artificial seawater (ASW) solutions with high K+ (110 mM) did not stimulate egg release unless bag cell extract was present. ASW with no Ca2+ and 3 mM EGTA or ASW containing Co2+ (10 mM) inhibited both bag cell induced and spontaneous (ASW alone) egg release.Therefore, brief exposure to bag cell peptide can trigger the egg release process, which is long lasting (~ 3 h) and Ca2+ dependent. The observation that high K+ did not stimulate egg release challenges the muscle contraction hypothesis of egg release.
Importance des plantes toxiques dans le régime alimentaire de Microtus pennsylvanicus à deux étapes opposées de leur cycle
Authors: Bergeron Jean-Marie
Published: December 2009

Freeland's hypothesis associating the quality of the habitat to the regular cycles of voles has been rejected by many because of the lack of evidence showing among other things that as population densities increase, the proportion of toxic plants in the diet increases. The results of the present study showed that small cyclical mammals prefer to eat nontoxic food first, but failed to show with certainty that the abundance of toxic plants in the diet increases at peak densities. However, voles did utilize more toxic species during the peak density year than during the phase of still increasing densities. By analyzing the importance of toxic plants in the diet for different age and sex groups, it appeared that preadults used much more toxic plants during peak year than during the other phase. The importance of toxic plants and their action on the population dynamics of cyclical voles are discussed.[Journal translation]
Intra- and inter-familial homologies of maxillary palpal sensilla of larval Simuliidae (Diptera: Culicomorpha)
Authors: Craig D. A. , Borkent A.
Published: December 2009

Light and scanning electron microscopy was used to examine innervation and external structure of maxillary sensilla of larvae of various species of Prosimulium, Twinnia, Gymnopais, Crozetia, Stegopterna, Cnephia, Metacnephia, Gigantodax and Simulium, with emphasis on palpal sensilla. For the palpus, 12 apical sensilla of six distinct morphological types are described, named, and homologies established within the Simuliidae. First instar larvae of Prosimulium, Twinnia, and Gymnopais have a linear array of apical sensilla plus apical spicules, both characters synapomorphic for these three taxa. Prosimuliini genera possess cuticular plates around the palpus apex, synapomorphic for these taxa.Interfamilial homologies for most of the Simuliidae larval palpal sensilla are established for those of larvae of Thaumaleidae, Chironomidae, Tanyderidae, and Blephariceridae. Very few homologies could be established for the Culicidae. Thirteen or 14 palpal sensilla appear to be plesiomorphic for larval nematocerous Diptera, with Simuliidae and Culicidae having reduced numbers.
Deer mouse trappability in relation to bait preference
Authors: Sullivan Druscilla S. , Sullivan Thomas P.
Published: December 2009

When given the choice between traps with or without a mixture of peanut butter and oats (peanut butter balls), deer mice (Peromyscus maniculatus) preferred the former. However, trappability of deer mice was not affected by the presence of peanut butter balls. Acceptable food in live traps is essential to successful trapping of small mammals as these animals will systematically return to traps for food. The peanut butter and oatmeal mixture would increase the nutritional and possibly water content of food in the trap and is thus recommended for deer mouse trapping.
Developmental processes underlying heterochrony as an evolutionary mechanism
Authors: Hall Brian K.
Published: December 2009

Heterochrony, the change in the relative time of appearance or rate of development of a character during phylogeny, has been an important mechanism for generating morphological change during evolution. Retardation and acceleration are two processes which drive heterochrony. I have considered the developmental mechanisms which govern three parameters of heterochrony (when growth starts, growth rate, when growth stops) during skeletal development and conclude that the number and mitotic activity of the cells in the initial skeletal condensation emerges as a fundamental level of control. A developmental explanation for heterochrony should therefore focus on what controls the size of condensation and where and when they arise. Inductive tissue interactions regulate the formation of the condensations in which skeletal elements form, and the timing of these interactions can be modified genetically. As an example, evidence is presented to show that the timing of the interaction which leads to the formation of Meckel's cartilage in the lower jaw varies from one vertebrate group to another, being earlier in birds and later in mammals than it is in amphibians. Variation in the timing of inductive tissue interactions is identified as one mechanism controlling skeletal condensations, and therefore as one possible basis for heterochrony.
On flotation and air breathing in Ambystoma tigrinum larvae: stimuli for and the relationship between these behaviors
Authors: Lannoo Michael J. , Bachmann Marilyn D.
Published: December 2009

Laboratory and field tests were conducted to show the roles of pelagic prey availability and nocturnal darkness in inducing floating and air-breathing behaviors in Ambystoma tigrinum larvae. Both pelagic prey availability and nocturnal darkness independently increase the frequencies of floating and air breathing. Air breathing and floating are correlated. Lungs are necessary for larvae to remain suspended and feed in the water column. Results suggest larvae float in response to darkness to feed on pelagic prey.
Haemolymph octopamine levels during and following flight in the American cockroach, Periplaneta americana L.
Authors: Bailey B. A. , Martin R. J. , Downer R. G. H.
Published: December 2009

Haemolymph octopamine levels of adult male cockroaches (Periplaneta americana) were monitored using high performance liquid chromatography with electrochemical detection. The octopamine concentration of haemolymph increases rapidly in response to experimental handling and the commencement of flight, with 77 and 123% elevations, respectively, observed within 1 min of initiating these activities. Resting levels are rapidly restored when flight ceases. The results support the suggestion that octopamine mediates a generalized sympathetic-like response to excitation.
Heligmosomoides, polygyrus, (syn. Nematospiroides, dubius), (Nematoda): distribution and net fluxes of glucose, H2O, Na+, K+, and Cl− in the mouse small intestine
Authors: Sukhdeo M. V. K. , Mettrick D. F.
Published: December 2009

Mice were infected with 150 larvae of Heligmosomoides, polygyrus, and the effect of the worms on net fluxes of glucose, H2O, and electrolytes was followed from days 1–21 postinfection (PI) by means of an in vivo, perfusion technique. Maximum recovery of larvae was 77% at 5 days PI, and 64% for adults at 12 days PI following their emergence and migration into the duodenal lumen between days 7 and 9 PI. Inflammation decreased rapidly from day 9 PI onwards. Net glucose flux significantly decreased during the emergence of the adult worms (7–9 days PI). Water flux decreased and Na+ fluxes became negative at 5 days PI; Na+ and Cl− fluxes were negative at 7 days PI. Following the relocation of the adult worms in the proximal small intestine, fluxes returned to their normal levels. The differential changes in the net fluxes of glucose, H2O, and electrolytes suggest the secretion of a toxinlike substance by the parasites. In the normal mouse host, small infections have a temporary pathophysiological effect on the intestinal mucosa, differing significantly from previous studies using the abnormal rat host and large larval infections. As normal transmission of H. polygyrus, is by contamination, small infections, as employed in this study, probably reflect the natural condition.
Impact de 12 plantes communes de milieu ouvert sur les variations de poids corporel et de poids d'organes internes du campagnol des champs (Microtus pennsylvanicus)
Authors: Bergeron Jean-Marie , Jodoin Louise
Published: December 2009

Among the very abundant plants found in the habitat of the meadow vole (Microtus pennsylvanicus) and often used as natural food by the animal, 12 were chosen as part of the diet of subadult voles in laboratory conditions. The preferred plants were reed phalaris (Phalaris arundinacea), timothy (Phleum pratense), awnless brome-grass (Bromus inermis), Canada thistle (Cirsium arvense), and couchgrass (Agropyron repens), which correspond to stomach analyses (done previously). Diets consisting of umbellate aster (Aster umbellatus), Canada thistle, simple aster (Aster simplex), and reed phalaris were the only ones found to cause weight loss in the animals. All diets contained a minimum of 11% crude proteins and an energy value of 4.3 kcal/g of dry weight (1 kcal = 4.1868 kJ). Weights of the spleen and adrenals did not differ significantly between treated and control animals. However, some diets caused significant decreases in the weight of the liver, while others caused significant increases in the weight of the kidneys. Many of the diets caused both effects, a phenomenon previously recorded in experiments on food poisoning in laboratory mice. Results are discussed in relation to recent hypotheses about protoxin.[Journal translation]
Chinook salmon (Oncorhynchus tshawytscha) density, growth, mortality, and movement in two Lake Michigan tributaries
Authors: Carl L. M.
Published: December 2009

Spawning density and the time of spawning (October) were similar in two tributaries of Lake Michigan in 1977 and 1978. Drift of recently emerged fry began in April and continued into June. During 1977–1979, the density of chinook salmon juveniles increased rapidly in early May to 0.3–2.9 fish/m2 and then declined to 0.2–0.8 fish/m2 by late June when most of the fish smolted. Instantaneous mortality estimates were variable between years and sites in both creeks, but overall mortality was similar in both streams with an average daily rate of 0.024 for Baldwin Creek and 0.025 for Pine Creek. A regression of the mortality rates versus initial density indicated the mortality rates were dependent on the initial fry density. There was no correlation between an index of spawner density and the number of smolts produced. No correlation was found between initial resident fry density and emergent fry colonization. Size-selective mortality was indicated in some stream sections. The daily growth rates for fish in both streams varied between 0.28 and 1.01 mm per day. These rates were similar to or higher than rates reported in the literature from other stocks of chinook salmon on the west coast of North America and Lake Ontario.
Intranuclear bodies in the tissues of the scolex of the cestode Hymenolepis microstoma
Authors: Webb Rodney A.
Published: December 2009

Intranuclear bodies were observed in the tissues of the scolex of Hymenolepis microstoma where they were most frequent and well developed in the rostellar tegumental cell bodies. The intranuclear bodies in the electron microscope appeared as bundles of fibrillae oriented in a loose lattice structure, set in a featureless lucent nucleoplasm. The fibrillae were ~8 nm in diameter with a longitudinal periodicity of ~6 nm. These bodies, restricted almost entirely to the scolex, were observed only after the scolex had migrated into the bile duct. The correlation of these bodies with possibly viral, pathological, and hypermetabolic states is discussed.
Development of Dirofilaria scapiceps (Leidy, 1886) (Nematoda: Filarioidea) in Aedes spp. and Mansonia perturbans (Walker) and responses of mosquitoes to infection
Authors: Bartlett Cheryl M.
Published: December 2009

Dirofilaria scapiceps (Leidy, 1886) developped in the abdominal fat body of Aedes canadensis, A. euedes, A. excrucians, A. provocans, A. punctor, A. stimulans/fitchii, A. vexans, and Mansonia perturbans which occur in enzootic areas in Ontario. Abundances of third-stage larvae were greatest in A. euedes and A. excrucians. Transmission took place in July and August. Development also occurred in Aedes aegypti (Liverpool strain) but not in A. triseriatus and A. trivittatus. Larvae in A. euedes and A. excrucians developed within syncytia containing hypertrophied adipocyte nuclei; third-stage larvae were first observed at 10 days postinfection (26 °C) and all larvae invariably developed to the third stage. Syncytia containing hypertrophied adipocyte nuclei apparently act as a nutrient source and may be essential for normal development of larvae. In A. stimulans/fitchii, syncytia did not form or formed abnormally, a longer period (12 days) was required for development to the third stage, and many larvae failed to reach the third stage. Many developing larvae in A. aegypti were surrounded by syncytia but adipocyte nuclei in them were not hypertrophied. Larvae in A. aegypti given one blood meal commonly did not reach the third-stage, although development proceeded normally in A. aegypti given two blood meals. Third-stage larvae have postdeirids, two terminal caudal papillae, and a terminal caudal cuticular cap and are readily distinguished from third-stage larvae of other Dirofilaria species. Male third-stage D. scapiceps possess spicular pouch primordia, previously unreported in infective filarioid larvae.
Coevolution of the rennin–angiotensin system and the nervous control of blood circulation
Authors: Wilson John X.
Published: December 2009

The mammalian renin–angiotensin system appears to be involved in the maintenance of blood volume and pressure because (i) sodium depletion, hypovolemia, and hypotension increase renin levels, and (ii) administration of exogenous angiotensin II rapidly increases mineralocorticoid and antidiuretic hormone production, transepithelial ion transport, drinking behavior, and peripheral vascular resistance. Are these also the physiological properties of the renin–angiotensin system in nonmammalian species? Signals for altered levels of renin activity have yet to be conclusively identified in nonmammalian vertebrates, but circulating renin levels are elevated by hypotension in teleost fish and birds. Systemic injection of angiotensin II causes an increase in arterial blood pressure in all the vertebrates studied, suggesting that barostatic control is a universal function of this hormone. Angiotensin II alters vascular tone by direct action on arteriolar muscles in some species, but at concentrations of the hormone which probably are unphysiological. More generally, angiotensin II increases blood pressure indirectly, by acting on the sympathetic nervous system. Catecholamines, derived from chromaffin cells and (or) from peripheral adrenergic nerves, mediate some portion of the vasopressor response to angiotensin II in cyclostomes, elasmobranchs, teleosts, amphibians, reptiles, mammals, and birds. Alteration of sympathetic outflow is a prevalent mechanism through which the renin–angiotensin system may integrate blood volume, cardiac output, and peripheral vascular resistance to achieve control of blood pressure and adequate perfusion of tissues.
Aggressive and territorial behaviour in female Red-winged Blackbirds
Authors: Hurly T. Andrew. , Robertson Raleigh J.
Published: December 2009

Female Red-winged Blackbirds were observed to interact aggressively with conspecific females during the breeding season. Redwing females attempted to repel intruding females through the use of vocalizations, displays, and aggressive chases. Mapped positions of marked individuals indicated that female Red-winged Blackbirds recognized male territory boundaries and defended subsections of the male's territory against new intruding females and against harem mates. Female vocalizations advertising territory ownership were clumped in time early in the breeding season, suggesting that neighbouring individuals were interacting vocally. These results support the competitive version of the polygyny threshold model. The observed aggressive interactions, territorial behaviour, and vocal interactions suggest that female Red-winged Blackbirds attempt to deter further recruitment into harems.
Behavior and dispersal of yearling Columbian ground squirrels
Authors: Festa-Bianchet Marco , King Wendy J.
Published: December 2009

Behavior of yearling Columbian ground squirrels (Spermophilus columbianus) was studied through intensive observations of an isolated, high-density population in southwestern Alberta from 1979 to 1981. All members of this population were individually marked. A greater proportion of yearlings disappeared during the active season than that of any other age-class. This loss appeared to be due to emigration, and was greater for males than for females. Some 2-year-old males may also have dispersed. Male yearlings played more than females, but both sexes displayed a similar frequency of aggressive interactions with other yearlings. As the season progressed, the frequency of play behaviors between yearlings decreased, and by the time of presumed emigration almost no play was seen. There was no clear relationship between a yearling's dominance status and whether it emigrated. Adults of both sexes behaved aggressively towards yearlings, particularly yearling males. Adult females were most aggressive just preceding the time of presumed emigration, and at this time yearlings changed their dispersion pattern within the meadow, apparently in an attempt to avoid female aggression. Postponement of dispersal to the yearling age appears to be an adaptation to a short active season. Adult squirrels may benefit from expelling yearlings by diminishing future competition, but the adaptive advantage of emigration for the yearlings themselves remains unclear.
Integumental glands associated with tactile hairs on the ovipositor of tephritid flies
Authors: Berube D. E. , Zacharuk R. Y.
Published: December 2009

The seventh abdominal segment, which forms the oviscape of the ovipositor in the tephritid flies Urophora affinis and U. quadrifasciata, bears setae in two bilaterally symmetrical rows on the dorsal and ventral aspects of its distal margin and scattered irregularly over the rest of its surface. At the anterior side of the base of each hair is a porous plaque covering a channel through the cuticle into which strands of a microtubular "secretory". material extend from the cytoplasm of a greatly enlarged gland cell. One such cell is associated with each hair, which is innervated by a single dendrite that terminates in a tubular body at the base of the hair. These gland cells are absent in male flies. The possible morphologic, functional, and taxonomic significances of these gland cells are discussed.
Description of Sarcocystis rauschorum sp. n. (Protozoa: Sarcocystidae) with experimental cyclic transmission between varying lemmings (Dicrostonyx richardsoni) and snowy owls (Nyctea scandiaca)
Authors: Cawthorn Richard J. , Gajadhar Alvin A. , Brooks Ronald J.
Published: December 2009

Sarcocystis rauschorum sp. n. (Protozoa: Sarcocystidae) is heteroxenous, with varying lemmings (Dicrostonyx richardsoni) as expermental intermediate hosts and snowy owls (Nyctea scandiaca) as natural and experimental definitive hosts. Free sporocysts of a Sarcocystis-like organism (11.6 × 9.2 μm with a diffuse residuum of numerous small refractile granules) from intestinal scrapings of a naturally infected snowy owl were orally administered to laboratory-reared varying lemmings. Meronts were present 7 days post inoculation (DPI) in hepatocytes. Cysts of S. rauschorum sp. n. developed in striated muscle and contained metrocytes (4.6 × 3.8 μm) 14 DPI; bradyzoites (6 × 2 μm) were present at least as early as 28 DPI. Cysts at 84 DPI were not macroscopic (greatest diameter 80.9 μm, least diameter 70.9 μm) with walls 0.35–0.70 μm thick. Laboratory-reared rats (Rattus norvegicus), house mice (Mus musculus), white-footed mice (Peromyscus leucopus), red-backed voles (Clethrionomys gapped), and brown lemmings (Lemmus sibiricus) were not suitable intermediate hosts. Carcasses of varying lemmings containing cysts (57 and 84 DPI) of S. rauschorum sp. n. were fed to three Sarcocystis-free snowy owls. The prepatent period was 7 days and the patent period 12 – 19 days. Sporogony occurred in the lamina propria throughout the length of the small intestine. Free sporocysts (10.4 × 8.2 μm with a compact residuum of numerous small refractile granules) from experimentally infected owls were infective for varying lemmings.
Effects of fly parasitoids on nightly calling duration in field crickets
Authors: Cade William H.
Published: December 2009

The song of male field crickets, Gryllus integer (Orthoptera: Gryllidae), attracts flies, Euphasiopteryx ochracea (Diptera; Tachinidae). Flies deposit larvae on male crickets and the larvae burrow in and consume the host. Effects of fly parasitism on duration of calling in G. integer were studied. Male crickets were collected at street lights and placed in jars and were electrically monitored for calling song. Calling duration was measured for 7 nights. Fly larvae were then placed on males and calling duration was measured for an additional 7 nights. In two replicates, males called significantly less following parasitism, and average calling duration declined gradually before death. Other males which remained free of fly larvae showed no reduction in calling. Field-collected males which subsequently died from fly parasitism called significantly less than non-parasitized males. Acoustically orienting flies reduce the ability of parasitized males to attract females acoustically.
Effects of environmental pH on the ionic composition of the white sucker (Catostomus commersoni) and pumpkinseed (Lepomis gibbosus)
Authors: Fraser Grant A. , Harvey Harold H.
Published: December 2009

White sucker (Catostomus commersoni) exposed to soft water ([Ca2+] = 0.207 mequiv./L) below pH 5 showed [Na+] and [Cl−] losses, that were approximately the same in plasma and whole body. At pH 4.5 (6- to 19-day exposure), body and plasma [Na+] were approximately 17% lower than in white sucker held at pH 6.6, and 42% lower in fish at pH 4 (<2 days). Since plasma ions are known to be affected by handling stress, whole-body [Na+] and [Cl−] in fishes may be a more useful indicator of ionoregulation status under field conditions. Pumpkinseed (Lepomis gibbosus) were clearly more acid tolerant, as indicated by greater survival and reduced ion loss in the same acid environments as white sucker. After 19 days exposure at pH 4.5, body Na+ was reduced by 8%; at pH 4 body Na+ was reduced by 38%. Hence, at pH 4, the net Na+ loss experienced by this acid-tolerant fish was similar to that observed in white sucker; however, the rate of loss in white sucker was 11-fold greater. White sucker in acidified, decarbonated hard water ([Ca2+] = 2.110 mequiv./L) at pH 4 (6 or 19 days), showed a 35% lower whole-body [Na+] than in fish held at pH levels of 4.5, 5, and 6.3; [Cl−] was 39% less. However, at pH 4 the ratio of whole-body Na+:Cl− losses was 1.4:1 in hard water and 1.08:1 in soft water. Total Na+ loss at pH 4 was similar to that in white sucker held at the same pH in soft water; however, the rate of loss in soft water was 15-fold greater.
L'utilisation des emprises de lignes de transport d'énergie électrique par l'orignal (Alces alces) en hiver
Authors: Joyal Robert , Lamothe Pierre , Fournier Robert
Published: December 2009

The influence of electric transmission rights-of-way on the activity of moose (Alces alces) was determined by aerial surveys during winter and inventories of browsed plant species the following summer. Moose make significant less use of the rights-of-way than the adjacent forest, but the edge zone is frequented more. Winter grounds are also found significantly less frequently in these transmission corridors. The difference in use between the two habitats is even more pronounced when the rights-of-way have been treated with a phytocide. The quantity of browse in untreated rights-of-way does not differ significantly from that found in the adjacent forest, but in treated corridors, it is three times lower. Rights-of-way that are 90 m wide are more frequently crossed in winter than those that are 140 m wide. Wild red cherry (Prunus pensylvanica) is the most browsed species in southern parts of the corridors, whereas white birch (Betula papyrifera) is the preferred plant of moose in northern areas. There is no difference between the types of forest stands in adjacent forest stations that are used by moose and those that are not. The influence of the electric transmission rights-of-way is considered weak because the natural density of the moose population is low.[Journal translation]
Life history patterns of Hydropsyche bronta and H. morosa (Trichoptera: Hydropsychidae) in summer-warm rivers of southern Ontario
Authors: Mackay Rosemary J.
Published: December 2009

Life history patterns are described for Hydropsyche bronta and Hydropsyche morosa in the Credit and Humber rivers of southern Ontario. In the lower reaches (stream orders 4 and 5) of these rivers, summer water temperatures exceed 24 °C for 3 months and reach maxima of 27–30 °C. Here H. morosa appeared to be bivoltine while at least half of the H. bronta population at each of four sites was trivoltine. At a fifth site below an impoundment on a second-order tributary to the Humber, H. bronta was bivoltine; H. morosa was extremely rare at this site and in upper reaches in general. Hydropsyche bronta is smaller than H. morosa and tends to overwinter in slightly older larval instars than H. morosa. Both these characteristics, and the fact that H. bronta is probably living in the optimal part of its habitat range in the Credit and Humber, may explain its ability to be trivoltine.