bluuebunny/crossref_metadata_2025 huggingface dataset:
Constraints on the genetic process of biochemical adaptation
Authors: Pogson Grant H.
Published: March 2009

The identification of selective constraints impeding the adaptive evolution of macromolecules and metabolic systems is compared between the two most prevalent approaches to the study of biochemical adaptation. Constraints discerned from the interspecific comparative method address the features of enzymes that are conserved across evolutionary lineages; constraints determined from the evolutionary genetic approach involve factors that interfere with the ability of natural selection to direct the adaptive process. Difficulties associated with the constraints identified by the comparative method are examined. These are shown to arise from the lack of an adequate definition of molecular adaptedness and from the confounding effects of factors that may act to constrain the process of biochemical adaptation. Constraints on this genetic process of biochemical adaptation are discussed at three levels of biological organization: populations, multienzyme pathways, and individual enzymes embedded within these pathways. A model is presented that allows for adaptive change in any pathway enzyme irrespective of its role in determining system flux.
The nature of evolution and adaptation: resolving the unity–diversity paradox
Authors: Hochachka P. W.
Published: March 2009

The concept of the unity of biochemical structures and functions creates the problem for biology of how to account for the pervasive species diversity and obvious adaptedness of living systems. A review of the current literature indicates that four principles, (i) the principle of conservation of critical sequences in both structural and regulatory loci, (ii) the principle of unique assembly of parts via unique (tissue-specific and temporal) activation of regulatory loci, (iii) the principle of genetic innovation via mechanisms internal or external to the genome, and (iv) the principle of biochemical adaptation via selection for favourable alleles of structural and regulatory genes or selection for advantageous genetic innovations, seem capable of resolving the paradox of the unity of biochemical systems despite patently vast species diversity and species adaptation. Evaluation of the current status of each of these principles suggests the especial need for more experimental studies of the role of regulatory loci in species diversification and adaptation.
Electron microscopical observations on the effects of sera from two species of Catostomus on the tegument of Hunterella nodulosa (Cestoidea: Caryophyllidea)
Authors: Li Min-Min , Arai H. P.
Published: March 2009

The effects of sera from Catostomus catostomus and Catostomus commersoni on Hunterella nodulosa incubated in different concentrations for different periods of time are presented. Scanning electron and transmission electron micrographs illustrate the process and extent of lysis of the body wall of the tapeworm. Except in minor details, the lytic damage appears similar to that reported for other cestodes.
Quantitative distributional patterns and aspects of the biology of the Mysidacea (Crustacea: Peracarida) in the zooplankton of the Bay of Fundy region
Authors: Corey Susan
Published: March 2009

Three mysids, Erythrops erythropthalma, Mysis stenolepis, and Neomysis americana occurred in the zooplankton of the Bay of Fundy and adjacent waters from 1973 through 1981. Erythrops erythropthalma occurred in low numbers in scattered areas, such as the mouth of Passamaquoddy Bay, Grand Manan Channel, the coast of Maine, and off St. Mary's Bay and southwest Nova Scotia. Mysis stenolepis was taken rarely and only in the shallower stations near the coast and in the inner Bay of Fundy. Neomysis americana was the most abundant mysid and the most widespread in its distribution. Populations were found at the head of the Bay of Fundy and in St. Mary's Bay. Seasonally, N. americana was least abundant in the spring, with numbers and area of distribution increasing in the summer and fall. The life history pattern of N. americana in the inner Bay of Fundy was the same as that found in other areas nearby. It rarely occurred in depths greater than 75 m and was more abundant in the zooplankton at night than during the day. Because of the great abundance of N. americana in the inner Bay of Fundy and St. Mary's Bay, it provides an excellent food source for larval and adult fish in these areas.
Effects of dietary fiber and diet diversity on digestive organs of captive Mallards (Anas platyrhynchos)
Authors: Kehoe F. Patrick , Ankney C. Davison , Alisauskas Ray T.
Published: March 2009

We studied the effects of dietary fiber, of plant versus animal diets, and of diet diversity on the digestive organ morphology of captive Mallards (Anas platyrhynchos). Four experimental diets were used: whole corn (low fiber, plant), trout chow (low fiber, primarily animal), rabbit chow (high fiber, plant), and a diverse diet consisting of each of the preceding diets fed daily in random order. Every 5 days for 25 days, we sampled birds from each diet group (N = 6–8) and weighed each bird and its abdominal fat, gizzard, ceca, small intestine, and liver, and then measured its ceca and small intestine length. Other than differences explained by their different body sizes, the sex of the birds had no effect on gut measurements. Changes in body weight and abdominal fat weight suggested that Mallards existed equally well on each of the four diets, presumably because changes in their digestive organs allowed them to have similar digestive efficiencies when eating different diets. Birds on the high fiber diet had the largest digestive organs, but birds on all diets showed changes in digestive organs. The diverse diet produced effects on digestive organ morphology similar to those of the two low-fibre diets. Except for a larger gizzard for macerating corn in birds on that diet, there was no difference in the digestive organs between birds eating animal foods and those eating low fiber plant foods. The maximum weight of gizzard, intestine, and ceca of birds on the high fiber diet was reached in 10 days. However, ceca and intestine lengths of these birds were still increasing after 25 days. This observation suggests that birds can continue to respond to a change in diet after limits to the mass of their digestive organs have been reached.
The influence of Trichinella pseudospiralis infection on the behaviour of captive, nonbreeding American kestrels (Falco sparverius)
Authors: Saumier Michèle D. , Rau Manfred E. , Bird David M.
Published: March 2009

Trichinella pseudospiralis infections induced mild behavioural changes in the American kestrel host (Falco sparverius) within the first 5 days postinoculation, a period that corresponds to the adult phase of the infection. However, more severe effects on mobility were precipitated as the larvae migrated and became established in the musculature. The debilitation persisted for at least 5 weeks postinoculation and involved a reduction in exercising, flying, elevated perching, and preening, and was accompanied by an increase in the frequency of walking and floor perching. Such behavioural effects, attributable to the presence of muscle larvae, may reduce the competitive fitness of infected individuals. The muscle larvae were randomly distributed among various muscle groups.
Cycle évolutif du Nemhelix bakeri Morand et Petter (Nematoda, Cosmocercidae), parasite de l'appareil génital de l'Helix aspersa Müller (Gastropoda, Helicidae)
Authors: Morand Serge
Published: March 2009

The development and transmission of Nemhelix bakeri Morand et Petter, a parasite of the genital tract of Helix aspersa Müller, are described. Free stages of this nematode were not found and laboratory infestations were not successful. The parasites were observed with snail spermatophores exchanged during copulation. Young snails were not infected. The larval stages of N. bakeri differ from those of C. Dukae. Only the L2 stage has lips in N. bakeri, while all larval stages of C. dukae, except the L3 stage, have some. Paleontologie and biogeographic data accredit the thesis of a secondary evolution of Cosmocercidae in land snails. It seems that this evolution occurred independently, in North America for C. dukae and in Europe for N. bakeri.
Nephtys cornuta (Polychaeta: Nephtyidae) and its subspecies, and use of the trinomials in pollution monitoring
Authors: Ellis D. V. , Ronaldson L. D.
Published: March 2009

The form of Nephtys cornuta separated as the Californian subspecies N. c. franciscana is found widely in British Columbia waters, co-occurring and intergrading with the nominate subspecies N. c. cornuta. Previous identifications to the trinomial have tended to be inaccurate (36% of 127 specimens reexamined). The co-occurring forms show no apparent ecological distinctions relevant to pollution monitoring objectives at one location where the species is both abundant and significant as an indicator of seabed recovery from mine-waste environmental impact. It is concluded that the trinomial, hence subspecific designation, should not be used in the British Columbia area of the species range.
On the analysis of life-history traits of North American game birds
Authors: Duncan David C.
Published: March 2009

Zammuto (R. M. Zammuto. 1986. Can. J. Zool. 64: 2739–2749) analyzed life-history traits among North American game birds and concluded that there was an inverse relationship between clutch size and longevity, independent of body mass. Problems with his selection of species, method of comparison, and estimate of longevity are pointed out, and it is suggested that his conclusion was premature.
Life histories of North American game birds: a reanalysis
Authors: Arnold Todd W.
Published: March 2009

Recently, Zammuto (R. M. Zammuto. 1986. Can. J. Zool. 64: 2739–2749) suggested that North American game birds exhibited survival–fecundity trade-offs consistent with the "cost of reproduction" hypothesis. However, there were four serious problems with the data and the analyses that Zammuto used: (i) the species chosen for analysis ("game birds") showed little taxonomic or ecological uniformity, (ii) the measures of future reproductive value (maximum longevity) were severely biased by unequal sample sizes of band recoveries, (iii) the measures of current reproductive effort (clutch sizes) were inappropriate given that most of the birds analyzed produce self-feeding precocial offspring, and (iv) the statistical units used in the majority of analyses (species) were not statistically independent with respect to higher level taxonomy. After correcting these problems, I found little evidence of survival–fecundity trade-offs among precocial game birds, and I attribute most of the explainable variation in life-history traits of these birds to allometry, phylogeny, and geography.
Seasonal changes in the gonadotropic cells of the male threespine stickleback, Gasterosteus aculeatus L.
Authors: Borg Bertil , Peute Jan , Paulson Göran
Published: March 2009

Pituitaries from threespine sticklebacks (Gasterosteus aculeatus) sampled in the field in different seasons were studied using light and electron microscopy. At the start of breeding in May the gonadotropic cells demonstrated an increase in the amount of dilated granular endoplasmic reticulum cisternae and in the size of Golgi complexes, indicating increased synthetic activity. When the breeding season ended in August these features declined. In the period April to August there was a continuous decrease in the amount and size of granules stored in the gonadotropic cells. The size of the gonadotropic cell nuclei was larger in April than in the breeding season and at the end of breeding it declined further.
Variation in occupancy of coniferous territories by male American woodcock
Authors: Redmond Gerald W. , Keppie Daniel M.
Published: March 2009

We investigated whether male American woodcock (Scolopax minor) were attracted differentially to territories in coniferous forest in northeast New Brunswick by continually removing males over several consecutive years. We removed 186 displaying males from 45 territories (1977–1981). Mean annual recruitment rate was 1.5 males per territory. Up to seven birds recruited to a single territory in a season. Median intervals between removal and replacement were 2 – 3 days each year and did not vary during display seasons. Not all territories were occupied every year; 81% were occupied during two or more seasons. Recruitment (Rn), replacement interval (Rs), annual use (Ua), and frequency of use within seasons (Uf) by male woodcock varied substantially among territories, but these parameters remained consistent for individual territories among years. A measure of overall occupancy (Qi) was calculated for 33 territories by summing Rn, Rs, Ua, and Uf scores. On territories designated as having high use, recruitment, annual use, and frequency of use were greater, and replacement occurred more quickly than on low-use territories. Results are discussed in the context of territory quality and mechanisms of territory selection by male woodcock.
The field energetics of winter-dormant black bear (Ursus americanus) in northeastern Minnesota
Authors: Maxwell Robert K. , Thorkelson Jeffrey , Rogers Lynn L. , Brander Robert B.
Published: March 2009

Black bears (Ursus americanus) can spend half of their lives in a severe winter climate using only internal sources of energy and exchanging energy only as heat with their external environment. This paper presents the energy requirement to maintain a bear, and the magnitude of the heat transfer pathways to the bear's surroundings. Flux rate densities of the heat budget were measured for two denning black bears. It was found that the surface area of an oblate spheroid simulating the shape of the curled-up bears balanced the budgets. From these data a simulated bear–den system was constructed for a 75-kg animal: a fur-covered spheroid that was electrically heated and maintained at 36 °C. The energy requirement and heat transport were measured through the skin and in the den over winter, as was the oxygen consumption of a live bear in a similar den nearby. Over a 145-day denning period, mass loss due to fat catabolism would have ranged between 24 and 28% for the simulated bear with the entrance sealed or open, respectively. Using the amount of oxygen consumed and holding body water constant, the mass loss of the live bear over the same period would have been 19% if just fat had been catabolized. However, additional protein catabolism near the end of the denning period caused the loss to increase to 31%, primarily through urination. Once net protein catabolism began, dehydration and not starvation became life threatening.
Estimated swimming speeds of migrating adult sockeye salmon
Authors: Quinn Thomas P.
Published: March 2009

Laboratory studies have indicated that the most efficient swimming speeds for adult sockeye salmon (Oncorhynchus nerka) are about 1.8 km/h, corresponding to 0.82 body length/s. Swimming is relatively efficient within the range of 1.0–2.6 km/h. To estimate the actual swimming speeds of migrants, ultrasonic tracking data for the ground speeds of 25 sockeye salmon returning to the Fraser River, British Columbia, were combined with simultaneous current speed data from drogues. There was significant variation in speed among fish but all estimates were within the range predicted from experimental results. The average estimated swimming speed, 66.75 cm/s (2.40 km/h) corresponded to 1.0 body length/s.
Tissue-specific allometry of an aerobic respiratory enzyme in a large and a small species of cyprinid (Teleostei)
Authors: Goolish Edward M. , Adelman Ira R.
Published: March 2009

The aerobic enzyme cytochrome-c oxidase (CCO) was used as a measure of tissue-specific metabolic capacity. Changes in tissue CCO activity with increased body size were combined with allometric relationships for tissue weight to describe changes in energy use with increased body size. A large (common carp, Cyprinus carpio) and a small (common shiner, Notropis cornutus) species of cyprinid were used to examine differences between ontogenetic and phylogenetic allometry. With increased size, shifts occurred in energy use from viscera (high metabolic rate) to muscle tissue (low metabolic rate) which would account for the negative allometry of whole-body metabolic rate. This shift was more severe for the larger (i.e., faster growing) species, common carp. Percent muscle mass was fairly constant in the shiner, but increased from 42 to 62% of total body mass in the carp. For both species, the greatest allometry in total tissue CCO activity occurred in the brain and intestine. Total intestinal CCO activity scaled as weight to the exponents 0.70 and 0.54 for the carp and shiner, respectively. The greater proportion of metabolically active visceral tissue in young individuals is apparently not an energetic disadvantage, because these fish often have the highest growth efficiencies. These efficiencies may be due to the more favorable ratio of food "processing" capacity to target growth tissue (muscle) in small fish. The negative allometry in processing ability is likely responsible for the decreases in ingestion and growth rates with increased size. The influence of growth on ectotherm metabolism is large and, because growth is allometric, it can affect the exponent for metabolic rate in ontogenetic allometry studies.
A taxonomic analysis of the Haplotaxidae (Annelida, Oligochaeta)
Authors: Brinkhurst R. O.
Published: March 2009

A combination of classical and computer-aided methods suggests that the Haplotaxidae can now be divided into several genera. Alphadrilus nov.gen. is monotypic for Alphadrilus smithii n.comb. Delaya nov.gen. contains D. bureschi, D. leruthi, D. corbarensis, D. cantabronensis, and D. navarrensis, all n.comb. Adenodrilus is retained for A. denticulatus, Heterochaetella for H. glandularis, and Villiersia for V. guanivora. The new genus Hologynus nov.gen. is erected for H. ornamentus and H. hologynus and its probable synonyms. Haplotaxis is retained for the gordioides-like species with specialized pharynx and chaetae associated with a predaceous habit. Pelodrilus is retained for P. violaceus and perhaps P. ignatovi and P. africanus (incertae sedis) and its probable synonyms. Tiguassu is elevated to the status of the type of a new family, Tiguassidae. Metataxis sensu Omodeo is placed incertae sedis in the order Lumbricina.
Skrjabinoclava bartlettae n.sp. (Nematoda: Acuarioidea) from the black-bellied plover (Pluvialis squatarola (L.)) (Charadriiformes: Charadriidae)
Authors: Wong P. L. , Anderson R. C.
Published: March 2009

Skrjabinoclava bartlettae n.sp. from black-bellied plover (Pluvialis squatarola (L.)) is described. The new species is most similar to Skrjabinoclava wilsoniae Wong and Anderson, 1988 and Skrjabinoclava semipalmatae Wong and Anderson, 1988 but can be distinguished from them by the longer spicules, the rounded cuticle surrounding the tip of the left spicule, and the lateral V-shaped sclerotized band and nipple-like tip of the right spicule.
Transmission of Skrjabinoclava morrisoni Wong and Anderson, 1988 (Nematoda: Acuarioidea) to semipalmated sandpipers (Calidris pusilla (L.)) (Charadriiformes: Scolopacidae)
Authors: Wong P. L. , Anderson R. C.
Published: March 2009

Skrjabinoclava morrisoni Wong and Anderson, 1988 of the proventriculus of semipalmated sandpipers (Calidris pusilla (L.)) developed to the infective stage in the marine amphipod Corophium volutator (Pallas). The first moult occurred 8 d and the second, 11 d postinfection at 20 °C. In the final host, fourth-stage larvae were recovered from one experimental bird examined 8 d postinfection. Juvenile birds collected at Long Point, Ontario, were not infected with S. morrisoni suggesting that transmission may not occur on the breeding ground. Transmission occurs, however, in the Canadian Maritimes and the Gulf of Mexico, as evidenced by the presence of juvenile S. morrisoni in birds collected on Grand Manan Island, New Brunswick, and birds recently arrived at Delta Marsh, Manitoba, from the Gulf Coast.
Effects of a synthetic precocene on late embryos and subsequent development of the cockroach Diploptera punctata
Authors: Pener M. P. , Tobe S. S. , Stay B.
Published: March 2009

Precocene III (PIII, 7-ethoxy-precocene II), dissolved in acetone, was applied to eggs in the brood sac of Diploptera punctata females, at 55–56 days or 62–63 days (about 83.5 ± 1.0% or 95.5 ± 1.0% of the gestation period, respectively) after the mother's ecdysis to adult. Controls received acetone alone or no treatment. Acetone itself induced abortion in many instances and reduced the number of surviving progeny from those females that did give birth. These lethal effects were more pronounced after PIII treatment. A portion of the surviving nymphs that had been treated as eggs with PIII developed normally up to the fourth stadium, although the duration of this development, especially that of the first stadium, was longer than in the controls. In contrast, another portion of the nymphs that had hatched from precocene-treated eggs exhibited disturbed development. Treatment of the eggs in 55- to 56-day-old mothers with the highest dose still permitting hatching (40 μg of PIII in 2 μL of acetone, into the brood sac) yielded the highest proportion of disturbed development. In almost all instances of such disturbed development, the moult from the second to the third stadium was greatly delayed and the insects died in or shortly after an unsuccessful ecdysis, some of them exhibiting slightly prothetelic wings. No sign of precocious metamorphosis was observed in the first or second stadium. These results are compared with those in the literature on the effects of surgical allatectomy of the second and later instars of D. punctata. The morphogenetic role of the juvenile hormone in the early part of postembryonic development is also discussed.
Wing fluttering display by incubating male Wilson's phalaropes
Authors: Colwell Mark A. , Oring Lewis W.
Published: March 2009

Wilson's phalarope (Phalaropus tricolor) exhibits extreme sex-role reversal. Males provide nearly exclusive parental care for eggs and chicks, whereas females compete directly for mates in scramble competition. Males on incubation recess are often harassed by unpaired females. Males flying to nests to resume incubation performed a distinctive flight display when followed by females. Conversely, unaccompanied males returning to nests rarely performed the display. We hypothesize that this display signals to females a male's unavailability as a prospective mate.
The Curculionidae of the Queen Charlotte Islands, British Columbia (Insecta; Coleoptera)
Authors: Anderson Robert S.
Published: March 2009

Nineteen species of weevils are reported from the Queen Charlotte Islands, British Columbia. Nine species are found throughout the coastal forest region from California north to Alaska or British Columbia. Three species are widespread throughout western North American forests. Four species are found on sand beaches from California north to British Columbia. One species is found in alpine areas from southern British Columbia north to Alaska and the Aleutian and Pribilof islands. Two species are introduced into North America from the Palearctic Region. Three additional species are reported from the islands but their occurrence was not confirmed and they are left as questionable records. Adult individuals of all known species from populations on the Queen Charlotte Islands do not appear structurally differentiated from individuals examined from representative localities elsewhere. Postglacial recolonization of the islands from a southern source area by all native lowland to montane species and from a northern source area by the sole alpine species appears to be the most parsimonious account for the origin of the weevil fauna. There is no evidence to suggest survival of any species in a Late Wisconsinan refugium as has been proposed elsewhere for a number of other animals and plants endemic to the Queen Charlotte Island archipelago.
Structure fine et rôle, dans la rétention hydrique, des enveloppes de l'oeuf d'un diptère subantarctique, l'Anatalanta optera Eaton (Sphaeroceridae)
Authors: Chauvin Georges , Vannier Guy , Vernon Philippe
Published: March 2009

Anatalanta aptera is a wingless subantarctic dipteran. Its egg is oblong with a flat upper wall separated from a convex lower wall by a ridge of respiratory horns. Just after the egg is laid, it possesses two distinct envelopes: a porous chorion and a dense vitelline membrane. The chorion is covered with a thin mucous layer. Its structure shows a complex system of cavities and a network of trabecular material. It consists of three layers: an outer, a middle, and an inner one. The chorion forms a respiratory plastron all over the egg surface. Water loss was recorded and analyzed in fertilized eggs with their two envelopes and in eggs from which the chorion had been removed. Transpiration measurements were performed in dried air (0–5% relative humidity) at temperatures rising from 5 to 50 °C at a regular rate of 0.5 °C/min. It appears that the vitelline envelope greatly reduces water loss within a fully desiccated atmosphere, at low to moderate air temperatures, but the egg is poorly adapted to dry and hot air conditions.
Intraspecific nest parasitism in Red-breasted Mergansers
Authors: Young Andrew D. , Titman Rodger D.
Published: March 2009

We studied intraspecific nest parasitism in an island nesting population of Red-breasted Mergansers (Mergus serrator) in New Brunswick. Of the nests examined, 64% contained eggs from more than one female. This estimate is probably low because the criteria to detect parasitism were conservative. Parasitized nests were initiated, on average, 3 days earlier than normal nests. Parasitic laying occurred throughout the nesting season. A larger proportion of eggs hatched from normal (89%) than from parasitized (75%) nests because 14% of the eggs in parasitized nests were laid during the host's incubation period and failed to hatch in time. A greater percentage of eggs hatched from parasitized nests during the peak nesting period. Parasitized and normal nests produced the same number of ducklings. There was no difference in the percentage of dead, infertile, and lost eggs from normal compared to parasitized nests. The number of nests containing at least one dead egg increased with clutch size. Most host females accepted parasitic eggs during incubation without deserting. Incubation was prolonged on parasitized nests and on nests with low synchronization of embryo development. Nest parasitism is a common reproductive tactic in at least some female Red-breasted Mergansers.
Effects of heat, cold, and rain on coastal black-tailed deer
Authors: Parker Katherine L.
Published: March 2009

Thermoregulatory responses of black-tailed deer (Odocoileus hemionus columbianus) were recorded in a metabolic chamber at dry air temperatures between −20 and 32 °C. For animals in summer pelage, respiratory rates, body core temperatures, and skin temperatures increased curvilinearly with increasing air temperature; thermally critical air temperatures occurred above 27 °C and below 10 °C. In winter, body temperatures were lower in adults than in fawns, skin temperatures were highly variable, and respiratory rates increased at lower air temperatures than in summer; metabolic expenditures associated with thermoregulation increased at temperatures less than −10 °C. Animals were also subjected to simulated rain (4.5 mm/h) over a 5-h period at temperatures above freezing. During summer trials in the rain, body and skin temperatures generally declined after 5 h. No increased metabolic stress associated with rain was observed for black-tailed deer in summer at air temperatures greater than 12 °C; at 10 °C, energy expenditures after 5 h of rainfall were greater than during heat or cold stress. For animals in winter pelage, changes in body temperature, skin temperature, and hair depth showed no consistent trends with duration of rainfall; only fawns increased metabolism at temperatures just above freezing (2–3 °C) in the rain. Data from this study suggest that rainfall may pose major energetic constraints for black-tailed deer in summer pelage. Managerial provisions for thermal cover should place highest emphasis on summer habitats.
Predation on moose and caribou by radio-collared grizzly bears in east central Alaska
Authors: Boertje R. D. , Gasaway W. C. , Grangaard D. V. , Kelleyhouse D. G.
Published: March 2009

Radio-collared grizzly bears (Ursus arctos) were sighted daily for approximately 1-month periods during spring, summer, and fall to estimate predation rates. Predation rates on adult moose (Alces alces) were highest in spring, lowest in summer, and intermediate in fall. The highest kill rates were by male grizzlies killing cow moose during the calving period. We estimated that each adult male grizzly killed 3.3–3.9 adult moose annually, each female without cub(s) killed 0.6–0.8 adult moose and 0.9–1.0 adult caribou (Rangifer tarandus) annually, and each adult bear killed at least 5.4 moose calves annually. Grizzly predation rates on calves and grizzly density were independent of moose density and are probably more related to area-specific factors, e.g., availability of alternative foods. An important implication of our results is that managers should not allow moose densities to decline to low levels, because grizzlies can have a greater relative impact on low- than on high-density moose populations and because grizzly predation can be difficult to reduce. Grizzly bears were primarily predators, rather than scavengers, in this area of low prey availability (11 moose/grizzly bear); bears killed four times more animal biomass than they scavenged.
The manifestation and significance of sexual dimorphism in anguid lizards: a case study of Barisia monticola
Authors: Vial James L. , Stewart James R.
Published: March 2009

The dimorphic expression of body size, body – head size relationships, and chromatic characters among anguid lizards is reviewed. These characteristics are quantitatively examined in a population of Barisia monticola. No sexual differences are found in body size. Head size is positively correlated with body size; however, allometric growth rates in head size are significantly greater in adult males than in females or juveniles. Adult males also differ significantly in eight of nine chromatic characters, the most pronounced being the presence of light dorsal scale markings. These differences are explored in the context of both natural and sexual selection. We hypothesize that the absence of dimorphism in overall body size is the result of natural selection operating to maximize female reproductive potential. In contrast, we predict that dimorphism expressed in body – head size relationships and dichromatism are consequences of sexual selection relating to agonistic and reproductive behavior of males.
Annual variation of tissue biomass and carbon and nitrogen content in the freshwater bivalve Corbicula fluminea relative to downstream dispersal
Authors: Williams Carol J. , McMahon Robert F.
Published: March 2009

Tissue dry weight biomass, ash-free dry weight, organic carbon content, nitrogen content, and organic carbon: nitrogen ratio (C:N) of individuals of Corbicula fluminea were monitored monthly over an annual reproductive cycle in a population living in an inlet from which a power station drew cooling water; the same variables were monitored for clams trapped on traveling screens in power station water intake embayments. These measurements were used to determine the relationship between tissue condition and downstream dispersal behavior. The ratio of dry tissue weight to dry shell weight showed marked seasonal variation: it was minimal during reproduction and maximal during overwintering, nonreproductive periods. Fractional ash content increased and organic content decreased during reproduction as shelled juveniles accumulated in the inner demibranchs. Seasonal variation in tissue organic C and N biomass corresponded directly to variation in dry tissue weight. Tissue C:N ratio was 6.0:1 in overwintering individuals and 4.9:1 during reproduction, indicating reduction of non-proteinaceous energy reserves. Reduction of the C:N ratio, dry tissue weight, and C and N biomass during reproduction suggests transfer of organic biomass to gamete production. Dry tissue weight, tissue organic C and N biomass, and C:N ratio were also reduced in individuals impinging on traveling screens, indicating poor nutritional status. Passive adult downstream dispersal onto traveling screens occurred only before periods during which clams incubated eggs and embryonic stages on the gills and released juveniles. Thus, downstream dispersal apparently allows relocation of individuals in poor nutritional condition to microhabitats more favorable for acquisition of energy for reproductive effort.
On the relationship between gonadal development and response time to photostimulation of sticklebacks living under natural conditions and under constant short-day conditions for long periods of time
Authors: Baggerman Bertha
Published: March 2009

In the threespine stickleback, Gasterosteus aculeatus L., gonadal development proceeds in two phases, each occurring in a different season. Phase 1 (spermatogenesis, endogenous vitellogenesis) begins in late summer and is completed during winter. Phase 2 (Leydig cell activation, exogenous vitellogenesis) does not start before late February and is completed in April; the breeding season lasts from April to August. These different developmental phases are also characterized by differences in response times to the stimulating influence of a long photoperiod, 16L:8D at 20 °C. As long as phase 1 was not complete, the response times (number of days until complete sexual maturity is attained) were longer than 34 ± 6 days in males and 33 ± 5 days in females. From the time phase 2 was initiated, the response times became progressively shorter. When sticklebacks were raised from the egg stage, or from within 3 months after hatching in an outdoor pond, under constant short-day conditions (8L:16D at 20 °C), only phase 1 was completed, whereas no development in phase 2 took place; the response times of these fish were comparable to those given above. Only small numbers of these short-day animals attained maturity spontaneously under the experimental photoperiod. The fish matured in June and July of the year following the one in which they hatched in June. These results suggest an endogenous annual reproductive rhythm.
Systematics of Onchocleidus Mueller, 1936 (Monogenea: Ancyrocephalidae): generic revision
Authors: Wheeler Terry A. , Beverley-Burton Mary
Published: March 2009

The genus Onchocleidus Mueller, 1936 (Monogenea: Ancyrocephalidae) is revised. Diagnostic characters for the genus include a dextral vaginal opening, a spiral filament encircling the penis, and dorsal hamuli with reduced deep roots. Haplocleidus Mueller, 1937 and Pterocleidus Mueller, 1937 are declared junior synonyms of Onchocleidus. Onchocleidus, as presently recognized, contains 24 valid species: O. ferox (Mueller, 1934) Mueller, 1936 (type species); O. acer Mueller, 1936; Onchocleidus affinis (Mueller, 1937) n.comb.; O. attenuatus (Mizelle, 1941) Beverley-Burton, 1984; Onchocleidus chaenobryttus (Mizelle and Seamster, 1939) n.comb.; O. chautauquaensis (Mueller, 1938) Murith and Beverley-Burton, 1984; O. chrysops (Mizelle and Klucka, 1953) Beverley-Burton, 1984; O. cyanellus Mizelle, 1938; O. dispar Mueller, 1936; O. distinctus Mizelle, 1936; Onchocleidus doloresae (Hargis, 1952) n.comb.; Onchocleidus flieri (Putz and Hoffman, 1966) n.comb.; Onchocleidus furcatus (Mueller, 1937) n.comb.; Onchocleidus grandis (Mizelle and Seamster, 1939) n.comb.; O. interruptus Mizelle, 1936; Onchocleidus macropterus (Harrises, 1962) n.comb.; O. mimus Mueller, 1936; Onchocleidus miniatus (Mizelle and Jaskoski, 1942) n.comb.; Onchocleidus nactus (Mayes and Johnson, 1975) n.comb.; Onchocleidus parvicirrus (Mizelle and Jaskoski, 1942) n.comb.; O. principalis Mizelle, 1936; O. similis Mueller, 1936; Onchocleidus tuberculatus (Allison and Rogers, 1970) Cloutman, 1988; and Onchocleidus variabilis (Mizelle and Cronin, 1943) n.comb. Six species (O. acuminatus Mizelle, 1936; Pterocleidus biramosus Mueller, 1937; O. helicis Mueller, 1936; O. perdix Mueller, 1937; O. spiralis Mueller, 1937; and Urocleidus wadei Seamster, 1948) are considered species inquirendae. A key to the species of Onchocleidus is included.
Life-history variation in Neomysis mercedis Holmes (Crustacea, Mysidacea) in the Fraser River estuary, British Columbia
Authors: Johnston N. T. , Northcote T. G.
Published: March 2009

The brackish-water mysid Neomysis mercedis in tidal marshes of the Fraser River produced overwintering and summer generations that differed in life-history traits. Summer generation females matured at a smaller size and produced fewer and larger eggs than the overwintering generation. Size-adjusted clutch weights were identical for summer and overwintering females. Reproductive effort was slightly lower for the overwintering females. Both generations were iteroparous, but the average frequency of breeding was higher for the overwintering generation. Seasonal variations in reproductive traits were strongly linked to fluctuations in the relative mortality rates of neonates and adults. Overwintering adults that bred in late spring had lower mortality rates than neonates, while mortality rates for summer adults were higher than those for neonates. Rearing suggested that changes in adult body size were a phenotypic response to temperature. Food availability had little additional effect on adult body size. A positive correlation between ambient water temperatures and the increase in mortality with increasing adult size provided a possible mechanism through which temperature-dependent phenotypic variation in adult body size could be selected.
Laboratory survival of four prey in the presence of northern pike
Authors: Robinson Clifford L. K.
Published: March 2009

I determined experimentally the relative survival of similar-sized yellow perch (Perca flavescens), brook stickleback (Culaea inconstans), fathead minnow (Pimephales promelas), and finescale dace (Phoxinus neogaeus), individually and in all possible species combinations, in the presence of northern pike (Esox lucius). Overall, perch showed the highest, sticklebacks and dace the intermediate, and fatheads the lowest relative survival. Differential laboratory survival of prey demonstrates the utility of single species experiments in predicting the results of multiple prey and predator interactions. The results also support the hypothesis that piscivory can maintain the distinctness of assemblages of predation-tolerant and piscivorous species versus assemblages of predation-intolerant species.
Normoxic and hypoxic breathing pattern in newborn grey seals
Authors: Mortola Jacopo P. , Lanthier Clement
Published: March 2009

We studied the breathing patterns of three newborn grey seals (Halichoerus grypus) at 2 – 3 days of age under normoxic and hypoxic conditions with the barometric technique, which does not require the animal to be restrained. Normoxic tidal volume was deeper and breathing rate slower than expected for newborns of this size on the basis of previously published allometric relationships. In addition, two characteristics were readily apparent: (i) occasional sudden long apneas, often exceeding 30 s in duration, and (ii) consistent brief interruptions of expiratory flow. Neither aspect is common in terrestrial newborns of this age, but both have been previously observed in adult seals. During hypoxia (10 min of 15% O2 and 10 min of 10% O2), ventilation increased markedly and steadily, at variance with what occurs in newborns of other species, indicating a precocial development of the regulation of breathing. This latter result also suggests that the blunted response to hypoxia previously reported in adult seals may be acquired postnatally with diving experience.
Effects of body mass on courtship, pairing, and reproduction in captive mallards
Authors: Pattenden R. K. , Boag D. A.
Published: March 2009

The object of this study was to examine the influence of body mass, a measure of nutrient reserves, on the breeding biology of captive mallards. Low body mass delayed initiation of courtship and pairing, and decreased the number of permanent pair bonds formed. However, pairing date was not correlated with laying date. Low body mass during winter had a greater influence on laying date than low body mass during spring, but neither affected clutch size. This suggests that an individual arriving on the breeding grounds with low body reserves relative to others will have a lower reproductive output that year.
Hybridization between northern redbelly dace (Phoxinus eos) and finescale dace (Phoxinus neogaeus) (Osteichthyes: Cyprinidae) in Alberta
Authors: Das Mrinal K. , Nelson Joseph S.
Published: March 2009

Hybridization between northern redbelly dace (Phoxinus eos) and finescale dace (Phoxinus neogaeus) was studied in Upper Pierre Grey Lake, Alberta. Sympatric parental and hybrid populations were compared with allopatric populations from Cameron Lake and Tay Lake, Alberta. Canonical variates and principal components analyses, using 31 morphological characters, revealed that the two parental groups were bridged by an intermediate all-female hybrid group in Upper Pierre Grey Lake. Hybrids made up approximately 33% of the individuals of the sympatic population. Neither backcross nor hybrid F2 individuals could be identified from the analyses, although the majority of hybrids were morphologically more similar to P. neogaeus than to P. eos. No clear evidence of introgressive hybridization was found in either of the sympatric parental species.
Seasonal movements of caribou in arctic Alaska as determined by satellite
Authors: Fancy S. G. , Pank L. F. , Whitten K. R. , Regelin W. L.
Published: March 2009

Between 1985 and 1987, 49 283 locations and 79 101 sets of activity data were obtained for 34 adult female caribou (Rangifer tarandus granti) of the Porcupine and Central Arctic herds using satellite telemetry. Daily movement rates of female caribou from the two herds, which differ greatly in size and separation of seasonal ranges, were similar except during the spring and fall migration periods. Movement rates in July exceeded those during migration in both herds. The minimum annual distances travelled by caribou cows, ranging to 5055 km, were the longest movements documented for any terrestrial mammal.
A summary of the database pertaining to the phylogeny of the major groups of parasitic platyhelminths, with a revised classification
Authors: Brooks Daniel R.
Published: March 2009

A previously published phylogenetic systematic analysis of the major groups of parasitic platyhelminths was based on 39 anatomical characters. The resulting phylogenetic tree had a consistency index, which indicates the degree of fit of the data to the tree hypothesis, of 95% due to two postulated cases of convergence. That tree is evaluated in light of 49 additional anatomical characters and 32 ultrastructural characters. The additional anatomical characters support the original hypothesis with a consistency index of 100%, indicating no additional convergence in the data. The total anatomical database has a consistency index of 97.8%. The ultrastructural characters provide a best fit to a phylogenetic tree of 94.1 %, due to two postulated cases of convergent evolution. That tree is the same as the one supported by the anatomical data. The combined database thus comprises 120 characters having a consistency index of 96.7%, due to four postulated cases of convergent evolution. A classification of the major groups of parasitic platyhelminths is proposed, and represents a compromise between two earlier proposed schemes.
Diet determination for small laboratory-housed wild mammals
Authors: Périssé Monica , da Fonseca Carlos Roberto Sörensen Dutra , Cerqueira Rui
Published: March 2009

Adaptation of wild mammals to captivity is a decisive and limiting step in laboratory research. Here we describe a method to determine a diet that meets the nutritional and water requirements of small wild mammals in captivity. Several kinds of food are offered to the animals and a preference index (P) is calculated. A diet prepared with foods obtaining P ≥ 1.00 for 50% or more of the individuals is given to the animals. This diet contains the same proportions of proteins, lipids, and glucides determined by the food preferences experiment. Two groups are fed on this diet, one with free water and the other without, and their weights are monitored for approximately 12 days. The results allow the detection of water and nutritional deficiencies. We used these procedures with the grey four-eyed opossum, Philander opossum (Polyprotodontia, Didelphidae), and obtained a balanced diet of eggs, meat, banana, and orange that has proved suitable for keeping these animals in good condition.
Introduction of muskoxen in northern Quebec: the demographic explosion of a colonizing herbivore
Authors: Hénaff Didier Le , Crête Michel
Published: March 2009

Between 1973 and 1978, 42 muskoxen (Ovibos moschatus), mostly immature, were released northwest of Kuujjuaq, along the south shore of Ungava Bay. Helicopter censuses, complemented by ground observations, were conducted over 725 km2 in 1983 and 1986: 148 and 290 animals were counted during the first and second surveys, respectively. The finite rate of increase of the population averaged 1.25 during the 3-year interval; that rate indicates high fecundity and low mortality, because the maximum finite rate of increase is 1.30 if all animals survive and if females first calve at 3 years of age and thereafter produce one calf each year. Ground observations confirmed a high productivity: calves constituted 26 and 23% of the population in 1983 and 1986, respectively; in terms of calves per 100 mature cows, the respective ratios were 97 and 86. Some animals dispersed up to 650 km from the area of release; populations may be establishing themselves in new locations. Muskoxen are now well established in the tundra of northern Quebec.
Counting muskoxen in the Northwest Territories
Authors: Graf Ron , Case Ray
Published: March 2009

Muskoxen (Ovibos moschatus) are difficult to sample because they generally live in groups and the groups are distributed in a strongly contagious manner. We examined various techniques by first creating a physical model of the known distribution of muskoxen of northern Banks Island, Northwest Territories. Then, we sampled the population of the model using different techniques at various levels of coverage, and used the coefficient of variation as the indicator of precision. Our recommendation was to use a stratified, random transect survey with the transects oriented across river valleys in high-density areas. If possible, only stratified surveys are now used in the field and they continue to produce good, precise results.
The use of snowmobiles in the drug immobilization of muskoxen
Authors: Jingfors K. , Gunn Anne
Published: March 2009

During the early winter in 1983 and 1985 on Victoria and Banks islands, respectively, we used snowmobiles to approach and hold muskoxen (Ovibos moschatus) in tight groups, while individual animals were darted with a mixture of M99 and Rompun. We immobilized 47 muskoxen with one capture-related mortality from an accidental overdose. The effective dosage that resulted in acceptable induction and recovery times for most adult muskoxen was 7–8 mg M99 and 25–30 mg Rompun. Considerably cheaper to use than helicopters, snowmobiles also were more effective in holding muskoxen together and in reducing stress prior to immobilization. Darts could be fired at close range allowing for easier selection of individual muskoxen and for proper dart placement. Simultaneous darting and recovery of several animals in a group further reduced animal stress and increased capture efficiency.