bluuebunny/crossref_metadata_2025 huggingface dataset:
Population genetics of the woodlousePorcellio scaberLatr. (Isopoda: Oniscoidea) in central Europe: passive dispersal and postglacial range expansion
Authors: Wang Magnus , Schreiber Arnd
Published: April 2011

Allozyme variability was studied in 581 Porcellio scaber from 20 population samples in Germany, France, and Poland that were spaced at geographic distances ranging from a few metres to 1200 km. Four of 12 inferred genetic loci proved to be polymorphic (Aat-2*, Gpi*, Mdh-2*, and Pgm*), with three (Aat-2*) to five (Gpi*, Mdh-2*, and Pgm*) alleles each. Average polymorphism (P), observed heterozygosity (Ho), and allelic diversity (AD) were 0.329, 0.155, and 1.72, respectively. Genetic among-sample distances, fixation indices, and principle component analysis of allele frequencies indicate considerable genetic homogeneity throughout the study area, except for one of two population samples from offshore islands. Isolation by distance was indicated by increasing genetic distances and declining fixation indices with increasing geographical distance between collection sites. The population genetic homogeneity of a litter-dwelling organism lacking efficient means for active dispersal is interpreted as resulting from the recent postglacial recolonization of the study area from a single ice age refugial area, by the large effective population size of P. scaber, and by passive human-aided dispersal.
Demography and sexual size dimorphism in northern water snakes, Nerodia sipedon
Authors: Brown Gregory P , Weatherhead Patrick J
Published: April 2011

We used data from a 9-year mark-recapture study to determine whether demographic factors could explain female-biased sexual size dimorphism in northern water snakes (Nerodia sipedon). Most males reached sexual maturity at 3 years of age, while most females delayed maturity for an additional year. Female survivorship was not significantly lower than that of males, despite the fact that females grow as much as four times faster than males. Among females, survivorship increased until maturity and decreased thereafter, suggesting a survival cost to reproduction. Life-table calculations indicated that the increase in both survival rates and fecundity with body size made 3 years the optimal age for females to reach sexual maturity. However, if females were not large enough at 3 years of age, their best strategy was to mature the following year. Seasonal patterns of mortality suggest that mating imposes a high mortality cost on males. Intermediate-sized males survived slightly but not significantly better than small and large males. This slight survival advantage of intermediate-sized males was not sufficient to explain why males are so much smaller than females. Therefore other selective factors must be responsible for males retaining a small size. A reproductive advantage associated with small size seems the most likely possibility.
Antibody labeling of the blue-sensitive cones in the retinae of teleost fishes
Authors: Veldhoen Kathy , Beaudet Luc , Runions John , Sharma Sansar , Hawryshyn Craig
Published: April 2011

Characterization of visual opsins can be achieved with the use of specific polyclonal or monoclonal antibodies. In this study, antiserum was raised against a conjugate protein including an N-terminal sequence of the short wavelength sensitive (SWS, commonly referred to as blue-sensitive) visual pigment opsin in goldfish (Carrasius auratus). The antiserum showed immunoreactivity to retinae of phylogenetically distant teleosts, including the goldfish, rainbow trout (Oncorhynchus mykiss), and bluehead wrasse (Thalassoma bisasciatum). Complementary DNA (cDNA) was synthesized from goldfish retinal messenger RNA. An N-terminal sequence of the SWS opsin was PCR-amplified from the cDNA and subsequently cloned into an expression vector. Expressed protein was purified by metal chelate affinity chromatography and used to immunize New Zealand white rabbits. Immune serum was collected and used in immunocytochemical assays, which revealed that the antiserum contains antibodies specific for an opsin that resides in single-cone photoreceptors of the goldfish, rainbow trout, and bluehead wrasse. The results confirm those from earlier studies of goldfish in which short-wavelength sensitivity was localized to single cones, and suggest that the association between short-wavelength sensitivity and single cones may be a feature common to many teleosts. The production of antiserum specific for SWS opsins provides a useful tool in the characterization of opsin expression within teleost retinae.
Effects of the blood parasite Leucocytozoon simondi on growth rates of anatid ducklings
Authors: Shutler Dave , Ankney C Davison , Mullie Adele
Published: April 2011

The blood parasite Leucocytozoon simondi is often associated with heavy mortality of ducks and geese, especially domestic ones, in North America. In contrast, in a previous study we found no mortality from L. simondi in our wild stock of mallard (Anas platyrhynchos) and American black duck (Anas rubripes) ducklings. However, because parasites can slow growth, which could extend the interval during which ducklings are susceptible to predators, we tested for parasite effects on growth rates. We analysed growth rates over the first 20 days of life, based on tarsus length, culmen, bill width, body mass, and a principal component of structural size. Growth rates of infected ducklings were not lower than those of uninfected ducklings. Similarly, more intense infections did not have a greater effect on growth rates. Hence, growth rates were not negatively affected by L. simondi, which suggests that effects of this parasite on wild duck populations have been overestimated.
Removal of seeds from vertebrate faeces by ants: effects of seed species and deposition site
Authors: Pizo Marco A , Oliveira Paulo S
Published: April 2011

We investigated the removal of seeds of three species (Philodendron corcovadense and Philodendron appendiculatum (Araceae) and Aechmea sp. (Bromeliaceae)) from the faeces of capuchin monkeys (Cebus apella) by ants in a lowland Atlantic rain forest in southeast Brazil. We examined seed removal by ants in the understory and in treefall gaps, which probably differ greatly in microclimatic conditions. We examined whether seed removal varied among seed species, between understory and gaps, and also among five gaps that differed in size and age. We recorded 17 ant species (4 subfamilies, 9 genera) on the faeces, 8 of which were observed removing seeds. On average, 68% of the seeds had been removed from faecal portions containing 15 seeds each after 24 h. For both the understory versus gap and the among-gap comparisons, seed species significantly affected the proportion of seeds removed, while deposition site (i.e., understory versus gaps or among gaps) had no effect. We interpreted these results as a consequence of the equalizing effect of three myrmicine species (Pheidole sp. 1, Pheidole sp. 3, and Pheidole sp. 7) upon seed removal. These ant species were the most frequently recorded on faeces (63 and 44% in understory and gap sites, respectively, for all three Pheidole species combined) and are among the most abundant litter-foraging ants in the understory and gaps. Because of the high abundance of ants in Neotropical forests, and the flexibility of some ant species in the microclimatic gradient they use, seed removal is likely to be less affected by differences in microclimatic conditions between understory and gaps than by the seed species involved.
Strategy and capability of wild belugas,Delphinapterus leucas, during deep, benthic diving
Authors: Martin A R , Smith T G
Published: April 2011

The diving capability and behavioural strategy of wild belugas or white whales (Delphinapterus leucas) was investigated during periods of sustained deep diving. Analysis was limited to dives with a "square" time-depth profile, the most common type of deep dive, which invariably reached the seabed. As water depth increased, whales partially compensated for the greater commuting distance by increasing dive duration and rates of descent and ascent. But time at the target depth (bottom time) still diminished as depth increased. The duration of a dive was independent of the surface intervals preceding and following it. The aerobic dive limit of wild adult belugas probably exceeds the submergence times (mean 13.1 min, maximum 22.9 min) routinely recorded in this study. Belugas extended the duration of dives after slow descents, so bottom time was not reduced, substantiating the impression that they were not working at their physiological limit during sequences of deep dives. Larger belugas dived for longer and had lower rates of vertical travel. For their body size, belugas have average diving capability compared with other odontocetes but perform poorly compared with pinnipeds. Belugas are much larger than sympatric pinniped competitors, however, so they dive for longer and have unique access to deeper benthic resources.
A major settlement event associated with minor meteorologic and oceanographic fluctuations
Authors: Balch Toby , Hatcher Bruce G , Scheibling Robert E
Published: April 2011

Settlement of ophiuroids (Ophiopholis aculeata, Ophiura spp.) was measured using artificial collectors at 3-day intervals during their annual 2-week settlement period in July-August 1993 in St. Margaret's Bay, Nova Scotia. Hydrographic (temperature, salinity, current velocity, wave height and period) and meteorologic conditions (atmospheric pressure and wind velocity) were recorded concurrently at the site or at nearby locations. A major settlement pulse occurred over one 3-day period, with declining settlement over the following 6 days. This pulse was associated with a shift in current direction and preceded by rapid temperature and salinity fluctuations. Similar changes in temperature occurred at a second site (4.5 km away), indicating at least bay-scale forcing. This period was characterised by the passage of weak atmospheric pressure gradients and a low-energy sea state. These meteorologic and oceanographic fluctuations were within the normal range for this time of year, indicating that major settlement events can occur at scales of days in association with minor fluctuations in the physical environment.
Variation in cuticular scales of the lynx spiders of the genus Hamataliwa and other genera (Araneae, Oxyopidae)
Authors: Townsend, Jr. Victor R , Felgenhauer Bruce E
Published: April 2011

This study presents the first complete description of the external and internal morphology of cuticular scales of spiders of the genus Hamataliwa and is also the first examination of intrageneric variation in the morphology of the scales of the lynx spiders (Oxyopidae). The cuticular scales of nine species, including taxa from Australia and Central and North America, were examined using scanning electron microscopy, paraffin carving, and transmission electron microscopy (whole mounts only). The surface morphology and internal anatomy of the scales exhibit considerable intra- and inter-specific variation. The structures that exhibit the most variation are (i) the plicae, small lateral ridges on the dorsal surface, which show variation in both morphology and pattern, and (ii) the rod-shaped, branched cuticular elements that occur within the lumina, which vary most dramatically in pattern. Scale morphology also varies regionally (i.e., with respect to location on the body) in most species. A comparison of the morphology of scales of Hamataliwa spp. with those of the striped lynx spider, Oxyopes salticus, and the green lynx spider, Peucetia viridans, suggests that scales may represent a useful phylogenetic character for understanding relationships both within and between genera in the Oxyopidae.
The use of energy, fat, and protein reserves by breeding Great Black-backed Gulls
Authors: Mawhinney K , Diamond A W , Kehoe F P
Published: April 2011

Changes in mass (adjusted for body size) and in nutrient reserve levels were examined in adult male and female Great Black-backed Gulls (Larus marinus), from arrival at the colony to 1 week prior to the fledging of young. During the prelaying period, males lost approximately as much of their prebreeding fat reserves as females gained in mass, suggesting that males contributed substantial energy to the reproductive investment of the pair. We did not analyze prebreeding females for fat or protein but, based on the mass-fat correlation, females likely put on fat during prebreeding that was to be allocated for egg formation. However, their overall loss in mass was equal only to the accumulation prior to laying, suggesting that increased body reserves serve breeding directly, as capital costs for clutch formation. In contrast, males did not regain prebreeding mass until prefledging, suggesting that costs associated with prebreeding activity by males were larger than those for females. Once the clutch was completed, both sexes carried comparable reserves; neither sex fully regained prebreeding levels during incubation. Female mass at the end of the chick-rearing period was lower than during or before incubation, while males recovered their prebreeding mass (adjusted for body size).
Life history and larval morphology of Monacon (Hymenoptera: Perilampidae), parasitoids of ambrosia beetles (Coleoptera: Platypodidae)
Authors: Darling D Christopher , Roberts Hywel
Published: April 2011

Species of Monacon are distributed from Africa to New Guinea and parasitize ambrosia beetles of economic significance to tropical forestry. This study, based on fieldwork in Papua New Guinea and in Seram, Indonesia, provides the first detailed examination of the interaction between these parasitoids and their hosts; Monacon robertsi is a solitary, monophagous ectoparasitoid of the pupa of Crossotarsus barbatus. The phenology of the parasitoid and its host are summarized with life-history diagrams, and information is presented on oviposition, distribution of parasitoids within the gallery system constructed by the host, behaviour of adults both within and outside the gallery system, and sex ratios. A sex pheromone produced by male C. barbatus during the initiation of a gallery system both reinforces host specificity and synchronizes oviposition by Monacon roberstsi with mating of the host. This results in the parasitoid attacking only the first few of many host egg batches, which reduces the overall parasitism rate. Monacon roberstsi eggs are strongly sculptured, suggesting plastron respiration, and are laid on the bark in the vicinity of the entrance to ambrosia beetle galleries. Development is hypermetamorphic; the first instar is a heavily sclerotized planidium that locates and attaches to the host, and subsequent larval instars are grublike and hymenopteriform. The planidia experience high mortality rates while transferring to successive host instars and only a single planidium remains when metamorphosis and feeding begin, which coincides with host pupation. The immature stages of M. robertsi are described and illustrated using both light and scanning electron microscopy and are compared with those of other genera of Perilampidae and with Eucharitidae. The potential of Monacon species as agents of biological control of economically important species of ambrosia beetles is discussed and judged to be poor.
Habitat factors affecting vulnerability of moose to predation by wolves in southeastern British Columbia
Authors: Kunkel Kyran E , Pletscher Daniel H
Published: April 2011

We compared habitat features at sites where wolves (Canis lupus) killed moose (Alces alces), sites 500 m from kills, telemetry locations of moose, and random sites, to examine the influence of logging and other landscape features on the vulnerability of moose to predation by wolves in southeastern British Columbia during the winters of 1984-1985 through 1995-1996. Moose-kill sites were located farther from the edges of seedling and pole size-class patches than telemetry locations. Road density was lower and wolf use was higher in areas where kill sites occurred than in areas where relocation or random sites occurred. Kill sites were located at lower elevations than relocation or random sites. A logistic regression model using road density, elevation, distance from trails, and distance from size-class polygon edges successfully classified 94.5% of sites as either kills or locations. Moose density was greater and hiding-cover levels were lower at kill sites than at control sites. Forest harvest practices in this study area apparently did not increase the vulnerability of moose to wolf predation.
Timing of breeding in subarctic passerines in relation to food availability
Authors: Eeva Tapio , Veistola Simo , Lehikoinen Esa
Published: April 2011

We studied timing of breeding in four species of hole-nesting passerines, the Siberian tit (Poecile cinctus), great tit (Parus major), pied flycatcher (Ficedula hypoleuca), and redstart (Phoenicurus phoenicurus), and the abundance of the arthropods in their diet (ground-dwelling spiders, winged insects, foliage-feeding lepidopteran and hymenopteran larvae) in Finnish Lapland for 6-12 years. Densities of the invertebrate groups varied considerably, both seasonally and annually. All the bird species started to breed in early summer, when weather conditions were often poor. At the beginning of the breeding season all species relied on ground-dwelling spiders, whose abundances peaked early and were less variable over the years than those of insects. Abundances and timing of emergence of caterpillars in birch and pine canopies (the major food sources for foliage-gleaners) were highly variable, but each year their abundances peaked in July or August, after the nestling period of the birds. This contrasts with reported cases in deciduous forests at midlatitudes and shows that at our site the birds did not time their nestling period ultimately to coincide with peak food availability. Mean clutch sizes declined seasonally in the tit species and the pied flycatcher but not in the redstart. The number of fledglings did not depend on laying date, except in the Siberian tit, for which dependence of fledgling number on laying date varied among years. Although early broods were not more productive (i.e., greater number of fledglings) than later ones, early breeding is ultimately a necessity for recruitment because of the short subarctic summer. Birds cannot delay breeding in the north because late breeding would shorten the time available for moulting, food-hoarding, and preparation for migration or wintering. Our results show that at the time of egg laying, passerines may receive proximate cues to allow them to predict food conditions during the nestling period. Still, exact prediction of food availability during later phases of nesting is constrained by an inherent discrepancy between warm-blooded birds and poikilothermic invertebrates: once a bird has started egg laying, the subsequent phases follow nearly automatically on certain calendar dates, whereas the development of the arthropods depends on the rate of temperature increase.
Chick provisioning by common terns in the southern Gulf of Maine, U.S.A.
Authors: Rossell, Jr. C Reed , Hamilton Christine D , Weber Louise M , Kress Stephen W
Published: April 2011

We examined chick provisioning by common terns (Sterna hirundo) in relation to hatching order, chick stage, and weather on Stratton Island, Maine, U.S.A., during the summer of 1997. Provisioning rates, recorded at 10 nests during 30-min observation sessions (n = 256), were calculated for first-, second-, and third-hatched chicks in three age-classes (1-5, 6-10, and 11-15 days). Mean provisioning rates did not differ significantly with hatching order of chicks. However, a trend toward differential provisioning was evident during the earliest chick stage. Mean provisioning rates increased significantly from age-classs 1 to 2 and decreased significantly from age-classes 2 to 3. Weather had no significant effects on provisioning rates, owing to the unusually mild and consistent conditions. These results indicate that during the earliest chick stage, older siblings in a brood may have an advantage in obtaining food, even when weather conditions are highly favorable for provisioning chicks.
Demography of a recovering wolf population in the Yukon
Authors: Hayes R D , Harestad A S
Published: April 2011

We studied the dynamics of a wolf (Canis lupus) population recovering from intensive reduction in the Finlayson Lake area, Yukon, Canada. Within 6 years, numbers increased from 29 wolves, then stabilized at 245. The colonization of vacant territories by young wolf pairs was the primary mechanism of early population recovery. Reproduction and a low dispersal rate increased pack size in later years, and pack splitting allowed dispersing wolves to remain near natal packs. The rate of increase in the wolf population was density-dependent and related to wolf density, but was also related to the dispersal rate. The dispersal rate was density-independent and related to mean pack size and prey biomass : wolf index. The survival rate was age-dependent and not related to wolf density. In the early years of recovery, the rate of increase was supported by high survival rates and low dispersal rates. In later years, dispersal rates increased, stabilizing mean pack size and wolf density. Wolf density stabilized at levels predicted by the prey supply, but whether the wolf population is regulated by the availability of prey resources remains unresolved. Wolf density, pack density, and mean pack size were similar in 1983 and 1996, despite a 2- to 3-fold difference in prey biomass. We suggest that the interaction of wolf density and mean pack size in stable prey systems needs to be studied to determine the roles played by food supply and wolf social behavior in regulating wolf abundance.
Kill rate by wolves on moose in the Yukon
Authors: Hayes R D , Baer A M , Wotschikowsky U , Harestad A S
Published: April 2011

We studied the kill rate by wolves (Canis lupus) after a large-scale wolf removal when populations of wolves, moose (Alces alces), and woodland caribou (Rangifer tarandus caribou) were all increasing. We followed a total of 21 wolf packs for 4 winters, measuring prey selection, kill rates, and ecological factors that could influence killing behavior. Wolf predation was found to be mainly additive on both moose and caribou populations. Kill rates by individual wolves were inversely related to pack size and unrelated to prey density or snow depth. Scavenging by ravens decreased the amount of prey biomass available for wolves to consume, especially for wolves in smaller packs. The kill rate by wolves on moose calves was not related to the number of calves available each winter. Wolves did not show a strong switching response away from moose as the ratio of caribou to moose increased in winter. The predation rate by wolves on moose was best modeled by the number and size of packs wolves were organized into each winter.
Wolf functional response and regulation of moose in the Yukon
Authors: Hayes R D , Harestad A S
Published: April 2011

We studied kill rates by wolves (Canis lupus) on a rapidly growing moose population in the east-central Yukon. We added these data to the cumulative functional response curve obtained in other North American wolf studies. Our kill rates are higher than those predicted at low moose densities. The kill rate increases rapidly, reaching 2.4 moose per wolf per 100 days at 0.26 moose/km2 and remains constant at this level. No data are available below 0.2 moose/km2 to indicate the shape of the ascending curve. Based on moose distribution and the low prey-switching ability of wolves, we suggest that the functional response curve is of type II. Our wolf predation rate model predicts that moose are held to a low density equilibrium between 0.07 and 0.12/km2, slightly below densities observed in interior Alaska and the Yukon.
Age-related feeding site selection in urban pigeons (Columba livia): experimental evidence of the competition hypothesis
Authors: Sol Daniel , Santos David M , Cuadrado Mariano
Published: April 2011

Although age-specific habitat use has received much attention in recent years, the mechanisms that underlie ecological separation are not well known. This study examined the age-specific feeding site selection and its ecological mechanism in free-ranging Rock doves (Columba livia; referred to as pigeons). The distribution of age-classes at the feeding sites adjusted to a partially truncated distribution as follows: adults were consistently found more often than expected in the most rewarding feeding site, while juveniles were more often found in suboptimal sites. A removal experiment was conducted to determine whether competition accounted for the niche segregation between juvenile and adult pigeons. The reduction in intraspecific competition following removal was accompanied by an increased use of the preferred feeding site by juveniles. However, when the population recovered its initial size through immigration, juveniles were once again more frequently found in the suboptimal site. The proportion of juveniles feeding in each site was related to the total number of birds present; the higher the total number of birds, the higher the percentage of juveniles feeding in the less preferred site. These results support the idea that segregation between age-classes is due to competition by which adults displace juveniles from the richer foraging sites.
The effects of sex, season, and hibernation on haematology and blood viscosity of free-ranging echidnas (Tachyglossus aculeatus)
Authors: Andersen Niels A , Mesch Ute , Lovell David J , Nicol Stewart C
Published: April 2011

We investigated seasonal changes in haematology and blood viscosity in free-ranging echidnas, Tachyglossus aculeatus (37 females, 28 males, and 17 juveniles), some of which had been fitted with radio transmitters, allowing them to be located and bled during hibernation. Only one haematological parameter, mean cell haemoglobin concentration, appeared to show any clear relationship with hibernation. Seasonal variation was most marked in females, with red-cell count, haematocrit, and haemoglobin levels highest in summer and lowest in spring (P < 0.001). Males had higher values than females or juveniles (P < 0.05). Plasma osmolality was highest in summer (307 ± 4 mosmol/kg, n = 11) and lowest in autumn (290 ± 6 mosmol/kg, n = 6). Contrary to expectation, blood from hibernating echidnas, when measured at 32°C and at a haematocrit of 45%, showed significantly higher viscosity than blood from nonhibernating echidnas. These increases in mean cell haemoglobin concentration and blood viscosity during hibernation appear to be due to a build-up of senescent red cells and a reduced rate of erythropoiesis.
Digestive efficiency and dry-matter digestibility in Steller sea lions fed herring, pollock, squid, and salmon
Authors: Rosen D AS , Trites A W
Published: April 2011

Dry-matter digestibility and energy digestive efficiency were measured in six juvenile Steller sea lions (Eumetopias jubatus) fed three diets each consisting of a single species: herring, pollock, and squid. Two of the animals were also fed pink salmon. Dry-matter digestibility (DMD) and digestive efficiency (DE) were measured using the energy and manganese concentration in fecal and food samples. DE values were high for all prey species (herring: 95.4 ± 0.7% (mean ± SD), pollock: 93.9 ± 1.4%, salmon: 93.4 ± 0.5%, squid: 90.4 ± 1.3%). Steller sea lions appear to digest prey of high energy density more efficiently than prey of low energy density. DMD values were also high for all prey species (herring: 90.1 ± 1.8%, pollock: 86.5 ± 3.4%, salmon: 87.3% ± 2.6, squid: 90.5 ± 1.2%). The low DMD value for pollock compared with herring and squid was due to the high proportion of bony material in pollock. There was a strong linear relationship between DE and DMD for each prey type, but the terms cannot be used interchangeably. DE measures are more meaningful than DMD in conveying the energetic benefits derived by sea lions from different types of prey. Species-specific measures of the digestible energy obtained from an array of prey items are a necessary component in understanding the bioenergetic consequences of consuming different prey species.
The effect of highly alkaline water (pH 9.5) on the morphology and morphometry of chloride cells and pavement cells in the gills of the freshwater rainbow trout: relationship to ionic transport and ammonia excretion
Authors: Laurent Pierre , Wilkie Michael P , Chevalier Claudine , Wood Chris M
Published: April 2011

Exposure of rainbow trout (Oncorhynchus mykiss) to alkaline water (pH 9.5) impairs ammonia excretion (JAmm) and gill-mediated ion-exchange processes, as characterized by decreased Cl-(JC1in) and Na+influx (JNain) across the gill. Scanning electron microscopy suggested that the depression of JC1inwas concomitant with an early decrease in the population of the most active chloride cells (CCs), partly compensated for by an increasing number of immature CCs. However, within 72 h after the onset of exposure to alkaline water, there was a 2-fold increase in the fractional apical surface area of CCs that paralleled complete recovery of the maximal Cl-influx rate (JC1max). These results suggest that recovery of JC1maxwas associated with greater CC surface area, resulting in more transport sites on the gill epithelium. Morphometric analysis of the outermost layer of pavement cells on the lamellar epithelium showed a greater density of microvilli during exposure to alkaline water, which may have contributed to partial restoration of the number of Na+transport sites (JNamax). Finally, the blood-to-water gill-diffusion distance decreased by 27% after 72 h at pH 9.5, and likely contributed to progressive restoration of ammonia excretion in alkaline water.
The closed-subpopulation method and estimation of population size from mark-recapture and ancillary data
Authors: Tuyttens Frank AM
Published: April 2011

The algebraic relationships, underlying assumptions, and performance of the recently proposed closed-subpopulation method are compared with those of other commonly used methods for estimating the size of animal populations from mark-recapture records. In its basic format the closed-subpopulation method is similar to the Manly-Parr method and less restrictive than the Jolly-Seber method. Computer simulations indicate that the accuracy and precision of the population estimators generated by the basic closed-subpopulation method are almost comparable to those generated by the Jolly-Seber method, and generally better than those of the minimum-number-alive method. The performance of all these methods depends on the capture probability, the number of previous and subsequent trapping occasions, and whether the population is demographically closed or open. Violation of the assumption of equal catchability causes a negative bias that is more pronounced for the closed-subpopulation and Jolly-Seber estimators than for the minimum-number-alive. The closed-subpopulation method provides a simple and flexible framework for illustrating that the precision and accuracy of population-size estimates can be improved by incorporating evidence, other than mark-recapture data, of the presence of recognisable individuals in the population (from radiotelemetry, mortality records, or sightings, for example) and by exploiting specific characteristics of the population concerned.
Relative use of contiguous and fragmented boreal forest by red squirrels (Tamiasciurus hudsonicus)
Authors: Bayne Erin , Hobson Keith
Published: April 2011

We examined whether forest fragmentation by agriculture influenced the abundance of North American red squirrels (Tamiasciurus hudsonicus) in the southern boreal mixedwood forest of Saskatchewan. During the summers of 1995 and 1997, we determined the relative abundance of red squirrels in 43 forest fragments ranging in size from 0.2 to 82 ha and in 15 sites in nearby contiguous forest. Relative abundance was determined using acoustic point count surveys, in which all squirrel vocalizations were recorded. Within the fragmented agricultural landscape, we found that red squirrel abundance increased slightly with forest-fragment size, whereas the abundance of red squirrels was negatively correlated with the amount of forest cover within 1 km of a site. We also compared squirrel abundance in forest fragments with that in contiguous forest and found that red squirrels were significantly more abundant in forest fragments than in contiguous forest. We speculate that changes in dispersal patterns in fragmented forest habitats, higher squirrel survival in forest fragments, and differences in diet between contiguous and fragmented forest habitats contributed to this pattern. Our results suggest that forest fragmentation may not be particularly detrimental to habitat generalists like the red squirrel. However, an increased abundance of red squirrels in forest fragments may result in negative effects on other species, such as forest songbirds.
Some ecological and evolutionary aspects of bear-salmon interactions in coastal British Columbia
Authors: Reimchen T E
Published: April 2011

I examine here quantity and characteristics of chum salmon (Oncorhynchus keta) captured by black bears (Ursus americanus) during autumn spawning migration in an old-growth watershed on Moresby Island (Haida Gwaii), western Canada. Spawning-salmon numbers ranged from 2300 to 6300 over 3 years of investigation (1992-1994) and there were a maximum of eight bears in the watershed. Following capture of a salmon, bears ate an average of 1.6 kg from each salmon carcass, including the brain, ovaries, and dorsal musculature, and generally tended to abandon viscera, testes, and bony remnants such as jaws. Complete counts of these jaws throughout the watershed in autumn 1993 demonstrated a total capture of 4281 salmon, for an average consumption rate of 13 salmon per day per bear over the 45-day spawning period. This comprised 74% of the salmon entering the stream (range among years 58-92%). Most salmon (70-80%) taken by bears were partially or completely spawned-out at the time of capture. Marginally but significantly higher predation rates occurred on males relative to their proportion in the stream, and on larger rather than smaller salmon of both sexes. Higher-quality salmon (larger, fresher) were transferred farthest from the capture site by bears, possibly to minimize competitive interference. Bear predation in this locality does not appear to seriously constrain total reproduction of the salmon, but it may have several genetic influences: (i) there may be selection against large body size of salmon in both males and females and (ii) high predation levels on partially spawned males may facilitate multiple paternity in spawning females and, therefore, increase effective genetic variance among fertilized eggs.
THE INFLUENCE OF FOOD WHEAST® AND RELATED SACCHAROMYCES FRAGILIS YEAST PRODUCTS ON THE FECUNDITY OF CHRYSOPA CARNEA (NEUROPTERA: CHRYSOPIDAE)
Authors: Hagen K. S. , Tassan R. L.
Published: April 2011

High fecundity from Chrysopa carnea was obtained from an inexpensive diet containing a commercially available product of dried, inactive Saccharomyces fragilis yeast and whey proteins. The effective diet consists of this product mixed with sucrose and water. S. fragilis autolysed 17 hours was more effective in diets than when autolysed for 36 hours or unautolysed, and was as effective as autolysed brewers’ yeast, S. cerevisiae.
A NEW EULOPHID PARASITE (HYMENOPTERA: CHALCIDOIDEA) FROM EGGS OF THE NURSERY PINE SAWFLY, DIPRION FRUTETORUM (HYMENOPTERA: TENTHREDINOIDEA)
Authors: Yoshimoto Cari. M.
Published: April 2011

A new genus and new species, Peckelachertus diprioni, is described and illustrated. Material was reared from eggs of the nursery pine sawfly, Diprion frutetorum (Fabricius) in Quebec, Canada.
DESCRIPTIONS OF THREE NEW SPECIES IN THE GENERA AMBLYSEIUS BERLESE AND TYPHLODROMUS SCHEUTEN (ACARINA: PHYTOSEIIDAE) IN CANADA, WITH DESCRIPTIONS OF MALES OF NINE OTHER SPECIES, AND SOME NEW COLLECTION RECORDS
Authors: Chant D. A. , Shaul E. Yoshida
Published: April 2011

Three new species, two in the genus Amblyseius Berlese and one in the genus Typhlodromus Scheuten, collected in Canada are described. Three additional Amblyseius species and one Typhlodromus species are recorded for the first time in Canada. The previously unknown males of 9 species are described. These new records bring the total numbers of species in the genera Amblyseius and Typhlodromus in Canada to 53 and 22 respectively.
SUPPRESSION OF CODLING MOTH, LASPEYRESIA POMONELLA (LEPIDOPTERA: OLETHREUTIDAE), BY RELEASE OF STERILE AND PARTIALLY STERILE MOTHS
Authors: Proverbs M.D. , Newton J.R. , Logan D.M.
Published: April 2011

Because laboratory and field cage experiments had shown that partially sterile (25 krad dose) male codling moths were sexually more competitive than sterile (40 krad) ones, a study was made in a British Columbia orchard in 1970 to determine whether release of 25 krad moths of mixed sexes would suppress this pest more effectively than release of 40 krad moths. Approximately 75,000 moths/ha were released from 24 April to 25 September for each dose level. In the 25 krad moth release plot, the percentage of apple fruits damaged by this pest at harvest was reduced from 0.21 in 1969 to 0.08 in 1970, whereas in the 40 krad plot damage was reduced from 0.04 in 1969 to 0.02 in 1970.

Release of 25 krad moths was also compared with insecticide sprays for codling moth suppression in two small areas at Cawston and Olalla, B.C. At Cawston, the percentage of apples damaged at harvest was reduced from 1.0 in 1969, after three sprays of phosalone, to 0.1 in 1970 after release of irradiated insects. In contrast, per cent damage in a nearby apple orchard, sprayed twice with azinphos-methyl in 1969 and 1970, increased from 2.0 in 1969 to 8.1 in 1970. At Olalla, per cent damage was about the same (0.5) in 1969, after three phosalone sprays, as in 1970 (0.6) after release of irradiated insects. In a neighboring apple orchard, sprayed twice with phosalone in 1969 and 1970, per cent damage was about the same (1.0–1.2) each year.
TRAFFIC THROUGH THE NEST ENTRANCE OF A COLONY OF VESPULA ARENARIA (HYMENOPTERA: VESPIDAE)
Authors: Pallett M. J. , Plowright R. C.
Published: April 2011

Statistical analysis of traffic data at the nest entrance of a colony of the yellowjacket, Vespula arenaria (F.), showed no evidence for the operation of social facilitation of the type described by Blackith (1957). As in bumble bees, the appearance of contagion in the temporal distribution of exits and sorties is the result of overall change in flight activity and is not due to social interaction between wasps.
A NEW GENUS OF EURYTOMIDAE (CHALCIDOIDEA: EURYTOMIDAE, AXIMINAE) FROM BRAZIL
Authors: Yoshimoto Carl M. , Gibson Gary A. P.
Published: April 2011

An interesting, highly unusual chalcidoid wasp was found recently for Dr. L. Masner in material collected for him by Mr. F. M. Oliveira from Brazil. This unique specimen proved to belong to an undescribed genus in the subfamily Aximinae of the family Eurytomidae. It keys to the genera Axima Walker and Conoaxima Brues in Burks’ (1971) key to the genera of Eurytomidae, but differs in a number of morphological characters discussed below.

The structure and sculpture of this unique female specimen are illustrated by scanning electron photographs, the wings and antennae by macrophotography.
SIMULATION MODEL OF EUROPEAN RED MITE POPULATION DYNAMICS DEVELOPED FOR A MINI-COMPUTER
Authors: Herne D. C. , Lund C. T.
Published: April 2011

A simulation model is described for the population dynamics of the European red mite, Panonychus ulmi (Koch). The model incorporates the following features: (a) development rate is dependent on effective daily temperature; (b) division of each population component into distinct daily age classes; (c) emergence of individuals from each population component is dependent on a log-normal probability distribution, and a temperature related development vector to accumulate a measure of the temperature effect on development. Validation runs on a mini-computer in 1976 and 1977 adequately described actual population curves determined from daily orchard sampling. A model of this type which can be used with small computers should prove useful in investigating the main factors affecting the population dynamics, and control strategies for this and other pests.
SOME INTERACTIONS OF TWO BACULOVIRUSES OF THE DOUGLAS-FIR TUSSOCK MOTH (LEPIDOPTERA: LYMANTRIIDAE)
Authors: Hughes Kenneth M.
Published: April 2011

Two nuclear polyhedrosis viruses were fed to larvae of the Douglas-fir tussock moth, Orgyia pseudotsugata. Mixtures of the two viruses in varying proportions and separate doses of the two with a varying time interval between were administered. Larvae dying of polyhedrosis were examined to determine the proportions of the two viruses found in the bodies of the insects. The multicapsid virus (BV) showed a tendency to predominate over the unicapsid virus (SV), particularly in massive doses. In small doses, SV appeared in mixed infections even when the proportion of SV in the infective dose was small. When BV was administered 24 h in advance of SV, the development of SV was inhibited completely. At shorter intervals of time between doses, mixed infections occurred.
SAMPLING SYSTEMS FOR THE BIRCH CASEBEARER (LEPIDOPTERA: COLEOPHORIDAE)
Authors: Raske A. G. , Alvo M.
Published: April 2011

Sample sizes needed to measure population levels of the birch casebearer, Coleophora fuscedinella Zeller, and its damage to white birch, Betula papyrifera Marsh, were calculated for various degrees of confidence and assurance. Both a non-destructive and a destructive sampling plan are presented and a new method to classify the damage level of a stand. This method uses a maximum likelihood technique to estimate the proportion of trees of various damage classes.
BIOLOGICAL STUDIES OF BUD MINING SAWFLIES, PLERONEURA SPP. (HYMENOPTERA: XYELIDAE), ON WHITE FIR IN THE CENTRAL SIERRA NEVADA OF CALIFORNIA: III. MORTALITY FACTORS OF EGG, LARVAL, AND ADULT STAGES AND A PARTIAL LIFE TABLE
Authors: Ohmart C. P. , Dahlsten D. L.
Published: April 2011

The mortality factors for three species of Pleroneura were identified for the egg, larval, and adult stages. Allophroides n.sp. and Scambus transgressus (Hymenoptera: Ichneumonidae) were observed parasitizing the larval stages and four spiders were found preying on Pleroneura adults. Quantitative assessments of mortality in the egg and larval stages were made and tabulated in the form of a partial life table. Allophroides n. sp. was the dominant mortality factor in the larval stage. Mortality of unknown cause also was a substantial mortality factor.
COMPARISONS OF BEHAVIORS IN EARLY VS. LATE FOUNDRESS ASSOCIATIONS OF THE PAPER WASP, POLISTES METRICUS (HYMENOPTERA: VESPIDAE)
Authors: Gamboa George J. , Dropkin Jennifer A.
Published: April 2011

A significant number of subordinates of the paper wasp Polistes metricus Say are former single foundresses that have had their position usurped by a more dominant foundress. Such a displaced foundress sometimes remains with the usurper as a subordinate. Some usurpers desert larger nests where they were single foundresses to usurp a smaller colony.

In early foundress associations (< 14 days old), queens frequently exhibit behaviors that are characteristic of subordinates in mature hierarchies. Early queens spend large proportions of their nest time inactive, adjacent to the nest. They also commonly retreat from approaching subordinates. In contrast early subordinates rarely retreat from queens and spend a large proportion of their nest time on the face of the nest where they are more active than the queen. These behaviors are reversed in more mature colonies with queens spending more time on the nest face and showing increasing activity and aggressive behavior towards subordinates.
A NEW SPECIES OF SWAMMERDAMIA HBN. (LEPIDOPTERA: YPONOMEUTIDAE) FROM BRITISH COLUMBIA
Authors: Doǧanlar Miktat
Published: April 2011

Swammerdami beirnei n. sp. (Lepidoptera: Yponomeutidae) is described from Vancouver district, British Columbia, and distinguished from the European species, S. pyrella (De Villers) and the North American species S. heroldella Hübner = syn. S. castaneae Busck, also = syn. S. cuprescens Braun by Duckworth (1965). Some biological aspects of the species are discussed.
SEASONAL VARIATION IN BODY SIZE AND REPRODUCTIVE CONDITION OF A PAPER WASP, POLISTES METRICUS (HYMENOPTERA: VESPIDAE)
Authors: Haggard Constance M. , Gamboa George J.
Published: April 2011

Seasonal morphometric analysis of 788 adult Polistes metricus Say showed that: (1) Queens sampled throughout the colony cycle were of similar body size but significantly smaller than fall gynes. (2) Queens’ ovaries are large in the spring, decline early in the colony cycle, peak near the mid-postemergence period and decline late in the colony cycle. (3) There are no significant correlations between head width, ovary width, and size of nest in workers or queens. (4) Early and late workers are small but workers emerging during the mid-postemergence period are large. (5) All workers and gynes emerge with small, similar sized ovaries but older workers may develop larger ovaries. (6) Queens are larger than early and late workers but the same size as workers emerging during the mid-postemergence period. (7) The class with the largest adults were intermediates collected when colonies began production of males. These adults, intermediate in fat content between workers and gynes, comprised a large proportion of females emerging late in the colony cycle. (8) The body size of gynes is independent of colony size. (9) Males were significantly more variable in body size than gynes.
THE EFFECT OF AERIAL INSECTICIDE SPRAYING ON HYMENOPTEROUS POLLINATORS IN NEW BRUNSWICK
Authors: Plowright R. C. , Rodd F. H.
Published: April 2011

The effects of aerially sprayed fenitrothion (210 g/ha) and aminocarb (70 g/ha) on several hymenopteran taxa in New Brunswick are reported. Exposure cage experiments showed fenitrothion to cause as high mortality among solitary bees and vespid wasps as that previously reported for bumble bees. Exposure cage experiments under aminocarb sprays revealed no detectably increased mortality for bumble bees, but a significant effect on solitary bees. Experiments in which whole bumble bee colonies were set out in fenitrothion and aminocarb spray blocks a few days before spraying gave comparable results to those from the exposure cage experiments.

A series of comparisons of bumble bee densities in sprayed and unsprayed areas confirmed our earlier finding that populations are greatly reduced after fenitrothion application. Population recovery during the rest of the season appears to be influenced by meteorological conditions. The ecological replacement of early-emerging by late-emerging Bombus species in fenitrothion spray blocks is further documented. No relationship between bee densities and aminocarb application was found.

A method for retrospective assessment of pollinator activity by measuring nectar levels in Clintonia borealis was successfully carried out on a small-scale basis.
A NEW SPECIES OF PHYLLONORYCTER HBN. (= LITHOCOLLETIS HBN.) (LEPIDOPTERA: GRACILARIIDAE) FROM WESTERN NORTH AMERICA
Authors: Doğanlar Miktat , Mutuura Akira
Published: April 2011

Phyllonorycter elmaella n sp. is described from specimens reared from ptychonomous mines on the lower surface of apple leaves from the vicinity of Vancouver, B.C. The species is compared with European P. sorbi (Frey) and the Japanese P. sorbicola (Kumata) n. comb., to which it is more closely similar than to species attacking apple and related trees in Eastern North America. The species has three generations a year and overwinters in the pupal stage.