bluuebunny/crossref_metadata_2025 huggingface dataset:
Food shortage for breeding Black-billed Magpies (Pica pica): an experiment using supplemental food
Authors: Hochachka Wesley M. , Boag David A.
Published: March 2009

Supplemental food was provided to a breeding population of Black-billed Magpies (Pica pica), starting before and after eggs were laid, to determine if and when natural food was limited. The production of fledgling magpies was increased only when supplemental feeding was begun before laying. Laying date was also advanced when supplemental feeding began before laying, but clutch and egg size were not significantly changed. Because the two feeding treatments were conducted in different years, we cannot conclude whether natural food was limiting before or after egg laying. However, out data suggest that the former may have been the case. An improved design for food supplementation experiments, which can be used to determine the time of food shortage, is suggested.
Propanidid, a useful anaesthetic for studying blood circulation in early development of fish
Authors: Veenstra Ronald S. , Balon Eugene K. , Flegler-Balon Christine
Published: March 2009

The effectiveness of propanidid was tested by comparing it with cocaine hydrochloride, urethane, and traicaine methanesulfonate, anaesthetics already established for studies of early ontogeny in fishes. Free embryos of the brook charr, Salvelinus fontinalis, and 7-day-old amargosa pupfish, Cyprinodon nevadensis amargosae, were anaesthetized with dilute solutions of these drugs. The times taken until the blood elements ceased moving through the capillary loops of the developing caudal fin were compared. Propanidid was found to be superior to the other drugs tested in maintaining the longest duration of unaltered blood flow.
Description of Capillaria forresteri sp.n. (Nematoda: Trichuridae) from the rice rat Oryzomys palustris in Florida, with notes on its ecology and seasonal variation
Authors: Kinsella J. M. , Pence Danny B.
Published: March 2009

Capillaria forresteri sp.n. is described from the fundic stomach of the rice rat Oryzomys palustris in Florida. It can be differentiated from related mammalian Capillaria spp. with lateral caudal alae in males by a combination of the following characters: location in the host, short (40–55 μm) lateral alae distinctly separated from caudal alae, and spicule length (380–426 μm). Prevalences were not different between male and female rats, but subadult and adult rats were more commonly infected than juveniles. Rice rats from freshwater marshes had a much higher prevalence than those from salt water marshes. Over a 2-year-period, both prevalence and intensity showed spring–summer peaks and sharp declines in autumn. Other species of mammals trapped in the same marshes were not infected with C. forresteri. The possibility of a paratenic or intermediate host in the life cycle is suggested.
The developmental stages of Neobrachiella robusta (Wilson, 1912), a parasitic copepod of Sebastes (Teleostei: Scorpaeniformes)
Authors: Kabata Z.
Published: March 2009

The morphology of the developmental stages of Neobrachiella robusta (Wilson, 1912) (Copepoda: Siphonostomatoida) is described. The copepod is parasitic on the gill rakers of Sebastes alutus (Gilbert, 1890) (Teleostei: Scorpaeniformes). The life cycle of this copepod consists of a copepodid stage, followed by four chalimus stages and a relatively long preadult stage, which undergoes extensive metamorphosis. The copepods aggregate on the outer row of long gill rakers of the first gill arch, as many as 97% of them being attached to these rakers. Some of the rakers become distorted, but a connection between the presence of N. robusta and these abnormalities could not be established.
Agaue obscura (Acari: Halacaridae) n.sp., a new circumpolar Antarctic mite
Authors: Bartsch I.
Published: March 2009

Agaue obscura n.sp., a circumpolar Antarctic species, is described. It is closely related to species known from Argentine waters and from deep-sea basins in the south and north Atlantic Ocean. Its legs, gnathosoma, and idiosoma are set with cuticular spinelets and filaments, which trap large amounts of detritus. This detritus coating might protect the mite from visual, tactile, or chemical detection by predators.
Occurrence and general behavior of balaenopterid cetaceans summering in the St. Lawrence Estuary, Canada
Authors: Edds Peggy L. , Macfarlane J. Andrew F.
Published: March 2009

Baleen whale movements were monitored from a hillside on the north shore of the St. Lawrence Estuary from 28 June to 27 September 1979. No diurnal or tidal relationships were apparent for the two most abundant species, the minke and finback. Single minke whales were seen almost daily. Adult pairs were only seen on four dates, and no adult-calf pairs were observed. Twenty-two small minkes were observed; three were possibly 1st-year calves. Finbacks occurred singly and in groups, particularly later in the field season. Resightings of distinctive finbacks indicate that adult pairings are temporary. One finback had been seen in the area in 1973–1975. Adult–calf pairs and seven single juveniles were also seen. Observations of finbacks pursued by whale watchers provide evidence that some regulation of the rapidly growing whale-watching industry may be warranted. Blue whales and humpback whales were seen far less frequently than minkes and finbacks. The relative abundances of minke, finback, and humpback were similar to 1973–1974 in the same area: however, blue whales were seen far more frequently in the past.
Aquatic Coleoptera and Hemiptera in some Canadian saline lakes: patterns in community structure
Authors: Lancaster J. , Scudder G. G. E.
Published: March 2009

Communities of aquatic Coleoptera and Hemiptera were examined in eight fishless lakes of varying salinities in central British Columbia. A total of 28 coleopteran and 8 hemipteran species were collected. Taxonomic and ecological classification schemes, cluster analysis, and quantitative parameters were used to elucidate patterns of community structure from survey data. Species were characteristic of high, moderate, or low salinities, or tolerant of all salinities encountered. Species distributions were disjunct at conductivities of 80 and 5000 μS cm−1, yet community complexity changed more gradually with salinity. Densities increased and species richness, species diversity, feeding guild diversity, and ecological category diversity decreased with increased conductivity. Predatory Coleoptera were well represented in all lakes, but herbivores were less abundant with increased salinity. A curious size–distribution pattern was observed: a wide range of species sizes occurred in the most freshwater lake, but fewer size classes and only small sizes were represented in more saline lakes. Several mechanistic hypotheses are suggested to explain the observed patterns.
Étude ultrastructurale de l'os des vertèbres du Sélacien Scyliorhinus canicula L.
Authors: Bordat Christian
Published: March 2009

The neural arches of the vertebrae of Scyliorhinus canicula were studied in detail. The extremities of each half arch consist of two pyramids of fibrous cartilage. These contain rows of convergent collagen fibers in the shape of a fan. The cells are arranged in series without forming real columns and without becoming enlarged. The central area of each arch contains a band of calcified cartilage with degenerating cells and numerous gaps that are invaded by urchin-shaped calcifications. This blade of cartilage is squeezed between an internal band of lamellar bone and an external nonlamellar zone of bone. The internal bony zone is bordered by osteoblasts and contains elongated osteocytes, many showing signs of degeneration. The external zone contains osteocytes joined by small canaliculi. Areas of resorption by mononucleated cells can be observed at the border of the external bone zone. These cells project digitations that the calcified border where fragmented collagen fibers are present; they react positively to acid phosphatases and show numerous signs of pynocytosis.[Journal translation]
Polystomoidella mayesi n.sp. (Monogenea: Polystomatidae) from the urinary bladder of a Malaysian box turtle, Cuora amboinensis
Authors: Richardson Jane P. M. , Brooks Daniel R.
Published: March 2009

A new species of polystome monogenean Polystomoidella mayesi, is described from the urinary bladder of a Malaysian box turtle, Cuora amboinensis. The new species most closely resembles members of Polystomoidella by having a single testis and a single pair of haptoral anchors, but differs from all other members of the genus by lacking genital hooklets. In this regard, the new species resembles Oculotrema hippopotami Stunkard, 1924, but that species lacks hamuli.
Biological alarm clock arouses hibernating big brown bats, Eptesicus fuscus
Authors: Twente John W. , Twente Janet
Published: March 2009

This laboratory study showed that the individual averages of the times of day of arousal from hibernation of 55 big brown bats, Eptesicus fuscus, maintained in darkness, ranged from 14:05 to 20:50 (2:05 p.m. to 8:50 p.m.). The data were interpreted as representing a persistent but inexact 24-h rhythm that functioned as a biological alarm clock. This rhythm was, according to the parameters measured, apparent only on the day of arousal. The rhythm was determined to be independent of the length of time the bat had hibernated; independent of temperature; persistent and did not drift and become free-running in continuous darkness; unapparent in daily cardiac patterns or themogenic activity; and independent of obvious exogenous variables.
Dispersal and survival of gypsy moth larvae
Authors: Weseloh Ronald M.
Published: March 2009

Marked, laboratory-reared gypsy moth, Lymantria dispar L., second instars were released at the base of oak trees in a declining gypsy moth population. By periodically noting the proportion of caterpillars observed that had been released, it was found that little intertree dispersal of second and third instars occurred. Movement within a tree did occur, however. Dispersal of gypsy moth fourth through sixth instars was measured by determining changes in the proportion of marked caterpillars resting under burlap bands placed around the trunks of isolated trees. Results suggest that large larvae disperse little except just prior to pupation. The lack of significant dispersal in all larval stages made it possible to estimate from mark–recapture studies the proportion of larvae that survive from one day to the next. Daily survival rates were 0.6–0.7 for small larvae and ca. 0.8 for large ones.
Plasma and blood volumes of the hooded seal (Cystophora cristata)
Authors: Keiver K. M. , Chandler M. , Frank R. J. , Ronald K.
Published: March 2009

Plasma volumes and haematocrits were determined in six hooded seals (Cystophora cristata) and blood volumes were estimated. Expressed on a total body weight basis, plasma volume was found to range from 39 to 109 mL∙kg−1 and blood volume from 93 to 222 mL∙kg−1. Logarithms of the values for plasma and blood volume varied directly with the total body weight of the seals.
Evidence of stereotyped underwater vocalizations of male Atlantic walruses (Odobenus rosmarus rosmarus)
Authors: Stirling Ian , Calvert Wendy , Spencer Cheryl
Published: March 2009

Adult male Atlantic walruses (Odobenus rosmarus rosmarus) vocalize extensively underwater during the breeding season. The individual calls are composed of one or more short repetitious pulses which may vary individually in the number, pattern, and rate at which they are given. Individual male walruses give repeated stereotyped vocalization cycles totalling several hundred pulses each for up to several hours at a time, both while the whole body is submerged and between breaths with the head submerged while at the surface. We analyzed the vocalization cycles of a sample of different walruses, and sound spectrograms of particular calls from within those cycles, to test the hypothesis that the stereotyped vocalizations of individuals are unique and recognizable. In our sample, the pulse patterns of particular calls given by individual walruses in a series of vocalization cycles were nearly identical but were consistently different from the same call given by other animals. One call, the diving vocalization of a recognizable male, was identical in two different years.
Adult longevity of workers of the bumble bees Bombus fervidus (F.) and Bombus pennsylvanicus (De Geer) (Hymenoptera: Apidae)
Authors: Goldblatt Janet W. , Fell Richard D.
Published: March 2009

We studied worker longevity in two colonies of Bombus fervidus (F.) and two colonies of Bombus pennsylvanicus (De Geer). In 1981, adult life expectation for B. fervidus workers was 21.8 days. In 1982, mean expectation of life at adult emergence was 34.1 days for workers of B. fervidus and 33.0 days for workers of B. pennsylvanicus. The longevities observed in 1982 are the highest yet recorded for temperate bumble bee species, and are intermediate between the previously described extremes of short life-span in north temperate species and high longevity in a tropical species. This study suggests that bumble bee life expectancy tends to decrease as one progresses northward. However, variation in life expectancy within B. fervidus at a single location in two consecutive years was almost as great as previously described differences in longevity between tropical and temperate species. Shortened life-span may therefore be associated with increased intensity of foraging activity during periods of low forage availability as well as with latitude. In both years, survivorship of late-emerging worker cohorts was consistently low, possibly because a larger proportion of late-emerging workers become foragers.
The paradox of age-related dominance in brown-headed cow birds (Molothrus ater)
Authors: Weatherhead Patrick J. , Teather Kevin L.
Published: March 2009

Studies of brown-headed cowbirds (Molothrus ater) suggest that yearling males are as successful at acquiring mates as adult males. Our aim in this study was to determine if dominance status of males was also independent of age when they were competing for access to food. Five mixed-age (adult and yearling) groups of 9 or 10 male brown-headed cowbirds were maintained in aviaries. Using 6829 interactions recorded at a feeding dish we computed dominance hierarchies, all of which proved to be linear and stable. In two of the five groups all adult males were dominant to all yearlings, with less clear-cut age differences in the remaining three groups. Adults were dominant in 54 of the 66 dyads consisting of an adult and a yearling in which one individual won a significant proportion of their interactions. Although adults were significantly heavier and larger than yearlings, weight and size contributed little to the outcome of dominance interactions. These results suggest that dominance status in one social arena may be a poor predictor of social status in another for brown-headed cowbirds. Our results do not explain why young male cowbirds are successful in competing for mates.
Incubation by young, nonbreeding birds: potential versus realization of behaviour
Authors: Jamieson Ian G. , Craig John L. , Minot Edward O.
Published: March 2009

Incubation behaviour is described in nonbreeders of two species of birds. Among communally breeding pukeko (Porphyrio porphyrio melanotus), some subadult members of a group incubate eggs but are not involved in courtship or mating. In one population of white-rumped swiftlet (Aerodramus spodiopygius), a single nestling is reared initially at each nest but that nestling incubates a second egg before fledging. The standard proximate and ultimate explanations given for parental incubation would be difficult to apply in these cases. Incubation of eggs might therefore be better understood by looking at the circumstances that cause birds to realize their potential for exhibiting incubation behaviour.
Reproduction of the winter tick, Dermacentor albipictus, under laboratory conditions
Authors: Drew Mark L. , Samuel W. M.
Published: March 2009

Reproductive performance and development of the winter tick, Dermacentor albipictus, were studied under controlled conditions using multiple replicates along a time series. Engorged female ticks cold stressed at various temperatures before incubation at 25 °C laid more eggs, and the number of eggs laid per gram of engorged female was higher, than female ticks held at constant 25 °C. No females survived a pretreatment of −22 °C. Females maintained under fluctuating temperature and relative humidity had a higher mortality rate and lower reproductive performance than those in either constant or cold-stress conditions. The preoviposition period decreased over time in most treatment groups.
Trehalose-hydrolysing activities in thoracic musculature of the American cockroach, Periplaneta americana
Authors: Jahagirdar A. P. , Viswanatha T. , Downer R. G. H.
Published: March 2009

Particulate and soluble forms of trehalose-hydrolysing enzymes were demonstrated in mitochondrial and cytosolic fractions of thoracic musculature from Periplaneta americana. Treatment with snake venom or phospholipase A2, in the presence of Ca2+, solubilizes 90–95% of the mitochondrial trehalase activity. Comparison of the substrate specificities of the mitochondrial and cytosolic enzymes indicates that the solubilized mitochondrial enzyme is specific to trehalose whereas the cytosolic enzyme functions as a general α-glucosidase.
The nudibranch genus Adalaria, with a description of a new species from the northeastern Pacific
Authors: Millen Sandra V.
Published: March 2009

A new species of Adalaria from the northeastern Pacific, Adalaria jannae sp. nov., is described. The relationship of the genus Adalaria Bergh, 1878 with the genus Onchidoris Blainville, 1816 is discussed. The new species is compared with extant Adalaria species, and the synonymy of some of these species with Adalaria proxima (Alder &Hancock, 1854) is proposed.
A new freshwater copepod, Mesocyclops brevisetosus sp.nov. (Crustacea, Cyclopoida) from Kalimantan, Indonesia
Authors: Dussart B. H. , Sarnita A. S.
Published: March 2009

A new species, Mesocyclops brevisetosus sp.nov., is described from Kalimantan, Indonesia. It has features intermediate between the genera Mesocyclops and Thermocyclops. The ratio of internal to external furcal seta length, the shape of the receptaculum seminis, and the unequal terminal P4 endopodite spines constitute a unique diagnostic combination.
Indiana roselyneae n.sp. (Oxyurida; Nematoda) from Madagascan Gryllotalpoidea (Orthoptera; Insecta) with comments on the structure of the cephalic extremity of Indiana
Authors: Adamson Martin L. , Waerebeke Daniel van
Published: March 2009

Indiana roselyneae n.sp. is proposed for an oxyuridan from Madagascan Gryllotalpoidea studied and referred to Indiana gryllotalpae Chakravarty, 1943 by Bain (Bain, O. 1985. Ann. Parasitol. Hum. Comp. 40:659–676). This species is most similar to Indiana coimbatoriensis Latheef and Seshadri, 1972 in that spines in the lateral region are markedly larger than adjacent spines. It differs from this latter species by the following: enlarged spines form two rather than three longitudinal rows; the cephalic umbraculum does not extend beyond the isthmus; and the vulva is located more posteriorly on the body. The cephalic umbraculum in Indiana consists of two circles of six elements each: an anterior circle arising from lip-like structures surrounding the oral opening consisting of one dorsal, one ventral, and four sublateral elements, and a posterior circle consisting of two subventral, two subdorsal, and two lateral elements.
Pregnancy test for meadow voles (Microtus pennsylvanicus) based on blood azurocyte counts
Authors: Mihok Steve
Published: March 2009

Voles of the genus Microtus possess a unique leukocyte that contains large purple inclusions visible with light microscopy. Counts of "azurocytes" from females in different reproductive states indicate that pregnancy can be diagnosed absolutely by the presence of at least 400 azurocytes/μL in the peripheral blood. Other criteria may be used for specific groups of animals to diagnose both sexual maturity and pregnancy with few false-positive diagnoses.
Chaoborus populations: response to food web manipulation and potential effects on zooplankton communities
Authors: Elser Monica M. , Ende Carl N. von , Sorrano Patricia , Carpenter Stephen R.
Published: March 2009

Chaoborus populations were studied in two lakes in which fish predation was experimentally reduced, and in a reference lake. In Tuesday Lake, major reduction of fish predation led to substantial increases in density of Chaoborus punctipennis. Analysis of crop contents and estimates of consumption rates suggested that C. punctipennis caused declines of rotifer and copepod populations following the manipulations. In Peter Lake, lesser changes in fish predation caused no major change in density of Chaoborus flavicans, perhaps because food limitation compensated for effects of reduced predation. In both Peter Lake and the reference lake, Paul Lake, C. flavicans preyed heavily and selectively on Daphnia less than about 1.4 mm in total length. Bioenergetic calculations indicated that up to 46% of the daphnids were consumed daily. At some times of the year, certain zooplankton populations (especially noncolonial rotifers, small copepods, and small cladocerans) were strongly influenced by Chaoborus predation.
The reaction of pearl dace (Pisces, Cyprinidae) to alarm substance: time-course of behavior, brain amines, and stress physiology
Authors: Rehnberg Bradley G. , Smith R. J. F. , Sloley B. D.
Published: March 2009

Pearl dace, Semotilus margarita (Pisces, Cyprinidae), respond behaviorally and physiologically to conspecific alarm substance. The behavioral alarm reaction was biphasic. A brief initial phase of rapid and unpredictable swimming was followed by a period of inactivity that was observable even after 5 h. In nature, biphasic behavioral reactions may function to remove alarmed fish from the area of greatest danger and then render them inconspicuous. The physiological alarm reaction included elements of a stress response. Concentrations of plasma cortisol and glucose were elevated at 15 min after the detection of alarm substance, but had returned to control levels by 5 h. There were no odor-induced changes observed in brain concentrations of dopamine, norepinephrine, 5-hydroxytryptamine, or tryptophan. The biphasic behavioral response and the physiological stress response were interpreted as adaptations that permit pearl dace to successfully react to threats of predation.
Odor preference and social behavior in meadow voles, Microtus pennsylvanicus: seasonal differences
Authors: Ferkin Michael H. , Seamon Joshua O.
Published: March 2009

Olfactory cues play a major role in inter- and intra-sexual agonistic behavior for Microtus pennsylvanicus. We show that seasonal changes in odor preference and behavioral interactions coincide with varying patterns of social organization. Odor preference trials were conducted in a Y maze and social behavior was measured in dyadic encounters in a neutral arena. During the breeding season, paired encounters between females contained more agonistic acts than did encounters between males, or those between males and females. Breeding males preferred the odor of females to the odor of conspecific males. In contrast, breeding females preferred their own odor and the odor of males to the odor of other females. The data support female exclusiveness during the breeding season. During the nonbreeding season, paired encounters between females contained fewer agonistic acts than did encounters between males or those between males and females. Nonbreeding females preferred the odor of female conspecifics to their own odor or the odor of male conspecifics. These results are consistent with group nesting and a relaxation of female territoriality during the nonbreeding season. Nonbreeding males did not exhibit a preference for their own odor, the odor of other males, or the odor of female conspecifics. Our results indicate that nonbreeding males are solitary, and overwintering groups are female-biased. Odor preferences may underlie seasonal changes in social organization.
Possible role of the central retinular cells in the ommatidia of male black flies (Diptera: Simuliidae)
Authors: McIver Susan B. , O'Grady Gail E.
Published: March 2009

In Cnephia dacotensis, a species that mates on rocks and plants without swarm formation, the eyes of the males are separate and undivided. Each ommatidium consists of two general regions: a distal dioptric apparatus and a sensory receptor layer with eight retinular cells. Six of these cells (R1–6) are located peripherally and two centrally; R7 occurs distally and R8 basally. In males of previously studied species in which females are detected as they fly above a male swarm, the compound eyes are holoptic and divided into distinct dorsal and ventral regions. Ommatidia in the dorsal region lack the R7 cell. If in black flies R7 is a blue receptor and R8 a uv receptor, then the absence of R7 means that swarm-forming males see the females against a background that provides a sharper contrast than a background of a uv to blue range. This would sharpen the visibility of the dark female against the background skylight, enabling the male to perceive her more swiftly.
A note comparing the primary structure of hemoglobin β chains of the arctic ground squirrel and the yellow-bellied marmot
Authors: Duffy Lawrence K. , Ehrhardt Margaret M. , Romero Michael , Florant Gregory L.
Published: March 2009

Hemoglobin β chains were isolated from both the arctic ground squirrel (Citellus parryii undulatus) and the yellow-bellied marmot (Marmota flaviventris). After various enzymatic and chemical cleavages, the primary structures of these β chains were determined. Only one sequence difference was found between the yellow-bellied marmot β chain and that of the European marmot (Marmota marmota). Ground squirrels (C. p. undulatus, Citellus townsendii, and Citellus citellus) showed more species-related differences than the marmots, with the β chain of the arctic ground squirrel differing from that of the townsend ground squirrel by four amino acid substitutions. In the amino terminal region of the β chain, a partial sequence analysis showed that Citellus tridecemlineatus was more similar to C. p. undulatus than to C. townsendii. These biochemical differences could reflect either an increased evolutionary rate of speciation in ground squirrels over that in the genus Marmota or a more recent origin of the species in the genus Marmota. The amino acid differences between these hemoglobins do not appear to be functionally significant in these ecologically similar animals.
Control of arrhythmic breathing in bimodal breathers: Amphibia
Authors: Boutilier Robert G.
Published: March 2009

Amphibians employ a system of gas exchange whereby various combinations of the lungs, gills, and skin are used to exploit gas exchanges in both air and water (bimodal breathing). Continuous lung ventilation is rarely observed in these animals. Instead, the dominant breath pattern is arrhythmic in nature and is believed to have evolved in response to a periodic need to supplement aquatic gas exchange. Such a need is largely dependent on the activity state of the animal concerned and its capacity for aquatic gas exchange. The overall control system appears to be one that turns lung ventilation on and off by trigger signals arising from chemo- and mechano-sensitive receptors responding to changing conditions during periods of breath holding and breathing. In amphibians in which the aquatic exchanger is a major avenue for CO2 elimination, [Formula: see text] levels in the lungs and blood do not change substantially in the latter stages of a breath hold. Under these conditions falling levels of oxygen may be the primary stimulus to terminate the breath hold and initiate breathing. There is, however, some interaction between the two gases since elevated CO2 levels affect the sensitivity of the predominantly O2-mediated response. Another major component in determining air-breathing patterns in these animals is their ability to delay the onset of breathing when certain behavioural activities take precedence over the need for additional gas exchange.
Sleep and hypometabolism
Authors: Heller H. Craig
Published: March 2009

Metabolic rate (MR) of endotherms is lower during sleep than quiet wakefulness (W), largely as a result of a regulated lowering of body temperature (Tb) during slow-wave sleep (SWS). In mammals this decrease in regulated Tb is evidenced by a lowered hypothalamic thermosensitivity. In avian thermoregulatory systems spinal thermosensitivity is lower in SWS than in W. In rapid eye movement sleep (REMS) there is a severe inhibition of the thermoregulatory systems. Hypothalamic cells that are thermosensitive during W become less so during SWS and become totally insensitive to temperature during REMS. The adjustments in thermoregulatory systems of endotherms that result in lower Tb and MR during SWS have been shaped by natural selection in different species to produce a variety of adaptations for energy conservation. Bouts of torpor, hibernation, or nocturnal hypothermia consist mostly of SWS, and these states involve a downward resetting of hypothalamic thermosensitivity in mammals and spinal thermosensitivity in birds. A physiological mechanism underlying this change in regulation of Tb may be related to the regulation of breathing and acid–base balance. Retention of CO2 occurs at the onset of sleep, shallow torpor, and hibernation and release of excess CO2 occurs when these states are reversed by arousal. Increased plasma CO2 may have a direct effect on hypothalamic neurons involved in thermoregulation, resulting in a decline in regulated Tb.
Metabolism in diving birds: studies in the laboratory and the field
Authors: Woakes A. J.
Published: March 2009

Heart rate has long been used as an indicator of the major physiological responses that many animals show to submersion. With the advent of modern techniques, particularly telemetry, it has been shown that the classical diving bradycardia, elicited by forced submersion, is not normally fully expressed during spontaneous diving. The classical bradycardia was shown to be a result of an oxygen-conserving response, the metabolic depression and associated anaerobiosis being easily demonstrated during forced submersion. Unfortunately, it is not yet feasible to measure directly the metabolic rate of voluntarily diving animals during the periods of apnoea. It is, however, possible to estimate oxygen consumption during a dive from the measurement of oxygen uptake between dives. By developing and using this technique, it has been shown that natural dives in two species of bird are primarily aerobic in nature. Anaerobic metabolism, previously thought to be of major importance during diving, now appears to be reserved for emergency situations.
Metabolic suppression and oxygen availability
Authors: Hochachka P. W.
Published: March 2009

The aerobic metabolic rates of cells, tissues, and even whole organisms remain relatively constant down to very low values (O2-regulating response) or decline steadily with O2 availability (O2-conforming response). (O2-regulating systems attempt to make up the energy deficit arising when O2 uptake begins to decline by activating anaerobic metabolism; this process is termed the Pasteur effect and typically involves 5- to 15-fold increases in glucose utilization rates. O2 conformers do not make up the energy deficit and thus enter a metabolically arrested state as O2 availability declines. Current data suggest that O2 conformers can maintain coupled metabolism–membrane functions at metabolically arrested states while O2 regulators cannot, presumably because of more permeable membranes and thus higher energy-dependent ion pumping requirements. These fundamental differences in response to, and tolerance of, hypoxia may be related to qualitative or quantitative differences in inducible stress proteins during O2 deprivation.
Hormone-mediated release of carbohydrate from locust fat body in vitro
Authors: Carlisle James A. , Loughton B. G. , Orchard Ian
Published: March 2009

In vitro incubations of locust fat body with adipokinetic hormone II (AKH II) show that this peptide acts directly on the fat body to cause release of carbohydrate into the medium. Red pigment concentrating hormone, an analogue of AKH II, mobilizes carbohydrate in vitro at similar concentrations to those estimated for AKH II. Adipokinetic hormone I (AKH I) will mobilize carbohydrate only at large doses. Octopamine, a hyperlipaemic hormone in locusts, will not mobilize carbohydrate from fat bodies in vitro.
Trematoda of sablefish, Anoplopoma fimbria (Pallas, 1811), as possible biological tags for stock identification
Authors: Kabata Z. , McFarlane G. A. , Whitaker D. J.
Published: March 2009

A total of 419 sablefish (Anoplopoma fimbria) was collected from 13 locations off Canada's west coast. Eleven of the stations were located on or near the continental slope, and two were located on seamounts. The fish were examined for prevalence and intensity of trematodes to determine the suitability of using these parasites as biological tags. The trematode fauna from the seamount sablefish was significantly different from that of slope sablefish, indicating that the seamount fish are distinct and separate stocks. Development of localized fisheries on these stocks could provide a significant yield to Canadian fishermen.
Resource limitation in mountain goats: a test by experimental cropping
Authors: Houston D. B. , Stevens V.
Published: March 2009

Changes are reported in the population dynamics and physical condition of mountain goats (Oreamnos americanus) following a reduction in their density at Olympic National Park, Washington, U.S.A. The goat population showed density-dependent responses in initial breeding ages and in litter size. Production and recruitment of kids were more variable at high densities, and these population attributes may show nonlinear density dependence. These shifts in dynamics were associated with increases in live weights and, possibly, in fat reserves. The density dependence shown was insufficient to compensate for removals that approximated the initial production of young, and goat numbers declined precipitously. The implications of these relationships to mountain goat ecology are examined.
Food selection by capercaillie chicks in southern Norway
Authors: Spidsø Tor K. , Stuen Odd H.
Published: March 2009

Food selection by capercaillie (Tetrao urogallus) chicks was studied using human-imprinted chicks. Invertebrates made up more than 50% of the chicks' diet during the 1st week. Feeding on plants increased to approximately 100% in 7-week-old chicks. Berries of Vaccinium myrtillus made up 85% of the plant material eaten. Berries were eaten once they ripened. Other important plant foods were flowers of Erica tetralix and Melampyrum pratense. Ants (Formicidae) were the most utilized invertebrate food. The observed decrease in the proportion of invertebrates in the diet with increasing age was not a result of decreasing invertebrate abundance. Sweep net samples showed significantly fewer invertebrates when chicks were 1 – 3 weeks old than when chicks were 4 – 6 weeks old.
Body form differences between the Enos Lake species pair of threespine sticklebacks (Gasterosteus aculeatus complex)
Authors: Baumgartner Jeffrey V. , Bell Michael A. , Weinberg Philip H.
Published: March 2009

Two ecologically and morphologically divergent species of the Gasterosteus aculeatus (threespine stickleback) species complex occur in Enos Lake, Vancouver Island, British Columbia. The limnetic species swims in open water most of the time and feeds on plankton, and the benthic species lives near the shore in a structurally complex environment where it eats larger benthic prey. Based on design criteria inferred from hydrodynamic considerations, from other fishes, or from other populations of Gasterosteus, and on ecological differences between the two species, we expected that limnetic sticklebacks would have a more fusiform body, longer pectoral fins and snout, and larger eyes. Although some of these expected differences had been observed in a previous study of this species pair, others were verified for the first time in this study. Shape divergence between our samples results both from allometric trends coupled with differences in overall mean size and from size-free shape differences. Standard length is a poor proxy for general size (i.e., the first principal component of the morphometric variables) because several major features which differ between the species are dorsoventrally oriented. The marked morphometric divergence between these species has probably evolved within about the past 13 000 years, since deglaciation of Vancouver Island.
Fascioloides magna (Trematoda) in woodland caribou (Rangifer tarandus caribou) of the George River herd, Labrador
Authors: Lankester Murray W. , Luttich Stu
Published: March 2009

Fifty-eight percent of woodland caribou (Rangifer tarandus caribou) of the George River herd, Labrador, were infected with up to 110 giant American liver flukes (Fascioloides magna). The prevalence and intensity of infection did not differ between 2 sampling years or between sexes. Prevalence tended to increase with age while intensity did not differ among age groups. Liver weight increased with intensity of infection but condition, as measured by the mean depth of back fat, did not differ between infected and uninfected animals. Caribou must be considered a suitable host of F. magna since the growth and maturation of the parasite and lesions produced in Rangifer resemble those in deer and wapiti.
Neobrachiella rostrata (Copepoda: Lernaeopodidae) on the gills of the Greenland halibut, Reinhardtius hippoglossoides from the Gulf of St. Lawrence
Authors: Rubec L. A.
Published: March 2009

A short form of Neobrachiella rostrata is found on the gills of Greenland halibut, Reinhardtius hippoglossoides, in the Gulf of St. Lawrence. Female copepods from Greenland halibut differ from females occurring on Atlantic halibut, Hippoglossus hippoglossus, in body size and shape of trunk; males differ in the specific structural details of the second antenna and maxilliped and in the presence of armed uropods and a tympanum between the second maxillae. Intraspecific variations are commonly found in females of the genus Neobrachiella but have never been reported in males.
Microhabitat variation in enzyme activities in the mosquitofish, Gambusia affinis
Authors: Zimmerman Earl G. , Liu Edwin H. , Smith Michael H. , Wooten Michael C.
Published: March 2009

Standard activities of adenosine deaminase, aspartate aminotransferase, lactate dehydrogenase, and malate dehydrogenase, and levels of soluble body protein were determined for populations of the mosquitofish, Gambusia affinis, from four habitats classed as cold (ambient), hot, past-hot (thermal effluent received in the past), or usually hot but reactor down at time of sampling, based on their history of receiving thermal effluents from nuclear production reactors at the Savannah River Plant. Major contributors to enzyme activity variation were thermal history of the site, creek of origin, and sex. Males had significantly higher enzyme activities, perhaps associated with microhabitat differences between the sexes. The most probable explanation for the observed variation is the interaction of stochastic processes, differential selection, and different demographic properties of the populations in a manner consistent with Wright's shifting balance model of evolution.
Common loon reproduction and chick feeding on acidified lakes in the Adirondack Park, New York
Authors: Parker Karl E.
Published: March 2009

The effects of lake acidification on common loon reproduction were studied on a total of 24 Adirondack lakes from May through August in 1983 and 1984. The lakes ranged in size from 10.5 to 179 ha; pH ranged from 4.65 to 6.77 and alkalinity from −66 to 111 μequiv./L. Although loons nesting on small, low-pH lakes had a high fledging rate, possibly because of reduced disturbance or predation, no significant relationship (P > 0.10) was found between lake acidity status and loon reproductive success. No chick mortality could be attributed to lake acidification, but chicks on low-pH lakes were generally fed prey much smaller or much larger than those normally preferred. A pair nesting on a fishless lake fed aquatic insects to their constantly begging chick, spending two to four times longer feeding the chick compared with loons on lakes with fish. This pair, alternating absences, flew to another lake to feed, and on three occasions returned to the nesting lake carrying a fish. Loons on the low-pH study lakes apparently adapted, at least in the short term, to food resource depletion associated with acidification. Despite this, acidification creates potentially severe feeding problems for chicks by reducing prey diversity and quantity.
Photoperiodic effects on body size and energetics of the collared lemming, Dicrostonyx groenlandicus
Authors: Reynolds P. S. , Lavigne D. M.
Published: March 2009

Resting metabolic rates of adult collared lemmings, Dicrostonyx groenlandicus, acclimated from weaning to either long, "summer" (22L:2D) or short, "winter" (2L:22D) photoperiod at 15 °C were examined as a function of ambient temperature. Winter morphs were significantly heavier than summer morphs (73.8 ± 7.7 (SD) and 54.5 ± 7.2 (SD) g, respectively). However, there were no differences in mass-specific metabolic rates between treatments at 15 and 20 °C. At low ambient temperatures (0 and −10 °C), metabolic rates of summer morphs were significantly higher than those of winter morphs, indicating a shift in the thermoneutral zone with photoperiod acclimation. There were no significant differences in core temperature between morphs at any ambient temperature. Thermal conductance of winter morphs was significantly lower (0.05 mL O2 (g∙h∙°C)−1) than that of summer morphs (0.09 mL O2 (g∙h∙°C)−1). Comparisons with other myomorph rodents do not support the contention that lemmings have unusually high metabolic rates. However, minimal thermal conductances of lemmings were much lower than expected on the basis of body size. These data suggest that although lemmings may differ in seasonal patterns of energetics from other microtines, there is little evidence to support the assertion that high rates of metabolism are characteristic of all microtines, or that observed basal rates represent a phylogenetic adaptation to cold.
The spatial and temporal distribution of four Simulium tuberosum (Diptera: Simuliidae) cytospecies in Waterville Valley, New Hampshire, U.S.A.
Authors: Pistrang Lawrence A. , Burger John F.
Published: March 2009

Four cytospecies of the Simulium tuberosum complex were collected from 13 sampling stations in the Mad River watershed. FGH, FG (St/FG and CDE/FG Y chromosome morphs), and CDE were the commonest cytospecies collected; A was less common. They exhibited a definite pattern of temporal succession that occurred consistently in both years in particular streams. When present, FGH was always the first to appear, followed by FG. The sequence FGH–FG–CDE occurred in larger, faster-flowing, nonoutlet streams with broad seasonal temperature ranges. The FGH–FG sequence occurred in streams with relatively narrow (cooler) seasonal temperature ranges. Cytospecies A was restricted to outlet sampling sites. Cytospecies FGH was invariably univoltine. The other cytospecies had one or two generations per year, depending on the seasonal temperature regime of particular streams. The principal factor controlling the occurrence and seasonal succession of S. tuberosum cytospecies appeared to be water temperature, specifically the seasonal temperature regime of particular streams. FGH and FG did not occur at sites where water temperature was above 11 °C in May, or at outlet sites where water temperature increased rapidly in May and June. In contrast to A, CDE did not occur in streams with seasonal water temperatures remaining below 13 °C, except at one outlet site. CDE and A did not coexist temporally in the study area. Differences in the color of the body and head and in ecological preferences can be used to distinguish FGH and FG from CDE and possibly from A.
Sexual differences in accumulation of mercury in four species of centrarchid fishes
Authors: Nicoletto Paul F. , Hendricks Albert C.
Published: March 2009

A 3-year study of fish from the South River, and the South Fork of the Shenandoah River, and the Shenandoah River in Virginia revealed significant differences in the muscle mercury content of males and females. Female rock bass, Ambloplites rupestris, redbreast sunfish, Lepomis auritus, pumpkinseed, Lepomis gibbosus, and bluegill, Lepomis macrochirus contained higher levels of mercury than the males of each species. An analysis of these species indicated that sex-related differences in mercury levels were not due to differences in body size but may have been related to the onset of reproduction. For example, mercury levels in 1-year-old male and female redbreast sunfish were not significantly different: females averaged 0.66 μg Hg/g and males averaged 0.63 μg Hg/g. However, at 2 years of age, when redbreast sunfish first reproduce, females contained significantly more mercury than males: females averaged 0.84 μg Hg/g and males averaged 0.60 μg Hg/g. Analysis of the other species yielded similar results.
Freeze tolerance: constraining forces, adaptive mechanisms
Authors: Storey Kenneth B. , Storey Janet M.
Published: March 2009

For a variety of ectothermic animals, survival of subzero temperatures is aided by a natural capacity to tolerate extracellular freezing. Both low temperatures and freezing place inescapable constraints on the behaviour of molecules and biological structures. For example, low temperature affects metabolic rates, membrane fluidity, and weak bond interactions governing protein structure and function, whereas damage from freezing includes osmotic stress, membrane deformation, dehydration, physical damage by ice, and the consequences of long-term ischaemia. Selected biochemical adaptations permit survival of exposure to freezing by maintaining cell integrity, subcellular structure, energy production, and homeostasis. The key adaptations for freeze tolerance deal with the following: (i) control of extracellular ice: ice-nucleating proteins induce ice formation at multiple extracellular sites and at high subzero temperatures, whereas thermal hysteresis proteins inhibit the recrystallization of ice during long-term freezing; (ii) regulation of cell volume: the colligative action of high concentrations of polyols limit freeze concentration of the cell beyond a critical cell volume; (iii) protection of subcellular organization: trehalose and proline stabilize membrane bilayer structure, polyols stabilize protein structure; and (iv) viability in the frozen state: a well-developed tolerance for ischaemia plus mechanisms of facultative metabolic depression support long-term survival. Potential constraints of low temperature on metabolic functions are overcome to produce a metabolism that remains integrated and balanced over a wide temperature range. In addition, temperature change is exploited as a signal for the induction of various freeze tolerance adaptations.