bluuebunny/crossref_metadata_2025 huggingface dataset:
The phylogenetic significance of ommatidium structure in the compound eyes of polyphagan beetles
Authors: Caveney Stanley
Published: August 2008

The structure of ommatidia in adults of more than 200 beetle species from 91 polyphagan families was surveyed. Three basic types of lens system (eucone, exocone, and acone) and two types of retinal unit (fused rhabdom, open rhabdom) are represented. The eucone (crystalline cone-containing) ommatidium is ancestral and prevails in primitive Eucinetoidea, Hydrophiloidea, and Scarabaeoidea; ommatidia of the primitive beetles Cupes and Omma as well as the Adephaga are of this type. The polyphagan founders most likely had ommatidia with small crystalline cones and narrow clear zones beneath the corneal facets. Exocone and acone eyes are derived structures, and their distribution suggests that both have evolved several times. Exocone ommatidia arose early in polyphagan evolution, possibly first in dascilloid-like founders of elateriform and bostrychiform beetles, where the exocone is commonly found. An exocone eye also evolved separately in the ancestors of several primitive scarabaeoid families; possible steps in this eucone to exocone transition may be seen in the Trogidae. The clear zones of eucone and exocone eyes are not homologous. The acone ommatidium is specialized and arose through a progressive loss of either crystalline cone or exocone. In the advanced staphylinoid beetles it is a relic of crystalline cone loss in their small ancestors. In the cucujiforms it arose likely from the loss of the exocone in their bostrychiform ancestors, associated here with a shift to an open rhabdom. Although the distribution of ommatidial types coincides with major lineages in the Polyphaga, a few anomalies remain. The Eucnemidae, Buprestidae, and Dryopidae are all eucone yet are placed in the elateriform series, in which 25 of 30 families are exocone. Scarab beetles have an extraordinary variety of lens types that presumably reflects the exceptional adaptability of the eye in this superfamily.
Sperm duct epithelium of brook trout: Na+ transport and seminal plasma composition
Authors: Marshall William S.
Published: August 2008

The transport of Na+ by the brook trout sperm duct (ductus deferens) was examined in vitro. Active Na+ uptake (averaging 0.6 μequiv.∙cm−2∙h−1) was not significantly different from transepithelial short-circuit current, indicating that the short-circuit current may be a measure of Na+ net transport. Transepithelial conductance was 4.1 ± 0.2 mS∙cm−2; an initially high short-circuit current and transepithelial potential (4–7 mV, serosa positive) dropped to near zero in the 1st hour in vitro. Short-circuit current and net Na+ transport were stimulated by cyclic adenosine monophosphate and 3-isobuty-1-methylxanthine; transient stimulations of short-circuit current were elicited using epinephrine (lumenally) and by acetylcholine. Brook trout seminal plasma contained high K+ (25 mM) and low Na+ (119 mM), relative to blood plasma, in part a result of ion transport by the sperm duct epithelium. Seminal plasma composition in turn ensures quiescence of maturing spermatozoa stored in the sperm duct for several weeks prior to spawning.
L'infestation du myoépithélium de l'oesophage par des microorganismes pigmentés et la structure des organes à bactéries du vestibule chez le Bryozoaire Chilostome Palmicellaria skenei (E. et S.)
Authors: Lutaud Geneviève
Published: August 2008

Blue lateral spots, corresponding to rows of myoepithelial cells invaded by spherular pigmented microorganisms, were observed in the oesophagus of every polypide in 75% of living colonies of Palmicellaria skenei from deep rocky sites off the northern coast of Brittany. Ultrastructural examination of the microorganisms showed that they are intracellular procaryonts with no membranous organelle of thylakoid structure. Their natural pigmentation and a cortical layer of vesicles cause them to resemble autotrophic bacteria with chlorophyllic pigments. The association is not obligatory, but it is specific and is restricted to the first contractile region of the digestive tract. Ultrastructural examination of the paired organs attached to the diaphragm of the tentacular sheath showed that each organ is formed by the adhesion of one of the glandular diverticula of the diaphragm to a pouch, itself derived from the vestibular wall and containing filamentous bacteria, which is divided by the folds of its internal cuticle. The structural characters of the bacteria are described. The interdigitated microvilli of the epithelium of this pouch and the presence inside it of fibrillated plates, probably originating from the adjacent secretory organ, suggest that there may be exchanges between the bacterial population and the host. The association is obligatory and probably symbiotic.
Redescriptions of and comments on four little-known Lernaeopodidae (Crustacea: Copepoda)
Authors: Kabata Z.
Published: August 2008

Four species of Lernaeopodidae (Copepoda: Siphonostomatoida) are redescribed and their taxonomic positions are reevaluated. Lernaeopoda bivia is considered a valid species and a key to the genera Lernaeopoda and Albionella is given. Salmincola stellatus is redescribed for the first time since its discovery in 1936. Clavella inversa is assigned to the new genus Mixtio and Clavellopsis laciniata is redescribed in detail.
Temperature, oxygen, photoperiod, and the hemoglobin system of the rainbow trout, Salmo gairdneri
Authors: Tun Nini , Houston A. H.
Published: August 2008

Blood O2-carrying capacity and hemoglobin system organization were examined in rainbow trout acclimatized to eight combinations of two treatment levels of three variables: temperature (5, 20 °C), O2 availability (≤ 30%, ≥ 75% saturation), and photoperiod (16L:8D, 8L:16D). Increases in hemoglobin, hematocrit, and individual hemoglobin isomorph abundances were associated with hypoxia, shortened day length, and increased temperature. Under nominal "summer" conditions (20 °C, hypoxia, 16L:8D) photoperiod influence was apparently masked by hypoxic and thermal effects, with the converse being true under "winter" circumstances (5 °C, normoxia, 8L: 16D). The complex, 12-membered hemoglobin system provided some evidence of differential isomorph formation during the acclimatization process. Cellular involvements remain unclear.
The effect of swimming depth on respiratory behavior of the honey gourami, Colisa chuna (Pisces, Belontiidae)
Authors: Bevan David J. , Kramer Donald L.
Published: August 2008

We tested the hypothesis that fish capable of bimodal respiration would respond to the increased travel costs of surfacing by decreasing their frequency of air breathing. Honey gouramis were permitted to move freely in a 220 cm deep aquarium, but their preferred depths were manipulated by changing the location of shelter and feeding sites. With increased depth the interval between air breaths increased. This supports the argument that travel to and from the surface is a significant cost for air-breathing fish. It provides evidence that respiratory behavior can be affected by factors not directly involved in the physiology of gas exchange. Furthermore, it suggests that retention of water-breathing capacity in air-breathing species may reduce the costs of breathing through adaptive changes in partitioning.
Atlantic wolffish (Anarhichas lupus L.; Pisces: Anarhichidae) predation on green sea urchins (Strongylocentrotus droebachiensis (O.F. Mull.); Echinodermata: Echinoidea) in eastern Newfoundland
Authors: Keats D. W. , Steele D. H. , South G. R.
Published: August 2008

The diet of the Atlantic wolffish was studied by examining the contents of the gastrointestinal tracts of 90 individuals collected from the sea urchin dominated rocky subtidal in eastern Newfoundland. Green sea urchins comprised 75% of the overall diet by weight. Horse mussels ranked second but comprised only 9.5% of the diet. The remainder of the diet consisted of several species of invertebrates and fish. The average (over the whole season) wolffish contained 120 g of urchins, equivalent to the biomass of urchins on 0.23 m2 in the middle of the urchin-dominated zone. During April–September, prior to breeding, the average male wolffish contained 174 g of urchins, and the average female contained 85 g of urchins, biomass values representing, respectively, 0.33 and 0.16 m2. Assuming that the contents of the gastrointestinal tract turn over every 3 days, it was calculated that during May through August each wolffish consumes on average 5.29 kg of urchins (males, 7.09 kg; females, 3.50 kg). Based on these figures, a density of 1 wolffish pair per 20 m2 would be required to consume the mean biomass (532 g m−2) of urchins present in the urchin-dominated zone in 1 year.
The effect of vertebrate predation on lotic macroinvertebrate communities in Québec, Canada
Authors: Reice Seth R. , Edwards Robert L.
Published: August 2008

To test the role of vertebrate predation on benthic community structure, experiments were performed in two third-order streams in northern Québec, Canada. Predators were either enclosed in or excluded from replicate benthic cages (20 × 30 × 10 cm). Ruisseau du Cran Carré (RCC) has a normal complement of fish, while Low Hope Creek (LHC) is fishless. In June 1983, two species of fish were manipulated (one fish per cage, five replicate cages per treatment) in RCC, while the salamander Eurycea bislineata was manipulated in LHC. In August 1983, brook trout fry were manipulated in both streams. It was anticipated that the fauna in LHC, having had no previous contact with fish, would be more susceptible to fish predation than the fauna of RCC. Gut analysis revealed that fish did feed in the cages. However, neither fish predation nor salamander predation had significant effects on prey communities in either stream in June. Community parameters (species richness and diversity, and total numbers of individuals) were not influenced by the presence or absence of fish or salamanders. In August, three-quarters of the taxa were more abundant without trout than with trout. However, few individual taxa were significantly affected by the fish. This effect was similar in both streams. By enclosing fish in a fishless stream, this experiment was designed to enhance the possible effects offish predation on the lotic macrobenthic community. This work strengthens the idea that brook trout are not major structuring agents of the macrobenthic communities of small streams.
An annual lipid cycle in a montane population of Peromyscus maniculatus
Authors: Millar John S. , Schieck Jim O.
Published: August 2008

The relative fat content of Peromyscus maniculatus from the Kananaskis Valley, Alberta, was examined in relation to age, sex, reproductive status, and season to test specific predictions related to the intrinsic regulation of energy reserves. Breeding adult males had a greater fat content than nonbreeding males, and females showed low levels of fat when lactating but not when simultaneously pregnant and lactating. These observations were consistent with the idea that energy reserves are regulated intrinsically. There were no seasonal or yearly differences in fat content. There was some evidence that deviations in environmental temperature from normal have proximate effects on fat content.
Observations of nonaggressive behavior between polar bear family groups
Authors: Lunn N. J.
Published: August 2008

The behavior of 26 polar bears in and around the Churchill, Manitoba, garbage dump was observed in the autumn of 1983. Females with cubs were the most aggressive bears; all others avoided them. As the season progressed, two family groups began to associate with each other. One set of cubs were yearlings, the other set were cubs of the year. No aggression between these family groups was observed. Although females with cubs are generally intolerant of all other bears, they do interact nonaggressively. The function of these nonaggressive interactions is not clear at present but may illustrate the adaptability of polar bear behavior.
Life history and production of the stream-dwelling mayfly Habrophlebia vibrans Needham (Ephemeroptera; Leptophlebiidae)
Authors: Lauzon Michel , Harper P. P.
Published: August 2008

Habrophlebia vibrans in Québec has a 2-year cycle, a feature unexpected in a small mayfly and unreported in Leptophlebiidae. Emergence (875/m2) occurred in June and was synchronous. Ovipositing females concentrated upstream (239 ± 94.7 eggs/female). Eggs hatched within 3 weeks. In summer, nymphs reached densities of 27 500/m2 and a size of 1.65 mm. During the next 18 months, densities decreased (4000–9500/m2). After a year, nymphs were 2.1 mm long and reached 3 mm at the end of their second summer. The final size (5.0 mm) was attained in the last weeks before emergence, and mean densities then were 648/m2. Nymphs lived on gravel where they preferred larger particles and scanty detritus. Drift occurred in small nymphs during August of their 1st year, in larger nymphs during spring runoff, and in mature nymphs at emergence. This resulted in a concentration of emergence in the lower reaches. Annual production was 710–829 mg/m2 and the production to biomass ratio was 2.5–3.2. About three-quarters of the production was due to the 2nd-year cohort, and one-half was accumulated during the last 2 months. No constant relation was found between production and drift and between production and emergence.
Distribution of retinoids and 3,4-didehydroretinoids in the goldfish
Authors: Tsin Andrew T. C. , Morales Jr. Santiago T. , Flores Janie M.
Published: August 2008

Using high-performance liquid chromatography, the quantity of retinol, retinal, and retinyl esters as well as their 3,4-didehydro derivatives were measured in several body compartments and in the remainder of the body of 11 goldfish. Eighty-six percent of these retinoids and 3,4-didehydroretinoids existed as retinyl and 3,4-didehydroretinyl esters, 10% as retinal and 3,4-didehydroretinal, and 4% as retinol and 3,4-didehydroretinol. Most (94%) of these retinoids and 3,4-didehydroretinoids were found in ocular tissues and high ratios of 3,4-didehydroretinoids/retinoids were observed in most tissue extracts. These data suggest that in the goldfish ocular tissues are important locations of retinoid and 3,4-didehydroretinoid metabolism, which favors the formation and (or) storage of 3,4-didehydroretinoids.
Responses to host kairomones and foraging behavior of the insect parasite Cotesia rubecula (Hymenoptera: Braconidae)
Authors: Nealis V. G.
Published: August 2008

Adult female Cotesia rubecula are attracted to and arrested by kairomones produced by the feeding activities of their obligatory host, Pieris rapae. Analysis of video recordings and direct observations of individual wasps foraging in the laboratory and in the field showed that the ability to find a host depends almost exclusively on the wasps' behavioral responses to these chemical cues. Wasps do not readily leave plants that have host feeding damage. The time spent on a plant with feeding damage is further increased when a host is found because of the time spent recovering (grooming) from an attack on a host. This recovery time and the frequency of successful oviposition vary with host size. These results are discussed in relation to the parasite's foraging strategy.
Variation in shell chemistry of terrestrial gastropods (Cerion incanum, Cerion uva, and Tudora maculata) from the Florida Keys and Bonaire
Authors: Brand U. , Wassenaar L. , Kanip J.
Published: August 2008

Cerion and Tudora from the Florida Keys and Bonaire secrete shells composed of prismatic, homogeneous, and crossed-lamellar aragonitic layers. Strontium, magnesium, and sodium contents of shells of Cerion from Sugarloaf Key are greatly influenced by the marine waters that regularly inundate this island. In contrast, the concentrations of these elements in shells in Cerion from Windley Key are controlled by both freshwater, in the form of precipitation, and seawater seeping through the rock into the quarry. Strontium and, to a lesser degree, magnesium are deficient and sodium is relatively high in shells of Cerion and Tudora from dried-out ponds on Bonaire. As with the other elements, concentrations of iron, manganese, and nickel in the shells of the studied gastropods are also controlled by the type and amount of water present in each local environment.
Multiple regression analyses of midwinter fattening of the white-throated sparrow
Authors: Blem Charles R. , Shelor Michael H.
Published: August 2008

Midwinter lipid depots of the white-throated sparrow (Zonotrichia albicollis) at Richmond, Virginia, are correlated with a suite of environmental and morphological variables. Lipid reserves allow this species to survive even the most extreme winter conditions for several hours. Variables having the greatest individual correlations with lipid reserve are average temperature of the 20 days prior to capture, fat class, body weight, and long-term (32-year) average temperature of the date of capture. A comprehensive multiple regression model based on analyses of all possible independent variables accounts for 87% of the variation in lipid reserves. The most important independent variables in this model are body weight, mean temperature of the 20 days preceding collection, fat class, extreme high temperature of the day of capture, long-term average temperature, relative humidity, chill factor, wet-bulb temperatures of the day before and the day of capture, wing length, and precipitation. The "best" equation using only measurements of environment as independent variables included time of collection in hours after sunrise and hours before sunset, Eastern Standard Time, temperature of the 20 days prior to capture, and mean wind velocity of the day before capture. Models computed solely from temperature measurements included dry-bulb temperatures of the day of capture and the day before capture, low extreme temperatures of the day of capture, wet-bulb temperatures of the day before capture, and the 20-day average dry-bulb temperature of the period prior to collection. Fattening in response to weather conditions appears to be a form of "fine-tuning" of energy reserves superimposed on a more stable, intrinsic cycle of winter fattening.
The influence of microtines on polygyny, productivity, age, and provisioning of breeding Northern Harriers: a 5-year study
Authors: Simmons Robert , Barnard Phoebe , MacWhirter Bruce , Hansen Gay L.
Published: August 2008

Breeding Northern Harriers, Circus cyaneus, and their principle prey, the vole Microtus pennsylvanicus, underwent synchronous fluctuations in New Brunswick between 1980 and 1984. Microtines were abundant in 1980 and 1983 and were significantly tracked by the number of nesting harriers (r = 0.90), the number of polygynous males (r = 0.89), the number of harem females (r = 0.90), and the mean clutch size (r = 0.94), but not the reproductive success of successful females (r = 0.72). Male nest defence likewise exhibited a strong relationship (r = 0.99, n = 3) with prey abundance, but nest predation did not. An unexpected association with prey abundance was the greater proportion of young females (≤ 2 years) breeding at vole lows; the reverse was true for yearling males. Young females that did breed at vole highs were significantly more productive than were old females breeding at highs. The difference arose principally through nest predation. Successful females also consistently reared significantly greater proportions of their hatchlings when voles were increasing than when they were decreasing. Our results suggest that New Brunswick harriers were affected by prey fluctuations in most aspects of their reproduction and population dynamics. Significant correlations between male food provisioning rates and clutch size and reproductive success over 3 years provide a proximate mechanism through which fecundity may vary annually. They may also provide a proximate pathway mediating for polygyny.
Wear and microwear on the teeth of a moose (Alces alces) population in Manitoba, Canada
Authors: Young William G. , Marty Therese M.
Published: August 2008

A group of wild moose from Manitoba, Canada, were documented as having excessive tooth wear. Replicas of one incisor tooth were collected from 16 individuals and from 19 controls for comparison by volumetric and scanning electron microscopic analysis. All animals were aged from tooth cementum lines. Tooth replicas were cast from silicone rubber impressions in epoxy resin and sputter coated with gold. Tooth wear with age was compared statistically by measuring crown height, percent tooth loss, interfacet distance, and facet area on the incisors. The unique pattern of wear on the anterior teeth of affected moose was described. In affected animals, crown heights were significantly reduced and percent tooth loss was excessive. Microwear analysis found that an abrasive agent, acting predominantly in a lingual to labial direction, had been responsible for loss of enamel and dentine incisally and interproximally, and on the facial and lingual surfaces to a lesser extent. Interdental facets became involved by vertical abrasion. Control teeth showed fewer but coarser scratches and only approached the pattern of wear found in affected moose in a few individuals in old age. The loss of tooth structure would lead to diminished cropping efficiency and damage to the periodontium.
Paronchocerca struthionus n.sp. (Nematoda: Filarioidea) from ostriches (Struthio camelus), with a redescription of Paronchocerca ciconiarum Peters, 1936 and a review of the genus
Authors: Bartlett Cheryl M. , Anderson Roy C.
Published: August 2008

Paronchocerca struthionus n.sp. (Onchocercidae: Splendidofilariinae) from the lungs of Struthio camelus L. (Struthionidae) from West Africa has a long, sacculate glandular oesophagus similar to that of Paronchocerca limboonkengi (Hoeppli and Hsü, 1929) n.comb. (= Lemdana limboonkengi), P. bambusicolae, P. tonkinensis, and P. sonini. It can be distinguished by delicate annular cuticular thickenings and, in the male, a preanal hypodermal swelling, three pairs of circumanal papillae, and the length of the right spicule in relation to the length of the tail. Also, lateral, postanal papillae are absent, although inconspicuous subterminal papillae are present. Paronchocerca ciconiarum Peters, 1936, the type species, is redescribed on the basis of material from the pulmonary arteries of Leptoptilus crumeniferus (Lesson) (Ciconiidae) from Uganda. Seventeen valid species are recognized in the genus. Paronchocerca sanguinisardeae, P. choprai, and P. badamii are regarded as species inquirendae and P. alii, as a species incertae sedis. Among larger avian filarioid genera, Paronchocerca appears unique in that each species seems restricted to a single family of birds. Paronchocerca may have become established in early Ornithurae and subsequently persisted in some of the "primitive" birds, as well as having transferred to "modern" groups which now occupy the aquatic adaptive zone originally occupied by the earliest Ornithurae. Paronchocerca apparently has been largely unsuccessful in transferring to other modern groups.
The eggshell of Drosophila melanogaster. V. Structure and morphogenesis of the micropylar apparatus
Authors: Zarani Flora E. , Margaritis Lukas H.
Published: August 2008

The micropylar apparatus in Drosophila melanogaster consists of two parts. The inner part is a protrusion of vitelline membrane, whereas the outer part is a chorionic protrusion containing a canal, through which the spermatozoon enters. In the formation of the micropylar apparatus two follicle cell subpopulations are involved: the border cells, i.e., a group of 9 follicle cells, and the peripheral cells (about 36 cells). The morphogenesis of the micropyle starts at stage 10B, when the border cells secrete the paracrystalline region of the vitelline membrane. The micropylar canal (length 7 μm, diameter 0.7 μm) and the pocket that penetrates within the paracrystalline structure are moulded by two border cell projections, full of microtubules. The formation of the micropyle terminates at stage 14B, when its chorionic part is completed and the border cell projections degenerate. The structure of the micropyle in fertilized and unfertilized laid eggs differs from the mature (stage 14B) egg in that the vitelline membrane is modified and appears homogeneous as in the rest of the eggshell. These transformations seem to be unrelated to sperm entry.
Larvae of Eustilicus Sharp, Rugilus Leach, Deroderus Sharp, Stilocharis Sharp, and Medon Stephens (Coleoptera: Staphylinidae: Paederinae: Paederini), and their phylogenetic significance
Authors: Frania Henry E.
Published: August 2008

First-instar larvae of Eustilicus Sharp and Rugilus Leach (Stilicina), and of Medon Stephens (sensu Casey), Deroderus Sharp, and Stilocharis Sharp (Medonina) are described and compared with larvae of other Paederini in the subtribes Stilicina, Medonina, Lithocharina, Scopaeina, Stilicopsina, Astenina, Lathrobiina, Paederina, and Cryptobiina. Three synapomorphies in larvae indicate that the first six subtribes are closely related. One synapomorphy in larvae provides evidence that Eustilicus, Deroderus, Stilocharis, and Medon are closely related. In contrast, there is no evidence that Rugilus is closely related to Eustilicus. These last two results conform largely to those obtained previously for adults, except that close relationship of Medon to Eustilicus, Deroderus, and Stilocharis was not demonstrated using adult characters. Larvae provide additional evidence that the Medonina and Stilicina are not monophyletic groups.
Tropical species of Kurzia (Crustacea, Cladocera) with a description of Kurzia brevilabris sp.nov.
Authors: Rajapaksa R. , Fernando C. H.
Published: August 2008

Kurzia longirostris (Daday) from throughout the tropical region was examined, together with a review of all previous records worldwide. It is clear that what was considered K. longirostris consists of two species in the Oriental region. This includes a new species, Kurzia brevilabris sp.nov. It differs from K. longirostris in the head pore configuration, the structure of the labrum, and the arrangement of the submarginal setules along the posteroventral corner of the carapace. A detailed description of the species is given. A detailed redescription of K. longirostris is given based on the types and material from Sri Lanka. The morphological variations observed in different populations of the tropical region are also included in the description.
Host specificity and morphometric variation of Haemoproteus meleagridis Levine, 1961 (Protozoa: Haemosporina) in gallinaceous birds
Authors: Atkinson Carter T.
Published: August 2008

Haemoproteus meleagridis was transmitted to a ring-necked pheasant, Phasianus colchicus L., to a chuckar partridge, Alectoris chuckar (Gray), and to domestic turkeys by the intraperitoneal inoculation of sporozoites from pools of infected Culicoides edeni Wirth and Blanton, 1947, and Culicoides hinmani Khalaf, 1952. Guineafowl, Numida meleagris (L.), northern bobwhites, Colinus virginianus (L.), and chickens, Gallus gallus (L.), were not susceptible. Parasitemias in the infected chuckar and the infected pheasant were lower and more transient than parasitemias in domestic turkeys infected with the same number of sporozoites. Mature gametocytes of Haemoproteus meleagridis were morphologically similar in each susceptible host species. Infected red blood cells in each host species underwent increases in total area and decreases in nuclear size and area. The current taxonomy of Haemoproteus meleagridis is discussed in relation to recent revisions in the taxonomy of the avian hosts.
Influence de l'épithélium cicatriciel, de la collagénase et de l'hormone de croissance sur la croissance des régénérats de doigts chez Rana ridibunda adulte
Authors: Revardel J.-L.
Published: August 2008

In Rana ridibunda, digits regenerate from the proliferation of skeletal tissues (cartilaginous or periosteal) and never from a blastema as is the case in Urodela. However, these chondroblastic regenerates have a very limited growth in normal conditions. Experiments have shown that the growth period of these regenerates, and hence their size, can be enhanced by injections of collagenase (which affects the reorganization of conjunctive matrices) or growth hormone (which favors the proliferation of chondrocytes). These neoformations seem to depend on factors that differ from those that influence the blastematic regenerates found in Urodela (which depend on the nervous system) and their growth is thus more directly affected by the conditions that control the metabolism of chondroblastic tissues.[Journal translation]
The effects of fish and pH on the distribution and abundance of backswimmers (Hemiptera: Notonectidae)
Authors: Bendell Barry E.
Published: August 2008

Backswimmer populations were sampled across a range of pH in lakes with and without fish. Irrespective of pH, backswimmers were abundant in lakes without fish, and usually absent or scarce in lakes with fish. The observed distribution of Notonecta spp. and Buenoa spp. among lakes does not appear to reflect competitive interactions among species, but is best explained by the presence or absence of fish predators and, in the case of Notonecta borealis, the poor dispersal ability of the species. To separate the effects of fish loss from other pH-related effects, the relationship between pH and backswimmer population densities was examined within the group of fishless lakes. Differences in population densities of Buenoa spp. among fishless lakes were found to be related to pH. However, the form of the relationship was best described by a curvilinear function that was not suggestive of a toxicological relationship.
The echolocation calls of hoary (Lasiurus cinereus) and silver-haired (Lasionycteris noctivagans) bats as adaptations for long- versus short-range foraging strategies and the consequences for prey selection
Authors: Barclay Robert M. R.
Published: August 2008

Amongst aerial-feeding insectivorous bats, differences in the design of echolocation calls appear to be associated with differences in foraging strategy. Recordings and observations of hoary (Lasiurus cinereus) and silver-haired (Lasionycteris noctivagans) bats in Manitoba, Canada, support such an association. Lasionycteris noctivagans use multiharmonic search–approach calls with an initial frequency sweep and a constant frequency tail. Such calls are suited for bats foraging in the open but near obstacles, and pursuing prey detected at relatively close range. This is the foraging strategy employed by this relatively slow, manoeuverable species. Lasiurus cinereus employ single harmonic search–approach calls that are low (20–17 kHz), essentially constant frequency signals. Calls of this design are suited for long-range target detection in open air situations, the foraging strategy used by L. cinereus. Differences in call design may explain dietary differences between the two species. Lasiurus cinereus consistently prey on large insects. The low, constant frequency design of their calls means that small insects are detectable only at close range and are thus difficult for this fast-dying bat to catch. The broad-band calls used by L. noctivagans do not restrict prey detection and these bats prey on a wider range of insects. Similar restrictions on prey detection, caused by echolocation call specializations, may be important in producing what might otherwise be considered active prey selection by some insectivorous bats.
Diet selection in Arctic lemmings (Lemmus sibiricus and Dicrostonyx groenlandicus): demography, home range, and habitat use
Authors: Rodgers Arthur R. , Lewis Martin C.
Published: August 2008

In this study we explore the relationships between demography, patterns of habitat use, and the diets selected by Lemmus and Dicrostonyx at Igloolik Island, N.W.T. The demography of both species at Igloolik is similar to that recorded at other localities, but maximal densities vary between sites and may be related to the abundance of suitable forage. Home range characteristics and patterns of habitat use in each lemming species are related to the spatial and temporal distribution of preferred foods: in summer, Lemmus uses low-lying wet meadow habitats dominated by graminoids and mosses, whereas Dicrostonyx uses mainly upland dry heaths dominated by shrubs; in winter, both species make greater use of moist transitional habitats. Although the two species differ in their patterns of resource use, these differences may be altered through interspecific and intraspecific interactions.
Life histories of birds: clutch size, longevity, and body mass among North American game birds
Authors: Zammuto Richard M.
Published: August 2008

Clutch size, longevity, and body mass data for 54 North American game birds were extracted from the literature to test the hypothesis that a trade-off exists between fecundity and survival among avian species. Species with larger clutch sizes live shorter lives than species with smaller clutch sizes (r = −0.38, n = 54, P < 0.01). This relationship still holds when the effects of body mass are removed (r = −0.34, 51 df, P < 0.05), indicating that the relationship is not simply a function of body mass. This latter finding is inconsistent with previous life-history studies, perhaps because previous researchers did not attempt to remove body mass effects from their life-history investigations. Results are similar (P < 0.05) when mean values of life-history traits are examined at the generic level. However, no relationships (P > 0.05) among mean values of life-history traits occur at any taxonomic level higher than genus or when species are grouped with respect to feeding habits. This might be the result of low sample size. I conclude that the evolution of clutch size is influenced by longevity, or vice versa, among species and genera of North American game birds.
Mitochondrial DNA restriction site variation in the Townsend's vole, Microtus townsendii
Authors: Thomas William K. , Beckenbach Andrew T.
Published: August 2008

The mitochondrial DNA (mtDNA) from the Townsend's vole, Microtus townsendii, was compared with mouse mtDNA by positioning vole restriction enzyme fragments on the known laboratory mouse mtDNA molecule by homology hybridization. The vole mitochondrial genome is conserved in general sequence organization and size but does contain a nonhomologous region of more than 600 base pairs not found in the mouse sequence. Thirty-five voles were collected from seven different localities throughout the range of the species, including insular populations on Bowen and Vancouver islands. The variation of vole mtDNA sequences within this species was assayed with six hexameric and four tetrameric type II restriction endonucleases. These individuals can be divided into seven distinct maternal lines. The level of nucleotide substitution between populations is shown to be as high as 0.896 ± 0.350%. The voles from Bowen Island showed no detectable variation within their population, or divergence from a mainland population on the adjacent coast. This fact suggests a recent colonization of Bowen Island. The samples from Vancouver Island fall into two major maternal lines, which show 0.453 ± 0.240% divergence. These insular maternal lines are 0.677 ± 0.257% divergent from the most closely related mainland population. These results suggest that the voles on Vancouver Island represent long-established maternal lines, and are not derived by a recent colonization from a mainland source population. Based on conservative estimates for rates of nucleotide substitution, Vancouver Island has been inhabited by the Townsend's vole since at least the Olympic interglacial.
Rôle des cellules S de l'épithélium caecal des Crustacés Isopodes dans la capture et la dégradation de protéines hémolymphatiques, et dans le stockage de catabolites (acide urique, sulfure de cuivre, phosphates)
Authors: Marcaillou C. , Truchet M. , Martoja R.
Published: August 2008

The S cells within the tubules of the hepatopancreas in the terrestrial isopod Oniscus asellus show numerous infoldings of the plasma membrane, which are involved in the uptake of hemolymph proteins, and a lysosomal apparatus that ensures the breakdown of the ingested material. The catabolic process leads to an accumulation of wastes in the form of spherocrystals. The most important components of the spherocrystals are uric acid, copper sulfide, which we consider to originate in the breakdown of hemocyanin monomers, alkaline-earth phosphates, which could be produced by enzymatic activities, and zinc. Moreover, in the marine species Ligia oceanica a silver salt (sulfide?) is stored in the spherocrystals. The S cells function as a storage type of excretory system. Their role is similar to urate cells in arthropods, nephrocytes in insects, and pore cells in molluscs. In the latter, the storage of silver is important in marine environments only.
The relationship between behavioral activity and underwater vocalizations of the white whale, Delphinapterus leucas
Authors: Sjare Becky L. , Smith Thomas G.
Published: August 2008

The underwater vocalizations of white whales, Delphinapterus leucas, summering at Cunningham Inlet, N.W.T. (74°05′ N, 93°45′ W), were recorded from mid-July to mid-August 1983. Vocalizations were classified into one of eight major whistle contour types, one of four pulsed call categories including click series and three types of pulsed tones, and noisy vocalizations. To determine the relationship between vocalizations and behavioral activities, a total of sixty-three 2-min samples were recorded when whales were resting, swimming in a directive manner, socially interactive, and alarmed. Differences in the total number of whistles, pulsed tones (including noisy vocalizations), and click series emitted per whale/min during each behavioral activity were examined. The number of whistles emitted did not differ with changes in behavioral activity (χ2 = 5.42, df = 3, p = 0.143); however, the number of click series (χ2 = 31.85, df = 3, p = 0.0001) and the total number of pulsed tones emitted (χ2 = 7.33, df = 3, p = 0.062) did show distinct trends. More specific analyses considering each of the major whistle contour types, the three types of pulsed tones, and noisy vocalizations were also completed. The rate at which one type of whistle, two types of pulsed tones, and the noisy vocalizations were emitted was influenced by changes in behavioral activity. These results reveal a general association between white whale behavioral activity and the types of vocalizations emitted.
Reproductive development and plasma levels of reproductive hormones of goldeye, Hiodon alosoides (Rafinesque), taken from the North Saskatchewan River during the open-water season
Authors: Pankhurst N. W. , Stacey N. E. , Kraak G. Van Der
Published: August 2008

Changes in gonadal condition and plasma levels of gonadotropin and sex steroids were measured in goldeye (Hiodon alosoides) captured from the North Saskatchewan River, Edmonton, Alberta, from May to October in both 1983 and 1984. Mature females and spermiated males were captured in May and June and spent fish were captured in June. Gonadal recrudescence occurred over the summer and by October, relative gonad weights had reached 70% (females) and 90% (males) of the prespawning maxima. In females, plasma calcium was significantly elevated in spent fish in June, and in August there was a decrease in liver weight. Plasma levels of gonadotropin were highest in females during June, and in males during May. 17α,20β-Dihydroxy-4-pregnen-3-one was elevated in preovulatory or spent females and prespawning males, then decreased throughout the summer, whereas testosterone was only detectable in the plasma of prespawning fish. Estradiol-17β and estrone were not detectable in the plasma of females at any stage, including the period of vitellogenesis.
Mercury levels in Ontario mink and otter relative to food levels and environmental acidification
Authors: Wren C. D. , Stokes P. M. , Fischer K. L.
Published: August 2008

Tissue mercury levels were determined in 94 mink and 84 otter collected from five study areas in Ontario during the 1983–1984 and 1984–1985 trapping seasons. The level of Hg in tissues of both mink and otter followed the order of liver, kidney > muscle > brain. There was no observed relationship between age, sex, or selenium content and tissue Hg levels in mink or otter within a study area. Tissue Hg levels in mink and otter were significantly different among locations. For example, the mean Hg concentrations in mink liver from the English River, Turkey Lakes, Muskoka, Sudbury, and Cambridge areas were 2.55, 2.36, 2.17, 0.56, and 0.14 μg/g, respectively. Mercury levels in fish and crayfish from the study areas followed a similar pattern. Mink and otters are, therefore, sensitive bioindicators of environmental Hg levels. The results contradict the general hypothesis of elevated Hg levels in biota from acid-stressed ecosystems, and suggest that environmental variables other than pH play a major role in governing biotic metal levels.
A comparison of the roosting and foraging behaviour of three species of African insectivorous bats (Rhinolophidae, Vespertilionidae, and Molossidae)
Authors: Fenton M. Brock , Rautenbach I. L.
Published: August 2008

We used radio tracking to study the roosting and foraging behaviour of Rhinolophus hildebrandti, Scotophilus borbonicus (=S. viridis and S. leucogaster), and Tadarida midas in the Pafuri Region of Kruger National Park, South Africa in November 1985. Although the species roosted in different locations (S. borbonicus in hollow mopane trees, R. hildebrandti in a hollow baobab tree, and T. midas in buildings), roost temperatures and the bats' body temperatures were generally similar. The S. borbonicus and T. midas flew continuously while foraging in pursuit of flying prey; the R. hildebrandti switched between continuous flight, and hunting from a perch also in pursuit of flying prey. All three species foraged for about 60 min nightly, but the T. midas ventured at least 10 km from their roosts, while for S. borbonicus and R. hildebrandti, comparable figures were 4 and 2 km, respectively. The three species showed a spectrum of wing morphology and echolocation call design features from clutter resistant (R. hildebrandti) to relatively clutter resistant (S. borbonicus) and clutter intolerant (T. midas) and the foraging areas used by the bats corresponded to these features. Rhinolophus hildebrandti foraged below the canopy in riverine forest and deciduous woodland, while S. borbonicus foraged around the canopy but not closer than 0.5 m to it, while T. midas foraged in the open well above the canopy. These differences are discussed along with variations in foraging behaviour in insectivorous bats.
Sequential muscle biopsies during a 6-h tracer infusion do not affect human mixed muscle protein synthesis and muscle phenylalanine kinetics
Authors: Volpi Elena , Chinkes David L. , Rasmussen Blake B.
Published: August 2008

Stable isotope tracer experiments of human muscle amino acid and protein kinetics often involve a sequential design, with the same subject studied at baseline and during an intervention. However, prolonged fasting and sequential muscle biopsies from the same area could theoretically affect muscle protein metabolism. The purpose of this study was to determine if sequential muscle biopsies and extended fasting significantly affect parameters of muscle protein and amino acid kinetics in six human subjects. After a 12-h overnight fast, a primed continuous infusion of l-[ ring-2H5]phenylalanine was started. After 120 min, we took the first of a series of five hourly muscle biopsies from the same vastus lateralis to measure mixed muscle protein fractional synthetic rate. Furthermore, between 150–180, 210–240, and 330–360 min, we measured leg phenylalanine kinetics using the two-pool and the three-pool arteriovenous balance models. Tracer enrichments were at steady state, and muscle protein FSR and phenylalanine kinetics did not change throughout the experiment ( P = not significant). We conclude that a 6-h tracer infusion during extended fasting (up to 18 h) with five sequential muscle biopsies from the same muscle do not affect basal mixed muscle protein synthesis and muscle phenylalanine kinetics in human subjects. Thus, when using a sequential study design over this period of time, it is unnecessary to include a saline only control group to account for these variables.
Long-term high-fat feeding induces greater fat storage in mice lacking UCP3
Authors: Costford Sheila R. , Chaudhry Shehla N. , Crawford Sean A. , Salkhordeh Mahmoud , Harper Mary-Ellen
Published: August 2008

Uncoupling protein-3 (UCP3) is a mitochondrial inner-membrane protein highly expressed in skeletal muscle. While UCP3's function is still unknown, it has been hypothesized to act as a fatty acid (FA) anion exporter, protecting mitochondria against lipid peroxidation and/or facilitating FA oxidation. The aim of this study was to determine the effects of long-term feeding of a 45% fat diet on whole body indicators of muscle metabolism in congenic C57BL/6 mice that were either lacking UCP3 ( Ucp3−/−) or had a transgenically induced approximately twofold increase in UCP3 levels ( UCP3tg). Mice were fed the high-fat (HF) diet for a period of either 4 or 8 mo immediately following weaning. After long-term HF feeding, UCP3tg mice weighed an average of 15% less than wild-type mice ( P < 0.05) and were 20% less metabolically efficient than both wild-type and Ucp3−/− mice ( P < 0.01). Additionally, wild-type mice had 21% lower, whereas UCP3tg mice had 36% lower, levels of adiposity compared with Ucp3−/− mice ( P < 0.05 and P < 0.001, respectively), indicating a protective effect of UCP3 against fat gain. No differences in whole body oxygen consumption were detected following long-term HF feeding. Glucose and insulin tolerance tests revealed that both the UCP3tg and Ucp3−/− mice were more glucose tolerant and insulin sensitive compared with wild-type mice after short-term HF feeding, but this protection was not maintained in the long term. Findings indicate that UCP3 is involved in protection from fat gain induced by long-term HF feeding, but not in protection from insulin resistance.
Corticotropin-releasing hormone stimulates SGK-1 kinase expression in cultured hippocampal neurons via CRH-R1
Authors: Sheng Hui , Sun Tingting , Cong Binhai , He Ping , Zhang Yanmin , Yan Jin , Lu Changlin , Ni Xin
Published: August 2008

Corticotropin-releasing hormone (CRH) has been shown to exhibit various functions in hippocampus. In the present study, we examined the effect of CRH on the expression of serum/glucocorticoid-inducible protein kinase-1 (SGK-1), a novel protein kinase, in primary cultured hippocampal neurons. A dose-dependent increase in mRNA and protein levels of SGK-1 as well as frequency of SGK-1-positive neurons occurred upon exposure to CRH (1 pmol/l to 10 nmol/l). These effects can be reversed by the specific CRH-R1 antagonist antalarmin but not by the CRH-R2 antagonist astressin 2B. Blocking adenylate cyclase (AC) activity with SQ22536 and PKA with H89 completely prevented CRH-induced mRNA and protein expression of SGK-1. Blockage of PLC or PKC did not block CRH-induced SGK-1 expression. Our results suggest that CRH act on CRH-R1 to stimulate SGK-1 mRNA and protein expression in cultured hippocampal neurons via a mechanism that is involved in AC/PKA signaling pathways.