bluuebunny/crossref_metadata_2025 huggingface dataset:
Observations of asymmetric reproduction along a morphocline of the blackspotted stickleback, Gasterosteus wheatlandi
Authors: Ayvazian Suzanne G.
Published: July 2008

Assortative mating has been documented within the Gasterosteus aculeatus complex. The outcome of laboratory mating trials between individuals from allopatric populations of the blackspotted stickleback, Gasterosteus wheatlandi, is reported. A total of 70 intra- and inter-population mating trials between individuals from Massachusetts and Connecticut were conducted between 1984 and 1987. The results showed differences in the proportion of successful matings, measured as nests constructed, eggs deposited, and young produced. Although intrapopulation mating trials yielded the greatest proportion of nests, eggs, and young, mating did not proceed beyond nest construction between males from Massachusetts population and females from Connecticut population. These results suggest asymmetric reproductive isolation between this mating combination, as all other mating types produced offspring. Further research is necessary to resolve questions concerning differences in motivational states and reproductive behavioral cues.
Chromosomal evolution and biogeography of collared lemmings (Dicrostonyx) in the eastern and High Arctic of Canada
Authors: Borowik Oksana A. , Engstrom Mark D.
Published: July 2008

Chromosomal variation was examined in 10 populations of Dicrostonyx in the eastern and High Arctic of Canada to determine the extent and nature of chromosomal variation and to examine chromosomal differentiation within and among species and subspecies. Chromosomal data are presented for two species of collared lemmings, D. hudsonius and D. groenlandicus, including D. g. groenlandicus, D. g. clarus, and D. g. lentus. Standard, G-banded, and C-banded karyotypes revealed variation among populations of D. groenlandicus due to Robertsonian fusions and the addition of B chromosomes. G-banding revealed complete homologous banding patterns of autosomal arms between D. groenlandicus and D. hudsonius; however, sex chromosome constitution differed between the two species. Dicrostonyx groenlandicus possesses a neo-XY, formed by a Robertsonian fusion of the sex chromosomes and a pair of autosomes. The neo-XY does not occur in D. hudsonius, and this absence appears to be the primitive state for the genus.
Application of a sensitive radioimmunoassay for the measurement of growth hormone in gilthead sea bream (Sparus aurata) and other sparid fish
Authors: Bail P.-Y. Le , Mourot B. , Zohar Y. , Pérez-Sánchez J.
Published: July 2008

The development of a homologous radioimmunoassay (RIA) for gilthead sea bream growth hormone (sbGH) is described. RIA sensitivity was 0.4 ng/mL, and ED50 was 1.74 ± 0.05 ng/mL. Intra- and inter-assay coefficients of variation were 3.4 and 8.8%, respectively, at ED50 levels. Mammalian growth hormones (GH), carp gonadotropin, chinook salmon gonadotropin, ovine porlactin, and recombinant tilapia prolactin did not show cross-reactivity. Serial dilutions of recombinant trout GH indicated a low but significant cross-reactivity. The displacement curves for plasma and pituitary homogenates from sparid fish (gilthead sea bream, blacktail, white sea bream, Couch's sea bream, and marmor-brassen) were parallel to that of the sbGH standard. Pituitary homogenates from other perciform fish tested (gaper, grey mullet, red mullet, and sea pike) also showed parallel slopes of inhibition. Pituitary homogenates from common sole, sea scorpion, forked hake, goldfish, rainbow trout, and European eel showed low or negligible cross-reactivity. These results suggest that the GHs of perciform fish have a number of similarities in structure. RIA of sea bream GH can be used to quantify the GH of sparid fish and perciform fish, provided a validation has been carried out.
Identification and behavioral assays of the trail pheromone of the forest tent caterpillar, Malacosoma disstria Hübner (Lepidoptera: Lasiocampidae)
Authors: Fitzgerald T. D. , Webster F. X.
Published: July 2008

Behavioral assays show that the steroid 5β-cholestan-3-one, isolated from the abdomen of the larva of the forest tent caterpillar (Malacosoma disstria), constitutes the chemical basis of trail following in this insect. Caterpillars follow artificial trails prepared from solvent dilutions of the compound at rates as low as 10−11 g∙mm−11 of trail, though the true threshold sensitivity is likely to be one or two orders of magnitude lower than this. Fourth-instar caterpillars store an average of 58 ng of the pheromone. Field and laboratory studies indicate that the compound is fully competitive with their authentic trails. The caterpillars are highly sensitive to differences in the concentration of the pheromone, preferring stronger trails to weaker trails. The caterpillars also respond to 5β-cholestane-3,24-dione, a chemical not found in M. disstria but known to be a component of the trail pheromone of the eastern tent caterpillar, Malacosoma americanum.
Environmental, ontogenetic, and genetic variation in egg size of Pied Flycatchers
Authors: Potti Jaime
Published: July 2008

Ontogenetic, genetic, and environmental variation in egg length, breadth, and volume were investigated in the Pied Flycatcher across four breeding seasons in central Spain. Egg length and breadth were poorly correlated and did not vary with laying date. There was an indication of decreasing egg breadth with increasing clutch size that may indicate a trade-off between both variables. Egg size increased with female condition and, independently, with territory quality. Mean egg size decreased with advancing female age, which is perhaps related to the increase of clutch size with age in this species. There were high, significant repeatabilities of almost all egg dimensions, including relative volumes of first and last eggs, among females, both within and between years. Also, nest boxes were repeatable in the relative volume of the last eggs of (different) females laying in them, suggesting an influence of territory quality on relative egg size. Territory quality also had positive influences on some egg measurements that were independent of female condition. Heritability, estimated by mother–daughter regression, was significant only for egg length. These results are discussed in relation to proximate constraints on egg formation, predictions from the brood-survival hypothesis, and a possible trade-off between clutch and egg sizes.
Population dynamics of muskrats in experimental marshes at Delta, Manitoba
Authors: Clark William R. , Kroeker Darryl W.
Published: July 2008

Muskrat populations were studied in relation to water level and vegetation succession in an experimental wetland complex at Delta Marsh, Manitoba, Canada, flooded to three different levels: normal (long-term average elevation); medium (30 cm above normal); and high (60 cm above normal). Trapping in October and May, combined with closed and open population estimators, was usesd to estimate population size, survival, and recruitment. Muskrat densities reached > 30/ha after the second growing season. Populations in medium and high treatments initially reached densities greater than in normal cells, but all populations decreased to < 1/ha in May 1988. Winter survival declined from 0.31 in 1986 to 0.09 in 1987 and recruitment had declined significantly by May 1988. Winter survival, per-capita recruitment, body condition, and winter mass changes were inversely related to population density, but not consistently related to water level treatments. Survival was directly related to winter mass gain although recruitment the following spring was not. The most influential demographic factor in observed declines in density was decreased winter survival, which was consistently low in all treatments once flooding reduced the emergent vegetation. In natural prairie marsh systems, spatial and temporal variation in vegetation response to flooding contributes to variation in the density dependence of both the survival and recruitment of muskrats.
Two distinctive new species of halictine bees from high altitude in the New World tropics (Hymenoptera: Halictidae)
Authors: Packer Laurence
Published: July 2008

Two new species of halictine bees are described. A distinctive new species from high altitude in Ecuador is described on the basis of a single male. It appears to fall within the genus Caenohalictus as presently understood, although this diverse genus is badly in need of revision and may not be monophyletic. The concept of Mexalictus is expanded to include a new subgenus, Georgealictus, which appears to be an epiponine wasp mimic with a petiolate abdomen and elongate propodeum. This new subgenus is the sister-group to the nominate subgenus of Mexalictus. Mexalictus (Georgealictus) polybioides is described on the basis of one male and two females, all from high altitude in the state of Chiapas, Mexico.
Physiological and morphological regulation of acid–base status during hypercapnia in rainbow trout (Oncorhynchus mykiss)
Authors: Goss Greg G. , Perry Steve F.
Published: July 2008

A kinetic analysis (Michaelis constant (Km) and maximal flux (Jmax)) of the branchial Na+ and Cl− influx mechanisms, along with measurements of blood total CO2 content [Formula: see text], net acidic–basic equivalent fluxes, and gill chloride cell morphology, was performed using rainbow trout (Oncorhynchus mykiss) before, during, and after 96 h exposure to environmental hypercapnia (water [Formula: see text]; 1 torr = 133.3 kPa). Exposure to hypercapnia caused (i) a net acidic equivalent loss (negative [Formula: see text]) that was accounted for entirely by reductions in titratable alkalinity flux (JTA), (ii) an increase in [Formula: see text] from 8.4 ± 0.5 to 20.7 ± 0.4 mmol/L, and (iii) no alteration either in [Formula: see text], [Formula: see text], or [Formula: see text]; [Formula: see text] increased (affinity was reduced). Chloride cell fractional area was reduced by 40% from 174 250 ± 15 650 μm2/mm2 under control conditions to 104 329 ± 17 991 μm2/mm2 after 96 h of hypercapnia. In the posthypercapnic period, there was (i) a net acidic equivalent gain (positive [Formula: see text]) that was accounted for entirely by an elevation in JTA, (ii) a rapid reduction of blood [Formula: see text], (iii) an increase of chloride cell fractional area to control values (179 105 ± 35 233μm2/mm2), and (iv) increases and decreases in [Formula: see text] (564 ± 50 versus 224 ± 21 μmol∙kg−1∙h−1 in the prehypercapnic period) and [Formula: see text] (381 ± 85 versus 585 ± 92 μmol∙kg−1∙h−1), respectively. The results suggest that morphological alteration of the gill chloride cell fractional area is an important response to acid–base disturbances. The results are discussed with respect to the relative roles of morphological alteration of gill chloride cell fractional area and variation in internal substrate (HCO3−) in modifying branchial Cl−/HCO3− exchange for acid–base regulation.
The persistence of moles in nesting at the same site as indicated by mushroom fruiting and nest reconstruction
Authors: Sagara Naohiko , Abe Hisashi , Okabe Hiroaki
Published: July 2008

Evidence is presented to show that under certain conditions, three species of Japanese talpine mole, Euroscaptor mizura, Mogera wogura, and Mogera kobeae, persistently use the same nest or nesting site. The moles' nesting sites were detected by the fruiting of an agaric species, Hebeloma radicosum, which specifically colonizes a mole's latrines near its nest. The nests were removed to observe the moles' response. During excavation, the moles often returned to the disturbed sites in search of their nests. The nests were soon reconstructed, followed by refruiting of the mushroom. Thus, one nesting site of E. mizura was used for more than 15 years, despite removal of the nest seven times, and another for more than 5 years, a period ended by the capture of the occupant. Similar results were also obtained with M. wogura and M. kobeae. The occupants may have changed generationally at each site. These persistently used sites seem to be associated with well-drained soil and appropriate vegetation.
On the life cycle of Diorchis bulbodes Mayhew, 1929 (Cyclophylhdea: Hymenolepididae), a parasite of waterfowl (Anseriformes: Anatidae)
Authors: Greaves T. A. , Burt M. D. B. , Pilgrim W.
Published: July 2008

During a survey of parasites of waterfowl, collected in New Brunswick during the hunting seasons of 1987 and 1988, the small intestine of one male wood duck, Aix sponsa, was found to contain 32 specimens of the cestode Diorchis bulbodes. After several repeated experimental infections of various crustaceans, full development of a tailed cysticercoid occurred in the ostracod Cypridopsis vidua.
Cold-hardiness of Lacanobia atlantica (Lepidoptera: Noctuidae), and a comparison with three other insect species that overwinter in the same habitat
Authors: Turnock W. J.
Published: July 2008

The pupae of Lacanobia atlantica (Grt.) overwinter in the soil and are susceptible to freezing. Cold injury and death occur at temperatures above the supercooling point (SCP) of −26.4 °C, and below ca. −12.6 °C. Mortality increases as temperature decreases and as exposure lengthens. These results are compared with those for Mamestra configurata Wlk., Delia radicum (L.), and Athrycia cinerea Coq., which have similar overwintering habits. Their mean SCPs (−27.3 to −20.3 °C) differ less than do the values representing the highest temperature at which cold injury occurs (≈−12.6 to ≈4 °C). Response curves of three of the species were similar for changes in temperature and duration of exposure, and similarly in a plot of the time to 50% survival (LT50) against temperature. They differed only in their relative cold-hardiness. In contrast, A. cinerea was less sensitive to changes in temperature and duration of exposure. A single parameter (e.g., the mean SCP) is not adequate to describe the cold-hardiness of these species because they vary not only in the upper and lower bounds of their cold-injury zones but also in their response to temperature and duration of exposure within this zone.
Sexual dimorphism in cordylid lizards: a case study of the Drakensberg crag lizard, Pseudocordylus melanotus
Authors: Mouton P. le F. N. , Wyk J. H. van
Published: July 2008

In a high-altitude population of the Drakensberg crag lizard, Pseudocordylus melanotus, most adult males, unlike adult females, are brightly coloured, and they are larger in body size and have relatively larger heads than females. Three basic colour phases can be distinguished among the brightly coloured adult males. No apparent differences in reproductive activity, number and differentiation state of the generation glands and femoral pores, or scar frequency were noted among the three colour phases. In males the development of bright colours and the differentiation of the epidermal glands coincide with the onset of sexual maturity. Sexual dimorphism in head size of adults is due to a decrease in female head size relative to juvenile head size as well as an increase in relative head size of males. Preliminary data indicate a social structure of territorial polygyny in P. melanotus and suggest that the dimorphism can partly be ascribed to sexual selection. There are also, however, indications of altitudinal variation in the expression of sexual dimorphism, which may be explained in terms of differential energy allocation by females at different altitudes.
Early maturation by northern Peromyscus maniculatus
Authors: Teferi Taye , Millar John S.
Published: July 2008

Female Peromyscus maniculatus rarely breed as young of the year in the Kananaskis Valley, southwestern Alberta. We monitored breeding by young-of-the-year females in unmanipulated sites from 1985 to 1991 and on manipulated sites (females removed, males removed, and food added) from 1989 to 1991. Breeding by young females was uncommon on all manipulated sites (16% when food was added, 3% when females were removed, 0% when males were removed). Females that matured as young of the year tended to have relatively high growth rates as nestlings. We conclude that individual quality is more important than social cues in regulating maturation by young females in this population.
Variation in weaning mass of pups in relation to maternal mass, postweaning fast duration, and weaned pup behaviour in southern elephant seals (Mirounga leonina) at South Georgia
Authors: Arnbom T. , Fedak M. A. , Boyd I. L. , McConnell B. J.
Published: July 2008

Female southern elephant seals, Mirounga leonina, assemble in large groups and each gives birth to a single pup which is nursed for some 3 weeks. Weaning mass is highly variable; some pups are three times as heavy as others at weaning. After weaning, the pup fasts for several weeks before departing to sea. The function of this fast is unknown. We examined the relationships between maternal mass, pup weaning mass, and pup behaviour during the postweaning fast in 377 pups and 128 adult females over four breeding seasons at South Georgia. Pup weaning mass was positively related to maternal postpartum mass, which accounted for 55% of the variation in weaning mass. Over all 4 years male pups were significantly heavier at weaning than female pups (130 vs. 123 kg) but this difference disappeared after maternal mass was controlled for. After fasting for 21–66 days, weaned pups went to sea at an average of 68% of weaning mass. Heavier pups remained on the beach longer after weaning than lighter pups. There was no evidence that pups synchronized their departure to sea. Only male pups were observed to take part in mock fights. With increasing age, weaned pups spent more time in the water. Mortality during the postweaning fast was negligible (0.1 %). The timing of departure of weaned pups may involve a trade-off between an early departure with greater fat (energy) stores but poorer foraging ability and a late departure with increased swimming, diving, and social skills but reduced fat stores.
Metabolic strategies for winter survival by Svalbard reindeer
Authors: Cuyler L. C. , Øritsland N. A.
Published: July 2008

Lying and standing metabolic rates were determined for two tame Svalbard reindeer while the animals were in their winter lethargic state during January and February. Mean nonfasting metabolic rates for the 59-kg animals were 1.25 W∙kg−1 for lying and 1.64 W∙kg−1 for standing at rest. So the metabolic rate for standing at rest was about 1.3 times the lying resting metabolic rate (RMR). For Svalbard reindeer the lying RMR was 66–78% of the values for other reindeer/caribou, and was 78–89% of the predicted value. The standing RMR was 44–88% of the values from other reindeer/caribou. Total body thermal conductance was 1.95 ± 0.17 W∙°C−1 for lying and 3.08 ± 0.77 W∙°C−1 for standing at rest. The daily energy expenditure during winter was estimated to be about 9654 kJ∙day−1 or 112 W, and was 1.5 times Kleiber's predicted basal metabolic rate. By remaining lying 45% of the time rather than 35% Svalbard reindeer may conserve the equivalent of about 15 days' energy requirement over the winter. With locomotion at 2% of the winter daily activity budget, the Svalbard reindeer conserve about 21 days' energy expenditure, more than that if locomotion were 8.2% of the budget as in caribou (Boertje 1985). Thus, their low energy expenditures for lying and standing and their sedentary activity budget may be considered energy-saving and survival strategies. It is possible that disturbances, which cause the animals to increase activity, may have a detrimental effect on their overall winter energy balance.
Maternal transfer of the 6-MBOA chemical signal in Microtus montanus during gestation and lactation
Authors: Frandsen Tim C. , Boyd Susan S. , Berger Patricia J.
Published: July 2008

A study was undertaken to determine how reproductive information from the plant metabolite 6-methoxybenzoxazolinone (6-MBOA) is transferred maternally to offspring in the montane vole, Microtus montanus. Adult female M. montanus were implanted with 10- or 20-mm Silastic capsules containing 6-MBOA (experimental) or empty capsules (control). Females were paired with males and monitored daily for births. On the day of birth, the offspring were either cross-fostered to other mated pairs, or maintained in the natal nest. Six groups were formed based on whether the litter was transferred to a female of the same treatment, to a female of the opposite treatment, or left in the cage of birth until weaning. The offspring were reared in the nest until 18 days and sacrificed 8 days after weaning. Data were collected on weight, total length, paired-testes weight (males), and uterine weight (females). The data indicate that offspring receiving 6-MBOA information demonstrate significantly increased growth and increased gonadal size compared with offspring receiving no 6-MBOA information, and that the 6-MBOA information is transferred maternally during both gestation and lactation.
Ctenella aurantia, genre et espèce nouveaux de cténophore tentaculé (Ctenellidae fam.nov.) méditerranéen sans colloblastes et avec ventouses labiales
Authors: Carré Claude , Carré Danièle
Published: July 2008

Ctenella aurantia gen. et sp.nov. is a small Mediterranean tentacled ctenophore. Its ovoid and flattened body is opaque and yellow-orange, with red-pigmented areas. Comb rows are arranged in pairs from the apex to the oral third of the body. The tentacular sheaths situated at the end of the oral third of the body open medially; they terminate in an aboral open groove which can close up around the unramified tentacles. The gastrovascular system is simple and follows the axis of the body; it has no peripheral canals but two long apical canals project into the aboral zone. The mouth forms a sagittal slit bordered by two thick lips, each bearing a sucker on its internal wall. The species also possesses very distinctive cytological features, notably the absence of colloblasts on the tentacles and the consistent presence of exogenic cnidocysts that are embedded in the gastrovascular wall. The muscular cells of the oral zone have no sarcomeres, but have both fine and thick myofilaments that are arranged alternately. The species is very distinctive, both in its cytological characteristics and its general organization. It is tentatively classified in the order Cydippida, and its relationship to some other species is mentioned.
Light and scanning electron microscopic studies on Trichodina labrisomi n.sp. from Labrisomas nuchipinnis (Osteichthyes: Labrisomidae) from Mangrove Lake, Bermuda
Authors: Rand Thomas G.
Published: July 2008

Trichodina labrisomi n.sp. from the gills of the hairy blenny, Labrisomas nuchipinnis (Quoy and Gaimard), in Mangrove Lake, Bermuda, is described using light microscopy and scanning electron microscopy (SEM). Light microscopy reveals that the dimensions and morphology of T. labrisomi are similar to those given for only 13 previously described species of Trichodina (T. acuta Lom, 1961; T. baicalensis Dogiel, 1957; T. cottomephori Stein, 1979; T. dalli Zhukov, 1964; Trichodina domerguei domerguei Lom and Shtein 1966; T. elegans Stein, 1979; T. fultoni Davis, 1947; T. jadranica Haider, 1964; T. jadranica noblei Lom, 1970; T. partidisci Haider, 1964; T. reticulata Hirschmann et Partsch, 1955; T. tenuidens Faure-Fremiet, 1943; and T. tenuiformis Stein, 1979). However, compared with these similar forms, T. labrisomi n.sp. is distinguished by the dimensions of its body and denticulate ring and (or) the appearance of its silver-impregnated adhesive disc and denticles. Features of T. labrisomi examined by SEM include the body shape, pellicle, aboral pellicular pores, border membrane, aboral ciliary complex, and adoral ciliature, which are described and compared with those of other trichodinids studied using SEM. SEM also revealed that bacilli were distributed circumequatorially over the oral surface of T. labrisomi.
Ultrastructure of the lophophoral tentacles in the genus Phoronis (Phoronida, Lophophorata)
Authors: Pardos F. , Roldán C. , Benito J. , Aguirre A. , Fernández I.
Published: July 2008

The lophophoral tentacles of two phoronids, Phoronis psammophila and Phoronis hippocrepia, are described from an ultrastructural point of view. The tentacles are hollow structures, with an epidermis exhibiting supporting cells, sensory cells, and four types of gland cells, A, B1, B2, B3. The epidermis rests on a connective tissue layer, tubular in shape, enclosing a coelomic space lined by myoepithelial mesothelium (peritoneum). There is a single blood capillary in the tentacular coelomic cavity, attached to the frontal face of the tentacle, with contractile walls derived from the peritoneum. Both erythrocytes and amoebocyte-like cells occur inside the capillary. Differences between the tentacles of these two species and those of Phoronis australis, whose structure is already known, mainly concern the abundance and distribution of the epidermal gland cell types and are related to the burrowing and tube-building activities of these animals in different substrata.
Variation in age structures in a subdivided population of Triturus cristatus
Authors: Miaud Claude , Joly Pierre , Castanet Jacques
Published: July 2008

Changes in age structure of local populations were analyzed to determine the migrations of adult crested newts (Triturus cristatus) in a network of ponds. An individual's age was estimated by applying a skeletochronological method to the phalanges. The local populations studied bred in four neighbouring cattle ponds, the distance between any two of which did not exceed 150 m. These ponds belong to the larger network. Though the size of the whole population doubled from one year to the next, one local population became extinct due to lack of recruitment of young breeders. The larger local population attracted not only young breeders but also older newts, which probably came from other ponds. In ponds inhabited by fish, the newts were mainly young animals (2–3 years old), suggesting that they leave such ponds after their first breeding season. The results are discussed with regard to the model proposed by Gill for metapopulations of Notophthalmus viridescens. In the crested newt, contrary to Gill's predictions, all the sites do not recruit young breeders, and fidelity to the breeding site may be broken. The two species differ in longevity and age at maturity, hence it is suggested that functional models of metapopulations must integrate life-history parameters.
Experimental infection of yellow perch (Perca flavescens) with Apophallus brevis (Digenea, Heterophyidae): parasite invasion, encystment, and ossicle development
Authors: Taylor Lawrence H. , Hall Brian K. , Cone David K.
Published: July 2008

Yellow perch (Perca flavescens) were exposed to cercariae of Apophallus brevis collected from naturally infected snails and maintained for up to 63 d postinfection (PI). Histochemistry revealed that attachment, penetration, migration, and encystment were complete by 2 d PI. By 14 d PI, a precursor to a host ossicle capsule surrounded the encysted metacercaria. Between 14 and 63 d PI a calcified matrix aggregated in a specific developmental pattern of islets, crescent, band, then ring, within an equatorial band at the cyst–capsule interface. The result was an ossicle ring of calcified tissue separating two uncalcified-matrix poles. Ossicle rings thickened and advanced over the cyst, but did not seal it off completely, forming an intermediate ossicle 49 d PI with two polarized canals. Pigmentation of ossicles through the appearance of melanocytes was not consistent between infections of the same age. Scanning electron microscopy revealed two distinct regions within fully developed ossicles. Randomly distributed interstitial fibres and ovoid and tubular lacunae surrounded by perilacunar collars formed the inner cellular region. The interstitial fibres within the outer region formed acellular/lamellar bands.
Details of a confrontation between two wild wolves
Authors: Mech L. David
Published: July 2008

A confrontation was photographed and videotaped at close range between a wild alpha male wolf (Canis lupus) of known history and an alien adult on Ellesmere Island, Northwest Territories, Canada. For 100–110 seconds the two stood near each other, maneuvered around, and snapped at each other until the alien fled. The alpha and his mate, who suddenly joined the encounter, chased the other wolf for 1.2 km and gave up without inflicting wounds. Discussed are possible reasons why this wolf was not killed, while other alien wolves have been.
The significance of precocity in the transmission of the nematode parasites of vertebrates
Authors: Anderson R. C. , Bartlett Cheryl M.
Published: July 2008

The significance of precocity in the transmission of heteroxenous parasitic nematodes is reviewed. Precocity of nematodes in intermediate hosts manifests itself in the following ways depending on the species: (i) the unusually large size of the infective larva; (ii) the advanced development of the genital primordium in the infective larva; (iii) development to the fourth stage in the intermediate host; and (iv) development to the subadult stage (early fifth stage) in the intermediate host. Precocity apparently accelerates gamete and egg production in the definitive host when the behaviour of intermediate and definitive hosts restricts transmission to confined limits of space and time. Examples of precocity are outlined and, whenever possible, related to the behaviour of definitive and intermediate hosts during transmission.
Genetic analysis of sterility in hybrids from crosses of Glossina morsitans submorsitans and Glossina morsitans centralis (Diptera: Glossinidae)
Authors: Gooding R. H.
Published: July 2008

When genetically marked Glossina morsitans submorsitans Newstead were mated to Glossina morsitans centralis Machado, viable offspring were obtained when using G. m. submorsitans females but not when using G. m. centralis females. The maternally inherited sterility factor, from G. m. submorsitans, that causes this asymmetry was inactivated or replaced during recurrent backcrossing to G. m. centralis. F1 hybrid males were sterile but most F1 hybrid females were fertile. There was little evidence for differential transmission of G. m. submorsitans and G. m. centralis chromosomes by hybrid females. Almost all backcross males were sterile if they had an X and a Y chromosome from two different taxa; the exceptional males had recombinant X chromosomes. The X chromosome locus for X/Y compatibility lies closer to the locus for esterase-X than to the locus for glucose-6-phosphate dehydrogenase. Heterozygosity in linkage group II is also a factor in causing hybrid male sterility; the locus for compatibility is closer to the locus for octanol dehydrogenase than to the locus for esterase-1. Among the backcross males that had an X and a Y chromosome from the same taxon, 12% of those obtained by backcrossing to G. m. centralis were fertile and 65% of those obtained by backcrossing to G. m. submorsitans were fertile. Backcrossing F1 hybrid females to G. m. submorsitans produced females that were equally likely to be fertilized by G. m. submorsitans and G. m. centralis. However, backcrossing to G. m. centralis produced females that had a much lower probability of being fertilized by G. m. submorsitans than by G. m. centralis.
Development of the olfactory organ of the Arctic charr, Salvelinus alpinus (L.) (Teleostei, Salmonidae)
Authors: Olsén K. Håkan
Published: July 2008

The structure of the olfactory epithelium in developing Arctic charr, Salvelinus alpinus, was studied by light and scanning electron microscopy. Embryos, larvae, free-swimming fry, and individuals up to the age of 96 months after hatching were studied. In larvae about 10 days after hatching, microvillar and ciliated olfactory receptor cells were located in a pit and no nares were differentiated. Fifty days after hatching, two nares were present on each side of the head, and about 20 days later one or two lamellae had started to differentiate and were visible as an elevation in the caudal part of the floor of the olfactory chamber. Six months after hatching there were 5 – 10 club-shaped lamellae, which in older fish acquired a more disk-like appearance. The number and size of lamellae increased with the size of the fish, reaching the maximum number, 10 – 15 per rosette, 18 – 30 months after hatching. At 18 months, secondary folding of the lamellae had started. Eighteen months later, differentiated secondary lamellae were present and most of the central raphe was composed of indifferent epithelium. The olfactory receptors were located in the depressions between the secondary folds. The development of the olfactory organ is discussed in relation to the results of behavioural studies.
Effects of starvation on iron concentration and deposition in tissues of larval lampreys, Petromyzon marinus L.: morphological and quantitative analyses
Authors: Youson J. H.
Published: July 2008

Light and electron microscopy, inductively coupled plasma atomic emission spectroscopy, and a biochemical assay were used to compare tissue distribution and concentration of iron in larval lampreys (Petromyzon marinus) under conditions of long-term starvation and feeding in the laboratory and in recently captured individuals. There were higher values for serum iron, red blood cell numbers, and haemoglobin in nonfeeding animals compared with the field-sample individuals. Iron concentration was similar in most tissues and organs of the two laboratory-held groups and significantly higher than in similar samples of recently captured individuals. This difference was due to heavy deposition of ferric iron in primary sites of adipose tissue and, to a lesser degree, to deposits of this metal in the liver. Electron microscopy of hepatocytes of starved animals showed both ferric and ferrous iron in dense bodies, ferric iron in the cytoplasmic matrix, an increased role for the cells in carbohydrate metabolism, and some signs of bile stasis. Extended laboratory holding of larvae in both presumed fed and nonfed conditions results in alteration in blood and tissue concentrations of iron that are more likely a result of alterations in metabolism and excretion than a result of uptake of the metal from the environment.
Bioenergetic responses to the initiation of winter and glycerol formation in the leech Nephelopsis obscura
Authors: Reddy D. C. , Davies Ronald W.
Published: July 2008

Changes in glycogen, total lipid, glycerol, triacylglycerols, and active phosphorylase were examined in the freshwater leech Nephelopsis obscura during acclimation from summer (20 °C) to winter (4 °C) temperatures, during exposure to winter temperatures, and after return to summer temperatures, with oxygen maintained at saturation. Total lipids, triacylglycerols, and glycogen did not increase significantly until the temperature dropped to 7 °C, and glycerol concentrations did not increase until after exposure to 4 °C for 3 days. Thus, while decreased temperature triggered increased energy storage, glycerol synthesis required a cold stress. Shifting cold-stressed N. obscura back to 20 °C resulted in rapid resynthesis of glycogen coupled with a decrease in glycerol, but no changes in total lipid and triacylglycerols.
Characterization and isolation of an agglutinin from seminal plasma of the sea urchin
Authors: Stabili Loredana , Pagliara Patrizia , Canicattì Calogero
Published: July 2008

We investigated the biological features of a hemagglutinin present in seminal plasma of the sea urchin Paracentrotus lividus. The erythroagglutinating activity restricted to rabbit erythrocytes is calcium-dependent, relatively heat-stable, and strongly inhibited by the L(−) configuration of both arabinose and xylose. This hemagglutinin, purified by gel filtration and ion-exchange chromatography, was a single molecular species of over 200 kDa. Experimental evidence suggests that the present protein is not involved in the sperm–egg interaction or in the protection of semen from bacterial growth.
Birth to weaning: parturition, duration of lactation, and attendance cycles of Australian sea lions (Neophoca cinerea)
Authors: Higgins Lesley V. , Gass Leila
Published: July 2008

Parturition, time to weaning, and female attendance patterns were studied over four breeding seasons in Australian sea lions, Neophoca cinerea, on Kangaroo Island, South Australia. Females generally exhibited site fidelity in their choice of birth sites, and arrived a mean of 1.8 days prior to birth. After birth, females stayed ashore a mean of 9.8 days before departing on their first foraging trip. Trips to sea were about 48 h in length although there was significant variation over time. Stays ashore were about 33 h long and were much less varied than trips to sea. Females moved pups away from the natal areas after about 1 month, and began spending less time with them while they were ashore. Linked with the extended breeding cycle of 17.6 months was an equally long period of maternal investment. Females suckled their pups for 15 – 18 months, or until about 1 month before the next birth. Twenty-nine percent of females did not pup consecutively each breeding season, but continued to suckle their offspring until the next birth, some for as long as 40 months.
The abundance and distribution of bottlenosed dolphins (Tursiops truncatus) in Doubtful Sound, New Zealand
Authors: Williams Jamelia A. , Dawson Stephen M. , Slooten Elisabeth
Published: July 2008

Photographic identification and standardized zigzag surveys were used to study the distribution and abundance of bottlenose dolphins in Doubtful Sound, New Zealand. Forty individuals were identified from nicks and markings on their dorsal fins. Chapman's and Bailey's modifications to the Lincoln–Petersen estimate and the computer program CAPTURE were used to estimate the number of marked individuals in the population, which ranged from 30 to 40 animals for three survey periods (two summers and a winter). The proportion of identifiable individuals in the population was assessed empirically as 65.5%. These data resulted in a total population estimate of approximately 58 individuals. The majority of the dolphins in the catalogue were found in each survey period, indicating their residency in the fiord. Movements of dolphins around the sound were not predictable, but there were areas in which dolphins were more likely to be found and other areas in which dolphins were never seen. However, there were no obvious seasonal or daily movement patterns.
Haliotrema species (Monogenea: Ancyrocephalidae) from Indo-Pacific boxfishes (Tetraodontiformes: Ostraciidae)
Authors: Klassen Greg J.
Published: July 2008

Gill material of 12 species of Indo-Pacific boxfishes was examined for species of Haliotrema. Four parasite species were recorded: H. trochaderoi n.sp., H. crymanum n.sp., H. lactoriae, and H. triacanthi. Haliotrema trochaderoi was taken from Ostracion meleagris, O. cyanurus, and O. cubicus from the West Pacific Ocean. Haliotrema crymanum was taken from O. cubicus from the Indo-West Pacific Ocean. The morphology of these two species was compared with that of 10 other species of Haliotrema with similar male copulatory apparatus. Duncan's multiple range test indicated the two new species to be distinct from one another in all but 5 of 35 measurements (p = 0.005); multivariate analysis of variance and canonical discriminant analysis indicated them to be distinct from all Atlantic species of Haliotrema from boxfishes (p = 0.001). Haliotrema lactoriae was recorded from Lactoria cornuta, L. fornasini, and L. reipublicae, in addition to its type host, L. diaphana. It is specific to species of Lactoria but occurs on these throughout the Indo-Pacific Ocean. Haliotrema triacanthi, previously known only from species of Triacanthus (Tetraodontiformes: Triacanthidae), was also found on Ostracion rhinorhynchus. It occurs on its hosts in the Indo-West Pacific Ocean.
Daily energy requirements of beaver (Castor canadensis) in a simulated winter microhabitat
Authors: Dyck Alvin P. , MacArthur Robert A.
Published: July 2008

Daily energy expenditure, food consumption, and aquatic activity were investigated in beavers housed in a microhabitat designed to simulate winter field conditions. Beavers consumed an average of 0.52 kg/day of woody forage, representing an estimated gross energy intake of 6547 kJ/day. Animals exhibited a distinct daily rhythm in metabolic rate, which averaged 2.87 W/kg, or 1.7 times the basal rate previously reported for beaver. Beavers spent an average of 140.5 min, or about 10%, of each 24-h measurement period in water. Mean daily energy expenditure was 3880 kJ/day, and was independent of both the cumulative immersion time and the frequency of aquatic excursions per day (P > 0.05). Based on previous estimates of the energy content and digestibility of forage cached prior to freeze-up, it is unlikely that the winter energy requirements of this species can be met solely from the submerged food cache.
Reproduction in the curly-tailed lizard Leiocephalus psammodromus from the Caicos Islands
Authors: Smith Geoffrey R. , Iverson John B.
Published: July 2008

Reproduction and population structure were examined for the curly-tailed lizard Leiocephalus psammodromus from the Caicos Islands, British West Indies, from 1973 to 1978. Females and males mature at about 65–70 and 75–80 mm snout–vent length, respectively, and at about 1.5–2 years of age. Both male and female reproduction were seasonal, with egg-laying beginning late in the dry season (late April) and ending well into the wet season (September), with hatching during the wet season (late June to December). Multiple annual clutches are probably produced. Clutch size was typically two eggs (mean = 1.72 for 42 clutches). Eggs (preserved) averaged 19.9 × 9.2 mm, and mean preserved egg mass was 1.04 g. Fat-body mass in both males and females decreases with the onset of the reproductive season. The age/size structure of the population varied from month to month, depending on recruitment of hatchlings. Reproduction in Leiocephalus psammodromus is similar to that of other tropical lizards in seasonal environments.
Thermal ecology of the high-altitude bunch grass lizard, Sceloporus scalaris
Authors: Smith Geoffrey R. , Ballinger Royce E. , Congdon Justin D.
Published: July 2008

The thermal ecology of a high-altitude lizard, Sceloporus scalaris, was investigated in the Chiricahua Mountains of southeastern Arizona, where the lizards are active on sunny days throughout the year. Mean body temperature was 32.6 °C (range 12.6–39 °C) and mean air temperature was 20.2 °C (range 5.2–36.4 °C). The slope of the body temperature versus air temperature regression was 0.23. Monthly differences in body temperature were observed, with the highest body temperatures observed in early summer. Lizards at three study sites with differing slope and vegetative cover had different mean body temperatures. Males had higher body temperatures than both nongravid and gravid females. Maintenance of elevated body temperatures even during winter lengthens the activity and growing season, permitting early maturity with potentially important life-history consequences.
Host specificity and abundance of parasitic nematodes (Ascaridoidea) from the stomachs of five phocid species from Newfoundland and Labrador
Authors: Brattey John , Stenson Garry B.
Published: July 2008

Stomachs of 270 phocids from five species (bearded, Erignathus barbatus; hooded, Cystophora cristata; grey, Halichoerus grypus; harbour, Phoca vitulina; and ringed, P. hispida), collected off Newfoundland and Labrador during 1985–1993 were examined, and the numbers and percentages of larval and adult ascaridoid nematodes determined. Samples of adult nematodes were also identified using previously described allozymes. Bearded seals were infected mainly with Contracaecum osculatum A, C. osculatum B, and Pseudoterranova decipiens C, whereas hooded seals harboured mostly Phocascaris spp. Grey seals harboured large numbers of C. osculatum B, and small numbers of adult Anisakis simplex; harbour and grey seals were the only phocids heavily infected with P. decipiens B. Ringed seal stomachs contained fewer nematodes than other seal species and were mainly infected with C. osculatum B and Phocascaris spp. In several seal species positive, but no negative, associations in abundance were observed between nematodes. Sex ratios of adult nematodes among individual seals were heterogeneous, but changes in sex ratio suggest a bias towards female nematodes among larvae infecting fish and a selective loss of adult females during maturation. Overall, the results suggest that grey and harbour seals are the main source of larval sealworm (P. decipiens B) occurring in fish stocks off Newfoundland and Labrador, although small numbers of adult P. decipiens B also occurred in hooded seals.
Influence of low temperature acclimation on fate of metabolic fuels in rainbow trout (Oncorhynchus mykiss) hearts
Authors: Bailey John R. , Driedzic William R.
Published: July 2008

Rainbow trout (Oncorhynchus mykiss) were acclimated to 5 and 20 °C. Oxygen consumption of isolated perfused hearts was measured at 5 or 15 °C with either glucose or palmitate as the exogenous fuel source. With glucose as the fuel there was no significant difference in oxygen consumption of hearts from either acclimation group at either temperature. With palmitate as the fuel source, hearts from fish acclimated to and tested at 5 °C had significantly higher oxygen consumption than hearts from fish acclimated to 20 °C and tested at either 5 or 15 °C. Hearts from fish both acclimated to and tested at 5 °C had a higher oxygen consumption with palmitate than when glucose was supplied. This reflects the preference for fatty acid fuels found in cold acclimated muscle tissue, and consequently the amount of oxygen required to utilize fats. Under all experimental conditions, 14CO2 production from either (6-14C)glucose or (1-14C)palmitate could account for less than 0.5% of oxygen consumption. Tissue chemical analysis showed that most of the label from (6-14C)glucose appeared in acid-soluble (glycolytic intermediates, citric acid cycle intermediates, amino acids, etc.) and lipid fractions while most of the label from (1-14C)palmitate appeared in lipid- or acid-soluble or acid precipitate (protein material) fractions. This indicates considerable dilution of exogenous fuels in endogenous pools, which could account for the discrepancy in measured O2 consumption and 14CO2 production. Glucose catabolism was little affected by either acute or chronic changes in temperature other than an increase in glucose incorporation into the glycogen pool. Hearts from fish both acclimated to and tested at 5 °C showed an increased handling of exogenous fatty acids as reflected by elevated rates of catabolism and incorporation into intracellular lipids.