bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence du parasitisme des moules sur l'alimentation des limicoles : exemple de l'Huîtrier pie hivernant dans l'Exe
Authors: Dréan-Quénec'hdu Sophie Le , Goss-Custard John D , le V dit Durell Sarah EA , West Andy D , Marion Loïc , Mahéo Roger
Published: April 2011

Parasite loads vary among feeding sites in European oystercatchers, Haematopus ostralegus, hibernating in the Exe Estuary, in Great Britain. This variation might be the result of active or passive selection of non-parasitised mussels (Mytilus edulis) because they are the preferred food of the oystercatcher in the area and are also the intermediate hosts of one of the main parasites of the bird. Parasite loads (Renicola sp. and Psilostomum brevicolle) of the mussels were studied in relation to morphological parameters known to influence the choice of prey by the oystercatcher: length of mussel, meat content, and thickness of shell. Smaller mussels generally carry the lightest parasite loads, but the number of metacercariae of the two parasites potentially consumed in a day varies with feeding site and mussel size. Thus, an oystercatcher will ingest fewer metacercariae of Renicola sp. and P. brevicolle by selecting smaller mussels from bank 1, which is one of the least visited sites in the estuary. However, the birds will have to select mussels of 37 mm or more on banks 30 and 31, which are among the most used sites. We suggest that there is no active selection of non-parasitised mussels, but rather a kind of passive selection as the mussels chosen for their energetic value happen to be also the least parasitised.[Journal translation]
Grey seal maternal attendance patterns are affected by water availability on North Rona, Scotland
Authors: Redman Paula , Pomeroy Paddy P , Twiss Sean D
Published: April 2011

Previous studies on grey seals (Halichoerus grypus) have shown that pools of water influence female distribution within inland breeding colonies. This study reveals that the availability of pools also affects maternal attendance patterns and may have implications for breeding success. An atypical dry period at the start of the 1998 breeding season on North Rona, Scotland, followed by a normal wet period, provided a natural experiment that allowed us to examine female behaviour in relation to the availability of pools. During the dry period, lactating grey seals (i) travelled long distances to gain access to water; (ii) had significantly greater rates of locomotion towards water and resulting from interactions between conspecifics; and (iii) spent significantly less time close to their pups. Long-distance locomotion and a reduction in time spent with the pup often lead to permanent mother-pup separation, resulting in starvation of the pup. However, the immediate need to gain access to water for thermoregulation or maintenance of a positive water balance outweighed the potential costs of reproductive failure, emphasising the importance of water for lactating grey seals even during the relatively cold and damp breeding season in the U.K.
Three-dimensional movements within individual dives by ringed seals (Phoca hispida)
Authors: Simpkins Michael A , Kelly Brendan P , Wartzok Douglas
Published: April 2011

We analyzed the three-dimensional movements within individual dives of five freely swimming ringed seals (Phoca hispida). We divided dives into a series of moves, each of which represented continuous movement in one direction, and evaluated several three-dimensional movement variables to distinguish between types of movement within dives. Horizontal directionality proved to be the most useful variable, and we distinguished convoluted and directional movements by fitting a mixture of two normal distributions to the observed horizontal-directionality values. Both convoluted and directional movements occurred within each phase of most dives, suggesting that ringed seals switched between behavioral modes within dive phases. Descent and ascent phases were not simply travel behavior, nor were bottom phases equivalent to patch time, complicating the formulation of optimal diving models for ringed seals. Most ringed seal dives appeared to consist of a series of patch times separated by travel times. Travel behavior accounted for the majority of dive times.
Patterns of sexually distinct scents in Microtus spp.
Authors: Ferkin Michael H
Published: April 2011

The sources of sexually discriminable scent were identified for montane voles, Microtus montanus, and compared with known sources in other species of voles. I tested two different hypotheses. The data support the hypothesis that each vole species has a unique number and pattern of sources of sexually distinct scent. The location, pattern, and number of these sources of scent on the integument may allow individuals to convey particular types of information to conspecifics. The data also support the hypothesis that the greater the number of sources of scent for signaling opposite-sex conspecifics, the greater the number of encounters that individuals within that species have with opposite-sex conspecifics. The montane vole, a semisocial species, has six sources of scent, which is intermediate between the numbers found in the meadow vole (Microtus pennsylvanicus), an asocial species, and the prairie vole (Microtus ochrogaster), a social species. The results suggest that the number, pattern, and locations of sexually distinct scents are positively associated with the frequency with which individuals encounter the scent marks of neighboring conspecifics.
Initiation of breeding after winter in bank voles: effects of food and population density
Authors: Eccard Jana A , Ylönen Hannu
Published: April 2011

We studied factors causing variation in the initiation of reproduction after winter in the bank vole (Clethrionomys glareolus), an iteroparous seasonal breeder, by offering different winter food supplements and monitoring local density variation. We used either sunflower seeds or barley to supplement the diet of populations of bank voles in grassland enclosures. In a parallel experiment we used spruce seeds, a natural winter food, to supplement the diet of bank vole populations in unfenced spruce forest. Survival, maturation, and breeding were monitored by livetrapping. Population density decreased during winter in grassland enclosures and remained constant in the forest, with no difference between food treatments. Breeding was initiated earlier in the grassland enclosures than in the forest, probably because of the supplemental food supply in both seed treatments and social and environmental stability in enclosures. Within both experiments, we found no differences in timing of parturition between food treatments. Inter actions of food treatment with density of females influenced the time of initiation of breeding in both experiments. At low densities, breeding started up to 1 month earlier than the population average. At high densities, a proportion of females did not breed during spring. Massive food supplements advanced the initiation of breeding, but among animals with similar food supplies, local population density seemed to have stronger regulatory effects. Local density variations may therefore create asynchronous breeding patterns within populations under similar wintering conditions.
Influence of breeding habitat on bear predation and age at maturity and sexual dimorphism of sockeye salmon populations
Authors: Quinn Thomas P , Wetzel Lisa , Bishop Susan , Overberg Kristi , Rogers Donald E
Published: April 2011

Age structure and morphology differ among Pacific salmon (Oncorhynchus spp.) populations. Sexual selection and reproductive capacity (fecundity and egg size) generally favor large (old), deep-bodied fish. We hypothesized that natural selection from physical access to spawning grounds and size-biased predation by bears, Ursus spp., opposes such large, deep-bodied salmon. Accordingly, size and shape of salmon should vary predictably among spawning habitats. We tested this hypothesis by measuring the age composition and body depth of sockeye salmon, Oncorhynchus nerka, and the intensity of predation in a range of breeding habitats in southwestern Alaska. Stream width was positively correlated with age at maturity and negatively correlated with predation level. However, salmon spawning on lake beaches were not consistently old, indicating that different factors affect age in riverine- and beach-spawning populations. Body depths of male and female salmon were positively correlated with water depth across all sites, as predicted. However, the mouths of some streams were so shallow that they might select against large or deep-bodied salmon, even in the absence of bear predation. Taken together, the results indicated that habitat has direct and indirect effects (via predation) on life history and morphology of mature salmon.
Differential predation by coyotes on snowshoe hares
Authors: Hodges Karen E
Published: April 2011

Differential predation on particular sex or age classes of a population can arise as a result of predator preferences or prey attributes. I examined the impacts of age, size, and body mass of snowshoe hares, Lepus americanus, on their susceptibility to predation by coyotes, Canis latrans. I observed coyote predation on naïve radio-collared hares during a fortuitous natural experiment: a coyote entered a predator exclosure fence in which hares of all ages had no previous experience with terrestrial predators, thus separating age from experience with this predator. I contrasted this manipulation with populations in which hares grew up in the presence of coyotes. Prey naiveté per se did not influence coyote predation, but older hares appeared to be more susceptible to coyote predation than younger ones. There were no obvious effects of body mass or size on coyote predation during the winter.
Does initial suppression of allofeeding in small jays help to conceal their nests?
Authors: Strickland Dan , Waite Thomas A
Published: April 2011

A neglected question in the study of communal breeding in birds concerns why alloparenting begins at variously late stages in the nesting cycle. We studied this phenomenon in the Gray Jay (Perisoreus canadensis), a species in which nonbreeders are excluded from the nest area by parental hostility and begin to feed young only during the fledgling period. We hypothesize that this pattern is favoured because of the risk of nest predation. By initially suppressing allofeeding, Gray Jay parents may reduce the frequency of predator-attracting visits to the nest when the young are most vulnerable. We evaluated this predator-avoidance hypothesis in a six-part meta-analysis using observations of 111 philopatric and immigrant nonbreeders associated with 647 pairs over 33 years and nest-visitation data for 307 other passerines. First, we found indirect evidence that Gray Jays and other corvids with non-allofeeding nonbreeders do reduce nest visitation by excluding nonbreeders. Second, we found that the hostility of adult Gray Jays towards nonbreeders peaks during the incubation and nestling periods, is stronger closer to the nest, and is directed towards both related and unrelated nonbreeders. We then found support for four predictions stemming from the predator-avoidance hypothesis. Compared with species having allofeeding nonbreeders, the Gray Jay and other corvids with non-allofeeding nonbreeders are characterized by (i) smaller clutches; (ii) lower parental nest-visitation rates (a consequence of larger food loads); (iii) a greater increase in parental feeding visits after fledging, paralleling the simultaneous relaxation of parental hostility towards potential allofeeders; and (iv) a smaller body size and smaller social groups, rendering them less able to deter nest predators. We discuss the potential value of the predator-avoidance perspective for understanding the occurrence or absence of allofeeding in other birds.
Fathead minnows learn to recognize predator odour when exposed to concentrations of artificial alarm pheromone below their behavioural-response threshold
Authors: Brown Grant E , Adrian, Jr. James C , Patton Todd , Chivers Douglas P
Published: April 2011

Hypoxanthine-3-N-oxide (H3NO) has been identified as the putative alarm pheromone of ostariophysan fishes. Previously we demonstrated a population-specific minimum behavioural-response threshold in fathead minnows (Pimephales promelas) to a H3NO concentration of approximately 0.4 nM. Minnows may, however, perceive low concentrations of H3NO as a predation threat, even though they do not exhibit an overt behavioural response. We conducted a series of laboratory trials to test the hypothesis that minnows can detect the alarm pheromone at concentrations below the minimum behavioural-response threshold. We exposed predator-naïve fathead minnows to H3NO at concentrations ranging from 0.4 to 0.05 nM paired with the odour of a novel predator (yellow perch, Perca flavescens) or distilled water paired with perch odour. We observed significant increases in antipredator behaviour (increased shoal cohesion, movement towards the substrate, a reduction in feeding, and an increase in the occurrence of dashing and freezing behaviour) in shoals of minnows exposed to a combined cue of 0.4 nM H3NO and perch odour (compared with a distilled-water control), but not by shoals exposed to lower concentrations of H3NO paired with perch odour or those exposed to distilled water paired with perch odour. When exposed to perch odour alone 4 days later, minnows initially conditioned to H3NO at concentrations of 0.40.1 nM exhibited significant increases in antipredator behaviour. These data demonstrate that minnows attend to the alarm pheromone at concentrations below the minimum behavioural-response threshold and are able to acquire the ability to recognize a novel predator even though they do not exhibit an overt behavioural response.
THE METAZOAN PARASITES OF THE HETEROSOMATA OF THE GULF OF ST. LAWRENCE: III. COPEPODA PARASITICA
Authors: Ronald Keith
Published: April 2011

Four species and one subspecies of parasitic copepods are recorded and briefly described from the Heterosomata of the Gulf of the St. Lawrence, and the distribution of the hosts indicated.
BORING SPONGES, CLIONA SPECIES, OF EASTERN CANADA, WITH A NOTE ON THE VALIDITY OF C. LOBATA
Authors: Warburton Frederick E.
Published: April 2011

Cliona celata occurs in Prince Edward Island; C. lobata in Prince Edward Island and on the Gulf shore of New Brunswick; C. vastifica in the Bay of Fundy, off Sable Island, off Prince Edward Island, and off Newfoundland. Intraspecies grafts of C. celata and C. lobata succeeded, but interspecies grafts failed. This should remove doubt about the taxonomic distinctness of these two species.
PECTINASE IN CERTAIN INSECTS
Authors: Adams J. B. , McAllan J. W.
Published: April 2011

Pectinase was found in the saliva of 23 species of aphids, one species of leafhopper, and one species of adelgid. The enzyme was not found in four species of aphids in their apterous form, and one species of psyllid, or in the saliva of the alate form of five species of aphids that contained pectinase in the apterous form. These results emphasize the need to consider each form of a species of aphid individually. The discussion considers similarities in the mode of tissue penetration by fungi and insects, and briefly the possibility that cell wall digestion by pectinase may facilitate the extraction of virus particles by insect vectors.
SOME ASPECTS OF THE EPIDEMIOLOGY OF A MIGROSPORIDIAN PARASITE OF THE SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA (CLEM.)
Authors: Thomson H. M.
Published: April 2011

Limited tests indicate that the microsporidian parasite Perezia fumiferanae is restricted to insect hosts of the genus Choristoneura and for practical purposes to the single species Choristoneura fumiferana (Clem.). Frozen spores of this parasite were found to be infectious longer than those kept under other conditions but no spores were infectious after 6 months' storage. There are two distinct methods of infection, oral and congenital. Immature eggs within infected female insects are infected by schizonts which develop into spores after the eggs are laid. All infected females, regardless of the degree of infection, transmit the parasite to their offspring, and for practical purposes all the progeny of such females are infected. Offspring of heavily infected females appear to contain more spores than those of lightly infected females. Infected males are sometimes capable of transmitting the parasite to a portion of their offspring. Congenital transmission is responsible for the passage of the parasite from host generation to generation. Increase in the incidence of the parasite occurs by oral ingestion of spores but the habits of the host larvae restrict most transmission to the late larval instars.
INVESTIGATIONS OF PERMEABILITY, DIAPAUSE, AND HATCHING IN THE EGGS OF THE MOSQUITO AEDES HEXODONTUS DYAR
Authors: Beckel W. E.
Published: April 2011

Methods for collection in the laboratory of many thousands of eggs from field-collected, blood-fed females are described. Also a way of separating fertile from infertile eggs is outlined. When the eggs are laid they are white but begin to darken within one-half hour. The darkening did not occur when the egg cell or early embryo was killed.Two changes in permeability in the prediapause stage of the eggs of Aedcs hexodontus were observed. The first took place as the chorion changed from white to black. The egg lost and gained water easily when first laid but resisted water loss and uptake as the chorion darkened. However, a complete waterproofing did not result. With the formation of the transparent cuticle a further change in permeability occurred. The egg lost hardly any water even when exposed to extreme desiccation and what little water was lost was regained very slowly. However, the cuticle, with the chorion removed in sodium hypochlorite, was quite permeable. The impermeability of the chorion and cuticle combination must result from the bonding between the two and this bonding must be disrupted by the dechorionation.To study the obligate diapause that occurs in the late embryogeny of the mosquito egg the effect of making water available to the embryo, of light, and of low temperature was studied. Diapause was not broken when water was available to the embryo, nor did alternate periods of light and dark at room temperature or at lower temperatures disrupt the diapause. To test the influence of cold the temperature of 1° and −3 °C. were used to simulate the temperatures in the field. The low temperatures were found to terminate the diapause but the numbers of eggs hatching did not steadily increase with an increase in the time of exposure to cold. No clue has as yet been discovered to explain these results. A hatching infusion of decaying adult mosquito bodies in distilled water was found to give more hatching than did distilled water alone. The mechanism of the hatching stimulus is not known.
THE MANNER IN WHICH THE SPONGE CLIONA BORES IN CALCAREOUS OBJECTS
Authors: Warburton Frederick E.
Published: April 2011

Boring in shells and calcite crystals was investigated, using a new type of reconstitution culture. No free acid was detected, and no detectable quantity of calcium was put in solution by the sponge. However, acid action is indicated by restriction of boring to calcium carbonate. Conchiolin is penetrated with difficulty. Cells in contact with the substratum form a reticulum of fine pseudopodia and filaments; a corresponding pattern of lines is etched into the calcite. The areas so marked out are the same size and shape as the fragments discharged by the sponge. These fragments are identical whether from shells or calcite crystals; their faces are curved but their edges sharp. Apparently the cytoplasmic filaments insinuate themselves into calcite by secreting minute amounts of acid, and undercut fragments which are carried through the sponge parenchyma to excurrent canals.
MORPHOLOGY OF DITYLENCHUS DESTRUCTOR THORNE, 1945 (NEMATODA: TYLENCHIDAE), FROM A PURE CULTURE, WITH SPECIAL REFERENCE TO REPRODUCTIVE SYSTEMS AND ESOPHAGEAL GLANDS
Authors: Wu Liang-Yu
Published: April 2011

Specimens of a pure line population of Ditylenchus destructor were studied. The female reproductive system is well differentiated into the ovary, oviduct, and uterus. The last is further differentiated into the seminal receptacle, quadricolumella, and uterus proper. There is a postuterine pouch, and this, with the vulva, is also described. The functional regions of the male reproductive system are distinct: the testis, vas deferens, seminal vesicle, and ejaculatory duct.The posterior ends of the two subventral esophageal glands extend caudad to about the same level, each with a small nucleus. The large dorsal gland, with a conspicuous, larger nucleus, extends behind the esophago-intestinal junction. The esophageal tube leaves the esophagus on the inner surface of the dorsal gland, just behind the subventral glands, where it joins the intestine. A pair of very small cells guard the entrance of the esophagus into the intestine.
THE BIOLOGY OF THE TROPICAL SEA URCHIN TRIPNEUSTES ESCULENTUS LESKE IN BARBADOS, BRITISH WEST INDIES
Authors: Lewis John B.
Published: April 2011

Tripneustes esculentus is a large white-spined sea urchin, common at Barbados and in coastal waters throughout much of the tropical Atlantic, which is exploited locally as food. Its biology is given here in terms of growth, reproduction, development, reactions, methods of feeding, and variability. Growth as a whole is relatively rapid during fall and winter months, but slows down during spring and summer, which is the period of gonad maturation. Ripening individuals tend to aggregate and spawning occurs throughout the three summer months. The larvae are described and also the metamorphosis of late plank-tonic stages. Adult animals move away from sources of light stimulus. They feed almost exclusively upon algae.
THE NORMAL BLOOD CHEMISTRY OF THE BEAVER (CASTOR CANADENSIS): B. BLOOD GLUCOSE, TOTAL PROTEIN, ALBUMIN, GLOBULIN, FIBRINOGEN, NON-PROTEIN NITROGEN, AMINO ACID NITROGEN, CREATINE, CREATININE, CHOLESTEROL, AND VOLATILE FATTY ACIDS
Authors: Stevenson A. B. , Kitts W. D. , Wood A. J. , Cowan I. McT.
Published: April 2011

Blood glucose, total protein, albumin, globulin, fibrinogen, non-protein nitrogen, amino acid nitrogen, creatine, creatinine, cholesterol, and volatile fatty acids have been determined on blood samples taken from yearling and adult beavers. In most cases the values of the summer determinations are much lower than those taken in the fall for the two age classes under study. Where different, the blood values of adult beaver are higher than those of yearlings.
Effects of pinealectomy and bilateral enucleation on the phototactic response and on the conditioned response to light of the goldfish Carassius auratus L.
Authors: Fenwick James C.
Published: April 2011

Intact goldfish in a light gradient were unevenly distributed and spent most of their time in the darker half of the gradient. Pinealectomized, bilaterally enucleated, or pinealectomized plus bilaterally enucleated goldfish were distributed uniformly throughout the light gradient. It was concluded that the phototactic response of goldfish depends upon the presence of the pineal organ as well as the eyes.In a conditioning situation, pinealectomized animals with intact vision showed significantly more responses to the conditioned stimulus than did the control animals with intact vision when the conditioned stimulus was light, but not when the conditioned stimulus was sound. Blind goldfish, with or without an intact pineal, could not be effectively conditioned to light although they did become conditioned to sound. Pinealectomy did not affect the conditioning of either the blind or the eyed goldfish to sound.Among goldfish with intact vision, pinealectomy increased the spontaneous swimming activity. Blinding enhanced the level of spontaneous swimming activity more than did pinealectomy. But blind plus pinealectomized goldfish displayed a level of spontaneous swimming activity which was intermediate between the level shown by pinealectomized eyed animals and blind animals with an intact pineal.The significance of these findings has been discussed in terms of the photosensory role of the goldfish pineal organ.
Occurrence of an endozoic alga in the giant scallop Placopecten magellanicus (Gmelin)
Authors: Naidu K. S. , South G. R.
Published: April 2011

Endozoic unicellular algae are described from the marine bivalve Placopecten magellanicus (Gmelin) in Newfoundland. The endobionts, tentatively reported as zoochlorellae, represent the first recorded instance of endozoic algae occurring in the Pectinidae.
Staining methods for sections of epon-embedded tissues for light microscopy
Authors: Leeson C. Roland , Leeson Thomas S.
Published: April 2011

Sections 0.5–2 μ thick are mounted on clean glass slides and allowed to dry. A number of staining procedures are described. After the sections are stained, permanent preparations are made by mounting them in a synthetic resin. The methods result in sections which are suitable for routine light microscopy and for comparison with adjacent electron microscopic sections.
Effects of hypophysectomy, methallibure, and thiourea on the ovary of the juvenile guppy, Poecilia reticulata Peters
Authors: Pandey S.
Published: April 2011

Ovaries and oviducts failed to differentiate in guppies which were hypophysectomized as juveniles. Likewise ovarian differentiation did not take place in juvenile guppies which had been treated with either thiourea or methallibure.
Some helminth parasites from Illex argentinus (de Castellanos, 1960) (Cephalopoda: Ommastrephidae)
Authors: Threlfall William
Published: April 2011

Helminths belonging to two genera of cestodes (Phyllobothrium and Pelichnibothrium) and two of nematodes (Anisakis, unidentified) were recovered from 132 specimens of Illex argentinus (de Castellanos, 1960) from Mar del Plata, Argentina. The cestodes are described and figured.
Site fidelity and seasonal range use by bighorn rams
Authors: Festa-Bianchet Marco
Published: April 2011

The seasonal dispersion of Rocky Mountain bighorn rams (Ovis canadensis canadensis) in southwestern Alberta was monitored over 5 years. Rams captured on a 10-km2 low-elevation range (a wildlife sanctuary) were relocated up to 48 km away. Numbers of rams in the sanctuary peaked in early June and in October. About 40–50 rams wintered in the wildlife sanctuary and in areas to the east, and for the two concentrations they were joined by nonresident rams, particularly in early June. Site fidelity of resident rams was > 98% for the two concentrations, 77% for the rut, and 62% for the summer. Younger rams were less migratory than mature rams. Exploitation of areas east of the sanctuary likely allowed early access to new growth forage, but rams did not consistently exploit the entire altitudinal range available to them. Individual rams had different seasonal dispersion patterns, and these were not rigidly repeated in successive years. It is suggested that gregariousness had a major role in determining distribution, and that the two concentrations may allow practice and development of social skills.
Fine structure of the pecten oculi of the common loon (Gavia immer)
Authors: Braekevelt C. R.
Published: April 2011

The pecten oculi of a diurnally active diving bird, the common loon (Gavia immer), was studied by light and electron microscopy. In this species the pecten consists of a pleated, highly vascular, pigmented structure that is situated over the optic nerve head and projects into the vitreous chamber. Fourteen to 15 accordion folds are joined apically by a heavily pigmented bridge of tissue, which holds the pecten in a fanlike shape, widest at the base. A distinct basal lamina encloses the entire pecten. Within each fold are numerous capillaries, melanocytes, and larger blood vessels that are often difficult to differentiate as either arterioles or venules. The capillaries are surrounded by basal laminae separated from the endothelial cells by several fibrillar layers. Pericytes are often enclosed within the basal lamina. These capillaries display numerous microfolds on their luminal surface, with a slightly reduced number of processes on the abluminal border. The endothelial cell body is extremely thin and most organelles are in the paranuclear region. The melanocytes, which are most numerous in the bridge region, form an incomplete sheath around these capillaries. As in other species, the morphology of the pecten in the loon indicates a heavy involvement in the transport of materials.
The life histories of Limnephilus externus Hagen, Anabolia bimaculata (Walker), and Nemotaulius hostilis (Hagen) (Trichoptera, Limnephilidae) in a pond in southern Alberta, Canada
Authors: Berté Stephen B. , Pritchard Gordon
Published: April 2011

Limnephilus externus and Anabolia bimaculata are caddisflies that typically inhabit temporary pools, while Nemotaulius hostilis is a species that inhabits permanent pools. In a permanent pond with a fluctuating water level, both groups could be accommodated. The temporary-pool species laid egg masses on the ground above the water level in late summer. Larvae hatched in the autumn but remained in the masses until submersed by the rising water in the spring. Larvae grew at rates faster than those for any permanent-water trichopteran studied to date. Limnephilus externus adults emerged through August and underwent a 1-month reproductive delay. Anabolia bimaculata adults emerged through July, but showed no signs of a reproductive delay. By contrast, N. hostilis oviposited on riparian vegetation and larvae entered the water on hatching in August. Larval growth rates approximated those of other detritivorous shredders found in permanent waters. Over 75% of adult emergence occurred in 1 week at the end of May and adults underwent a reproductive diapause of slightly over a month's duration. The metabolic cost of high water temperatures on cool-adapted limnephilid caddisflies is postulated as the driving force behind the evolution of reproductive diapause in this family.
The behaviour of mature male sperm whales on the Galápagos Islands breeding grounds
Authors: Whitehead Hal
Published: April 2011

The behaviour of mature male sperm whales (Physeter macrocephalus) was observed off the Galápagos Islands between 1985 and 1991. The abundance of males peaked in April and May at 3% of the population. Only 1 of the 18 photographically identified males was sighted off the Galápagos in two different years. In their residency periods off the Galápagos and their lack of preferred ranges, and in many aspects of their behaviour, males were similar to females. However, unlike females, males were sometimes seen alone and never performed any aerial behaviour. Although they were occasionally seen or heard together, there are indications that males avoided one another, perhaps by listening for the "slow click" vocalizations made by males approximately 75% of the time. One incidence of possible aggression between males was observed, and many males possessed parallel scars on their heads, presumably made during aggressive encounters. Males moved between groups of females, spending very approximately 8 h with each group. Groups of females were often revisited by particular males over periods of a few days but never over more than 1 week. Males showed no obvious preference for particular groups, although a few close associations between individual males and individual females were noticed over intervals of a few days. When males were present, females showed increased rates of making spyhops and sideflukes (indicating manoeuvring) and codas (a communicative vocalization). Copulation was not observed. The evidence is consistent with males' maximizing their expected reproductive success by roving between groups of females.
A new species of duck leech from North America formerly confused with Theromyzon rude (Rhynchobdellida: Glossiphoniidae)
Authors: Davies Ronald W. , Oosthuizen J. H.
Published: April 2011

In North America, Theromyzon specimens with three annuli between the male and female gonopores belong to the newly described species Theromyzon trizonare. A detailed description of the new species is provided, with a description of the external and internal features that differentiate it from other species in this genus. The diagnostic features of T. trizonare include the presence of three annuli between the gonopores, two female pores opening to the exterior, and atrial cornua at the terminal ends of the paired male ducts.
Evaluation of the diet of Sowerby's beaked whale, Mesoplodon bidens, based on isotopic comparisons among northwestern Atlantic cetaceans
Authors: Ostrom Peggy H. , Lien Jon , Macko Stephen A.
Published: April 2011

Sowerby's beaked whale, Mesoplodon bidens, is a poorly known and infrequently encountered species. Consequently, its behavior and habitat requirements are largely unknown. Evidence of the trophic level and diet of M. bidens was obtained through a comparison of δ13C and δ15N values for this species with those for eight other cetaceans and the basking shark, Cetorhinus maximus. The δ13C value for M. bidens (−18.5 ± 1.1‰) was similar to that for all other cetaceans (−18.7 to −17.2‰) except the sperm whale, Physeter macrocephalus, and the blue whale, Balaenoptera musculus (−22.8 and −20.1‰, respectively). At least a portion of the range of δ13C values for the cetaceans and the basking shark is thought to be related to variations in the lipid content of the samples. Nitrogen isotope values appear to reflect trophic position. Based on δ15N, organisms can be ordered along a trophic continuum bracketed by the planktivorous basking shark (9.9‰) and the piscivorous white-beaked dolphin, Lagenorhynchus albirostris (16.2‰). The trophic position of M. bidens (δ15N = 11.7‰) is intermediate between those of the pygmy sperm whale, Kogia breviceps (δ15N = 11.9‰), and the sperm whale, Physeter macrocephalus (δ15N = 11.1‰), and thus supports previous suggestions that these species feed at similar trophic positions. The estimated δ15N value of the diet of M. bidens, 8.7‰, is consistent with a diet that has a large contribution from small offshore squid, δ15N = 9.3‰.
Fine structure and immunocytochemistry of cells within the endocrine pancreas of the gar (Lepisosteus osseus)
Authors: Groff Karen E , Youson John H
Published: April 2011

Routine electron microscopy and immunocytochemistry were used to describe the cell types in the islets of the endocrine pancreas of the gar Lepisosteus osseus, an actinopterygian fish of the order Semionotiformes, which has an ancient lineage. The general fine-structural features of cells composing the islets reflect their synthesis and packaging of protein for liberation at their perivascular surface. Cells are directly apposed to numerous capillaries and they are richly innervated with nerve terminals containing dense-cored vesicles. The islet tissue comprises many B cells, which are easily distinguished by their ubiquitous granules with polymorphous matrix cores and a loose-fitting membrane. These granules are only immunoreactive with an insulin antiserum. Only one type of D cell is found throughout the islets and it contains many granules of varying electron density, the most abundant granule profile being dumbbell-shaped. All granules in this cell type have a tight-fitting limiting membrane and they immunostain with antisomatostatin-14 and -34. Cells at the periphery of the islet contained granules of similar morphology to those in the D cells, but the granules were less numerous. Many granules in the cells were immunoreactive with both antiglucagon and antineuropeptideY, while others immunostained with only one of these antibodies. Since no cells stained exclusively for either glucagon or neuropeptide Y, it was concluded that there are only three cell types in the endocrine pancreas of the gar: B and D cells and a third cell type (A/F) that co-localizes peptides of the glucagon and pancreatic polypeptide family. Although this co-localization is not uncommon in the vertebrate endocrine pancreas, it may have some phylogenetic and (or) ontogenetic significance in this organism.
Reproduction and productivity of semidomesticated reindeer in northern Finland
Authors: Kumpula Jouko , Colpaert Alfred , Nieminen Mauri
Published: April 2011

The increase in the Finnish semidomesticated reindeer (Rangifer tarandus tarandus) stock and the high level of meat production during the 1980s and the beginning of the 1990s were mainly due to reindeer-management practices. However, the continuing deterioration of winter-range quality has now forced reindeer managers to invest increasingly in supplementary feeding. At the same time, carrying-capacity models for semidomesticated- reindeer ranges have proved difficult to develop. This study deals with reproduction and productivity of the reindeer stock in northern Finland during the period 1987-1995. The results reveal that reproduction and productivity of reindeer in the study area are largely regulated by density-dependent factors related to the quantity and quality of winter ranges. Reindeer densities on total rangeland had the strongest effect on the slaughter body masses of reindeer, which indicates the special importance of summer and autumn pastures for growth and autumn condition of reindeer. Through intensive calf slaughtering, the natural mortality rate was minimised and reproduction rates and reindeer meat production were increased, although winter ranges were heavy grazed. Developing semidomesticated-reindeer husbandry to be more economical in the future by keeping sustainable meat production at a sufficiently high level while maintaining reindeer rangeland in adequate condition and supplementary feeding quite marginal in Finland involves consideration of both ecological and management factors. One way of looking at the economic carrying capacity of Finnish semidomesticated-reindeer ranges is to develop a model based on dependence among the factors presented in this study. Sustainable net incomes from reindeer husbandry could then be optimised by studying and modelling the economy of reindeer management itself with respect to stock density.
Haematogram of the tilapiaOreochromis niloticus(Cichlidae, Teleostei) and application of a putative phenoloxidase for differentiating between neutrophilic granulocytes and monocytes
Authors: Witten P Eckhard , Villwock Wolfgang , Renwrantz Lothar
Published: April 2011

To date, little is known about the haematology of the tilapiaOreochromis niloticus, which is one of the most important species in freshwater aquaculture worldwide. We present a haematogram of O. niloticus obtained by means of panoptical staining and cytochemical procedures such as demonstration of acid phosphatase, peroxidase, oxidase, esterase, and the CD14 receptor. Emphasis was placed on the differentiation between neutrophils and monocytes, which in the past has been difficult to accomplish for many fish species. Monocytes were detected with monoclonal antibodies raised against the human CD14 receptor. Neutrophilic granulocytes displayed oxidase activity, unique for this cell type. The enzyme has many properties of a phenoloxidase. In O. niloticus this enzyme is a good marker for distinguishing neutrophils from cells of the monocyte-macrophage lineage.
Direct and indirect effects of pollution on the foraging behaviour of forest passerines during the breeding season
Authors: Brotons Lluís , Magrans Marc , Ferrús Lluís , Nadal Jacint
Published: April 2011

Direct and indirect effects of acid deposition on the foraging behaviour of three forest passerine species, the Crested Tit (Parus cristatus), Long-tailed Tit (Aegithalos caudatus), and Coal Tit (P. ater), during the breeding season were studied. In two areas, one affected by pollution from a nearby coal-fired power station and the other unaffected by pollution, we measured needle density and arthropod availability on tree branches; both factors are recognised as affecting the foraging behaviour of forest birds. Tree-site use and movement patterns of birds searching for prey were also determined in both areas. Branch needle density was lower in the polluted area, as were densities of the main arthropod groups found on needled twigs (Homoptera and Aranae); however, the total abundance of arthropods did not differ between the areas, and some groups even seemed to increase slightly in abundance in the polluted area. Bird behaviour differed between zones in both tree-site use and foraging activities. The Coal Tit showed the greatest number of differences between the areas. The three species showed lower pecking and higher vigilance rates in the polluted area. Higher vigilance rates are interpreted as a response to a higher predation risk due to thinned canopies in polluted forests. The results are discussed in relation to species' breeding performance and ecology. It is concluded that, through increasing levels of stress, the indirect effects of pollution have a negative impact on bird foraging behaviour during the breeding season.
Growth in a cold environment: body size and sexual maturity in a northern population of spotted turtles, Clemmys guttata
Authors: Litzgus Jacqueline D , Brooks Ronald J
Published: April 2011

Using mark-recapture data collected from 1978 to 1997, we examined growth rates, adult body size, and age and size at sexual maturity of spotted turtles (Clemmys guttata) in a northern temperate climate. Relative instantaneous growth rate analyses indicated that growth rates were inversely related to body size, individual variation in growth rate was high, and females and males did not differ with respect to growth rates. Growth of our spotted turtles was described well by both the von Bertalanffy and logistic growth models, although the von Bertalanffy model provided a slightly better fit to our data. Asymptotic sizes and intrinsic growth factors did not differ between the sexes. Northern spotted turtles reach a larger mean adult body size relative to southern populations. Turtles were not sexually size dimorphic with respect to carapace length; however, plastron length was greater in females than in males. Sexual maturity was reached at a larger size (a carapace length of approximately 103 mm for females and 105 mm for males) and estimated age (12-15 years for females and 11-13 years for males) in northern spotted turtles relative to more southerly conspecifics.
The development of salmon lice (Lepeophtheirus salmonis) on artificially infected post smolts of sea trout (Salmo trutta)
Authors: Bjørn Pål Arne , Finstad Bengt
Published: April 2011

The developmental rate, distribution on the host, and pathogenicity (skin damage) of salmon lice (Lepeophtheirus salmonis) were tested on artificially infected sea trout (Salmo trutta) post smolts. Male lice developed faster than females, taking approximately 29 and 38 days, respectively, to reach the adult stage at 10°C. During this time, infection intensity decreased. Less than 40% of the lice reached the adult stage, and their distribution changed from overdispersed towards a more random pattern. The chalimus larvae of the lice exhibited a preference for the gills and fins, especially the dorsal fin, and caused only minor skin damage. When the preadult and adult stages appeared, skin damage became severe, especially on the preferred head and dorsal areas, causing mortality of the most heavily infected fish.
Morphometric differentiation in populations of the Central European sculpin Cottus gobio L., a fish with deeply divergent genetic lineages
Authors: Riffel Michael , Schreiber Arnd
Published: April 2011

The morphological differentiation between four population collectives of the Central European sculpin Cottus gobio from southwestern Germany and adjacent France (the contact region of the Rhine, Danube, and Rhône drainage basins) was evaluated using multivariate analysis of 34 morphometric and 3 meristic characters. Body shape separated Neckarian and Danubian sculpins, Rhenish stocks taking a somewhat intermediate position. These morphological differences between populations from various drainage basins were slighter than the deeper allozyme differentiation observed in a previous study. However, both allozymes and morphometry indicated the same population groupings. It is concluded that C. gobio displays an accelerated rate of allozyme evolution, or that stabilizing selection conserves its phenotype despite ongoing evolution at the protein level. The morphological data do not support the distinction of species in the area of the Rhine/Danube watershed.
Fluctuating asymmetry in an ornamental trait in the cave weta, Pleioplectron simplex Hutton (Orthoptera: Rhaphidophoridae): no role for parasites
Authors: Thomas F , Ward D F , Poulin R
Published: April 2011

Using digitised pictures of the pronotum, we investigated the influence of nematomorph and mermithid parasites on the expression (intensity and fluctuating asymmetry) of cuticular ornamentation in the cave weta, Pleioplectron simplex. Because P. simplex is nocturnal, this ornamentation is probably not subject to strong directional or stabilising selection. Based on measurements of brightness, we found no significant difference in the amount of pigmented area between unparasitised and parasitised males or females. Parasitised individuals were not significantly more asymmetrical than unparasitised ones. This result was not due to measurement error. Among parasitised wetas, brightness and the fluctuating asymmetry were not related to the length of the parasite, even when the size of the host was taken into account. These results are discussed in relation to current ideas concerning the influence of parasites on fluctuating asymmetry of traits in the host.
Morphological correlates of flightlessness in southern African Scarabaeinae (Coleoptera:Scarabaeidae): testing a condition of the water-conservation hypothesis
Authors: Chown Steven L , Pistorius Pierre , Scholtz Clarke H
Published: April 2011

Flightlessness in desert beetles is thought to have evolved either as a response to decreased environmentalheterogeneity or directly to reduce water loss. The water-conservation hypothesis rests on three conditions: that spiraculartranspiration is greater than cuticular transpiration; that cuticular transpiration rates are lower in desert species; and thatchanges in body form associated with flightlessness lead to an overall reduction in water loss rates. The extreme form of themorphological-convergence condition suggests that this change in body shape should be most pronounced in desert-dwellingtaxa. The morphological-convergence condition was examined using a morphometric analysis of body shape in flying andnonflying dung beetle species from two southern African tribes occurring in arid and mesic habitats. Although the Canthoninihave a more rounded body than the Scarabaeini, flightless species in both tribes have a more rounded body than the flying ones,except at the smallest body sizes. This rounding is more pronounced in flightless, desert-dwelling Scarabaeini than in flightlessspecies from more mesic habitats. All three conditions required by the water-conservation hypothesis are met in various beetletaxa, but the hypothesis and its conditions have yet to be tested on a single, monophyletic taxon.