bluuebunny/crossref_metadata_2025 huggingface dataset:
Pronghorn male spatial organization: population differences in degree of nonterritoriality
Authors: Maher Christine R.
Published: July 2008

Pronghorn (Antilocapra americana) vary in spatial organization. A literature review revealed that males occupied undefended home ranges in 12 populations and maintained territories in 11 populations. Low-productivity habitats and high or low population density could preclude territoriality. Using activity budgets, interaction rates, and home-range overlap, male social organization was described for a translocated pronghorn population in central California and compared with that of another population studied at Sheldon National Wildlife Refuge, Nevada, to determine if males were organized differently. Interaction rates were highest during spring, decreased in summer, then increased in late summer coincident with the rut. Home-range overlap ranged from 0 to 85% and averaged 30.6%; small amounts of overlap resulted from geographical features rather than from behavioral interactions. Males joined groups of females and fawns during summer; few behavior patterns associated with territoriality were observed. Males occupied undefended home ranges and this spacing system may have been influenced by food abundance and distribution, population density, or a combination of these factors. Comparisons between Sheldon and Carrizo males indicated that, while neither population was territorial, the behavior of Sheldon males was closer to the territoriality end of a continuum between territoriality and undefended home range than was that of Carrizo males. Behavior patterns were very similar between the populations but some occurred more frequently among Sheldon males. Both populations lived in semi-arid habitats, where low primary productivity would make the costs of maintaining territories greater than the benefits. Differences between the populations could be based on differences in population density. The Carrizo population was small and widely dispersed and male–male competition appeared low; therefore, the opportunity to interact with other males was lower than in areas of higher population density. Comparisons with other populations were difficult to make because of a lack of quantified data on behavioral and ecological variables. Such data are required if more is to be learned about the effects of ecology and demography on social organization.
Site fidelity and effects of body mass on home-range size of Egyptian mongooses
Authors: Palomares F.
Published: July 2008

Home-range size has been found to be related to body mass of some animals both across species and within species when the spatial strategies of the sexes differ. I studied home-range size in a polygynous carnivore, the Egyptian mongoose (Herpestes ichneumon), and compared observed home-range size with predictions based on body mass. First, I tested whether mongooses actually exhibited site fidelity (for daily and multiday periods). Mongooses always showed site fidelity for a multiday home range, but in only 59% of the cases for daily home range. Adult males exhibited less daily site fidelity than did adult females or young. Multiday home-range size was similar among age–sex classes, but males had significantly more core areas than females or young. Multiday home-range size was positively correlated with body mass for adult males (r2 = 0.98, P = 0.0122) and negatively correlated with body mass of adult females (r2 = 0.40, P = 0.0374). Differences in these relationships and daily site fidelity between adult males and females suggest that the spatial strategies of male and female Egyptian mongooses are different, with the larger females defending the areas richer in resources and the larger males having more access to females.
Helminth community structure and pattern in a migratory host (Anas platyrhynchos)
Authors: Fedynich Alan M. , Pence Danny B.
Published: July 2008

The helminth community at the southern periphery of the mallard (Anas platyrhynchos) breeding range on the Southern High Plains of Texas consisted of species commonly reported in this host at northern latitudes. Although prevalence, abundance, and dominance values varied and this helminth community was species-rich and diverse, species composition was relatively consistent over temporal and host variables. Mallards had higher mean abundances of helminths in summer than winter; 80% of all helminth individuals occurred in juveniles. Recurrent groups formed during summer and within juvenile mallards were larger and more complex than groups formed during winter or in adults. Of the 15 helminth species forming group memberships, only Cloacotaenia megalops, Microsomacanthus hopkinsi, Amidostomum acutum, and Tetrameres spp. commonly co-occurred during each of four seasons in juvenile mallards, whereas C. megalops and Capillaria contorta persisted temporally in adult mallards. These species occupy different host microhabitats, suggesting little or no interaction between temporally persistent species that commonly co-occur in mallards. The results of our study suggest that helminth communities reflect the density distribution of the host species across their annual geographic range, where the breeding range represents the epicenter of origin for this host–helminth system.
Spatial and behavioral response of white-tailed deer to forage depletion
Authors: Kohlmann Stephan G. , Risenhoover Kenneth L.
Published: July 2008

We tested predictions regarding the effects of forage depletion on patterns of foraging effort, diet selection and quality, and patch selection by white-tailed deer (Odocoileus virginianus). Two deer were allowed access to four 150-m2 enclosures (patches) for 8, 16, 24, and 32 days, resulting in the exposure of the patches to deer for 16, 32, 48, and 64 animal-days and different levels of forage depletion. When the deer were given simultaneous access to all four enclosures, feeding patch selection was markedly skewed toward heavily and lightly grazed environments, while moderately depleted patches were selected least. Deer primarily consumed woody browse in patches with low (16 days) and high (64 days) forage depletion, and forbs in patches that were moderately depleted (32 and 48 days). Deer responded to forage depletion by foraging less selectively, reducing movement rates, and increasing average bite size. During the last phase of the trial, biting rates on forbs declined but increased on woody browse in response to declining forage availability. Diel foraging times remained unaffected by changes in forage availability. The behavior of deer foraging in experimental patches appeared to be consistent with predictions based on the maximization of nutrient (protein) gain, although use of the most depleted patch was greater than expected. We conclude that vegetative biomass alone is a poor indicator of foraging rewards for highly selective herbivores.
Macrobenthic associates of bioherms of the polychaete Sabellaria cementarium from northern Puget Sound, Washington
Authors: Gherardi Francesca , Cassidy Paul M.
Published: July 2008

Bioherms of Sabellaria cementarium Moore, 1906 were examined as the habitat of a diversified community in northern Puget Sound, Washington. Aggregations of around 3500 tubes/m2 were found 15–40 m below the surface, in the aphotic zone. A rich assemblage of macrobenthos finds refuge and food in this habitat, which favors most organisms (especially those leading a sedentary life). The community seems stable and is composed of a unique fauna, which differs greatly from the species collected from adjacent habitats with diverse substrates.
Sabellarian tubes as the housing of the hermit crab Discorsopagurus schmitti
Authors: Gherardi Francesca , Cassidy Paul M.
Published: July 2008

Discorsopagurus schmitti (Stevens, 1925) has been reported as the only crustacean decapod that both ecologically depends on and zoogeographically is restricted to worm bioherms. This species lives exclusively inside empty Sabellaria cementarium tubes, and actively chooses them when also presented with gastropod shells in the laboratory. The fascinating question arises as to why this species (presumably descended from shell-carrying ancestors) turned to this unusual housing, which has also caused the appearance of new modes of behavior and the evolution of a sedentary life-style.
Body composition of harp seals
Authors: Gales Rosemary , Renouf Deane , Noseworthy Elizabeth
Published: July 2008

Using chemical analysis we measured the composition of 26 harp seals (Phoca groenlandica) representing both sexes, aged between 3 months and 30 years, and encompassing a wide range of body conditions. Predictive relationships between total body water and total body fat contents, total body protein content, and gross energy were calculated. These equations allow accurate estimation of harp seal body composition provided total body water content and body mass are known. Using these data we compared the accuracy of three existing equations that have been used to predict body fat content of other species. We found that in adult harp seals, lean body mass has a relatively stable hydration of 70% but the hydration of blubber varied with body condition. Lipid content, and thus energy density of blubber, increased with increasing body condition.
Urogyrus cichlidarum gen.nov., sp.nov., Urogyridae fam.nov., monogène parasite de la vessie urinaire de poissons cichlidés au Cameroun
Authors: Bilong C. F. Bilong , Birgi E. , Euzet L.
Published: July 2008

Urogyrus cichlidarum gen.nov., sp.nov. (Dactylogyridea, Urogyridae fam.nov.) is proposed for a monogenean found in the urinary bladder of Chromidotilapia batesi Boulenger, 1901, Nanochromis caudifasciatus Boulenger, 1913, Pungu maclareni Trewavas, Green and Corbet, 1972, Stomatepia pindu Trewavas, Green and Corbet, 1972, and Tilapia sp., freshwater Cichlidae in Cameroon. The new genus is distinguished from other urinary bladder monogeneans and from all Dactylogyridea by the haptor with 2 unequal ventral hooks, a single ventral transverse bar, and 14 ventral marginal hooklets, and by a vas deferens loop around left intestinal branch as well as by a male copulatory apparatus with two accessory pieces in a claw shape. This new genus is proposed as the type of a new family, Urogyridae, and its systematic position is discussed.
Comment — Missed opportunities in the study of activity and body temperature of beaver (Castor canadensis)
Authors: Bovet Jacques
Published: July 2008

Two papers published recently in this journal have examined the relationship between patterns of activity and patterns of body temperature in free-ranging beavers in winter (D.W. Smith, R.O. Peterson, T.D. Drummer, and D.S. Sheputis, 1991. Can. J. Zool. 69: 2178–2182; and A. P. Dyck and R.A. MacArthur, 1992. Can. J. Zool. 70: 1668–1672). I argue that both papers missed their objective, owing to the use of procedures that were inadequate to detect and (or) characterize behavioral or physiological rhythms that were free-running with periods ≠ 24 h.
The search for a metabolic depression in the beaver: "lost opportunities" or red herrings? A reply to J. Bovet
Authors: MacArthur Robert A. , Dyck Alvin P.
Published: July 2008

In his critique of our recent paper (A.P. Dyck and R.A. MacArthur. 1992. Can. J. Zool. 70: 1668–1672), Bovet identifies a potential analytical problem in our treatment of the temporal patterns in activity and body temperature of free-ranging beavers in winter. We show that, while a legitimate concern, this problem reflects a calculated trade-off in the sampling methods employed, but did not prevent us from meeting our stated primary objectives. We further demonstrate, with additional analyses, that this source of error in no way undermined or invalidated our essential conclusion that beavers in this study failed to exhibit seasonal hypothermia.
Reply — Studies of beaver activity and body temperature: a historical perspective
Authors: Smith Douglas W. , Drummer Thomas D. , Peterson Rolf O.
Published: July 2008

Bovet claims that Smith et al. (D.W. Smith, R.O. Peterson, T.D. Drummer, and D.S. Sheputis, 1991. Can. J. Zool. 69: 2178–2182) and Dyck and MacArthur (A.P. Dyck and R.A. MacArthur, 1992. Can. J. Zool. 70: 1668–1672) analyzed their data on activity and body temperature of beavers (Castor canadensis) incorrectly because they ignored the likelihood that northern beavers in winter have activity rhythms with periods >24 h. The analysis by Smith et al. was in fact appropriate for demonstrating seasonal changes in body temperature and its correlation with activity. These are important issues because researchers have obtained conflicting results and because seasonal changes in activity and body temperature have implications for colony energetics in the context of food-hoarding behavior and social organization.
Dissodactylus xantusi and Dissodactylus lockingtoni (Decapoda: Brachyura: Pinnotheridae): larval development of two sympatric Pacific species
Authors: Pohle Gerhard W.
Published: July 2008

Dissodactylus xantusi and D. lockingtoni are small pinnotherid crabs living with D. nitidus as ectosymbionts on the Pacific sand dollars Encope grandis, E. californica, E. micropora, and Mellita longifissa. Like D. nitidus, D. xantusi and D. lockingtoni develop through four zoeal stages before metamorphosing to the megalopa. This is in contrast to the Atlantic species with known larval development, which all have three zoeal stages. All larval stages are described in detail, including the distribution of chromatophores and the types of setae. Beginning with the first zoea, the mean durations of the stages were 4.0, 3.8, 3.3, and 4 days for D. xantusi, the first megalopa appearing 15 days after hatching. The mean durations of the first three zoeal stages of D. lockingtoni were 3.3, 4.0, and 4.0 days, the only moult to a fourth zoea taking place 12 days after hatching. Laboratory-reared megalopae of D. lockingtoni were not obtained, but wild megalopae of both species were collected from hosts. Compared with Atlantic species of Dissodactylus, whose larvae differ interspecifically, zoeae of D. xantusi, D. lockingtoni, and D. nitidus are morphometrically and meristically very similar. In the first zoeal stage the relative length of the dorsal spine of the carapace is the only distinction between D. lockingtoni and the other two species, the differences in carapace spination becoming a little more pronounced as development proceeds. Megalopae of the three species can be readily distinguished on the basis of size, shape, chromatophore pattern, and setation. Dissodactylus xantusi shares with D. nitidus an oversize seta on the fifth leg that is not found in any megalopa of other Dissodactylus species. Collectively, larvae of the three Pacific species resemble more closely those of other members of the "large-palped," adult-defined subgroup (D. crinitichelis, D. mellitae, D. nitidus, D. primitivus) than those of members of the "small-palped" subgroup (D. stebbingi, D. rugatus), which has recently been proposed to be included in a separate genus, Clypeasterophilus.
Sealworm (Pseudoterranova decipiens) infections in demersal fish from two areas in Norway
Authors: Jensen Tor , Andersen Karin , Clers Sophie des
Published: July 2008

Fish from Torbjørnskjær, in the outer Oslofjord in southern Norway, and from Vega in Nordland in central Norway were examined for infections of the larval nematode Pseudoterranova decipiens transmitted by seals. Three sites were sampled between 1990 and 1992, two (S1 and S2) in Torbjørnskjær and one (S3) in Vega, and 3361 fish were examined in total. In Torbjørnskjær, fish were collected from shallow waters (S1) near skerries where a colony of common seals (Phoca vitulina) regularly haul out, and from deeper waters outside these skerries (S2). In Vega, an extensive zone of rocks and shallow water is inhabited by a colony of grey seals (Halichoerus grypus) and some common seals. In Vega, fish were caught from the littoral zone to 40–50 m depth, except for cusk (Brosme brosme), which were caught in deeper waters. Only demersal and benthic fish were infected in both areas, infection levels being highest in shallow waters close to the rocks (sites S1 and S3). Sculpins (Myoxocephalus scorpius) had the highest infection levels (an average abundance of 36 and 23 worms per fish, respectively), with cod (Gadus morhua) and cusk also heavily infected; the latter species was found only at Vega. Two somewhat different transmission routes to seals are suggested for the two areas.
Food consumption, feeding behaviour, and growth of triploid and diploid Atlantic salmon, Salmo salar L., parr
Authors: Carter C. G. , McCarthy I. D. , Houlihan D. F. , Johnstone R. , Walsingham M. V. , Mitchell A. I.
Published: July 2008

To test whether triploid Atlantic salmon (Salmo salar L.) parr were at a disadvantage compared with diploid parr the growth and feeding behaviour of individual parr in separate and mixed groups of diploid and triploid fish were studied in two experiments. At the end of the first experiment (separate groups) the diploid parr had significantly higher mean specific growth rates than the triploid parr. This was due to significantly higher growth during the first 40 days of the experiment; growth was not significantly different over the last 52 days. The consumption rates of individual parr were measured using radiography. There were no consistent differences in consumption rates between triploid and diploid parr in mixed or separate groups. However, at the start of the experiment the mean consumption rates of the triploid parr were significantly lower than those of the diploid parr and could explain their lower growth rates. There were no differences in the amount of damage to the caudal fin between triploid and diploid parr in either experiment. However, in a mixed group, damage to the dorsal fin of triploid parr was more severe than to the dorsal fin of diploid parr, which suggested that triploid parr in mixed groups were more likely to be the recipients of agonistic actions than the diploid parr. However, the specific growth rates of the diploid and triploid parr in mixed groups were not significantly different. It was concluded that under certain circumstances. triploid and diploid Atlantic salmon parr may exhibit differences in growth and feeding behaviour.
Observations on the axenic culture of metacestodes of Hymenolepis diminuta
Authors: Hurd Hilary , Burns Ian
Published: July 2008

The modification of a technique originally developed by Voge and Green for the axenic culture of Hymenolepis diminuta metacestodes is reported. Hatched oncospheres, cultured in microtitre plate wells at a density of 125 parasites per well, grew to the stage of scolex retraction in a minimum of 13 days in Schneider's Drosophila medium supplemented with 20% foetal calf serum and L-cysteine. Parasite growth was found to be density dependent. Initially, high parasite densities significantly increased the growth rate, but at later stages growth was suppressed. Metacestodes grown in this system were infective to rats 29 days post hatching. The effect of various changes to the culture conditions are discussed, notably the lethal effect of adding haemolymph from an intermediate host, Tenebrio molitor.
Inter- and intra-specific variability in female salmonid spawning behaviour
Authors: Barlaup Bjørn T. , Lura Harald , Sægrov Harald , Sundt Rolf C.
Published: July 2008

Egg pocket characteristics determined from the excavation of 29 stranded redds made by Atlantic salmon (Salmo salar) and brown trout (Salmo trutta) in the River Vosso in western Norway are presented. The egg pockets of Atlantic salmon were, on average, deeper (27.0 vs. 14.8 cm) and contained more eggs (707 vs. 148) than those of brown trout. An adaptive "test-digging" behaviour was indicated by the finding of a significant association between false redds and gravel classified as low-quality spawning substrate. Based on fecundity data and number of eggs per redd, it was estimated that individual Atlantic salmon and brown trout deposited their eggs in 8.4 and 5.7 different redds, respectively. A 100-year data series indicates that the high proportion of stranded salmon redds (23%) can be attributed to the high frequency (27% of the years) and random occurrence of low water discharge rates. Estimated probabilities of extinction and associated variances in fitness assigned different spawning behaviours suggest that the temporal and spatial variation in offspring survival produces a selective advantage for the multiple-redd tactics over the single-redd tactic. Moreover, in contrast to iteroparous salmonids, semelparous Oncorhynchus species invariably place all their offspring in one redd. This dichotomy can most likely be ascribed to the provision of parental care (i.e., redd guarding) by semelparous salmonids.
Summer diet of the mountain hare (Lepus timidus L.) in a low-alpine area in southern Norway
Authors: Johannessen Viviann , Samset Elisabeth
Published: July 2008

The summer diet of the mountain hare (Lepus timidus L.) was studied in a low-alpine area in southern Norway. Dietary preferences were determined for 11 hares in cafeteria trials. The hares were later equipped with radio transmitters and released, and diet selection was observed directly. The results demonstrate that mountain hares seem able to utilize a wide variety of different plants, although they selected herbs in the field. Based on the available literature, diet overlap and diet niche breadth were estimated for five sympatric herbivores; reindeer, sheep, willow grouse, Norwegian lemming, and mountain hare. Generally, the noncyclic herbivores had broader diet niches and greater dietary overlaps than the cyclic herbivores.
Body mass variation in semidomesticated reindeer
Authors: Helle T. , Kojola I.
Published: July 2008

The between-years and within-year variation in mass of semidomesticated reindeer calves and females was studied in four herds in Finnish Lapland. Mass data covered 11–23 years. In two of the herds the intensity of supplemental feeding in mid and late winter increased throughout the sampling period, whilst in two other herds the amount of food available per capita fell drastically as a result of increased density (about 1–4 individuals/km2). Calf mass increased in both supplementally fed herds and female mass in one of them. In herds on natural ranges female mass was density dependent. Both calf mass (three herds) and female mass (one herd) correlated negatively with the number of warm days in midsummer, most likely because of severe insect harassment. The sum of snow depth during the two or three preceding winters influenced body mass inversely in one herd and positively in another herd, where snow depth probably increased the availability of arboreal lichens. The detrimental effect of warm midsummers disappeared with intensification of supplemental feeding and the resultant improvement of female condition in winter. Within-year coefficients of variation (CV) correlated negatively with mean mass for calves in all four herds and for females in one herd. For calves (two herds) and for females (one herd) CV correlated positively with the number of warm days in midsummer. We suggest that late-born calves, and females who lost body reserves in winter, were most sensitive to insect harassment.
Embryology of the teleost (Oncorhynchus mykiss) lens
Authors: West J. A. , Sivak J. G. , Moccia R. D.
Published: July 2008

Embryological studies of the teleost lens have attracted little attention. The morphology of the rainbow trout (Oncorhynchus mykiss) lens during embryonic development was investigated using light microscopy. Results indicate that in general, the embryology of the rainbow trout lens proceeds much like that which has been described for other vertebrates. However, evidence in this study indicates that both layers of the lens placode invaginate, forming a lens pit, contradicting earlier descriptions of lens development in fishes. Furthermore, a hollow lens vesicle does not appear during development, as is typically described for the mammalian lens. Most importantly, the posterior limit of the anterior epithelium is situated well beyond the equator, three-quarters of the distance from the anterior pole of the lens. As a result, the germinative and transitional zones are located more posteriorly than traditionally described. The consequence of these features and their relevance to the shape of the lens are discussed.
Helminth communities of Pontoporia blainvillei (Cetacea: Pontoporiidae) in Argentinian waters
Authors: Aznar F. J. , Balbuena J. A. , Raga J. A.
Published: July 2008

We studied the helminth communities of franciscanas (Pontoporia blainvillei) to establish the relative importance of ecological and evolutionary factors in their organization. Forty-six animals obtained from by-catch in Argentinian waters from 1988 to 1990 were surveyed. The helminth communities were depauperate. Only five helminth species were detected, two of them (Hadwenius pontoporiae and Polymorphus (Polymorphus) cetaceum) accounting for about 99% of all specimens. Three species (H. pontoporiae, P. (P.) cetaceum, and Anisakis simplex) formed a recurrent group. Contrary to the stochasticity observed in other cetacean species, the helminth infracommunities were largely predictable, with little change over the years. The low vagility and coastal bottom-feeding habits of the franciscanas may account for this. The distribution of helminth species among their hosts was bimodal and colonization was nonrandom. This pattern might result from helminth specificity and tnhe specialized diet of the host. The depauperate condition of both the component community and infracommunities contrasts with general predictions for large aquatic endotherms. Comparison with franciscanas from Uruguay suggests that the helminth communities are unsaturated and have low potential for colonization. This probably shows the influence of host evolution on the helminth component community, as previously proposed for other cetacean species.
Movement patterns and territory acquisition by male red-winged blackbirds
Authors: Shutler Dave , Weatherhead Patrick J.
Published: July 2008

Movements of nonterritorial ("floater") male red-winged blackbirds (Agelaius phoeniceus) were monitored to test the hypothesis that floaters enhance their chances for territory acquisition by becoming familiar with a specific area, i.e., by restricting their geographical movements and monitoring only a few occupied territories. Intensive observations from two separate study areas did not support the hypothesis. Only 8% of the 410 males banded as floaters in an unmanipulated study area claimed territories or were ever recaptured on that study area, suggesting that floaters visited a very large number of territories. When territory owners were experimentally removed in a second study area, a greater proportion of floaters remained in the vicinity (29% of 80 males), indicating that one proximate control of floater dispersal was the availability of vacancies. Radiotelemetry confirmed that floaters ranged widely. Floaters continued to disperse as they aged, and most floaters that acquired territories probably did so outside the study areas. These patterns of dispersal and territory acquisition suggest that familiarity with a small number of territories and their owners is not a better strategy than continual dispersal for most floater red-winged blackbirds in these populations. Once adulthood was reached, younger floaters were not less successful than older floaters at claiming vacancies. This, combined with the effects of mortality, results in the majority of floaters and the majority of new territory claimants being young adult males.
Multiple areas of acute vision in two freshwater teleosts, the creek chub, Semotilus atromaculatus (Mitchill) and the cutlips minnow, Exoglossum maxillingua (Lesueur)
Authors: Collin Shaun P. , Ali M. Ather
Published: July 2008

The topography of Nissl-stained cells within the retinal ganglion cell layer is examined in two closely related freshwater teleosts from the family Cyprinidae. Regardless of the close phylogenetic relationship and the sympatric habitats of the two species, pronounced differences in the number and position of areas of increased cell density are observed in their retinae. in the creek chub, Semotilus atromaculatus, a midwater crepuscular feeder, three retinal specializations or areae centrales are identified in the dorsonasal, nasal, and temporal regions of the retina. In the cutlips minnow, Exoglossum maxillingua, a benthic diurnal feeder, two areae centrales are identified in temporal and nasal retina. The upper limits of the spatial resolving power of each species are calculated from the spacing of cells within the ganglion cell layer. Differences in the arrangement of isodensity contours appear to reflect the symmetry of each species' visual environment. The development and significance of up to three visually acute zones are discussed.
Application of the stage-projection model with density-dependent fecundity to the population dynamics of Spanish ibex
Authors: Escos J. , Alados C. L. , Emlen John M.
Published: July 2008

A stage-class population model with density-feedback term included was used to identify the most critical parameters determining the population dynamics of female Spanish ibex (Capra pyrenaica) in southern Spain. A population in the Cazorla and Segura mountains is rapidly declining, but the eastern Sierra Nevada population is growing. The stable population density obtained using estimated values of kid and adult survival (0.49 and 0.87, respectively) and with fecundity equal to 0.367 in the absence of density feedback is 12.7 or 16.82 individuals/km2, based on a non-time-lagged and a time-lagged model, respectively. Given the maximum estimate of fecundity and an adult survival rate of 0.87, a kid survival rate of at least 0.41 is required to avoid extinction. At the minimum fecundity estimate, kid survival would have to exceed 0.52. Elasticities were used to estimate the influence of variation in life-cycle parameters on the intrinsic rate of increase. Adult survival is the most critical parameter, while fecundity and juvenile survival are less important. An increase in adult survival from 0.87 to 0.91 in the Cazorla and Segura mountains population would almost stabilize the population in the absence of stochastic variation, while the same increase in the Sierra Nevada population would yield population growth of 4–5% per annum. A reduction in adult survival to 0.83 results in population decline in both cases.
Patterns of daily torpor and day-roost selection by male and female big brown bats (Eptesicus fuscus)
Authors: Hamilton Ian M. , Barclay Robert M. R.
Published: July 2008

Daily torpor can provide significant energy savings, but in bats may reduce rates of fetal and juvenile development and spermatogenesis. We examined the use of torpor during the day by male and female big brown bats (Eptesicus fuscus) in the field during the female gestation, lactation, and postlactation periods. While both sexes used torpor, males used it significantly more often and used deeper torpor than did reproductive females, indicating that the costs of torpor are higher for reproductive females. We suggest that by using shallow torpor, females may gain some of the benefits of torpor while minimizing the fitness costs. The different patterns of torpor may be responsible for observed differences in day-roost location amongst males, reproductive females, and nonreproductive females. Males should choose roosts with lower ambient temperatures than do females in order to increase the energy savings of torpor. Males and nonreproductive females roosted away from the maternity colonies more often than did reproductive females. Within one maternity colony, males roosted in the west end of the colony, while females roosted in the east end. These patterns of roosting may be related to how the roost warms during the day.
Two new species of congrogadins (Teleostei; Pseudochromidae), with range extensions for four other species
Authors: Winterbottom Richard , Randall John E.
Published: July 2008

Two specimens of a distinctive new species of the congrogadin genus Haliophis were recently collected off the south coast of Oman. This species differs from its congeners in morphometric and meristic characteristics, as well as in its highly contrasted black and white pattern. It is described and compared with the other two species of Haliophis, and a key to the species is given. A range extension for Haliophis guttatus from Aden to the vicinity of Misrat, Oman, is reported. A new species of Halidesmus is described from 13 specimens from the southern Oman coast. It is related to H. thomaseni (which is here reported to reach as far west as Masirah Island, Oman). The new species differs from H. thomaseni in most meristic values, in the form of the snout crest, and in reduced squamation. A key to the species in the genus is provided. Halimuraena shakai, known from the Kwazulu coast of South Africa and from a single specimen from Mauritius, is here recorded from the Comoro Islands. Blennodesmus scapularis, known from northwestern and northeastern Australia, is here recorded from the vicinity of Phuket, Thailand.
A survey of the parasites of Greenland halibut (Reinhardtius hippoglossoides) caught off Atlantic Canada, with notes on their zoogeography in this fish
Authors: Arthur J. R. , Albert E.
Published: July 2008

A survey of the parasites of Greenland halibut (Reinhardtius hippoglossoides) caught in Canadian Atlantic waters extending from Cumberland Sound, Northwest Territories, to the Gulf of St. Lawrence and Saguenay Fjord was conducted during the period January 1990 to March 1991. From examination of 350 fish a total of 46 parasite taxa were identified (4 Myxosporea, 1 Monogenea, 19 Digenea, 6 Cestoda, 8 Nematoda, 5 Acanthocephala, 2 Crustacea, and 1 Hirudinoidea). Included among these are 15 taxa previously unreported from this fish (Genolinea laticauda Manter, 1925; Gonocerca phycidis Manter, 1925; Neophasis sp.; Podocotyle reflexa (Creplin, 1825); Prosorhynchus squamatus Odhner, 1905; Steringophorus sp.; Eubothrium parvum Nybelin, 1922; Proteocephalus sp.; Ascarophis arctica Polyansky, 1952; Ascarophis filiformis Polyansky, 1952; Spirurida gen. sp. larva; Corynosoma validum Van Cleave, 1953; Corynosoma wegeneri Heinze, 1934; Gnathia elongata (Krøyer, 1849); and Notostomum laeve Levinsen, 1882). New Canadian records include only Steringophorus sp. and N. laeve. The parasite fauna of Greenland halibut is characterized by a large number of ubiquitous species, including many larval forms that show little host specificity, and a smaller number of species typical of pleuronectiform fishes, two of which (Myxoproteus reinhardti (Wierzbicka, 1986) and Hatschekia reinhardtii Wierzbicka, 1989) are known only from this fish. A complete listing of all parasites reported from Greenland halibut is included as an appendix.
Body size and seasonal coexistence of North American dabbling ducks
Authors: Nudds Thomas D. , Wickett Robert G.
Published: July 2008

Controversy exists about whether (i) regular character (usually body size) ratios among coexisting species might result from interspecific competition and (ii) migratory dabbling ducks (Anas sp.) might be limited by the abundance of invertebrate prey on wintering or breeding areas. We tested these ideas by comparing the extent to which coexistence of dabbling ducks on breeding and wintering grounds depended on differences in body size which, in turn, reflect differences in prey size. Species of dabbling ducks that differ in body size by less than a factor of 1.2 co-occurred less frequently than expected by chance during the breeding season when duck assemblages are characterized by low dominance (i.e., the fractional abundances of species are roughly similar). In winter, when duck assemblages are characterized by high dominance (i.e., a few abundant species and many rarer ones), the pattern of species co-occurrence in relation to differences in body size could not be discerned from that which might occur by chance. This implies that competition for invertebrate prey, at least, is unlikely during winter. These results contrast with data from assemblages of other sexually reproducing vertebrate species, and with recent theories which predict that species' assortment patterns should be more regular than random in assemblages characterized by high dominance. Our results are consistent with the idea that communities of dabbling ducks are assembled, except during winter, according to some limiting size similarity and are influenced more by interspecific interactions than by chance.
Effect of using the doubly labelled water technique on long-term recapture in the brown long-eared bat (Plecotus auritus)
Authors: Entwistle A. C. , Speakman J. R. , Racey P. A.
Published: July 2008

A banding study of Plecotus auritus was carried out in northeast Scotland between 1978 and 1991. A total of 526 bats were caught, and of these 211 had the procedures involved in the doubly labelled water technique performed on them (injection with isotopes, and in most cases removal of a small blood sample from the interfemoral vein). Recaptures of these bats in subsequent years allowed a direct comparison to be made between the proportions of recaptured bats which had been injected, those which had been both injected and bled, and those which had had neither procedure performed on them. The proportion of bats recaptured did not differ between the test and control groups, which suggests that these procedures had little or no effect on the long-term survival of this species, over and above any effect of the initial capture and handling.
Can radio collars affect dominance relationships in Microtus?
Authors: Berteaux Dominique , Duhamel Rémi , Bergeron Jean-Marie
Published: July 2008

We measured the effects of radio-collar mass (3.9–17.3% of live body mass) on dominance relationships between adult female meadow voles (Microtus pennsylvanicus). Fifty individuals of known dominance status were fitted with dummy transmitters and their status was measured 2 and 14 days later. There was no significant change in dominance when collar mass was < 10% of live body mass. However, we registered a significant loss of dominance after voles received collars of > 10% of live body mass. Body mass and activity levels of voles decreased after collar attachment, but these reductions were not correlated with collar mass. Control voles did not experience such decreases. The radiotelemetry technique as it is generally used in microtine research is not put in doubt by our results, but we demonstrate social costs associated with the use of heavier transmitters.
Effect of temperature and stimulus train duration on the departure from theoretical maximum work in fish muscle
Authors: Luiker Eric A. , Stevens E. Don
Published: July 2008

The goal of the present study was to compare the effect of temperature on contraction kinetic parameters of fish muscle with its effect on oscillatory work. In particular we studied the effect of stimulus train duration or duty cycle (the fraction of the imposed length change that the muscle was stimulated). We compared the actual work done by the muscle with a theoretical maximum work loop that would be achieved if it were fully and instantaneously relaxed at the onset of shortening and fully and instantaneously relaxed at the onset of lengthening. Temperature had a small effect on force but a marked effect on contraction and relaxation times. Thus, work was more temperature sensitive than force. The effect of temperature on work could not be predicted by its effect on any one contraction kinetic parameter. To achieve maximum work at lower temperatures, the duty cycle must be decreased because of the longer relaxation time.
Reproduction in laboratory colonies of Clethrionomys gapperi and Microtus pennsylvanicus: a comparison between species and among populations
Authors: Innes Duncan G. L. , Millar John S.
Published: July 2008

Reproduction in laboratory colonies of Clethrionomys gapperi and Microtus pennsylvanicus was examined by comparing six populations (three per species) to test the general hypothesis that populations subject to the lowest temperatures and the shortest breeding seasons would be at the "fast" end of the "fast–slow" continuum. All colonies were derived from three sites in western Canada from females that were inseminated in the wild. Postpartum mass, mass of adult females during lactation, litter size, litter and neonate masses at birth, litter mass at weaning, age when the eyes opened, and age at weaning as well as two variables describing the energetics of reproduction were examined between species and among populations within species. Three indices of physiological reproductive effort were also compared. Only neonate mass, age when eyes were open, and one index of reproductive effort differed between species. In C. gapperi, litter mass, litter size, age when the eyes opened, age at weaning, and one index of reproductive effort differed among populations. In M. pennsylvanicus, postpartum, litter (at birth and weaning), and neonate mass, age when eyes open, age at weaning, and maintenance costs during lactation were different among populations. In both species, some differences could be attributed to sampling biases, while others were simply a consequence of differences in maternal mass. In both species, the maximum difference in the age at weaning and the age when the eyes opened was less than 2 days. Differences among populations did not appear to be related to meteorological conditions, and populations in either species could not be ranked on a continuum.
New records of Ergasilus (Copepoda: Ergasilidae) in the Laurentian Great Lakes, including a lakewide review of records and host associations
Authors: Hudson Patrick L. , Bowen II Charles A. , Stedman Ralph M.
Published: July 2008

Ergasilus nerkae was found infecting ninespine stickleback (Pungitius pungitius) in lakes Huron, Michigan, and Superior and threespine stickleback (Gasterosteus aculeatus) and round whitefish (Prosopium cylindraceum) in Lake Huron. Based upon the literature and study of archived material, we propose that E. nerkae is enzootic to the Great Lakes and that ninespine stickleback are a preferred host in Lake Huron. Prevalence of E. nerkae on ninespine stickleback increased from 17% in June to 68% in September, but mean intensity remained light. Prevalence and mean intensity increased with host length. Ergasilus luciopercarum is also reported on lake trout (Salvelinus namaycush) and largemouth bass (Micropterus salmoides) for the first time. Host–parasite records of Ergasilus spp. in North America are reviewed, biology and taxonomy are summarized, and a checklist of Great Lakes host–parasite–locality records is provided. At present, eight species of Ergasilus are known to infect 42 Great Lakes fish species.
A mass budget for transgenic "Supermice" engineered with extra rat growth hormone genes: evidence for energetic limitation
Authors: Kajiura Lovaye J. , Rollo C. David
Published: July 2008

Genetically engineered "Supermice" (Mus musculus, transgenic strain Tg[MT-1,rGH],Bri2) possess multiple copies of rat growth hormone genes yielding growth rates 220% that of normal mice. To discover how Supermice alter their acquisition and allocation of resources under elevated costs of growth, a resource allocation study was conducted on forty 50-day-old normal and transgenic male mice. Individual dry mass budgets were used to compare rates of growth, consumption, faecal deposition, digestive assimilation, and respiration over 11-day intervals. The mean body mass of transgenic mice was 153% that of normal animals during this period. Surprisingly, on a mass-specific basis, Supermice consumed 6% less food despite their higher investment in growth (normal: 0.50 ± 0.01 mg food/mg dry body mass per day; Supermice: 0.47 ± 0.01 mg food/mg dry body mass per day). Assimilation efficiency was also slightly lower in Supermice (64.1%) than in normal animals (66.7%). Enhanced growth was achieved entirely through improved conversion efficiencies. Gross and net production efficiencies of Supermice were 227 and 244% those of controls, respectively. Such increased efficiencies appeared to be the result of diverting resources from processes such as behaviour, longevity assurance, and other respiratory demands. Evidence for such trade-offs supports the "principle of allocation," a key assumption for theories of life-history evolution.
Scanning electron microscopy of lattice organs in cyprids of the Rhizocephala Akentrogonida (Crustacea: Cirripedia)
Authors: Jensen Peter Gram , Høeg Jens T. , Bower Susan , Rybakov Alexey V.
Published: July 2008

The morphology and disposition of lattice organs, putative sensory structures in the carapace of cyprids, are described with scanning electron microscopy from six rhizocephalan species representing four of the five families in the suborder Akentrogonida: Clistosaccus paguri and Sylon hippolytes (Clistosaccidae), Arcturosaccus kussakini (Duplorbidae), Mycetomorpha vancouverensis (Mycetomorphidae), and Diplothylacus sinensis and Thylacoplethus reinhardi (Thompsoniidae). The disposition of pores and setae on the cyprid carapace is also surveyed. In T. reinhardi, poor quality of the specimens allowed only confirmation that lattice organs are present. Cyprids of all other species except M. vancouverensis have two anterior and three posterior pairs of lattice organs on the carapace, just as in almost all other Cirripedia. Cyprids of C. paguri and S. hippolytes are nearly identical in both general shape, carapace setation, and morphology of the lattice organs. In both species the lattice organs are oval–circular pore fields, except the second pair which is very elongate and match-shaped, a morphology unique to the Clistosaccidae. The similarities in cyprid morphology are interpreted as apomorphies supporting the monophyly of the recently rediagnosed Clistosaccidae. Both thompsoniid species have oval–circular lattice organs, indicating a possible sister-group relationship between the Clistosaccidae and the Thompsoniidae. None of the lattice organs of A. kussakini are oval or match-shaped. In M. vancouverensis there is only a single anterior pair of lattice organs, a probable autapomorphy. But the morphology of the M. vancouverensis cyprid is otherwise very reminiscent of those in the Rhizocephala suborder Kentrogonida, such as in being ornamented with numerous (> 100) carapace setae in no fixed pattern compared with the few (< 80) setae in a fixed disposition seen in the other akentrogonids. In cyprids of all Akentrogonida examined, the lattice organs lack a large terminal pore. By out-group comparison with all other cirripedes and with the Ascothoracida, this is regarded as an apomorphy that supports the monophyly of the Akentrogonida.
Mitochondrial DNA variation in Atlantic and Pacific walruses
Authors: Cronin Matthew A. , Hills Susan , Born Erik W. , Patton John C.
Published: July 2008

We used restriction enzyme analysis of polymerase chain reaction amplified mitochondrial DNA to assess genetic differentiation of two subspecies of walruses: Atlantic walruses (Odobenus rosmarus rosmarus) from Greenland and Pacific walruses (O. r. divergens) from the Chukchi Sea. Each subspecies has distinct monophyletic mitochondrial DNA haplotypes. Mitochondrial DNA sequence divergence between Atlantic and Pacific subspecies was 1.0–1.6%. Several haplotypes were observed for each subspecies. Haplotype frequencies varied among sampling locations of Atlantic walruses, suggesting that mitochondrial DNA may be useful for walrus stock identification.