Changes in dental wear and breakage in arctic foxes (Vulpes lagopus) across space and time: evidence for anthropogenic food subsidies?
Canadian Journal of Zoology, Ahead of Print. Increased human presence in the Arctic may affect its vulnerable ecosystems. Effects on arctic and red foxes provide notable examples. Both have been documented to take anthropogenic subsidies when available, which can change diet and ranging patterns in complex ways that can either benefit or harm populations, depending on the situation. Understanding this complexity requires new tools to study impacts of increasing human presence on endemic mammals at high latitudes. We propose that dental ecology, specifically tooth wear and breakage, can offer important clues. Based on sampl...
Source: Canadian Journal of Zoology - June 9, 2022 Category: Zoology Authors: P.S. Ungar B. Van Valkenburgh N. Sokolova I. Fufachev V. Filippova K. Shklyar A. Sokolov Source Type: research
Drivers of winter population cycles in the Varied Thrush (Ixoreus naevius)
Canadian Journal of Zoology, Ahead of Print. The drivers of year-to-year difference in winter abundance patterns, particularly dramatic in the “eruptions” of many boreal seed-eating birds, are poorly understood. Varied Thrush (Ixoreus naevius (Gmelin, 1789)), endemic to the Pacific Northwest of North America, is a boreal species that exhibits pronounced, often biennially cyclic, changes in winter abundance within most of its normal win tering range. Although the drivers of this variability have not previously been explored, it has been suggested that differences in acorn abundance, a key winter food resource, might be ...
Source: Canadian Journal of Zoology - June 9, 2022 Category: Zoology Authors: Walter D. Koenig Johannes M.H. Knops Source Type: research
Fear as an enemy? Behavioral changes of Ananteris mauryi (Scorpiones: Buthidae) triggered by chemical cues from an intraguild predator
Canadian Journal of Zoology, Ahead of Print. Fear level and intraguild predation are factors that act together to directly influence animal behavior, population dynamics, and community structure. These factors trigger stress, which promotes behavioral, morphological, physiological, and demographic changes, especially in the prey. Some invertebrates, such as scorpions, are known to have a refined chemoreception system to perceive both prey and predators. Therefore, we investigated the ability of an intraguild prey, the scorpion Ananteris mauryi Louren ço, 1982, to detect chemical traces of its predator, the scorpion Tityus...
Source: Canadian Journal of Zoology - June 9, 2022 Category: Zoology Authors: Matheus L.B. Feitosa Welton Dionisio-da-Silva Andr é F.A. Lira Wendel J. Teles-Pontes Source Type: research
Insights into Chinook salmon (Oncorhynchus tshawytscha) movement ecology in the terminal reaches of the upper Yukon River during the spawning migration
Canadian Journal of Zoology, Ahead of Print. Chinook salmon (Oncorhynchus tshawytscha (Walbaum, 1792)) from the upper Yukon River are highly unique, with some populations migrating nearly 3000 km to spawning habitat near the northern range limit for the species. We conducted a 4-year study to understand the behaviour of Chinook salmon in the terminal reaches of their migration by tagging salmon with acoustic and radio transmitters in Whitehorse, Yukon, Canada, ∼2800 km from the ocean. Various migration characteristics were quantified for Chinook salmon, including en route mortality, diel behaviour, migration rates, and...
Source: Canadian Journal of Zoology - June 1, 2022 Category: Zoology Authors: W.M. Twardek K.L. Knight C.H. Reid R.J. Lennox S.J. Cooke N.W.R. Lapointe Source Type: research
Influence of maternity penning on the success and timing of parturition by mountain caribou (Rangifer tarandus caribou)
Canadian Journal of Zoology, Ahead of Print. Invasive conservation actions that require the capture and handling of individual animals are common, but the implications for both survival and reproduction are often not studied. Across North America, most populations of woodland caribou (Rangifer tarandus caribou (Gmelin, 1788)) are Threatened or Endangered. Maternity penning, where pregnant females are held in an enclosure until the calf is less vulnerable to predation, is one conservation action that is designed to increase population growth. Few studies have reported the influence of maternity penning on the occurrence or ...
Source: Canadian Journal of Zoology - May 31, 2022 Category: Zoology Authors: M. Mueller C.J. Johnson R.S. McNay Source Type: research
Differential behavioral responses of benthic and nektonic tadpoles to predation at varying water depths
Canadian Journal of Zoology, Ahead of Print. Predators influence microhabitat selection and activity level of tadpoles, but it is still unclear how such responses to predators differ among species and how water column's depth influences this predator –prey interaction. Here, we experimentally tested whether the presence of Odonata water nymphs influenced the spatial use and activity of benthic and nektonic tadpoles in different food availability contexts. Benthic tadpoles occupied and consumed more food at the bottom level, irrespective of pre dator's presence. However, when predators were at the bottom, benthic tadpoles...
Source: Canadian Journal of Zoology - May 31, 2022 Category: Zoology Authors: Yasmim Caroline Mossioli de Souza Fabiane Santana Annibale Lu ísa Gigante Carvalheiro Tiago Silveira Vasconcelos Denise de Cerqueira Rossa-Feres Source Type: research
Adaptive divergence of lateral plate ultrastructure in threespine stickleback (Gasterosteus aculeatus)
Canadian Journal of Zoology, Ahead of Print. The lateral plates of threespine stickleback (Gasterosteus aculeatus Linnaeus, 1758) are well studied for their adaptive morphological responses to predators, yet it is unknown whether habitat influences plate ultrastructure. We investigated using scanning electron microscopy the lateral plate ultrastructure (tubercles and ridges) of stickleback (N = 61 adult fish) from nine Haida Gwaii (coastal British Columbia, Canada) wild-type populations, two experimental transplants, and two lab-reared cohorts reared from source populations. Tubercle density, but not ridge density, diff...
Source: Canadian Journal of Zoology - May 30, 2022 Category: Zoology Authors: Debra L. Wertman Thomas E. Reimchen Source Type: research
Protogynous hermaphroditism in Crustacea: a new example from Tanaidacea
Canadian Journal of Zoology, Ahead of Print. Hermaphroditism has been widely reported in the Crustacea, but protogyny, in which females change to males, is apparently rare and restricted to the peracarid orders Isopoda and Tanaidacea. In the latter, protogyny has been demonstrated in only seven species representing six genera by rearing experiments and indicated for several other genera and species through morphology. Here, we show through rearing experiment and histological observations, protogynous hermaphroditism in the tanaidacean species Nesotanais sp. aff. ryukyuensis Kakui, Kajihara and Mawatari, 2010. Our rearing e...
Source: Canadian Journal of Zoology - May 6, 2022 Category: Zoology Authors: Keiichi Kakui Chizue Hiruta Source Type: research
Survival of off-host Dermacentor albipictus (Acari: Ixodidae) adult females and larvae underwater
Canadian Journal of Zoology, Ahead of Print. The winter tick (Dermacentor albipictus (Packard, 1869); Acari: Ixodidae) significantly affects the health and productivity of North American moose (Alces alces (Linnaeus, 1758); Artiodactyla: Cervidae). Survival of off-host stages of Ixodid ticks depends on microclimate driven in part by extrinsic factors resulting from weather, such as temperature, humidity, drought, and floods. The impact of some of these abiotic factors is unclear for D. albipictus. The effect of water submergence on biological parameters of engorged, adult, females, and unfed larvae was assessed in the labo...
Source: Canadian Journal of Zoology - April 29, 2022 Category: Zoology Authors: C.F. Sullivan B.L. Parker M. Skinner Source Type: research
Feeding ecology of the endangered Apennine Yellow-bellied Toad (Bombina pachypus) in central Italy
Canadian Journal of Zoology, Ahead of Print. Anurans are generalist opportunistic consumers, but many species show some degree of diet specialization. Within populations, individuals may specialize in specific dietary resources (individual specialization). Indeed, generalist populations may be composed of individuals using the whole range of available resources or of diverse individuals exploiting specific food items. Based on the niche variation hypothesis (NHV), an increase in population niche width may be related to a higher incidence of individual specialization. We analyzed the feeding ecology of the endangered Apenni...
Source: Canadian Journal of Zoology - April 27, 2022 Category: Zoology Authors: Annagiulia de Meis Alessandra Maria Bissattini Alberto Venchi Marco Alberto Bologna Leonardo Vignoli Source Type: research
Conserving wetlands in agroecosystems can sustain aerial insectivore productivity and survival
Canadian Journal of Zoology, Ahead of Print. Agricultural intensification simplifies natural landscapes and frequently results in the loss of biodiversity. Wetlands are highly productive and may offset these losses, but the amount of wetland area needed to support declining avian species on farmland is unknown. Using an avian aerial insectivore, the Tree Swallow (Tachycineta bicolor (Vieillot, 1808)), we tested whether a gradient of pond area (visible surface water in wetland basins within 500 m of nest boxes; range 0.2%–30% pond area) at cropland and grassland sites was related to aquatic insect biomass, reproductive ...
Source: Canadian Journal of Zoology - April 7, 2022 Category: Zoology Authors: Lisha L. Berzins Christy A. Morrissey David W. Howerter Robert G. Clark Source Type: research
The coastal breeding habitat of Bank Swallows (Riparia riparia) in an Atlantic Canada National Park: assessing habitat use in relation to availability
Canadian Journal of Zoology, Ahead of Print. Understanding bird habitat selection has become a priority in conservation, particularly for bird species facing long-term population declines. The Bank Swallow (Riparia riparia (Linnaeus, 1758)), a species whose eastern distribution limit is in Atlantic Canada, declined by 98% between 1970 and 2011, prompting its listing as a threatened species in 2017. Its decline is hypothesized to be due in part to habitat loss and, hence, this study aimed to identify critical habitats within a protected area along Prince Edward Island. We used two types of survey to examine the availability...
Source: Canadian Journal of Zoology - April 5, 2022 Category: Zoology Authors: Tyler J. Power Hailey Paynter Marina Silva-Opps Pedro A. Quij ón Source Type: research
Changes in antioxidant enzyme levels following capture in juvenile American Alligators (Alligator mississippiensis) are tissue dependent
In this study, we investigated how capture stress and handling associated with sampling influence antioxidant status in American Alligators (Alligator mississippiensis (Daudin, 1802); hereinafter Alligator), long-lived, top-trophic carnivores found in the southeastern United States, by measuring levels of two antioxidant enzymes in destructive (brain and pancreas) and nondestructive (tail scutes) tissues: superoxide dismutase 1 (SOD1) and glutathione peroxidase 1 (GPX1). Capture stress had no effect on pancreatic SOD1 and no effect on brain and pancreatic GPX1 (all p > 0.05). However, brain SOD1, scute SOD1, and s...
Source: Canadian Journal of Zoology - April 5, 2022 Category: Zoology Authors: John W. Finger Meghan D. Kelley Matthew T. Hamilton Yufeng Zhang Ruth M. Elsey Mary T. Mendonca Andreas N. Kavazis Source Type: research
An investigation of bat mortality in British Columbia, Canada
Canadian Journal of Zoology, Ahead of Print. Identifying causes of wildlife mortality can yield an understanding of the factors that impact wildlife health. This is particularly significant for species that are facing population declines because this information can inform conservation and management practices. We evaluated causes of mortality for bats in British Columbia, Canada, submitted to the provincial veterinary laboratory between 2015 and 2020, and assessed whether cause of death varied by species and (or) was associated with bat characteristics (e.g., sex and body condition). Of the 275 bats included in this stu...
Source: Canadian Journal of Zoology - March 31, 2022 Category: Zoology Authors: Imara Beattie Delaney Schofer Glenna McGregor Michael J. Lee Lisa K.F. Lee Chelsea G. Himsworth Kaylee A. Byers Source Type: research
Summer habitat use and movements of invasive wild pigs (Sus scrofa) in Canadian agro-ecosystems
Canadian Journal of Zoology, Ahead of Print. Resource selection informs understanding of a species ’ ecology and is especially pertinent for invasive species. Since introduced to Canada, wild pigs (Sus scrofa Linnaeus, 1978) remain understudied despite recognized negative impacts on native and agricultural systems globally. Elsewhere in North America, pigs typically use forests and forage in ag ricultural crops. We hypothesized Canadian wild pigs would behave similarly, and using GPS locations from 15 individuals, we examined diel and seasonal resource selection and movement in the Canadian prairie region. Forests were p...
Source: Canadian Journal of Zoology - March 30, 2022 Category: Zoology Authors: Corey J. Kramer Melanie R. Boudreau Ryan S. Miller Ryan Powers Kurt C. VerCauteren Ryan K. Brook Source Type: research
