Anti-parasite treatment and blood biochemistry in raptor nestlings
In conclusion, anti-parasite treatments led to changes in s everal BCCVs, suggesting differences in nutrient absorption and physiological state of chicks that are possibly related to the costs of parasitism, but maybe also to the parasite treatment itself. (Source: Canadian Journal of Zoology)
Source: Canadian Journal of Zoology - June 23, 2017 Category: Zoology Authors: Sveinn Are Hanssen Christian Sonne Jan Ove Bustnes Lisbeth Schnug Sophie Bourgeon Manuel Ballesteros Igor Eulaers Truls Moum Trond Vidar Johnsen Mads Kjelgaard-Hansen Dorte Herzke Veerle L.B. Jaspers Adrian Covaci Marcel Eens Duncan J. Halley Kjell Einar Source Type: research

Distributional range, ecology, and mating system of the Cape mole-rat (Georychus capensis) family Bathyergidae
Canadian Journal of Zoology, e-First Articles. Interpopulation variation in life-history patterns are influenced by intrinsic and extrinsic factors. Life-history patterns have been intensely studied in the eusocial African bathyergid species, largely neglecting the solitary species. Of these solitary genera, the Cape mole-rat (Georychus capensis (Pallas, 1778)) is endemic to South Africa with a disjunct distribution across its range. Knowledge regarding this species is rudimentary; therefore, this study aimed to investigate the current distribution of the species with particular attention to common ecological variables, di...
Source: Canadian Journal of Zoology - June 16, 2017 Category: Zoology Authors: J.H. Visser N.C. Bennett B. Jansen van Vuuren Source Type: research

Dietary niche partitioning among black bears, grizzly bears, and wolves in a multiprey ecosystem
Canadian Journal of Zoology, e-First Articles. Identifying mechanisms that promote coexistence of sympatric species is important for predicting ecological effects of anthropogenic change. Many caribou (Rangifer tarandus (L., 1758)) populations are declining, and it is unclear to what extent sympatric predators consume caribou or how alternative prey affect caribou –predator relationships. We used stable isotope mixing models to estimate diets of black bear (Ursus americanus Pallas, 1780), grizzly bear (Ursus arctos L., 1758), and grey wolves (Canis lupus L., 1758) during early, middle, and late summer of 2009–2...
Source: Canadian Journal of Zoology - June 8, 2017 Category: Zoology Authors: Jerod A. Merkle Jean L. Polfus Jonathan J. Derbridge Kimberly S. Heinemeyer Source Type: research

Retinoic acid as a chemoattractant for cultured embryonic spinal cord neurons of the African Clawed Frog, Xenopus laevis
In this study, we investigated the effects of two retinoid isomers, all-trans retinoic acid (atRA) and 9-cis retinoic acid (9-cisRA), on cultured embryonic spi nal cord neurons of X. laevis. Both isomers significantly enhanced neurite outgrowth compared with the vehicle control. In addition, atRA induced growth cone turning, which was blocked with a retinoic acid receptor (RAR) antagonist, selective for the β receptor subtype. Immunostaining also revealed RAR immunoreactivity in the neurites and growth cones of these cells. Interestingly, the 9-cisRA isomer also induced significant growth cone turning and this respons...
Source: Canadian Journal of Zoology - June 8, 2017 Category: Zoology Authors: C.D. Rand G.E. Spencer R.L. Carlone Source Type: research

Gal ápagos sperm whales (Physeter macrocephalus): waxing and waning over three decades
Canadian Journal of Zoology, e-First Articles. While population sizes and structures naturally fluctuate over time, rapid within-generation changes are usually driven by shifts in habitat quality and (or) abrupt mortality. We evaluate how sperm whales (Physeter macrocephalus L., 1758 = Physeter catodon L., 1758) responded to the dynamic habit off the Gal ápagos Islands over 30 years, relating it to variation in prey availability and whaling operations in the tropical Pacific. In the 1980s, males and females were commonly sighted foraging and socializing in the northwest of the archipelago. Sightings decreased during...
Source: Canadian Journal of Zoology - June 8, 2017 Category: Zoology Authors: M. Cantor A. Eguiguren G. Merlen H. Whitehead Source Type: research

The larval sensilla on the antennae and mouthparts of five species of Cossidae (Lepidoptera)
In this study, we selected Eogystia hippophaecolus (Hua, Chou, Fang and Chen, 1990), Deserticossus artemisiae (Chou and Hua, 1986), Deserticossus arenicola (Staudinger, 1879), Yakudza vicarius (Walker, 1865), and Streltzoviella insularis (Staudinger, 1892) to understand how these species locate new hosts in their larval stages. Scanning electron microscopy (SEM) was used to determine the typology, morphology, number, and distribution of sensilla on the antennae, maxillary palps, galeas, and labial palps of these five species. There were no differences in typology, morphology, and number of sensilla between the five species...
Source: Canadian Journal of Zoology - June 8, 2017 Category: Zoology Authors: Lili Xu Jiahe Pei Tao Wang Lili Ren Shixiang Zong Source Type: research

The effects of inbreeding on sperm morphometry of captive-bred endangered mammals
Canadian Journal of Zoology, e-First Articles. Captive breeding is used for the conservation of endangered species, but inbreeding can result when a small number of founders are used to establish populations. Inbreeding can reduce the proportion of normal sperm in an ejaculate, but may also have effects on sperm size and shape (morphometry). We investigated the effects of inbreeding on sperm morphometry of black-footed ferrets (Mustela nigripes (Audubon and Bachman, 1851)) and red wolves (Canis rufus Audubon and Bachman, 1851) from captive breeding programs to determine if more inbred males produced sperm of poor quality (...
Source: Canadian Journal of Zoology - June 7, 2017 Category: Zoology Authors: M. Lawrence G. Mastromonaco K. Goodrowe R.M. Santymire W. Waddell A.I. Schulte-Hostedde Source Type: research

Influences of habitat and arthropod density on parasitism in two co-occurring host taxa
We examined infection with trematode (flatworm) parasites in two commonly co-occurring host taxa (larval amphibians and larval odonates (dragonflies and damselflies)) to investigate links with landscape-level features, including agricultural activity. We also assessed pond community composition with respect to the abundance and richness of aquatic arthropods known to prey upon tadpoles and (or) free-swimming trematode infectious stages. Larval amphibians from agricultural sites were most likely to be parasitized but had lower infection intensities, and infected hosts were positively associated with increasing distance to t...
Source: Canadian Journal of Zoology - June 7, 2017 Category: Zoology Authors: J. Koprivnikar T.M.Y. Urichuk D. Szuroczki Source Type: research

Influences of migration phenology on survival are size-dependent in juvenile Atlantic salmon (Salmo salar)
Canadian Journal of Zoology, e-First Articles. Long-distance migratory species can reduce mortality risks by synchronizing the migration event and create confusion by swamping predators with high densities. To reduce confusion, predators are known to primarily select aberrant prey. We hypothesized that at the start of their sea sojourn, particularly small and large Atlantic salmon (Salmo salar L., 1758) would spread the risk by also migrating at other times of the year. Based on data from the Norwegian river Imsa between 1976 and 2015, we found that juveniles, 14 –19 cm in total length, started their sea sojourn duri...
Source: Canadian Journal of Zoology - June 7, 2017 Category: Zoology Authors: B. Jonsson M. Jonsson N. Jonsson Source Type: research

Electrosedation of freshwater fishes for the surgical implantation of transmitters
We examined recovery times and short-term survival while using a commercially available electroanaesthesia unit to prepare fishes for transmitter implantation surgeries and ran experimental tests without surgery on different electrosedation settings. Our results indicate that electrosedation is a quick and efficient form of anaesthesia, with full anaesthesia achieved, surgeries completed, and recovery in under 10 min for common carp (Cyprinus carpio L., 1758), goldfish (Carassius auratus (L. 1758)), and others. We had zero mortality over at least 24 h associated with electrosedation. We found no significant differences in ...
Source: Canadian Journal of Zoology - June 7, 2017 Category: Zoology Authors: Jaewoo Kim Bradley Doyle Nicholas E. Mandrak Source Type: research

St. Matthew Island colonized through multiple long-distance red fox (Vulpes vulpes) dispersal events
Canadian Journal of Zoology, e-First Articles. Expansion of red fox (Vulpes vulpes (L., 1758)) into new arctic habitat and the potential for competition with arctic fox (Vulpes lagopus (L., 1758)) are of considerable conservation concern. Previous work has focused on red fox expanding into contiguous areas with few barriers to dispersal. Here, we examine mitochondrial DNA in red fox on recently colonized St. Matthew Island in the Bering Sea to determine their ultimate origin. Though limited in sample size (n = 7), we found that St. Matthew Island was colonized by North American lineages; surprisingly, despite the>400 km...
Source: Canadian Journal of Zoology - June 7, 2017 Category: Zoology Authors: K.E. Colson James D. Smith Kris J. Hundertmark Source Type: research

Fatty acid composition and concentration of alternative food of Semipalmated Sandpipers (Calidris pusilla) in the upper Bay of Fundy, Canada
Canadian Journal of Zoology, e-First Articles. Semipalmated Sandpipers (Calidris pusilla (L., 1766)) that migrate through the upper Bay of Fundy, Canada, depend on a rich food supply to fuel their continued migration. Although past studies have reported a diet dominated by the amphipod Corophium volutator (Pallas, 1766), an animal rich in n –3 polyunsaturated fatty acids (PUFAs), recent evidence suggests that sandpiper diets are broad. This is beneficial in that it allows Semipalmated Sandpipers to respond to a changing food base, but quality of food is also important. PUFAs are important in providing the energy requ...
Source: Canadian Journal of Zoology - May 9, 2017 Category: Zoology Authors: J.T. Quinn D.J. Hamilton C.E. Hebert Source Type: research

Seasonal foraging strategies of Alaskan gray wolves (Canis lupus) in an ecosystem subsidized by Pacific salmon (Oncorhynchus spp.)
Canadian Journal of Zoology, e-First Articles. Despite frequent observations of gray wolves (Canis lupus L., 1758) using nonungulate prey, the seasonal and interannual variation in the use and relative importance of alternative prey sources to gray wolf diets have not been studied at the individual scale. We used stable isotope analysis ( δ13C and δ15N) of guard hair and blood components (clot and serum) collected over 4 years to examine the occurrence, extent, and temporal variation of Pacific salmon (genus Oncorhynchus Suckley, 1861) as a food resource by both individual wolves and social groups in Lake Clark...
Source: Canadian Journal of Zoology - May 9, 2017 Category: Zoology Authors: Ashley E. Stanek Nathan Wolf Grant V. Hilderbrand Buck Mangipane Douglas Causey Jeffrey M. Welker Source Type: research

Salinity acclimation and advanced parr –smolt transformation in growth-hormone transgenic coho salmon (Oncorhynchus kisutch)
This study compared the capacity for seawater acclimation of GH transgenic coho salmon (Oncorhynchus kisutch (Walbaum, 1792)) to that of wild-type fish, allowing examination of responses to sustained (chronic) exp osure to elevated GH. GH transgenic fish (GH TG) smolted 1 year in advance of wild-type salmon and showed a greater capacity to hypo-osmoregulate in seawater. As GH TG fish were much larger than the wild-type fish, a second experiment was conducted with three size-matched groups of coho salmon (a 1+ -year-old wild-type group, a 1+-year-old ration-restricted GH TG group, and a 0+-year-old fully fed GH TG group). W...
Source: Canadian Journal of Zoology - May 8, 2017 Category: Zoology Authors: J.S. Bystriansky W.C. Clarke M.M. Alonge S.M. Judd P.M. Schulte R.H. Devlin Source Type: research

Age and experience affect the reproductive success of captive Loggerhead Shrike (Lanius ludovicianus) subspecies
Canadian Journal of Zoology, e-First Articles. Two explanations are often used to interpret the positive relationship between reproductive success and age: (1) trade-offs between current and future breeding and (2) age-related improvements in competence. Captive populations provide a unique opportunity to test these explanations because several mechanisms that result in age-related improvements in competence are managed. We modelled the effect of age and experience on the reproductive success of captive migrant Loggerhead Shrike (Lanius ludovicianus L., 1766) subspecies (formerly Lanius ludovicianus migrans W. Palmer, 1898...
Source: Canadian Journal of Zoology - May 8, 2017 Category: Zoology Authors: T.L. Imlay J.C. Steiner D.M. Bird Source Type: research

Geographic variation in winter adaptations of snowshoe hares (Lepus americanus)
Canadian Journal of Zoology, e-First Articles. Understanding adaptations of nonhibernating northern endotherms to cope with extreme cold is important because climate-induced changes in winter temperatures and snow cover are predicted to impact these species the most. We compared winter pelage characteristics and heat production of snowshoe hares (Lepus americanus Erxleben, 1777) on the southern edge of their range, in Pennsylvania (USA), to a northern population, in the Yukon (Canada), to investigate how hares might respond to changing environmental conditions. We also investigated how hares in Pennsylvania altered movemen...
Source: Canadian Journal of Zoology - May 8, 2017 Category: Zoology Authors: L.C. Gigliotti D.R. Diefenbach M.J. Sheriff Source Type: research

Philometra rubra (Nematoda: Philometridae) — first description of the male from striped bass (Morone saxatilis) and implications for re-introduction of an extirpated population
Canadian Journal of Zoology, e-First Articles. Philometra rubra (Leidy, 1856) is a pathogenic parasitic nematode infecting striped bass (Morone saxatilis (Walbaum, 1792)) in eastern North America. Identification of philometrids is difficult, male P. rubra have never been found, and transmission is poorly understood. To re-establish the “Extirpated” striped bass population in the St. Lawrence Estuary (SLE), Quebec, young-of-the-year (YOY) striped bass from the Miramichi River, New Brunswick, were collected and released into the SLE. The present study was undertaken to find Philometra in striped bass from the Mir...
Source: Canadian Journal of Zoology - May 4, 2017 Category: Zoology Source Type: research

Evidence for genetic hybridization between Ixodes scapularis and Ixodes cookei
Canadian Journal of Zoology, e-First Articles. Ixodes scapularis Say, 1821 (the black-legged tick) is becoming established in Canada. The northwards expansion of I. scapularis leads to contact between I. scapularis and Ixodes cookei Packard, 1869, a well-established tick species in Eastern Canada. Examination of I. cookei and I. scapularis collected from New Brunswick revealed ticks with ambiguous morphologies, with either a mixture or intermediate traits typical of I. scapularis and I. cookei, including in characteristics typically used as species identifiers. Genetic analysis to determine if these ticks represent hybrids...
Source: Canadian Journal of Zoology - April 23, 2017 Category: Zoology Authors: James W. Patterson Anna M. Duncan Kelsey C. McIntyre Vett K. Lloyd Source Type: research

Regional differences in the whistles of Australasian humpback dolphins (genus Sousa)
Canadian Journal of Zoology, e-First Articles. Characteristics of whistles may be used to study differentiation in dolphins to complement morphological and genetic studies. The whistles of four populations of Chinese humpback dolphins (Sousa chinensis chinensis (Osbeck, 1765)), one population of Taiwanese humpback dolphins (Sousa chinensis taiwanensis Wang, Yang, and Hung, 2015), and one population of Australian humpback dolphins (Sousa sahulensis Jefferson and Rosenbaum, 2014) were compared to determine if differences in whistles support current views of population structure and regional and species differentiation in the...
Source: Canadian Journal of Zoology - April 22, 2017 Category: Zoology Source Type: research

Resource competition and apparent competition in declining mule deer (Odocoileus hemionus)
Canadian Journal of Zoology, e-First Articles. Resource competition and apparent competition have both been suggested as the cause of mule deer (Odocoileus hemionus (Rafinesque, 1817)) decline concurrent with white-tailed deer (Odocoileus virginianus (Zimmerman, 1780)) increase. I tested for both hypotheses by conducting a “press” and “release” experiment in a mule deer, white-tailed deer, and cougar (Puma concolor (L., 1771)) community. If resource competition is causal, then predation should decrease, but other sources of mortality should increase following increased mortality of cougars and relea...
Source: Canadian Journal of Zoology - April 22, 2017 Category: Zoology Source Type: research

Sodium –hydrogen exchangers in the nematode Caenorhabditis elegans: investigations towards their potential role in hypodermal H+ excretion, Na+ uptake, and ammonia excretion, as well as acid–base balance
In conclusion, the study suggest that hypodermal apically localized EIPA-sen sitive Na+/H+ exchangers do not likely play a role in ammonia excretion and Na+ uptake in the hypodermis of C. elegans, whereas apical amiloride-sensitive Na+ channels seem to be involved not just in hypodermal Na+ uptake but indirectly also in NH4+ and H+ excretion. (Source: Canadian Journal of Zoology)
Source: Canadian Journal of Zoology - April 21, 2017 Category: Zoology Authors: Aida Adlimoghaddam Michael J. O ’Donnell Alex Quijada-Rodriguez Dirk Weihrauch Source Type: research

Nest site selection and breeding biology of Western House Wrens (Troglodytes aedon parkmanii) using natural cavities in Western Canada
Canadian Journal of Zoology, e-First Articles. House Wrens (Troglodytes aedon Vieillot, 1809) are among the best studied songbirds in North America, but most of what is known about this model species derives from studies using artificial nestboxes. Consequently, we know comparatively little about the natural breeding biology of House Wrens and whether it corresponds to patterns reported from nestboxes. To address these issues, we report a study of nest site selection and breeding phenology in Western House Wrens (Troglodytes aedon parkmanii Audubon, 1839) using natural cavities in aspen forests in southwest Alberta, Canada...
Source: Canadian Journal of Zoology - April 11, 2017 Category: Zoology Source Type: research

Dynamics of ovarian maturation throughout the reproductive cycle of the Neotropical cichlid fish Cichlasoma dimerus (Teleostei, Cichliformes)
In this study, we analyzed gene expression profiles, plasma steroids concentrations, and gonadal morphology throughout the reproductive cycle of female Cichlasoma dimerus (Heckel, 1840), a monogamous cichlid fish exhibiting social hierarchies. Fish were analyzed at six phases encompassing their annual cycle, namely resting (during the nonreproductive period), prespawning, 30 h post spawning, 4 days post spawning, 10 days post spawning, and subordinate (during the reproductive period). The histological and histomorphometric analysis showed that C. dimerus exhibits asynchronous ovarian development. Similar to resting females...
Source: Canadian Journal of Zoology - April 10, 2017 Category: Zoology Source Type: research

Integrated analysis of sexual maturation through successive growth instars in the spider crab Leurocyclus tuberculosus (Decapoda: Majoidea)
Canadian Journal of Zoology, e-First Articles. An integrative analysis of sexual maturity associated with growth was developed for the spider crab Leurocyclus tuberculosus (H. Milne Edwards and Lucas, 1842). Sexual maturity was characterized based on gonadal, morphological, morphometric, and functional sexual maturity. Progress in sexual maturation was described through 13 growth stages (instars) detected by the examination of size (carapace width) frequency distributions. Mature females displayed mature ovaries, developed vaginae, open gonopores, allometric changes in the abdomen, and ovigerous stage in the transition fro...
Source: Canadian Journal of Zoology - March 23, 2017 Category: Zoology Source Type: research

Experimental addition of cover lowers the perception of danger and increases reproduction in meadow voles (Microtus pennsylvanicus)
Canadian Journal of Zoology, e-First Articles. Predation danger is pervasive for small mammals and is expected to select strongly for behavioural tactics that reduce the risk. In particular, since it may be considered a cost of reproduction, predation danger is expected to affect the level of reproductive effort. We test this hypothesis in a population of meadow voles (Microtus pennsylvanicus (Ord, 1815)) under seminatural conditions in field enclosures. We manipulated the voles ’ perception of predation danger by adjusting the available cover and measured giving up density (GUD) in food patches to verify that the pe...
Source: Canadian Journal of Zoology - March 23, 2017 Category: Zoology Source Type: research

Comparison and correlation between chemical profiles of cephalic salivary glands and cuticle surface of workers of Apis mellifera (Hymenoptera, Apidae)
In conclusion, glands and cuticle profiles were phase-related and the CSG may be a potential auxiliary source of cuticular hydrocarbon replenishment in the studied species. (Source: Canadian Journal of Zoology)
Source: Canadian Journal of Zoology - March 23, 2017 Category: Zoology Source Type: research

Hybridization of domestic mink with wild American mink (Neovison vison) in eastern Canada
Canadian Journal of Zoology,Volume 95, Issue 6, Page 443-451, June 2017. Farmed American mink (Neovison vison (Schreber, 1777)) pose a risk to biodiversity owing to escape and release from farms. Feral mink may affect native species in locations where American mink are not endemic, such as Europe. In contrast, escaping domestic mink may hybridize with wild mink in North America, leading to introgression of domestic traits via hybrid-mediated gene flow. We tested this idea in eastern Canada, which has a history of mink farming. We sampled known domestic and free-ranging mink, and profiled 508 individuals at 15 microsatellit...
Source: Canadian Journal of Zoology - March 23, 2017 Category: Zoology Source Type: research

Amphibian terrestrial habitat selection and movement patterns vary with annual life-history period
Canadian Journal of Zoology, e-First Articles. Identification of essential habitat is a fundamental component of amphibian conservation; however, species with complex life histories frequently move among habitats. To better understand dynamic habitat use, we evaluated Wood Frog (Lithobates sylvaticus (LeConte, 1825)) habitat selection and movement patterns during the spring migration and foraging periods and described the spatiotemporal variability of habitats used during all annual life-history periods. We radio-tracked 71 frogs in Maine during 2011 –2013 and evaluated spring migration, foraging activity center (FAC...
Source: Canadian Journal of Zoology - March 22, 2017 Category: Zoology Source Type: research

Indirect effects of prey fluctuation on survival of juvenile arctic fox (Vulpes lagopus): a matter of maternal experience and litter attendance
Canadian Journal of Zoology, e-First Articles. Reproductive experience affects juvenile survival in a wide range of species with possible links to differences in foraging capacity and predation. Using supplementary feeding, we aimed to limit direct effect of prey abundance to investigate indirect effects of small-rodent availability and maternal experience on juvenile summer survival rates in an endangered population of arctic fox (Vulpes lagopus (L., 1758)). We used data spanning 7 years, included a complete small-rodent cycle, comprising 49 litters and 394 cubs. The effect of small-rodent abundance on juvenile survival d...
Source: Canadian Journal of Zoology - March 22, 2017 Category: Zoology Source Type: research

Intraspecific differences in endurance swim performance and cardiac size in sockeye salmon (Oncorhynchus nerka) parr tested at three temperatures
This study provides further support that sockeye salmon parr are locally adapted to their environmental conditions. (Source: Canadian Journal of Zoology)
Source: Canadian Journal of Zoology - March 7, 2017 Category: Zoology Source Type: research

Dehydration resistance and tolerance in the brush-legged wolf spider (Schizocosa ocreata): a comparison of survivorship, critical body water content, and water-loss rates between sexes
This study examines aspects of dehydration resistance and tolerance in the brush-legged wolf spider, Schizocosa ocreata (Hentz, 1844) (Araneae: Lycosidae), commonly found in the leaf litter of eastern deciduous forests of North America. Sexes differ in morphology, physiology, reproductive strategy, and life history, likely resulting in divergent abilities to resist and tolerate dehydration. We used humidity-controlled chambers to examine relative survivorship by sex under varying humidity regimes, water-loss rates, body water content, and critical water mass. Spiders survived significantly longer in higher humidity regimes...
Source: Canadian Journal of Zoology - March 7, 2017 Category: Zoology Source Type: research

Wild Peromyscus adjust maternal nest-building behaviour in response to ambient temperature
Canadian Journal of Zoology, e-First Articles. The heat dissipation limit (HDL) hypothesis suggests that energy output during lactation in mammals might be constrained by their ability to dissipate heat. This hypothesis predicts that wild mammals ought to adjust nest insulation in response to heat load, but these predictions have rarely been tested in wild mammals. Here we developed a simple score of nest-building for wild deer mice (Peromyscus maniculatus (Wagner, 1845)) on an ordinal scale from 0 to 4, based on three qualitative and easy to observe aspects of nest-building behaviour: bedding quality, nest shape, and mous...
Source: Canadian Journal of Zoology - March 6, 2017 Category: Zoology Source Type: research

Mixed haemosporidian infections are associated with higher fearfulness in Yellow Wagtail (Motacilla flava)
Canadian Journal of Zoology, e-First Articles. Blood parasite infections have been shown to influence behavioural traits of their avian hosts, in particular activity level and boldness. Following the hypothesis that a mixed infection by different parasite species should have higher effects than single-species infections, we analysed activity and boldness in wild-caught Yellow Wagtails (Motacilla flava L., 1758), a trans-Saharan migrant, during the energetically demanding spring migration. Eighty-five percent of the birds were naturally infected with Haemoproteus Kruse, 1890 or Plasmodium Marchiafava and Celli, 1885 (Sporoz...
Source: Canadian Journal of Zoology - March 6, 2017 Category: Zoology Source Type: research

Morphological differentiation in northern pike (Esox lucius): the influence of environmental conditions and sex on body shape
Canadian Journal of Zoology, e-First Articles. Morphological differentiation may allow individuals to cope with prevailing environmental conditions. Morphological differentiation in fish characterized by sagittiform shape and ambush predator behaviour, such as northern pike (Esox lucius L., 1758), has rarely been addressed. Morphological differentiation was assessed in two rivers exhibiting contrasting flow regimes: a hydropeaking river characterized by large and frequent fluctuations in flow rates and an unregulated river. An increase in northern pike movement rate was observed in the hydropeaking river. Therefore, morpho...
Source: Canadian Journal of Zoology - March 6, 2017 Category: Zoology Source Type: research

Effects of environmental warming during early life history on libellulid odonates
Canadian Journal of Zoology, e-First Articles. Climate warming affects ectotherms globally, yet we know little regarding the variability in species ’ responses to warming, particularly in early life stages. Additionally, intraspecific variation in response to warming is understudied but may determine species’ resilience to warming. To assess how temperature affects egg development rate in co-occurring dragonfly species, we manipulated tempe rature (range: 22–31 °C) and measured time to hatching. Warming decreased egg development time across all species, indicating that while climate warming will advan...
Source: Canadian Journal of Zoology - March 6, 2017 Category: Zoology Source Type: research

Patterns of intraspecific aggression inferred from injuries in an aquatic turtle with male-biased size dimorphism
Canadian Journal of Zoology, e-First Articles. Patterns of sexual size dimorphism (SSD) in turtles are correlated with ecological mode, and it has been hypothesized that mating systems are also shaped by ecological mode. Male combat and coercive mating are competing explanations for male-biased SSD, but are difficult to assess empirically in aquatic species with cryptic behaviour. We quantified SSD and compiled observations of putative combat wounds collected from over 500 captures of Snapping Turtles (Chelydra serpentina (L., 1758)) in Algonquin Provincial Park, Ontario, to test hypotheses of mate competition and coercion...
Source: Canadian Journal of Zoology - February 26, 2017 Category: Zoology Source Type: research

Parasitism, immune response, and egg production of the spearhead bluet (Coenagrion hastulatum) damselfly
Canadian Journal of Zoology,Volume 95, Issue 5, Page 367-372, May 2017. Theoretical models predict that parasites reduce reproductive success of their hosts, but very few empirical studies have given support to this. Using the spearhead bluet (Coenagrion hastulatum (Charpentier, 1825)) damselfly, we tested how immune response, wing length, and the number of both endo- and ecto-parasites affect egg production of host damselflies. The study was conducted with four different populations in southwest Finland. We found a negative association between endoparasitic gregarines and number of host eggs. Furthermore, immune response ...
Source: Canadian Journal of Zoology - February 26, 2017 Category: Zoology Source Type: research

Size and shape of eggs of Neognathae: effects of developmental mode and phylogeny
Canadian Journal of Zoology, e-First Articles. We evaluated the variation in absolute size and shape of birds ’ eggs and the effects of developmental mode and phylogenetic relatedness on these traits. Eggs were characterized by length, diameter, and three indices of egg shape. Indices of egg shape were calculated as the ratio of radii that described the curvature of pointed end (cloacal zone), blunt end ( infundibular zone), and lateral zone to egg diameter. We found that eggs shape was less variable than the absolute size of eggs. Index of the cloacal zone was the most changeable and index of the infundibular zone w...
Source: Canadian Journal of Zoology - February 26, 2017 Category: Zoology Source Type: research

Silent sounds in the Andes: underwater vocalizations of three frog species with reduced tympanic middle ears (Anura: Telmatobiidae: Telmatobius)
Canadian Journal of Zoology, e-First Articles. Underwater vocalization in anurans is restricted to a few, distantly related species. In some of them, sound is transmitted through tympanic and extra-tympanic pathways. Members of the Andean genus Telmatobius Wiegmann, 1834 lack a tympanic membrane, and earlier reports assumed the absence of vocalizations in the genus. We recorded underwater vocalizations and examined the middle-ear morphology in three species of Telmatobius with different lifestyles: Telmatobius oxycephalus Vellard, 1946 (semiaquatic, riverine); Telmatobius hintoni Parker, 1940 (markedly aquatic, riverine); ...
Source: Canadian Journal of Zoology - February 26, 2017 Category: Zoology Source Type: research

Rock crevice morphology and forest contexts drive microhabitat preferences in the Green Salamander (Aneides aeneus)
Canadian Journal of Zoology, e-First Articles. Little is known about how vertical rock habitats are selected by organisms in forest ecosystems. Multiple lungless salamanders use rock outcrops in the Appalachian Mountains of eastern North America, with Green Salamanders (Aneides aeneus (Cope and Packard, 1881)) showing the strongest associations as an outcrop specialist. Although previous work has identified environmental correlates of rock face and arboreal habitat use in this species, it remains to be known if and how Green Salamanders select crevice refugia as a function of both outcrop morphology and the context of outc...
Source: Canadian Journal of Zoology - February 26, 2017 Category: Zoology Source Type: research

Calcium decline reduces population growth rates of zooplankton in field mesocosms
Canadian Journal of Zoology, e-First Articles. Regional calcium (Ca) decline, a legacy of acid deposition and logging, is a potential threat to aquatic organisms. Lake surveys and laboratory studies indicate that Ca-rich daphniids are likely most susceptible, allowing for competitive release of other taxa with low Ca demand. Indeed, dramatic shifts in zooplankton community structure have been documented in lakes where Ca has declined, amid multiple other stressors. Given the perceived threat of this large-scale stressor, manipulative studies are needed to evaluate causal relationships between Ca decline and zooplankton com...
Source: Canadian Journal of Zoology - February 26, 2017 Category: Zoology Source Type: research

Coyote (Canis latrans) diet in an urban environment: variation relative to pet conflicts, housing density, and season
Canadian Journal of Zoology,Volume 95, Issue 4, Page 287-297, April 2017. Coyotes (Canis latrans Say, 1823) are highly successful in urbanized environments, but as they populate cities, conflict can occur and often manifests in the form of incidents with pets. To better understand whether coyotes view pets as prey or, alternatively, as competitors or a threat, we conducted a diet analysis of coyotes in the Denver metropolitan area (DMA) by analyzing scats. We also examined differences in diet between high- and low-density housing and among seasons. We found only small percentages of trash and domestic pets in the coyote di...
Source: Canadian Journal of Zoology - February 26, 2017 Category: Zoology Source Type: research

Fecal DNA, hormones, and pellet morphometrics as a noninvasive method to estimate age class: an application to wild populations of Central Mountain and Boreal woodland caribou (Rangifer tarandus caribou)
This study illustrates the possibilities of using noninvasive methods to determine an age class in wild ungulate populations. (Source: Canadian Journal of Zoology)
Source: Canadian Journal of Zoology - February 24, 2017 Category: Zoology Source Type: research

Differences in nutrient content of eggs and larvae as indicators for improvement of broodstock nutrition in walleye (Sander vitreus) production
Canadian Journal of Zoology, e-First Articles. The aim of this study was to increase our knowledge about the nutritional needs of walleye (Sander vitreus (Mitchill, 1818)) broodstock. Two dietary treatments were tested: the first consisted of frozen Atlantic mackerel (Scomber scombrus L., 1758) pieces with a supplement of experimental dry pellets and the second consisted of frozen Atlantic mackerel pieces with a supplement of commercial trout pellets. Hatching success was highest in eggs from the wild broodstock. Eggs and larvae from wild fish were characterized by the highest levels of linoleic (LOA; 18:2 n –6) and ...
Source: Canadian Journal of Zoology - February 11, 2017 Category: Zoology Source Type: research

Resource partitioning among five species of waterfowl (Anas spp.) at an autumn migratory stopover: combining stable isotope and mercury biomarkers
Canadian Journal of Zoology,Volume 95, Issue 4, Page 279-286, April 2017. The Saskatchewan River Delta (SRD) is North America ’s largest inland delta and an important stopover site for waterfowl in the Central Flyway. However, little is known about their basic feeding ecology at this site and how species segregate or overlap in resource use. We used stable carbon (δ13C) and nitrogen (δ15N) isotopes and mercury concentr ations ([Hg]) in liver tissue to trace use of local nutrient sources by five waterfowl species and tested for differences in diets among species, sexes, and age groups. Macrophytes were the...
Source: Canadian Journal of Zoology - February 8, 2017 Category: Zoology Source Type: research

Local weather and regional climate influence breeding dynamics of Mountain Bluebirds (Sialia currucoides) and Tree Swallows (Tachycineta bicolor): a 35-year study
Canadian Journal of Zoology, e-First Articles. Many songbirds are under increasing pressure owing to habitat loss, land-use changes, and rapidly changing climatic conditions. Using citizen science data collected from 1980 to 2014, we asked how local weather and regional climate influenced the breeding dynamics of Mountain Bluebirds (Sialia currucoides (Bechstein, 1798)) and Tree Swallows (Tachycineta bicolor (Vieillot, 1808)). Mountain Bluebird reproduction was strongly associated with local weather: number of nestlings and fledglings both decreased in years of high rainfall. Clutch size and number of fledglings also decli...
Source: Canadian Journal of Zoology - February 8, 2017 Category: Zoology Source Type: research

Experimental immune activation using a mild antigen decreases reproductive success in free-living female Dark-eyed Juncos (Junco hyemalis)
Canadian Journal of Zoology, e-First Articles. Seasonal animals time breeding so that offspring rearing coincides with favorable conditions. Offspring rearing is energetically demanding; therefore, additional energetic challenges during this life-history stage may allocate energy away from offspring care, decreasing reproductive success. Activation of the immune system may be one such energetic challenge, and may have a disproportionately higher impact on reproductive success earlier in the breeding season when resources are less abundant and thermoregulatory demands are greater. We monitored nestling growth and survival i...
Source: Canadian Journal of Zoology - February 8, 2017 Category: Zoology Source Type: research

Environmental drivers of carry-over effects in a pond-breeding amphibian, the Wood Frog (Rana sylvatica)
Canadian Journal of Zoology, e-First Articles. Breeding animals confront a complex environment when deciding where to oviposit, and this decision may depend on fine-scale variation in environmental conditions that have the potential to affect not only embryos but also subsequent larvae. I evaluated the influences of two variables, light and temperature, at oviposition sites of Wood Frogs (Rana sylvatica LeConte, 1825). First, in four ponds varying in canopy cover, I moved a subset of egg masses from the original oviposition site to an alternative site in the same pond and monitored embryos until hatching commenced. I found...
Source: Canadian Journal of Zoology - February 8, 2017 Category: Zoology Source Type: research

Thermal consequences of subterranean nesting behavior in a prairie-dwelling turtle, the Ornate Box Turtle (Terrapene ornata)
Canadian Journal of Zoology, e-First Articles. Many oviparous reptiles deposit eggs in excavated nest chambers, and the location and depth at which eggs are laid can affect predation risk, incubation duration, mortality rates, and hatchling phenotype. Among turtles, nest depth also influences incubation conditions of some large-bodied species, but nest depth is generally expected to vary less among small-bodied species. We monitored nesting behavior of Ornate Box Turtles (Terrapene ornata (Agassiz, 1857)) for two seasons in Illinois. We used direct observations to confirm that, among 31 nesting events, six females oviposit...
Source: Canadian Journal of Zoology - February 6, 2017 Category: Zoology Authors: Charles R. Tucker Jeramie T. Strickland David K. Delaney Day B. Ligon Source Type: research

Fitting in with the crowd: the role of prospecting in seabird behavioural trends
Canadian Journal of Zoology, e-First Articles. Prebreeding, subadult seabirds have been documented prospecting or visiting multiple sites throughout the breeding season to gather information on colony reproductive success, identify suitable habitat, evaluate prey abundance, and locate potential partners; however, many aspects of prospector biology remain unknown. We explored prospector behaviour as a means of furthering our understanding of postnatal seabird dispersal and colony attendance using Least Auklets (Aethia pusilla (Pallas, 1811)) and Crested Auklets (Aethia cristatella (Pallas, 1769)) breeding at Gareloi Island,...
Source: Canadian Journal of Zoology - February 5, 2017 Category: Zoology Source Type: research