bluuebunny/crossref_metadata_2025 huggingface dataset:
Adaptation, constraint, and convergence among vertebrate LDH isozymes: an evolutionary perspective
Authors: Baldwin John
Published: March 2009

The lactate dehydrogenase isozymes of vertebrates constitute a family of homologous proteins well suited for investigating adaptation and constraint at both the structural and the functional level. Viewing this system from an evolutionary perspective offers the possibility of identifying situations in which apparently conserved properties are in fact the products of convergent evolution. A reexamination of the evolutionary relationships among lactate dehydrogenase subunits of lower vertebrates provides several examples where both the catalytic properties and the amino acid compositions of isozymes appear to have converged under the selective influence of limited oxygen availability.
Temperature acclimation of the caudal photoreceptor response in the crayfish Orconectes rusticus (Girard)
Authors: Belanger Jim H.
Published: March 2009

Crayfish (Orconectes rusticus (Girard)) were acclimated for 3 weeks at 5 and 25 °C. The effects of temperature and temperature acclimation on the latency, maximum frequency, and sensitivity to stimulus intensity of the caudal photoreceptor response were examined in isolated abdominal nerve cords. Each of these components was temperature dependent. The maximum frequency of the response showed thermal capacity acclimation but latency did not. Caudal photoreceptor response was insensitive to stimulus intensity at low temperatures but acclimation improved sensitivity.
An analysis of life histories in freshwater bivalves (Mollusca: Pisidiidae)
Authors: Way Carl M.
Published: March 2009

A survey of patterns of covariation of six life history traits in 13 species (26 populations) of pisidiid bivalves was carried out using canonical discriminant analysis. The analysis separated the three genera of pisidiids into significantly different clusters. The traits that separated the genera have been called life history tactics and the genera have been placed along an r–K continuum. Univariate phenotypic correlation statistics were used to identify specific life history traits that covary at the genus and interspecific levels. The identifiable groupings of life history traits and traits that strongly covary appear to be influenced in part by phylogeny (size differences between genera), allometry (size differences within a cohort), and habitat (both localized and historical influences). At the present time there is a lack of the detailed intraspecific life history data necessary to sort out the causality behind the groupings of traits. It will be necessary to make detailed comparisons of life histories at the intraspecific level to attain an understanding of the proximal processes involved in causing life history variability.
Distribution patterns during winter and fidelity to wintering areas of American black ducks
Authors: Diefenbach Duane R. , Nichols James D. , Hines James E.
Published: March 2009

The distribution patterns during winter of American black ducks (Anas rubripes) were compared among age – sex classes using band recovery data. In addition, fidelity to wintering areas was compared between sexes and between coastal and inland wintering sites. We did not find evidence of age- or sex-specific differences in distribution patterns (P > 0.10). Black ducks exhibited a stronger fidelity to coastal wintering areas (P < 0.01), but there were no sex-specific differences (P > 0.30). We believe that the early formation of breeding pairs and possibly predictable food resources may reduce age – sex segregation in distribution patterns during winter. The predictability of food resources in coastal, as opposed to inland, wintering areas is likely responsible for the greater fidelity of black ducks to coastal wintering sites.
Studies on seasonal changes and latitudinal differences in the metazoan fauna of the shiner perch, Cymatogaster aggregata, along the west coast of North America
Authors: Arai H. P. , Kabata Z. , Noakes D.
Published: March 2009

The results of studies to assess seasonal changes and to determine latitudinal differences in the parasite fauna of Cymatogaster aggregata are presented. Certain elements of this fauna show significant seasonal fluctuations and others show distributional patterns that appear to assume an orientation based on geography. Some factors that may be involved in determining such fluctuations and patterns are discussed.
Structure en taille des crustacés planctoniques d'un lac dimictique du Bouclier canadien
Authors: Martin Lucie , Pinel-Alloul Bernadette
Published: March 2009

From May 1981 to July 1982, 28 zooplankton samples were taken from the pelagic zone of Lake Cromwell, Quebec. Seasonal variation in the size structure of the planktonic crustacean community was studied using three different multidimensional analyses: intermediate linkage clustering, principal coordinate analysis, and chronological clustering. The results of these analyses showed the existence of distinct patterns in the size distribution of planktonic crustaceans during the annual cycle. During winter, the community was dominated by intermediate-sized organisms (0.51–0.60 mm), and by a few of larger size (0.96 mm). In springtime, nauplii appeared, and the larger size classes were reduced, giving the size spectra a characteristic shape. Small organisms (0.06–0.22 mm) dominated the population throughout the summer. The fall season was characterized by the opposite observation: small organisms slowly decreased in number while the intermediate classes (0.51–0.60 mm) increased in number to reach their peak in winter. These size–frequency patterns may be related to varying food levels and composition throughout the year.
Maternal aggression in northern elephant seals: the effect of the pup
Authors: Ribic Christine A.
Published: March 2009

Female northern elephant seals (Mirounga angustirostris) were observed for three breeding seasons on Southeast Farallon Island to determine the effect of the pup on maternal aggression. For females that lost their pups before weaning them, the mean percentage of aggressive encounters started and won decreased after the death of the pup. A higher percentage of females moved away at the end of an aggressive encounter from females that ultimately weaned their pups than from females that ultimately lost their pups. There was, however, no difference between the two categories in mean percentage of aggressive encounters started and won. Among females that weaned pups in all three seasons, individuals did not win more encounters but differed in percentage of females that moved away and in mean percentage of aggressive encounters started as they aged. A number of variables were associated with an increased probability that a female would successfully wean her pup: early arrival date, having a high percentage of females that moved away, and a high mean percentage of aggressive encounters won. Raising a pup in an area of high female density or where animals had access to the beach were associated with a decreased probability of weaning a pup.
Nesting parameters in a high density, declining population of blue grouse
Authors: Zwickel Fred. C. , Lewis Richard A. , McKinnon Donald T.
Published: March 2009

Of four nesting parameters (clutch size, egg fertility, egg hatchability, and nesting success) in a population of blue grouse, Dendragapus obscurus fuliginosus, at Hardwicke Island, British Columbia, only clutch size differed between yearling and adult females. There was no difference among years for any of the parameters considered. This population declined from very high to moderate density during the studies reported here, and clutch size, egg fertility, and hatchability were significantly lower than reported for a more stable population (Comox Burn) in the same general region. Nesting success at Hardwicke Island, however, was higher than at Comox Burn. Collectively, the parameters examined do not, by themselves, explain the observed decline. Nevertheless, they suggest that the population at Hardwicke Island differed from that at Comox Burn in some fundamental aspects of reproduction that may be symptomatic of other factors possibly involved in its decline, e.g., the survival of chicks.
Life history characteristics and movements of the woodland jumping mouse, Napaeozapus insignis, in Nova Scotia
Authors: Ovaska Kristiina , Herman Thomas B.
Published: March 2009

We examined abundance, reproduction, movements, and adult–juvenile interactions of Napaeozapus insignis in a 5-year mark–recapture study in Nova Scotia. Densities of N. insignis varied greatly between years, mainly as a result of variation in overwintering survival of juveniles and breeding success of females. Year-to-year survival rates of adults were relatively constant (approximately 26%), whereas those of juveniles fluctuated widely. Adult females produced only one litter per season, and no juvenile reproduced in the summer of her birth. Length of the active season was 12–17 weeks, and timing of emergence from hibernation varied little from year to year. Males emerged from hibernation 15–33 days earlier than females, and their captures were clustered along portions of the transects adjacent to steep slopes, which may have provided well-drained hibernation sites. The overall sex ratio did not differ from 1:1, but in May it was biased towards males, and in July and August adult females outnumbered adult males. Distances moved by adult males and females within 24 h were similar (mean for males = 97 m, for females = 61 m), but home ranges of males between June and August were greater than those of females (mean distance between two farthest captures for males = 447 m, for females = 175 m). Results from a removal experiment, as well as examination of trapping records, indicated that adult females inhibited early capture of juveniles when densities of adults were high. We suggest that the suite of life history traits (long life-span, late maturity, infrequent reproduction) that northern zapodids exhibit relative to southern zapodids is best explained by a bet-hedging hypothesis. Long winters and short summers in the north contribute to low and unpredictable overwintering survival of juveniles. By directing energy from reproduction into accumulation of hibernation fat, adults increase their chances of surviving to breed again the next summer and thus decrease the probability of leaving no young at all.
Lakes Michigan and Huron limit gene flow between the subspecies of the butterfly Limenitis arthemis
Authors: Waldbauer G. P. , Sternburg J. G. , Ghent A. W.
Published: March 2009

Near the Straits of Mackinac, the Limenitis arthemis population on Michigan's Upper Peninsula consists mostly of the disruptively banded L. a. arthemis, while the population on its Lower Peninsula consists mostly of the unbanded, mimetic L. a. astyanax and arthemis–astyanax intergrades. Except at the straits, the Upper and Lower peninsulas are broadly separated by lakes Michigan and Huron. On the Lower Peninsula, arthemis-like forms are most common on the shore close to the Upper Peninsula but are much less frequent only 20 km south, probably because of the northward flow of astyanax genes. Neither population is in Hardy–Weinberg equilibrium because of a deficiency of "hétérozygotes," possibly because of cross-lake emigration at the straits.
A long-term study of food-niche dynamics in the Common Barn-Owl: comparisons within and between populations
Authors: Marti Carl D.
Published: March 2009

Food niches of Common Barn-Owl (Tyto alba) populations were studied for 8 years in Utah and Idaho. Small mammals dominated the diet as they do in most parts of the barn-owl's range. Mean prey weight was nearly identical between the two owl populations. Food-niche breadth, though, was significantly broader in Idaho than in Utah. Food-niche breadth was also more variable in Idaho than in Utah both within and between years. Voles (Microtus spp.) were predominant prey for both owl populations and were the only prey whose numeric variation in the diet significantly affected mean prey weight and food-niche breadth. Vegetative composition was less varied and more uniformly favorable to voles in Utah. The Idaho area contained a smaller poportion of good vole habitat but had a greater diversity of vegetation including deserts suitable for small mammal species not found in the Utah study area. These vegetative differences and their effects on small mammal species diversity and density were the most apparent causes of food-niche differences between the two owl populations.
Inbreeding in a population of meadow voles, Microtus pennsylvanicus
Authors: Pugh Stephen R. , Tamarin Robert H.
Published: March 2009

The level of inbreeding in a population of meadow voles, Microtus pennsylvanicus, was determined using a radionuclide–electrophoresis technique. Of the matings that successfully produced offspring, 36.4% were inbred. This value is much higher than other figures reported for birds and mammals. However, the level of inbreeding observed was equal to what was expected assuming random mating. We conclude that the voles in this population were not avoiding inbred matings.
Effect of temperature on rate of water loss in some water boatmen (Hemiptera: Corixidae)
Authors: Cannings S. G. , Cooper P. D. , Scudder G. G. E.
Published: March 2009

Evaporative water loss was compared in Cenocorixa bifida, Cenocorixa expleta, Cenocorixa blaisdelli, and Callicorixa vulnerata and examined in relation to environmental temperature change. In Ce. bifida, evaporative water loss was also studied with respect to rearing temperature and temperature of adult acclimation. Cenocorixa bifida (reared at 20 °C and acclimated to 20 °C) had the lowest rate of water loss at 20 °C of all species, while Ce. expleta had the highest. This pattern also occurred when the activation energy for water loss among species was compared: Ce. expleta had the lowest and Ce. bifida, the highest. High rearing temperatures and high acclimation temperature both reduced water loss at 20 °C in Ce. bifida. This pattern was also reflected in the activation energy for water loss in the different groups of insects exposed to the various temperatures of emergence or acclimation. These data suggest that cuticle lipids vary among these water boatman species and that changes in the proportions of unsaturated lipids may occur in relation to prior long-term exposure to high temperature. Despite differences in rates of water loss and activation energy for water loss, it appears that temperature does not restrict the distribution of any of these insects.
Water temperature, vertical distribution, and risk of ectoparasitism in juvenile sticklebacks
Authors: Poulin Robert , FitzGerald Gerard J.
Published: March 2009

We tested the hypothesis that the risk of juvenile sticklebacks (Gasterosteidae) being parasitized by the crustacean ectoparasite Argulus canadensis decreases with increasing water temperature. In the laboratory, juvenile sticklebacks and parasites were acclimated to three different temperatures, 18, 22, and 26 °C. The attack performances of single parasites on groups of 20 fish were measured at each temperature. We found no significant effect of temperature on the attack success (percentage of attacks successful) or the attack rate (number of attacks per minute) of parasites. In addition, we sampled sticklebacks in their natural habitat, salt marsh tide pools, three times per day, when water temperatures were lowest, intermediate, and highest. The relative abundance of parasites on fish (total number of A. canadensis divided by the total number of sticklebacks sampled) was twice as high during midafternoon, when temperature was highest, than in the early morning, when temperature was lowest. Sticklebacks usually swam close to the bottom of tide pools, where parasites were resting, in midafternoon, and at the water surface in the early morning. These changes in the vertical distribution of the fish may result from diel fluctuations in temperature or in other abiotic factors, and small differences in these factors between the bottom and the surface of the pools. Our results indicate that, while it had no direct effects on the attack success and attack rate of the parasites, water temperature, or other abiotic factors, may have indirectly affected the sticklebacks' chances of being parasitized by changing their vertical distribution, and thus their spatial overlap with parasites.
Role of water current and related variables in determining buoyancy in the sticklebacks Culaea inconstans and Pungitius pungitius
Authors: Beaver Barbara J. , Gee John H.
Published: March 2009

The sticklebacks Culaea inconstans and Pungitius pungitius alter buoyancy (lift from the swim bladder) in the field primarily in response to changes in water velocity. Potential adjustment is extensive and is only realized when fish are exposed to current for several days. Buoyancy measured on fish from the field showed an inverse relationship with water velocity and temperature. Buoyancy was also highest in fish living among vegetation. However, vegetation was restricted to still water or areas of very low velocity. In the laboratory, water temperature affected buoyancy of C. inconstans in current only; there, at 6 °C, buoyancy was greater than at higher temperatures. In the field an unknown factor(s), dependent on temperature, affects buoyancy. An inverse relationship was found between buoyancy and water velocity in the laboratory, and adjustment of buoyancy was slow. The time required for buoyancy to decrease from maximum to minimum levels was 4 and 7 d for P. pungitius and C. inconstans, respectively. In the field, minimum buoyancy levels were not reached because fish were exposed to weak current velocities for short intervals. The ability to reduce swim bladder lift (volume) in strong velocities and replace it with hydrodynamic lift and vice versa is seen as an adaptation to environments where water velocity varies in time and space permitting fishes to use the most effective source of lift.
Light microscopical and cytochemical study on the adhesive and epidermal gland cell secretions of the branchiobdellid Cambarincola fallax (Annelida: Clitellata)
Authors: Gelder S. R. , Rowe J. P.
Published: March 2009

Eight types of gland cells are present in six different epidermal glands in the branchiobdellid Cambarincola fallax. The anterior and posterior adhesive organs are both composed of viscid and releaser adhesive gland cell types, and their secretions open onto the anterior attachment site on the ventral surface of the ventral peristomial lip and onto the posterior attachment disc, respectively. The secretion granules of the viscid gland cell type are composed of neutral mucosubstances with basic proteins containing arginine and (or) lysine; the releaser gland cell type contains basic proteinaceous granules with a tryptophan component. These adhesive glands are very similar to duo-gland adhesive organs described elsewhere. Use of the term "sucker" should be discontinued as there is no suctorial mechanism at the anterior attachment site and only circumstantial evidence of such action at the posterior disc. Two epidermal gland cell types occur together in groups of two to four cells at sites scattered over the body surface except in trunk segments 6 and 7. One of these epidermal gland cell types produces granular secretions formed of neutral mucosubstances with a basic protein component, and the other produces globular secretions composed of a carboxylated acid mucosubstance. Secretions from the peristomial gland cells open onto the dorsal and ventral lips. The posterolateral gland cells form three pairs: two pairs in segment 8 and one pair in segment 9. Both peristomial and posterolateral gland cells have granular secretions composed of neutral mucosubstances with a basic protein component. The two types of clitellar gland cells are arranged in groups of 7 to 13 cells with a granular secretion type predominating over one with globular secretions. The granular type consists of neutral mucosubstances with amyloid-like and strong basic protein components, and the globular type consists of a carboxylated acid mucosubstance with a nonbasic protein component.
Infraciliature, système myonémique, argyrome et bipartition de l'Astylozoon pyriforme (Ciliophora, Peritrichida)
Authors: Guinea A. , Sola A. , Rueda M. C. , Fernández-Galiano D.
Published: March 2009

Astylozoon pyriforme is a stalkless peritrich whose ciliature is restricted to the oral region and reduced to a few aboral bristles at the posterior pole. As in other peritrichs, the infraciliature is located in two zones, oral (peristome and infundibulum) and aboral (trochal band and scopule). We also observed an epistomial membrane located in the region where the peristomial infraciliature begins, to the right of the haplokinety. The myonemic system of this ciliate has three parts: an oral myonemic ring, a peristomial myonemic network, and longitudinal myonemes. The argyrome consists of 35 to 40 thin concentric striations that surround the cell but not the peristome. During the stomatogenic process, the germinal kinety and the haplokinety are the origin of the new buccal structures, as in other peritrichs.
Studies of the honey bee tracheal mite (Acarapis woodi) (Acari: Tarsonemidae) during winter
Authors: Otis Gard W. , Bath Judy B. , Randall Deborah L. , Grant Gordon M.
Published: March 2009

Changes in the populations of tracheal mites (Acarapis woodi) in individual honey bees were quantified in New York during winter. Mite prevalence increased greatly from November to February, then declined again in late spring. The simultaneous increases in prevalence values and in slight infestations restricted to the outer portions of the tracheae strongly suggest that many older bees were becoming infested with mites during the winter period when no brood was being reared. Trends in mite infestations varied greatly in different colonies for reasons that are not clear. Although mite reproduction was generally low (< 2.5 immatures per female), it appeared to be higher in October than during the rest of the winter. The sex ratio (3.04) was biased in favour of females. These patterns are different in some respects from those described for the same organism in Europe, emphasizing the need to carefully evaluate the biology of tracheal mites in North America and their interactions with their bee hosts before predicting their economic impact.
Ultrastructure des bourgeons du goût du téléostéen marin Dicentrarchus labrax L.
Authors: Connes R. , Granie-Prie M. , Diaz J. P. , Paris J.
Published: March 2009

The taste buds of the oropharyngeal cavity of the bass, Dicentrarchus labrax L., were examined by scanning and transmission electron microscopy. Each bud consists of a pear-shaped grouping of clear cells, dark cells, and basal cells, sunk into the epidermis and set on a projection of the underlying dermis, the dermal papilla. The clear cells contain abundant smooth endoplasmic reticulum and numerous mitochondria, as well as microtubules; they end in a single large apical microvillosity. Dark cells are packed with microfilaments and contain many secretory vesicles; the tip of each of these cells consists of numerous small microvilli. These two categories of cells are closely attached to one another and opaque cells are further attached to the basal lamina by hemidesmosomes. The basal cells and the extremities of the opaque cells are always close together but they are never attached by specialized junctions. The three types of cells contained in the taste buds are linked by synaptic contacts to the myelin-free nervous fibers that form an important network system in the lower part of the organ. These structures are compared to their homologues in other fishes and the respective functions of the different cell categories are discussed.[Journal translation]
The development and pathogenesis of Eustrongylides tubifex (Nematoda: Dioctophymatoidea) in piscivorous birds
Authors: Measures Lena N.
Published: March 2009

Experimental infections of laboratory-raised birds supported field data indicating that Common Mergansers (Mergus merganser L.) (prevalence = 20.8%, mean intensity = 3.2) and Red-breasted Mergansers (Mergus senator L.) (prevalence = 4.0%, mean intensity = 1) are important hosts of Eustrongylides tubifex in Ontario. Fourth-stage larvae from naturally infected fish were used to infect birds. In birds, the fourth moult occurred 2 days postinfection and adult worms retained the fourth-stage cuticle. In experimentally infected mergansers, E. tubifex developed in the tunica muscularis of the proventriculus, eliciting raised, oval tumours. Worms matured rapidly, produced eggs 10 to 17 days postinfection, and then degenerated. Tumours resolved rapidly in the proventriculus which returned to its normal condition by approximately 30 days postinfection. Worms were sometimes found in aberrant locations such as the gizzard and liver but this occurred less frequently in Common Mergansers and Red-breasted Mergansers than in other experimentally infected birds (Hooded Mergansers (Mergus cucullatus L.), Great Blue Heron (Ardea herodias L.), Double-crested Cormorants (Phalacrocorax auritus (Lesson), and domestic ducks (Anas platyrhynchos L.).
A contribution to the taxonomy of the aquatic Oligochaeta (Naididae) of South America
Authors: Harman W. J. , Brinkhurst R. O. , Marchese M.
Published: March 2009

The number of South American species of the family Naididae has yet to be determined. Some 27 species are discussed here, and a list of South American species in 15 genera is presented. Nais simplex, Dero (Aulophorus) vagus, and Pristinella acuminata are new to the list. Nais raviensis is regarded as a member of the genus Dero in accordance with recent literature. The subfamily Stylarinae, thought to be the oldest in the family, is scarce or absent in the region, in contrast to austral or southern distributions for supposedly more primitive families or primitive genera in other families.
Interrelationships within a raptor guild in the central Canadian Arctic
Authors: Poole K. G. , Bromley R. G.
Published: March 2009

The interrelationships of an arctic raptor guild comprising golden eagles (Aquila chrysaetos), gyrfalcons (Falco rusticolus), peregrine falcons (Falco peregrinus), rough-legged hawks (Buteo lagopus), and common ravens (Corvus corax) (a functional raptor) were studied from 1983 to 1986. Partitioning of time, space, and food generally related to body size; small-bodied species (peregrines and rough-legged hawks) nested later, had shorter reproductive periods, used smaller cliffs with less overhang, and took smaller prey than large-bodied species. The raven, a passerine, was often the exception. The onset of laying for each raptor was closely related to arrival or emergence of major prey species. Gyrfalcons and ravens selected well-protected sites, while other species selected sites with southerly aspects but little overhang protection. Overlap in prey use was high between eagles and gyrfalcons early in the breeding season. The spacing of all species except the rough-legged hawk tended to be regular, apparently as a result of intraspecific rather than interspecific factors. However, all species tended to nest far from occupied eagle sites. Reproductive success was not affected by distance to nearest intra- or inter-specific neighbor, except among gyrfalcons whose reproductive success was significantly lower when conspecifics nested within 5 km than when they nested farther away. Golden eagles, a species on the edge of its geographic range, had the lowest reproductive success of all species.
Phagodrilus gen.nov. (Lumbriculidae): systematics and biology of a predaceous oligochaete from western North America
Authors: McKey-Fender Dorothy , Fender William M.
Published: March 2009

The genus Phagodrilus (Lumbriculidae) is erected for Phagodrilus macnabi sp.nov., a predaceous worm with a paryngeo-esophageal region resembling that of Agriodrilus, a monotypic genus from Lake Baikal, often cited as a potential progenitor of the leeches. The pharynx or gizzard of Phagodrilus has the opposite dorsoventral orientation of its triangular section to that of Agriodrilus (apex dorsad in Phagodrilus, ventrad in Agriodrilus). While the latter appears closely related to Lamprodrilus in terms of its reproductive system, Phagodrilus resembles the Stylodrilus–Hrabea complex. These characteristics clearly indicate separate origins of the predatory habit and convergence of these two taxa, which suggests reexamination of the relationship between them and the leeches and branchiobdellids.
The structural relationship: regression in biology
Authors: McArdle B. H.
Published: March 2009

Most biologists are now aware that ordinary least square regression is not appropriate when the X and Y variables are both subject to random error. When there is no information about their error variances, there is no correct unbiased solution. Although the major axis and reduced major axis (geometric mean) methods are widely recommended for this situation, they make different, equally restrictive assumptions about the error variances. By using simulated data sets that violate these assumptions, the reduced major axis method is shown to be generally more efficient and less biased than the major axis method. It is concluded that if the error rate of the X variable is thought to be more than a third of that on the Y variable, then the reduced major axis method is preferable; otherwise the least squares technique is acceptable. An analogous technique, the standard minor axis method, is described for use in place of least squares multiple regression when all of the variables are subject to error.
Glioarchitecture de la moelle épinière du crapaud (Bufo bufo L.): étude au microscope optique avec des techniques d'imprégnation métallique
Authors: Bodega G. , Fernandez B. , Suarez I. , Gianonatti C.
Published: March 2009

Astroglial cells were studied in the spinal cord of the toad Bufo bufo L. and the distribution of these cells and their relationships with other components of the central nervous system were analyzed. Cells were examined by photonic microscopy in conjunction with metal impregnation techniques, the sublimated gold technique of Cajal and the Golgi – Rio Hortega method. Displaced epithelial cells were the only astroglial cells found. Another type might be found in the lateral column. Displaced epithelial cells are often related to blood vessels. The sub-pial glial wall is composed of displaced epithelial cell projection and is different in the various columns of the white matter.[Journal translation]
Differentiation of three species of Hymenolepis (Cestoidea) using enzyme isoelectric focusing on thin-layer agarose gels
Authors: Dixon Brent R. , Arai Hisao P.
Published: March 2009

In recent years, numerous gel electrophoretic techniques have been used as alternatives to the traditional morphological means of identifying tapeworm species. The present study describes the technique of enzyme isoelectric focusing on thin-layer agarose gels and its use in the differentiation of three closely related species of Hymenolepis. Clear species-specific banding patterns were obtained with each of five enzymes. The enzyme profiles of a given species were always similar, regardless of the definitive host species used. This technique provides a distinct advantage over morphological means of identification, which may be influenced by different host species. Further, while morphometric analyses generally require well-developed reproductive structures, enzyme patterns appear to be independent of the age of the worm. These results suggest that the technique could have considerable value in parasite surveys and clinical diagnoses in which non-host-specific tapeworms, of different developmental stages, are obtained.
Effects of dietary sodium and potassium on mineral balance in captive meadow voles (Microtus pennsylvanicus)
Authors: Christian Donald P.
Published: March 2009

Na+ and K+ balance of captive meadow voles (Microtus pennsylvanicus) were studied at dietary levels of 100 and 1000 ppm Na+ and 6000, 18 000, and 36 000 ppm K+. Na+ loss and Na+ balance were not significantly affected by high dietary K+ content; this result does not support the hypothesis that K+ loading is a major cause of the apparent Na+ imbalances shown by some herbivores during spring and early summer. Voles maintained or approached Na+ balance on the low Na+ diets. The relative size of the zona glomerulosa of the adrenal gland was not increased on the low Na+ diet. In contrast, high dietary K+ had a significant effect on zona glomerulosa size; this pattern and other data suggest that excreting K+ under conditions of high dietary K+ may represent a much greater physiological challenge to meadow voles than conserving Na+ on low Na+ diets. There was no indication that bone Na+ played an important role in Na+ balance in this species. Levels of Na+ and K+ in hair varied significantly with respective dietary levels.
An improved method for staining mouse mast cells
Authors: Novak M. , Nombrado S.
Published: March 2009

An improved method for staining mouse mast cells with alcian blue is reported. The reaction differentiates between mucosal mast cell and connective tissue mast cell types, especially under pathological conditions.
Differences in growth parameters of Ross' Geese and Snow Geese: evidence from hybrids
Authors: MacInnes C. D. , Misra R. K. , Prevett J. P.
Published: March 2009

Ten Ross' Geese, 14 hybrid Snow – Ross' Geese, and 4 Snow Geese were raised together at McConnell River, Northwest Territories. The birds fed on native vegetation, supplemented by dog food. Measurements taken at regular intervals of weight, tarsus length, culmen length, and culmen height were fitted to the Gompertz curve, and the three growth parameters derived therefrom were subjected to genetic analysis. Results showed that Ross' Geese had more genes contributing to a higher growth constant than Snow Geese, but little allelic dominance was observed. Snow Geese grew to a larger final size, with evidence that dominance was more important in that process. Reasons for the faster growth but smaller adult size are discussed with reference to the severity of conditions on nesting areas during the gosling period.
Complex population differentiation in checkerspot butterflies (Euphydryas spp.)
Authors: Brussard Peter F. , Baughman John F. , Murphy Dennis D. , Ehrlich Paul R. , Wright Janet
Published: March 2009

Gel electrophoresis was used to obtain an estimate of the genetic similarity among populations of Euphydryas anicia, Euphydryas chalcedona, and Euphydryas colon in an effort to determine whether they should be considered separate species or arbitrary groupings of populations in a single polytypic species. The average genetic distances between these entities, which collectively are referred to as the "ACC complex," are of the magnitude found between insect subspecies rather than between insect species. Furthermore, these entities show no unique combinations of morphological or biochemical characters that permit all individuals to be assigned with assurance to a specific taxon. Although cases of apparent reproductive isolation between some sympatric populations within the ACC complex have been reported, they appear to be terminal populations of "rings of races," rather than points of contact between completely isolated reproductive units. We recommend that the ACC complex be treated as a single highly variable species, Euphydryas chalcedona.
Approximation of K carrying capacity for moose in eastern Quebec
Authors: Crête Michel
Published: March 2009

Estimation of moose density ranged between 18 and 20 animals/10 km2 in a 120-km2 boreal area of eastern Quebec that has been excluded from hunting for many decades. Moose were sedentary; 81% of telemetry locations of 12 adults (6 of each sex) that were captured in the area were within the block boundary. Use of winter forage was low for balsam fir, but variable and relatively high (29%) for deciduous twigs. When pooling the present results with comparable studies done elsewhere in Quebec, a significant positive linear relationship was found between percent deciduous browse removal and moose density. Annual summer and winter forage production of deciduous species was low in the study area in comparison with other areas in Quebec; however, the situation was the reverse for balsam fir. The K carrying capacity was estimated to exceed 20 moose/10 km2 when considering actual density in the study area. The same conclusion was reached by comparing forage consumption rate by moose for the whole winter and the annual production of 14 kg∙ha−1 of deciduous twigs. Daily forage needs versus annual production led to an unrealistic estimate of the K carrying capacity when also taking into account the annual production of balsam fir. Prime moose habitats in eastern North America probably possess comparable or higher K carrying capacities.
An ultrastructural and histochemical developmental study of Drosophila auraria salivary gland cells during the third-instar period
Authors: Thomopoulos George N. , Neophytou Eleftherios P. , Kastritsis Costas D.
Published: March 2009

Early in the third-instar stage of Drosophila auraria, the salivary gland cells produce small secretory granules of low electron density which empty their flocculent contents into the lumen of the gland. At that stage, the Golgi complexes consist of vesiculated, round cisternae which, as middle third instar is approached, change to their classical appearance. Cytoplasmic protrusions, intramitochondrial granules, and close contacts of mitochondria with lipid droplets are observed during the early developmental stages. At about the middle of the third instar the glue secretory granules start being produced. These secretory granules contain a granular material (where small amounts of vicinal glycol and sulfated groups of complex carbohydrates have been detected) of medium electron density. The glue secretory granules can be classified according to their electron density into two populations. Before exocytosis large amounts of glycogen particles are observed, providing some of the energy needed during the final step of exocytosis. Two different types of ribonucleoprotein particles in puffing sites of the chromosomes are observed. Of these, the larger ones consist of a core surrounded by smaller particles; we suspect that they may be produced in the Balbiani rings observed in the polytene chromosomes of this species. Nuclear blebs and oval bodies are common, particularly during the late developmental stages. The functional significance of these findings during development is discussed.
Effect of siblings on growth of juvenile coho salmon (Oncorhynchus kisutch)
Authors: Beacham Terry D.
Published: March 2009

Five male coho salmon (Oncorhynchus kisutch) were mated to 10 females in a nested mating design, and juveniles from these 10 families were marked and reared for 30 weeks. Juveniles from each family were reared in one of three environments: with full-sibs, with paternal half-sibs, and with all members of the other nine families in a communal tank. Juveniles reared with full-sibs showed the greatest within-family variation in body weight and those reared with nine other families in the communal environment showed the least, so that the phenotypic expression of body weight was influenced by the degree of kinship of individuals in the environment. Significant genotype – social environment interactions were observed in juvenile body weight, with the average weight of a family member dependent upon the other genotypes present in the rearing environment.
Taxonomic descriptions and comments on the life history of new species of Eulimdana (Nematoda: Filarioidea) with skin-inhabiting microfilariae in the Charadriiformes (Aves)
Authors: Bartlett Cheryl M. , Anderson R. C. , Bush Albert O.
Published: March 2009

Eulimdana juventarum n.sp. from Willets (Catoptrophorus semipalmatus (Gmelin)), Eulimdana asperum n.sp. from Wilson's Phalaropes (Phalaropus tricolor (Vieillot)), and Eulimdana pseudolari n.sp. from Red-necked Phalaropes (Phalaropus lobatus (L.)) in Canada are described. The name "Eulimdana lari (Yamaguti, 1935)" is restricted to filarioids described by Yamaguti from the Eastern Common Gull (Larus kamtschatschensis (Bonaparte)). Numerous reports of "E. lari" in other charadriiforms are probably incorrect, and new taxonomic studies of lemdanine filarioids in palaearctic charadriiforms are required. Eulimdana bibulbosa (Annett, Dutton, and Elliott, 1901) n.comb. is proposed for Filaria bibulbosa Annett, Dutton, and Elliott, 1901. The 11 species in Eulimdana and their host groups are listed. Adult worms of the three new species occurred in subcutaneous tissues of the neck and connective tissues around the trachea and oesophagus. Microfilariae of E. juventarum and E. asperum occurred in skin, and skin-inhabiting microfilariae may be common in charadriiform birds. Microfilariae of E. asperum were also found in blood, but less frequently than in skin. Microfilariae of E. pseudolari were found in blood but probably occur in both blood and skin; skin was not examined. Prevalence of infection will be underestimated if hosts are examined only for microfilariae as sterile infections (those with only male or only female worms) are common. Adult worms in patent infections (those with mocrifilariae) apparently are short-lived and then completely resorbed by the host. In late patency infections, therefore, skin-inhabiting microfilariae occur in the absence of adult worms. Patent infections probably produce a protective immunity. Amblyceran lice probably transmit species of Eulimdana in the Charadriiformes.
Mise en évidence et évolution, au cours du cycle biologique, de neurones producteurs d'une substance apparentée à la motiline porcine dans le ganglion supraoesophagien de la sangsue Theromyzon tessulatum
Authors: Malecha J. , Verger-Bocquet M. , Tramu G.
Published: March 2009

The life cycle of Theromyzon tessulatum has been divided into stages defined on the basis of feeding pattern and reproductive activity. The use of an antiserum raised against porcine motilin demonstrated the presence of immunoreactive cells and fibers in the supraesophageal ganglion throughout the life of the leech. Immunopositive fibers are present in the neurohemal area of the dorsal commissure. The highest number of immunopositive neurons is found during stages 3B, 3C, and 3D, which precede egg-laying. The control of oogenesis by a substance related to porcine motilin is postulated.
Seasonal distribution and ecology of three helminth species infecting carp (Cyprinus carpio) in northwest Iowa, U.S.A.
Authors: Sutherland Daniel R.
Published: March 2009

The intestinal helminths most frequently infecting 522 Little Sioux River and 255 Lower Gar Lake carp (Cyprinus carpio) were Khawia iowensis, Pomphorhynchus bulbocolli, and Capillaria catostomi. Prevalence and mean intensity of K. iowensis were significantly higher in Little Sioux River than in Lower Gar Lake carp. Prevalence and mean intensity of P. bulbocolli and mean intensity of C. catostomi were significantly higher in Lower Gar Lake than in Little Sioux River carp. During 1979–1981, the prevalence and mean intensity of K. iowensis were highest in summer 1979 and summer 1980. Pomphorhynchus bulbocolli and C. catostomi were nonseasonal in prevalence and mean intensity. All three helminths were overdispersed within the carp population. Khawia iowensis usually occurred in the anterior third of the carp gut. Capillaria catostomi was found throughout the intestine, but most worms occurred in the posterior quarter of the gut in light infections. Pomphorhynchus bulbocolli exhibited a preference for the posterior third of the intestinal tract. Significant correlation coefficients were calculated between carp length and prevalence and (or) mean intensity of Little Sioux River K. iowensis and P. bulbocolli. Male and female carp had similar prevalences and mean intensities of each parasite species.
Basal and gonadotropin releasing hormone stimulated gonadotropin levels in the female red fox (Vulpes vulpes L.). Negative feedback of ovarian hormones during anoestrus
Authors: Bonnin M. , Mondain-Monval M. , Audy M. C. , Scholler R.
Published: March 2009

In the red fox, Vulpes vulpes L., an inhibition of gonadotropic function is observed in early anoestrus, particularly during lactation. During this period, secretion of progesterone as a result of the persistent corpora lutea after parturition and episodic releases of estradiol signify ovarian activity, suggesting involvement of these hormones in the modulation of pituitary hormones (luteinizing hormone (LH), follicle-stimulating hormone (FSH)). Effects of ovariectomy and (or) progesterone or estradiol treatments in vivo upon basal and gonadotropin releasing hormone (GnRH)-stimulated LH and FSH were observed. After ovariectomy, a great increase in the basal level of both gonadotropins and in GnRH-stimulated LH release, but not GnRH-stimulated FSH release, were observed. Progesterone treatment induced a decrease in GnRH-stimulated LH and FSH secretions and a decrease in basal LH and FSH levels in ovariectomized females. Estradiol treatment abolished basal secretions and GnRH responses for both hormones. These results suggest a negative feedback of both ovarian steroids at the hypothalamopituitary level on LH and FSH secretions during early anoestrus.
Demography of the meadow vole along a simple habitat gradient
Authors: Adler Gregory H. , Wilson Mark L.
Published: March 2009

A population of meadow voles (Microtus pennsylvanicus) was monitored by livetrapping in five different habitat types in eastern Massachusetts for 5 years. An index of grass cover was estimated for each habitat type, and the relationship between population statistics and grass cover was examined. Numbers of voles and survival rates increased rapidly with increasing grass cover until an asymptote was reached. Other population statistics were unrelated to the gradient. Grass cover appears to represent a predictive measure of environmental suitability. The ability to select simple habitat gradients representing suitability should facilitate demographic comparisons of habitat use by sympatric generalists and specialists.
Selective factors in the evolution of insect wings: response to Kukalová-Peck
Authors: Kingsolver Joel G. , Koehl M. A. R.
Published: March 2009

Kukalová-Peck (J. Kukalová-Peck. 1987. Can. J. Zool. 65: 2327–2345) has recently criticized the hypothesis that selection for increased thermoregulatory capacity was important in the early evolution of wings from protowings. Here we argue that the current paleontological, embryological, and experimental evidence cannot be used to reject the thermoregulatory hypothesis. Experimental studies of aerodynamics and thermoregulation suggest that knowledge of the body size of ancestral pterygotes is crucial to evaluating the relative importance of aerodynamic and thermoregulatory factors in the evolution of flight.