bluuebunny/crossref_metadata_2025 huggingface dataset:
Coyote – kit fox interactions as revealed by telemetry
Authors: White P. J. , Ralls Katherine , Garrott Robert A.
Published: July 2008

Red foxes (Vulpes vulpes) avoid areas used extensively by coyotes (Canis latrans), apparently to reduce encounters with coyotes and possible injury or death. It is conceivable that kit foxes (Vulpes macrotis) behave in a similar manner. We used telemetry to examine the spacing patterns and interactions among 24 coyotes and 38 San Joaquin kit foxes (V. m. mutica) in California during a period of declining and low prey abundance (1989–1991). Coyotes showed either territorial (n = 13) or transient (n = 11) spacing patterns, whereas all kit foxes were territorial. Spatially and temporally, coyote home ranges overlapped >30% of each fox home range. Both species used the overlap areas more than expected (P < 0.001), possibly because prey such as kangaroo rats were more abundant in these areas. Fifty-five percent of the areas used extensively by foxes during their nocturnal activities were overlapped by coyote nocturnal-use areas. Concurrently monitored coyotes and foxes that occupied overlapping home ranges (n = 25 combinations) were neither farther apart nor closer together than expected (P = 0.09–0.87), even when the coyote was in the fox's home range. Kit foxes did not avoid coyotes and may be able to coexist with them by exploiting certain prey species better than coyotes and maintaining numerous (≥20) dens throughout their home ranges to facilitate escape. Apparent differences in coyote – red fox and coyote – kit fox relations may be partially attributed to differences in resource selection and predator-avoidance strategies among fox species.
Undernutrition in relation to changed tissue composition in red deer (Cervus elaphus)
Authors: Wolkers Hans , Wensing Theo , Schonewille J. Thomas , Klooster Arie Th. van 't
Published: July 2008

The effect of long-term dietary restriction on the composition of the liver, the kidney, and several muscles was studied in red deer (Cervus elaphus). Food-restricted animals (n = 3) received approximately 20% of the ration of control animals (n = 3) for 13–23 weeks. Extreme undernutrition was associated with a reduction in body mass and a relatively large reduction in mass of the liver and kidney. Total protein and total DNA content as well as the protein/DNA ratio of the liver and kidney of food-restricted animals were lower, whereas the DNA concentration was higher, than in the control animals. The findings suggest a reduction in organ mass through a reduction in both cell size and cell number. The lower protein/DNA ratio and the increased DNA concentration in muscle of food-restricted animals suggest a reduction of cell size. The results obtained from different muscles indicate considerable variation in response to undernutrition among muscles. It is concluded that protein mobilization contributes to a depression of ketone body formation. The quantity of protein loss differed between anatomical sites. The concentration of protein and DNA and the protein/DNA ratio in the liver, kidney, and several muscles provide information about the nutritional status of red deer.
Spatial distribution, survival, and growth of sibling groups of juvenile coho salmon (Oncorhynchus kisutch) in an experimental stream channel
Authors: Quinn Thomas P. , Dittman Andrew H. , Peterson N. Phil , Volk Eric
Published: July 2008

The spatial distribution, survival, and growth of two full-sibling families of coho salmon (Oncorhynchus kisutch) in an experimental outdoor stream channel were compared between the families and with the performance of one of the families in an allopatric control channel after 75 d of rearing. No difference in survival was observed between families (81.2% overall), but their spatial distributions in the channel differed markedly. One family or the other numerically dominated 5 of 7 riffle-pool habitat units within the sympatric treatment channel. The family that was larger at the beginning of the experiment (0.52 vs. 0.37 g mean mass) was also larger at the end (2.03 vs. 1.58 g). While there was little evidence of density-dependent growth overall, the growth of each family was correlated with the density of siblings in the unit. However, the larger bodied family showed negative density-dependent growth, whereas the smaller bodied family showed positive density-dependent growth. These patterns of distribution and growth may have arisen from sibling recognition or some other proximate mechanism such as assortative distribution based on size or interfamily variation in aggression. Regardless of the mechanism, intrapopulation variation in distribution and growth may lead to considerable variation in fitness among families because these factors affect success in subsequent freshwater and marine life history stages.
Interactions between body size and mating history influence the reproductive success of males of a tortricid moth, Zeiraphera canadensis
Authors: Carroll Allan L.
Published: July 2008

The independent and interacting effects of male body size, age, and previous number of matings on (i) spermatophore size and (ii) female reproductive performance were examined in the laboratory using Zeiraphera canadensis Mut. &Free. (Lepidoptera: Tortricidae). Spermatophore size was not influenced by male age, but large males produced larger spermatophores and their size decreased with the number of consecutive matings. The capacity of males to produce spermatophores on successive days was size dependent. Large males produced well-defined spermatophores over five consecutive copulations, whereas small males were no longer able to produce a discernible spermatophore by the fourth mating. Male body size and mating history, independently or in combination, did not affect female fecundity or longevity despite their influence on spermatophore size, suggesting that potential spermatophore-derived nutrients were not utilized for reproduction or somatic maintenance. However, the number of previous matings on consecutive days influenced successful insemination as well as the receptivity of successfully inseminated females to additional matings. Moreover, the influence of multiple male matings on insemination success and mating receptivity was also size dependent. After several consecutive copulations, small males were less likely to successfully inseminate females and "switch off" the females' mating receptivity than large males. The size-dependent decline in ability to inseminate and switch off females, independent of spermatophore size, suggests that small males were more limited than large ones in their capacity to produce accessory gland secretions other than those required for spermatophore construction. Large Z. canadensis males may experience higher reproductive success than small ones by inseminating more females over consecutive evenings and leaving fewer females receptive to remating.
Oxygen transport efficiency of multiple-component hemoglobin in Daphnia magna
Authors: Kobayashi Michiyori , Ishigaki Ken-ichi , Kobayashi Michisuke , Igarashi Yoshihiko , Imai Kiyohiro
Published: July 2008

The Adair constants for Daphnia magna hemoglobin (Hb) oxygen equilibrium curves (OECs) were determined, and the fractional oxygen saturation (Y) was differentiated in terms of partial O2 pressure (p), for Hb-rich (YR) and for Hb-poor (YP) animals. Y′ (dY/dp), which depends on loading and unloading p values of Hb, is used to estimate O2 transport efficiency. The ratio of the Y′ values (Y′R/Y′P) peaked (2.9) at a value close to the p50 of HbR. Using two OECs (YI and YII) for monocomponent human adult Hb A, which have similar O2 affinities to HbR and HbP, respectively, a markedly high ratio of differential coefficients (Y′I/Y′II) was obtained. It is therefore considered that the occurrence of multiple Hb's showing an inverse correlation between Hb concentration and p50, as in D. magna, minimizes the total Hb concentration required for adaptation to a wide range of O2 conditions.
Factors affecting reproductive success in free-ranging convict cichlids (Cichlasoma nigrofasciatum)
Authors: Wisenden Brian D.
Published: July 2008

This study examines the effect of parent size, fry growth rate, and habitat-related brood predation pressure on two measures of reproductive success (percent brood survival and fry number at independence from their parents) of free-ranging convict cichlids (Cichlasoma nigrofasciatum). Four populations in Costa Rican streams were studied, two in "pool" habitat and two in "stream" habitat. The number of fry that emerged from the spawning site (as free-swimming young) was positively correlated with female standard length (SL) for sites with a relatively wide size range of breeding females. SL of males had no effect on fry number at emergence, nor did size of either parent affect the probability of a brood reaching fry independence. Large parents reared more fry to independence than small parents in stream habitat but not in pool habitat. There was a significant difference among sites in fry number at emergence but not at independence (mean = 27 fry), suggesting a maximum number of fry that two parents can economically defend. Fry growth rate had no effect on either measure of reproductive success. Reproductive success was largely determined by the effect of habitat. Adult Cichlasoma dovii in pool habitat may have reduced mean brood survival from 47% (n = 126 broods) in stream habitat to 14.9% (n = 141 broods) in pool habitat. Predators such as juvenile C. dovii may be more effective in the dim ambient light in pool habitat, overwhelming the effect of parent size on brood defence.
Habitat preferences of alpine marmots, Marmota marmota
Authors: Allainé Dominique , Rodrigue Isabelle , Berre Michel Le , Ramousse Raymond
Published: July 2008

Habitat preferences of alpine marmots, Marmota marmota, were investigated at two sites in the French Alps. The use of a logistic-linear model allowed us to model the probability of marmot settlement in different ecological situations. Marmots preferred sites with a southern or eastern aspect (where snow melts relatively early), intermediate slopes, moderate plant cover, and a low level of human disturbance, and they seemed to select their habitat according to a nested system. To test if habitat quality affected individual fitness, we investigated the effects of sun exposure and two home-range characteristics on litter size at emergence, frequency of female reproduction, and retention of subordinates. Sun exposure and home-range size are two major components of home-range quality that may affect individual fitness.
Ultrastructure d'un organe sensoriel antennaire de l'isopode terrestre cavernicole Titanethes alba
Authors: Crouau Y.
Published: July 2008

The triangular scales of the antennae of Titanethes alba (Koch) contain seven sensory cells. One unit is mechanosensitive and ends at the base of the seta; the remaining six units are probably chemoreceptive and extend up to the tip of the seta that displays a pore. The mechanosensitive unit differs from the other six but does not display characteristic features of usual crustacean mechanosensitive cells. It displays a tubular body at its distal end and a ribbon-like ciliary root. Some hypotheses are proposed to explain these unusual observations.
Diet selection of the plains vizcacha (Lagostomus maximus, family Chinchillidae) in relation to resource abundance in semi-arid scrub
Authors: Branch Lyn C. , Villarreal Diego , Sbriller Alicia Pelliza , Sosa Ramon Alberto
Published: July 2008

The diet of the plains vizcacha (Lagostomus maximus) was studied in semi-arid scrub of central Argentina from November 1985 to May 1987 as a basis for understanding the effects of this herbivore on plant communities. Diet composition was documented with microhistological analyses. Fecal nitrogen, an index of diet quality, and vegetation cover were used as measures of resource abundance. Vizcachas consumed a wide variety of grasses, forbs, and shrubs. Grasses were observed in the feces significantly more than expected on the basis of plant cover in the field. Intensive foraging on grasses is consistent with observations of a lower abundance of grasses on colony sites than in the surrounding matrix. Diet quality and breadth of the grass–forb component of the diet were strongly correlated, and comparisons within a season between years showed that diet selectivity decreased with increasing plant cover. Our results contrast with many other studies of foraging strategies that have shown higher selectivity with increasing resources. The inverse relationship we observed could be related to constraints on diet selection due to low food availability.
Systematics and biogeography of Eastern Caribbean frogs (Leptodactylidae: Eleutherodactylus), with the description of a new species from Dominica
Authors: Kaiser Hinrich , Green David M. , Schmid Michael
Published: July 2008

Populations of Eleutherodactylus on the island of Dominica, West Indies, differ from other Lesser Antillean members of the genus by their vocalizations, morphology, sexual size dimorphism, allozymes, and chromosomes. Thus, these populations comprise a new endemic species, closely related to E. johnstonei and E. martinicensis. The new species is most abundant in montane forest habitats at elevations of more than 500 m. Females commonly attain snout–vent lengths of more than 35 mm, making them the largest Lesser Antillean Eleutherodactylus. Frogs are brown during the day, but change color to dark orange when active at night. This species is the ninth Eastern Caribbean Eleutherodactylus species and the fifth single-island endemic. A phylogenetic analysis of external and internal morphological characteristics shows that Eastern Caribbean Eleutherodactylus are members of two distinct clades, one of South American origin, the other of Greater Antillean ancestry. We suggest that the present distribution of these species results from the dispersal of elements of the larger herpetofaunas from the Greater Antilles and South America, and that rapid divergence of the Eastern Caribbean Eleutherodactylus fauna may be continuing. The phylogenetic analysis also confirms that morphological characters of Eleutherodactylus species can be highly homoplastic.
A new feeding technique for experimental and routine culturing of the insect Rhodnius prolixus
Authors: Huebner Erwin , Harrison Rene , Yeow Karen
Published: July 2008

We report a method for artificially feeding the reduviid insect Rhodnius prolixus that utilizes heparinized rabbit blood enclosed in an artificial-membrane envelope. Envelopes of Parafilm M® or Nescofilm® are made by heat sealing two pieces, one of which is stretched first, on three sides. Blood is then put into the envelope, the air expelled, and the fourth side sealed with a bag sealer. The blood-filled envelopes are then placed on a standard slide warmer set at 37 °C and insects in jars with wire-mesh tops are allowed to feed. Normal gorging and subsequent molting of instars were attained. Adult females show normal fecundity (the E value was 0.19 for mated females) and egg hatchability was also normal. The method is simple, cost effective, and easy to implement. It is especially suited for experimental feedings.
Morphometric similarity of Mallards and American Black Ducks
Authors: Hanson Alan R. , Ankney C. Davison
Published: July 2008

Morphometric data were collected from 347 American Black Ducks (Anas rubripes), and 1466 Mallards (Anas platyrhynchos) taken by hunters in the Lake St. Clair and Lake Erie regions of southwestern Ontario during autumn 1986 and from 511 American Black Ducks shot throughout the province of New Brunswick during the 1988 and 1989 hunting seasons. Discriminant function analyses based on eight external morphometric variables (wing chord, tarsus length, middle toe length, hind toe length, culmen, head length, naris width, and bill width) did not accurately distinguish Black Ducks from Mallards. Discriminant function analyses produced correct classification rates that, averaged over the four age–sex classes, were 61% for Mallards and 71% for Black Ducks. The highest classification rates were from the discriminant function analyses of Ontario Black Ducks and New Brunswick Black Ducks that, averaged over the four age–sex classes, were 74% for Ontario Black Ducks and 80% for New Brunswick Black Ducks. Although our morphometric analyses did not incorporate all morphometric characteristics of Black Ducks and Mallards, they do show that Black Ducks and Mallards collected in eastern Canada are morphometrically very similar.
Development of intentional stranding hunting techniques in killer whale (Orcinus orca) calves at Crozet Archipelago
Authors: Guinet Christophe , Bouvier Jérome
Published: July 2008

This paper describes the trend in the practice of what we interpret to be the "intentional stranding" hunting technique of two juvenile female killer whales (Orcinus orca), A4 and A5, belonging to pod A on the beaches of Possession Island, Crozet Archipelago. Pod A was composed of three adult females, A2, A3, A6, and one adult male, A1. A2 is A4's mother and A3 is A5's mother. The year of birth and thus the probable age of the two juveniles were estimated from their growth curve determined by means of a photogrammetric technique. These observations indicate that at Crozet Archipelago, juvenile killer whales first practiced intentional stranding on their own when they were 4–5 years old. Their first attempt to capture elephant seal pups by means of this technique was observed when they were 5–6 years old. However, 5- to 6-year-old juveniles still needed the assistance of an adult female to return to the water with their prey. This study indicates that learning hunting techniques needs a high degree of skill and requires high parental investment to reduce the associated risk. Furthermore, social transfer, through apprenticeship, is probably one of the mechanisms that enables the high degree of adaptability observed in killer whales.
Historical biogeography and modes of speciation across high-latitude seas of the Holarctic: concepts for host – parasite coevolution among the Phocini (Phocidae) and Tetrabothriidae (Eucestoda)
Authors: Hoberg Eric P.
Published: July 2008

Species of Anophryocephalus are host-specific parasites of pinnipeds in the Holarctic. Phylogenetic analysis of 7 species postulates A. anophrys as the basal taxon and A. inuitorum as basal to A. skrjabini; A. arcticensis is basal to A. nunivakensis and A. eumetopii + A. ochotensis (single tree; consistency index = 74.4%; homoplasy slope ratio = 36.45%). Evaluation of host and geographic distributions postulates ringed seals of the Atlantic–Arctic as ancestral hosts, and the Arctic basin as a paraphyletic area with respect to the North Pacific. Cospeciation within this assemblage was dependent on intense isolation of small effective populations of definitive hosts during the late Tertiary and Pleistocene glacial stages. Rapid modes of parasite speciation, compatible with microallopatry and peripheral isolation, appear to have been associated with isolation of pinniped populations in refugial habitats of the Arctic basin and Beringia. The biogeography of host–parasite assemblages among pinnipeds and Alcidae (Charadriiformes) during the Pliocene and Quaternary contrasts in part with the history elucidated for some free-living invertebrate taxa in the Arctic basin.
Townsend's chipmunk populations in Douglas-fir plantations and mature forests in the Oregon Coast Range
Authors: Hayes John P. , Horvath Eric G. , Hounihan Patrick
Published: July 2008

Despite the abundance and ecological importance of Townsend's chipmunks (Tamias townsendii) in coniferous forests in the northwestern United States and southwestern Canada, little is known about either the habitat associations of the species or the influence of forest structure on population density. We livetrapped chipmunks in three mature, fire-regenerated coniferous forests (>140 years old) and nine 10- to 35-year-old Douglas-fir plantations in the Oregon Coast Range to examine patterns of their population density and habitat associations. Estimations of density of chipmunk populations among stands ranged from 0.0 to 23.8/ha. Population density within a stand did not significantly change between autumn and spring. Population density, mean maximum distance moved, and sex ratio did not differ significantly between young and mature stands, although mean body mass of chipmunks in mature forests was greater than mean body mass of those in young stands during autumn. Chipmunk population density was correlated with the percentage of salal (Gaultheria shallon) in the understory, suggesting that forest stand structure plays an important role in determining habitat quality for this species. Habitat characteristics in the Oregon Coast Range are highly favorable to Townsend's chipmunks, probably because of mild winters, high rates of primary production, structural characteristics of the stands, and minimal competition from other species of sciurids.
A cladistic analysis of Trombidiidae (Acari: Parasitengona): congruence of larval and adult character sets
Authors: Zhang Zhi-Qiang
Published: July 2008

Two morphological data sets for eight trombidioid genera (Acari: Parasitengona) were analyzed separately and in combination using cladistic methods. One data set comprised 15 adult morphological characters, whereas the other comprised 29 larval morphological characters. Analyzed separately, the data on adults produced five equally parsimonious trees and the data on larvae produced three equally parsimonious trees. Analyses of both data sets revealed two distinct clades in Trombidiidae: clade A (Podothrombium, Pollicotrombium, Paratrombium, and Trombidium) and clade B (Dinothrombium, Clinotrombium, and Allothrombium). However, the within-clade generic relationships were resolved by data from larvae only in clade A and by data from adults only in clade B. Analysis of the combined data produced a single most parsimonious tree, with both clade A (Podothrombium (Pollicotrombium (Paratrombium, Trombidium))) and clade B (Dinothrombium (Clinotrombium, Allothrombium)) completely resolved. Thus, data on larvae and postlarvae are not only congruent but also complementary in revealing the phylogenetic relationships of these mites. The results support the principle of total evidence and the use of all available data for a single parsimony analysis.
Remarkable convergence between two taxa of ascid mites (Acari: Mesostigmata) adapted to living in pore tubes of bracket fungi in North America, with description of Mycolaelaps new genus
Authors: Lindquist Evert E.
Published: July 2008

All instars of a new genus and new species of ascid mite, Mycolaelaps maxinae, are described and illustrated. This mite manifests a variety of morphological specializations, above all an unusually elongated body, as adaptations for a way of life inside the lumen of bracket fungus pores. In these ways it resembles Hoploseius tenuis Lindquist, which is similarly specialized for living in bracket fungus pores. As the new taxon is shown to be a member of the tribe Melicharini, in contrast with H. tenuis, which is in the tribe Blattisociini, their resemblance is shown to be a remarkable case of convergence to living in the same niche.
Thy-1 immunoreactivity in the larval sea lamprey (Petromyzon marinus L.), a vertebrate without a definitive thymus
Authors: Zurbrigg R. E. , Beamish F. W. H.
Published: July 2008

Agnathans are the only vertebrates without a thymus, yet lampreys possess putative lymphocytes whose responses parallel those of T cells in gnathostomes. The phylogenetically conserved Thy-1 antigen is often associated with the thymus, thymocytes, and T cells. An immunohistochemical study, using commercial anti-rat brain Thy-1.1 antiserum and an immunoperoxidase procedure (peroxidase anti-peroxidase) was conducted to identify any Thy-1 antigenicity in various tissues of larval sea lampreys (Petromyzon marinus L.) lightly fixed in a chilled aldehyde-based solution. The primary focus of the experiment was to discover if Thy-1 immunoreactivity was associated with haemopoietic sites and (or) leukocytes. This technique permitted conventional histological sectioning, preserved tissue architecture, and retained Thy-1 antigenicity. In the haemopoietic typhlosole, the peripheral stroma and many lymphocyte-like cells stained intensely, as did similar cells in the opisthonephros, intestinal venous sinus, and liver. Immunoreactivity in the pharynx was evidenced only by weakly staining stroma in small labyrinthine subdermal foci dorsal and ventral to some external gill openings. It is proposed that if functions analogous to thymic activities exist in the larval lamprey, the typhlosole is the most likely site for their discovery.
Glycolysis and energetics in organs of hibernating mice (Zapus hudsonius)
Authors: Storey Kenneth B. , Kelly David A.
Published: July 2008

Hibernation-induced changes in the concentrations of glycolytic intermediates, creatine phosphate, and adenylates were monitored in brain and skeletal muscle of the meadow jumping mouse, Zapus hudsonius, after both short (24 h) and long (5 – 7 d) periods of hibernation. Levels of hexose phosphates were greatly reduced in both organs after 24 h of hibernation, suggesting strong suppression of carbohydrate catabolism early in hibernation and indicating enzymatic regulation at the level of carbohydrate input into glycolysis. Both organs showed large changes in energy status during hibernation. Creatine phosphate content declined progressively over time to levels in 5 – 7 d hibernating animals that were 50 and 60% of control values in brain and muscle, respectively. Total adenylates and ATP levels also fell sharply during hibernation, but the net effect of changing adenylate levels on energy charge was minimal; energy charge was 0.94 in both organs of control animals and fell to 0.88 –0.90 in hibernating animals. The overall reduction in the pool sizes of phosphagen and adenylates in organs of hibernating animals may be one factor involved in metabolic suppression during hibernation.
Variability in snow-urine assays
Authors: White P. J. , Garrott R. A. , Heisey D. M.
Published: July 2008

Urea nitrogen: creatinine ratios in snow urine have become popular for assessing the extent of winter nutritional deprivation in ungulates. During winter 1992 – 1993, we collected 10–17 sequential snow-urine samples (402 total) from 27 individually identifiable free-ranging adult female elk. Within-animal variance accounted for 91% of the total variance (351.66 mg2/dL2) in creatinine, 86% of the total variance (637.03 mg2/dL2) in urea nitrogen, and 82% of the total variance (0.56) in urea nitrogen: creatinine ratios. This substantial within-animal variability was unexpected and led to experiments that examined whether the variability was due to sample collection and measurement technique or actually reflected biological variability. Factors examined included dilution effects, measurement (assay) repeatability, and short-term (<24 h) within-animal constancy in metabolite excretion. No dilution effects were detected when the initial concentrations of snow-urine samples were diluted <75% with water. Measurement variability accounted for 0.78, 0.37, and 27.7% of the total variance in creatinine, urea nitrogen, and urea nitrogen: creatinine ratios, respectively. Within-animal metabolite excretion was reasonably constant within 24 h, suggesting that creatinine provides a valid index for comparing urinary metabolites. We conclude that variability in urea nitrogen: creatinine ratios due to dilution, measurement variability, and short-term temporal variability in metabolite excretion was small compared with the total within-animal variance. Urea nitrogen: creatinine ratios should provide an accurate estimate of the true ratios of these metabolites in an elk's bladder urine. However, the interpretation of urea nitrogen: creatinine ratios is often complex, since they reflect the immediate dynamics between fat depletion, protein catabolism, and dietary intake. Differences in ratios between collections may be partially due to variations in recent dietary intake or restriction, in addition to true differences in long-term nutritional status. The best method for statistically analyzing snow-urine data remains unresolved.
Emigration and survival of orphaned female deer in Illinois
Authors: Etter Dwayne R. , Thomas Jeanette A. , Nixon Charles M. , Sullivan Joseph B.
Published: July 2008

Emigration and survival were examined for 13 orphaned and 94 nonorphaned female white-tailed deer (Odocoileus virginianus) captured at < 10 months of age from free-ranging populations in Illinois. Emigration rates were higher (P = 0.026) for female orphans than for nonorphans. Nine of 13 (69%) orphans emigrated in spring through early summer. In contrast, only 35 of 94 (37%) nonorphans emigrated. Annual survival rates for all females from three Illinois study areas were 0.59, 0.71, and 0.80 for the east-central, west-central, and northern study areas, respectively. Possible stimuli for emigration among orphaned female white-tailed deer include pregnancy, low social position, and loss of maternal support.
Low summer temperatures cause juvenile Atlantic salmon to become nocturnal
Authors: Fraser Neil H. C. , Metcalfe Neil B. , Heggenes Jan , Thorpe John E.
Published: July 2008

The diel and seasonal activity patterns of salmonids are predominantly governed by the annual changes in photoperiod and temperature. In winter salmonids become increasingly nocturnal, hiding in refuges by day but emerging to feed at night. This behaviour may be linked to either one of the controlling influences mentioned above or to an inherent annual rhythm. Here we show that the previously described switch by Altantic salmon (Salmo salar L.) from predominantly diurnal to nocturnal activity in winter also occurs at other times of the year in response to low, "winter" temperatures; this is demonstrated both in laboratory experiments and by field observations in glacial rivers. This indicates that there is no underlying inherent annual rhythm to this behaviour nor any photoperiodic influence. Furthermore, in the laboratory experiment this temperature-dependent shift to nocturnalism was explained by a suppression of daytime activity rather than an increase in activity at night.
A redescription ofLeptosynapta clarkiHeding (Echinodermata: Holothuroidea) from the northeast Pacific, with notes on changes in spicule form and size with age
Authors: Sewell Mary A. , Chia Fu-Shiang , Thandar Ahmed S.
Published: July 2008

Leptosynapta clarki is redescribed on the basis of the type material and new collections from Bamfield and Gabriola Island, British Columbia, and False Bay, San Juan Island, Washington. Both intraspecific and zoogeographic variations are recorded. Further, notes are added on changes in spicule form and the size of the anchor plates with age in a single population of the species from Grappler Inlet, Bamfield. Leptosynapta roxtona Heding, 1928, described from three fragments, is declared a synonym of L. clarki, and L. lens Heding, 1928 a synonym of L. albicans (Selenka, 1867). Leptosynapta transgressor Heding, 1928 is suspected to be a subtidal ecological variant of L. clarki, but is tentatively retained until living material becomes available.
Twenty-four-hour urinary creatinine and urea nitrogen excretion in male white-tailed deer
Authors: DelGiudice Glenn D. , Asleson Mark A. , Hellgren Eric C. , Varner Larry W.
Published: July 2008

During 5-d trials in spring and summer we investigated the constancy of creatinine and urea nitrogen excretion and the urea nitrogen:creatinine ratio in 24-h urine samples from 12 male white-tailed deer (Odocoileus virginianus) and the relationship of these metabolites with body mass and dietary nitrogen intake. During both trials, 24-h urinary creatinine excretion remained stable (CV of 13.5 and 18.5% for the spring and summer trials, respectively), and there was no difference between deer fed a high-protein diet and those fed a low-protein diet. However, urinary urea nitrogen excretion and urea nitrogen:creatinine ratios were significantly lower in the latter group. Mean daily creatinine coefficients (0.22–0.27 mmol excreted/kg body mass) were comparable to those in other mammalian species. During both trials, urinary creatinine excretion was significantly related to body mass but not to dietary nitrogen intake. Urea nitrogen excretion and urea nitrogen:creatinine ratios were significantly related to mass-specific nitrogen intake, but not to body mass or 24-h urinary creatinine excretion. Using 24-h urinary creatinine excretion, mean muscle mass of our deer was estimated to be 58 and 57% of whole body mass in the spring and summer trials, respectively.
Foraging patterns of California sea otters as indicated by telemetry
Authors: Ralls Katherine , Hatfield Brian B. , Siniff Donald B.
Published: July 2008

Foraging behavior was studied in 38 sea otters (Enhydra lutris) implanted with radio transmitters. The observed foraging behavior of instrumented individuals was similar to that of uninstrumented otters observed in previous studies: dive duration varied with prey type but not with prey size, dive success was highest for small prey, and the length of surface intervals increased with prey size. However, telemetry revealed that some otters foraged farther offshore and made longer dives than was indicated by visual observations. Individuals within age–sex classes varied in several aspects of foraging behavior, including the duration of dives and length of surface intervals. There were no overall differences between the dive durations or surface intervals during the day and during the night, though some individuals had longer dives or surface intervals during either the day or the night. There were differences in the foraging behavior of the various age–sex classes, the most striking being those between juvenile males and females. Juvenile males foraged much farther offshore [Formula: see text] in deeper water [Formula: see text] than other otters and made long dives during both the day [Formula: see text] and the night [Formula: see text]. Juvenile females fed for longer periods than other otters.
Cucumaria pallida, a new species of sea cucumber from the northeast Pacific Ocean (Echinodermata, Holothuroidea)
Authors: Kirkendale Lisa , Lambert Philip
Published: July 2008

A new species of dendrochirote holothuroid from the northeast Pacific Ocean is described. Cucumaria pallida n.sp. is compared with two similar species, Cucumaria fallax Ludwig, 1874 and Cucumaria miniata (Brandt, 1835). Cucumaria pallida, previously thought to be a pale form of C. miniata, is a common subtidal species with a cream–white skin and delicate, translucent tentacles. Cucumaria pallida n.sp. is known from the Alaska–British Columbia border south to the Channel Islands, California, and from the intertidal zone to a depth of 91 m. The shape and size of the ossicles, number of stone canals, body colour, and reproductive characteristics distinguish C. pallida from other species of Cucumaria.
Morphological variation in the Pacific sand dollar Dendraster excentricus
Authors: Nakamura Raymond K.
Published: July 2008

Correlations between latitude, habitat, and morphology in the Pacific sand dollar Dendraster excentricus were identified with principal component analysis. Twenty-two lengths were measured on the oral and aboral surfaces of 615 specimens from 31 sites. Samples were divided at latitude 34°30′N (Point Conception) and into bay and coastal habitats by relative wave exposure. Principal components (PC) were estimated from a correlation matrix of sample means of log-transformed measurements. PC1 accounted for 90% of the variance and was a measure of overall size. All 22 PC1 coefficients were positive and differed significantly from 0, according to a jackknifing test. PC1 differed significantly with latitude (ANOVA, p < 0.01) but not habitat. Southern populations tended to be smaller. PC2 accounted for 5% of the variance and described overall shape. Of the 22 variables, 13 had significant coefficients that varied in sign. PC2 varied significantly with habitat (ANOVA, p < 0.05) but not latitude. In coastal populations, the peristome and petaloids tended to be more posteriorly positioned and the food grooves were branched more peripherally. These features correspond to the greater tendency for coastal specimens to use their posterior end to suspension feed.
New taxa of Rhagidiidae (Acari: Prostigmata) from North America. Part II. The genera Kouchibouguacia Zacharda and Shibaia Zacharda
Authors: Zacharda Miloslav
Published: July 2008

Two new species of rhagidiid mites, Kouchibouguacia transcendata n.sp. and Shibaia spiraesolenidiata n.sp., from the Nearctic region are described. Keys to the known species of the genera Kouchibouguacia and Shibaia are given.
Multilocus DNA fingerprints in seven species of salmonids
Authors: Heath Daniel D. , Devlin Robert H. , Hilbish Thomas J. , Iwama George K.
Published: July 2008

DNA fingerprinting is a molecular biological technique that is widely used for identifying parentage and relatedness in plants and animals. To identify new DNA fingerprinting probes for use with salmonids, Southern blots of genomic DNA from chinook salmon (Oncorhynchus tshawytscha) were hybridized at low stringencies with 12 different oligonucleotides designed from published core sequences of variable number of tendem repeats. Seven of the 12 oligonucleotides produced highly variable fingerprint-like patterns; however, only 3 of these had clear, distinct bands. The estimated heterozygosity for one population of chinook salmon using the three oligonucleotides as probes ranged from 0.64 to 0.77. Those three oligonucleotides were further hybridized with DNA from two unrelated individuals from six other species of salmonids. A single-locus DNA fingerprint probe originally developed for chinook salmon was also hybridized with DNA from the other six species at moderate stringency. There were differences in the complexity and signal strength of the resulting banding pattern between species for a given probe. Estimates of variability (heterozygosity and band sharing) for the three oligonucleotide probes and OtSL1 were high, indicating that the probes were potentially useful genetic markers. The availability of these additional DNA fingerprint probes should assist in ecological and evolutionary studies in salmonids, as well as in efforts to estimate genetic diversity of populations.
Male dominance, plasma hormone concentrations, and availability of milt in male rainbow trout (Oncorhynchus mykiss)
Authors: Liley N. R. , Kroon F. J.
Published: July 2008

The relationships among social status, endocrine profile, and amounts of milt available by stripping were examined in pairs of male rainbow trout (Oncorhynchus mykiss) competing for access to sexually active females in laboratory spawning channels. Gonadotropic hormone (GtH II), the gonadal steroids 11-ketotestosterone, testosterone, and 17α,20β-dihydroxy-4-pregnen-3-one, and milt volumes increased in dominant males in response to stimuli provided by a nesting female. Subordinate males in the same location did not show endocrine or milt responses. Following the removal of the dominant male of each pair, plasma hormone and milt levels increased in the previously subordinate males. This result indicates that endocrine and spermiation responses depend upon close-range sensory and behavioural interaction with the sexually active female. Treatment with testosterone did not cause a change in behaviour or social status of smaller males predicted to be subordinate.
Song degradation and estimation of acoustic distance in Black-capped Chickadees (Parus atricapillus)
Authors: Fotheringham James R. , Ratcliffe Laurene
Published: July 2008

Black-capped Chickadees (Parus atricapillus) sing a two-note song termed fee bee. Frequency descends within the fee note and between the fee and bee notes. Within-song frequency ratios are highly invariant, while among songs, absolute frequency is variable. We conducted sound-transmission studies to analyze how Black-capped Chickadee songs degrade in different native habitats. We then subjected colour-banded territorial males to playback of undegraded and degraded songs to see if they could estimate the distance to a conspecific singer by means of degradation cues. In transmission studies conducted in an open field and a dense deciduous forest, significant effects of reverberation and amplitude modulation were measured for songs at three different frequencies. A new technique, cross-correlation of song spectrograms, allowed for a measure of holistic song degradation, which varied significantly over distance in open versus forested habitat. Polynomial regressions for the effects of reverberation, amplitude modulation, and cross-correlation measures of general degradation revealed different trends in open versus forested habitat, regardless of absolute frequency. Male Black-capped Chickadees did not differ in their response to playback of undegraded and degraded songs when the two types were broadcast from the same position in the territory at the same amplitude. We suggest that heterogeneity of Black-capped Chickadee native habitat may preclude the use of song degradation as a reliable distance cue.
Predator identification at simulated waterfowl nests using inconspicuous hair catchers and wax-filled eggs
Authors: Pasitschniak-Arts Maria , Messier François
Published: July 2008

We tested the efficiency of thin, inconspicuous wire hair catchers and wax-filled eggs to differentiate between mammalian and avian predators of upland nesting ducks. In contrast to a previously tested hair catcher (lacerated metal sheeting, modified bridge-stake design), our hair catcher was designed to be unobtrusive, to avoid attracting predators to nests. In total, 578 simulated nests (78 with metal sheeting and 500 with inconspicuous wire hair catchers) were set up in Thickwood Hills, Saskatchewan. Each nest contained seven fresh chicken eggs and two wax-filled eggs for collecting tooth and beak marks of predators. Predation by mammals and birds accounted for 30 and 70% of depredated nests (n = 78) with metal-sheeting hair catchers compared with 76.5 and 23.5% (n = 143) of nests with inconspicuous wire hair catchers, respectively; metal-sheeting hair catchers created a severe bias toward bird predation. Restricting our analysis to nests with inconspicuous wire hair catchers, hair and feather samples were obtained at 45.1 and 2.2% of depredated nests (n = 317), respectively. Another 30.3% of depredated nests contained marked wax-filled eggs, of which 75% related to mammalian predation and 25% to avian predation. Overall, we could differentiate between mammalian and avian predation in 77.6% of destroyed nests. Based on hair samples, the striped skunk (Mephitis mephitis) was the dominant predator (75% occurrence) among mammalian species.
Functional morphology of the mymariform and sacciform larvae of the egg parasitoidAnaphes victusHuber (Hymenoptera: Mymaridae)
Authors: Nénon J.-P. , Boivin G. , Lannic J. Le , Baaren J. Van
Published: July 2008

The mymariform and sacciform larvae of Anaphes victus Huber (Hymenoptera: Mymaridae), an egg parasitoid of Curculionidae, are apneustic and segmented. We found a perioral cordiform structure around the buccal cavity of the mymariform larva that may have a role in the ingestion of host contents or in fights with conspecific larvae in situations of superparasitism. We observed fights between mymariform larvae, which regulate superparasitism in this strictly solitary species, in which sensorial structures of two distinct types found on the thoracic setae could have played a role. The adaptive value of these larval fights is discussed.
Pod-specific call repertoires and compound calls of killer whales, Orcinus orca Linnaeus, 1758, in the waters of northern Norway
Authors: Strager Hanne
Published: July 2008

Underwater vocalizations of 9 photoidentified pods of killer whales (Orcinus orca) were recorded in northern Norway from 1986 to 1992. In total, 34 call types and 20 subtypes were identified from the recordings. The pods had repertoire sizes ranging from 3 to 16 call types (average 9.0 call types). Pod-specific calls were found in 6 of the 9 pods. All pods had a unique repertoire combination. This study thus supports the hypothesis that vocal traditions are characteristic of killer whales. Some calls were combined, forming a total of 21 different syntactically organized compound calls. The function of this was not known, but it was suggested that adding size and flexibility to a small and rigid vocal repertoire may be advantageous.
Histogenesis of fat tissue in the regenerating tail of the lizard (Lampropholis spp.)
Authors: Alibardi Lorenzo
Published: July 2008

The differentiation of fat cells in the regenerating tail of the lizards Lampropholis delicata and L. guichenoti was studied until the 55th day post amputation. To study the proliferation of and protein synthesis in fat cells, tritiated thymidine and proline were injected into lizards after 3 weeks of tail regeneration and the tracers were revealed by optical and electron microscopic autoradiography. After 3 weeks of tail regeneration, adipocytes are rarely seen in the apical regions of the regenerating tail and most of the preadipose cells are visible in the submuscular connective tissue in the proximal regions. Fat cells begin to proliferate and accumulate visible lipid droplets in the proximal submuscular connective tissue after about 3 weeks of tail regeneration. The kinetics of [3H]thymidine uptake after progressive postinjection periods suggest that fat tissue mass increases mostly as as result of fat cell hypertrophy, with only limited cell multiplication. During the initial stages of their differentiation, lipoblasts also take up [3H]proline, but the ergastoplasm and Golgi apparatus become reduced during the process of fat accumulation. The final size of regenerated fat cells was less than that of the original fat cells.
Apportionment of genetic variance in migrating and wintering mallards
Authors: Rhodes Jr. Olin E. , Chesser Ronald K. , Smith Loren M.
Published: July 2008

Mallards (Anas platyrhynchos, n = 289) wintering in the Southern High Plains of Texas were collected from 15 October 1988 to 7 February 1989 and electrophoretically surveyed for genetic variation at 30 biochemical loci. Genetic data were used to detect mixtures of breeding populations in the wintering aggregation of mallards that migrate into the Southern High Plains and to estimate the proportion of total genetic variation partitioned among breeding populations represented on the study area there. Wintering mallards represented mixtures of genetically heterogeneous breeding populations with a minimum of 10.4 – 11.7% of the genetic variation partitioned among populations represented. Genetic information may be useful in detecting mixtures of breeding populations in specific wintering areas within and among flyways.
The identity of Phytoseius macropilis (Banks) (Acari: Phytoseiidae), with a note on its distribution
Authors: Yoshida-Shaul E. , Chant D. A.
Published: July 2008

Based on examination of the holotype specimen, Phytoseius macropilis (Banks) is redescribed and its identity clarified. Fifty-nine specimens of "macropilis" from Ontario and Quebec, Canada, and from the eastern United States were examined to determine their conspecificity with macropilis using principal components analyses and a multivariate discriminant analysis. Twenty morphometric characters were used in the analyses. Results of the analyses confirmed the conspecificity of Ohio specimens with macropilis. Thirty-seven of the 59 specimens are confirmed as macropilis and range in distribution from North Carolina to the James Bay region. The remaining 22 specimens are reidentified as Phytoseius delicatus Chant. Most of the specimens of P. macropilis were collected from the "deciduous" forest region and their host plants tend to be of dry, upland areas.