No evidence for dominance –discovery trade-offs in Pheidole (Hymenoptera: Formicidae) assemblages
Canadian Journal of Zoology, Ahead of Print. Understanding the mechanisms that allow species coexistence across spatial scales is of great interest to ecologists. Many such proposed mechanisms involve trade-offs between species in different life-history traits, with distinct trade-offs being expected to be prevalent at varying temporal and spatial scales. The dominance –discovery trade-off posits that species differ in their ability to find and use resources quickly, in contrast to their ability to monopolize those resources, a mechanism analogous to the competition-colonization trade-off. We investigated the occurrence ...
Source: Canadian Journal of Zoology - October 23, 2021 Category: Zoology Authors: Cristian L. Klunk Marcio R. Pie Source Type: research
Foraging gene expression patterns in queens, workers, and males in a eusocial insect
In this study, we compare the expression level of the for- α transcript variant across four life stages of the queen caste, two behavioural groups of workers, and males of a eusocial sweat bee Lasioglossum laevissimum (Smith, 1853). Foundresses collected prior to the onset of the foraging season and males had the highest for-α expression levels. All activ e (post-hibernatory) queens and workers had similar for-α expression levels independent of behaviour. These results suggest that the for gene in L. laevissimum acts as a primer before foraging activity and that caste-specific expression patterns correlate with the timi...
Source: Canadian Journal of Zoology - October 22, 2021 Category: Zoology Authors: David N. Awde Adonis Skandalis Miriam H. Richards Source Type: research
Morphological differences in skulls and feeding apparatuses between Antarctic (Balaenoptera bonaerensis) and common (Balaenoptera acutorostrata) minke whales, and the implication for their feeding ecology
In this study, we compared 21 skull and 11 feeding apparatus (baleen and mouth-related parts) measurement points between these two species using hundreds of individuals covering a wide r ange of body lengths in both sexes. Their engulfment capacities were estimated using these measurements. Our results show that Antarctic minke whales have (i) proportionally larger skulls to the body length, (ii) more dorsoventrally and laterally curved rostra, (iii) proportionally larger feeding apparatuses to the condylobasal length, and (iv) significantly larger engulfment capacity than common minke whales. These differences could i...
Source: Canadian Journal of Zoology - October 19, 2021 Category: Zoology Authors: F. Nishimura Y. Kim T. Bando Y. Fujise G. Nakamura H. Murase H. Kato Source Type: research
Changing winter diet of Thick-billed Murres (Uria lomvia) in southwest Greenland, 1990s versus 2010s
Canadian Journal of Zoology, Ahead of Print. Southwest Greenland constitutes an internationally important wintering area for seabirds, including Thick-billed Murres (Uria lomvia (Linnaeus, 1758)), but their prey may be affected by the general warming of this sub-Arctic region. We compared murre diet collected in winter in the 1990s and in the 2010s around Nuuk, Greenland. Fish made up 36% of the diet (wet mass) and crustaceans 63% in the 1990s, changing to 22% and 78% in the 2010s, respectively. Capelin (Mallotus villosus (M üller, 1776)) was the dominant fish species, and the smaller contribution in the 2010s coincided w...
Source: Canadian Journal of Zoology - October 19, 2021 Category: Zoology Authors: Flemming Ravn Merkel Jannie Fries Linnebjerg Ole Gorm Norden Andersen Nicholas Per Huffeldt Teunis Jansen Rasmus Hedeholm Morten Frederiksen Source Type: research
Space use in free-ranging canids: are gonadal hormones required for territory maintenance?
We examined territorial fidelity, home-range size and overlap , and survival of 179 surgically sterilized free-ranging canids (124 coyotes (Canis latrans Say, 1823), 55 coyote – red wolf (Canis rufus Audubon and Bachman, 1851) hybrids) with gonadal hormones present (tubal-ligated females (n = 70), vasectomized males (n = 73)) versus absent (spayed females (n = 22), neutered males (n = 14)). The absence of gonadal hormones did not influence annual home-range size and home-range overlap, territory fidelity, and annual survival rates. Additionally, no differences were detected across sexes and hormonal treatments in an...
Source: Canadian Journal of Zoology - October 8, 2021 Category: Zoology Authors: Eric M. Gese Patricia A. Terletzky Source Type: research
Understanding environmental patterns of canid predation on white-tailed deer (Odocoileus virginianus)
Canadian Journal of Zoology, Ahead of Print. The outcome of encounters between predators and prey affects predation rates and ultimately population dynamics. Determining how environmental features influence predation rates helps guide conservation and management efforts. We studied where gray wolves (Canis lupus Linnaeus, 1758) and coyotes (Canis latrans Say, 1823) killed white-tailed deer (Odocoileus virginianus (Zimmermann, 1780)) in northern Wisconsin, USA. We monitored 499 white-tailed deer for cause-specific mortality between 2011 and 2014 using VHF radio collars. We investigated the locations of 125 deer mortalities ...
Source: Canadian Journal of Zoology - September 30, 2021 Category: Zoology Authors: L.O. Olson T.R. Van Deelen D.J. Storm S.M. Crimmins Source Type: research
The effectiveness of decommissioning roadside mineral licks on reducing moose (Alces alces) activity near highways: implications for moose –vehicle collisions
Canadian Journal of Zoology, Ahead of Print. Roadside mineral licks form when road salt used to de-ice highways in winter runs off road surfaces and accumulates in roadside ditches. Some ungulates are attracted to these roadside licks as they seek to satisfy their mineral requirements. Within the distribution of moose (Alces alces (Linnaeus, 1758)) in North America, motorists often encounter moose visiting roadside licks in mid-summer, with many jurisdictions reporting summer peaks in moose –vehicle collisions (MVCs) at these locations. We used camera traps to monitor the moose visitation of 22 roadside locations (includ...
Source: Canadian Journal of Zoology - September 29, 2021 Category: Zoology Authors: Roy V. Rea Matthew C. Scheideman Gayle Hesse Matthew A. Mumma Source Type: research
Relative skull size as one of the factors limiting skull shape variation in passerines
Canadian Journal of Zoology, Ahead of Print. Despite a considerable interest among researchers in understanding the variation in skull shapes of birds and the factors influencing it, some of the drivers associated with the design features of an entire bird body, which are important for both successful terrestrial locomotion and flight, have been overlooked. One such factor, in our opinion, is relative skull size (skull length in relation to body mass), which can affect the position of the body ’s center of gravity. We tested the effects of relative skull size, allometry (i.e., absolute skull size), and diet on variation ...
Source: Canadian Journal of Zoology - September 27, 2021 Category: Zoology Authors: Oksana V. Shatkovska Maria Ghazali Source Type: research
Influence of environmental parameters on habitat use by sympatric freshwater eels Anguilla marmorata and Anguilla japonica on Yakushima Island, Japan
Canadian Journal of Zoology, Ahead of Print. It is known that environmental parameters, such as water depth, size of substrate material, and current velocity, influence the organization of stream fish communities. However, few studies have investigated the effects of these parameters on the sympatric freshwater eels. Here, the habitat use of two anguillid eels, the Indo-Pacific eel (Anguilla marmorata Quoy and Gaimard, 1824) and the Japanese eel (Anguilla japonica Temminck and Schlegel, 1846), coexisting in the same river systems in Japan, was investigated. It was found that the tropical species A. marmorata exclusively us...
Source: Canadian Journal of Zoology - September 24, 2021 Category: Zoology Authors: Yusuke Kumai Mari Kuroki Kentaro Morita Source Type: research
Seasonal patterns in nutritional condition of caribou (Rangifer tarandus) in the southern Northwest Territories and northeastern British Columbia, Canada
Canadian Journal of Zoology, Ahead of Print. Evaluating nutritional condition provides insights of nutritional influences on wildlife populations. We sampled three measures of condition — body fat, body mass, and loin thickness — of adult female caribou (Rangifer tarandus (Linnaeus, 1758)) in boreal settings in the Northwest Territories (NT), Canada, in December and March, 2016–2018, and in mountain and boreal settings in British Columbia (BC), Canada, in December and Febr uary, 2014–2015. We evaluated the effect of calf-rearing on condition in December, compared influences of summer–autumn versus winter on co...
Source: Canadian Journal of Zoology - September 8, 2021 Category: Zoology Authors: John G. Cook Allicia P. Kelly Rachel C. Cook Brad Culling Diane Culling Ashley McLaren Nicholas C. Larter Megan Watters Source Type: research
Filling in the holes: The reproductive biology of the understudied Mahali mole-rat (Cryptomys hottentotus mahali)
This study aimed to discern if this species exhibits a seasonal or aseasonal breeding pattern and whether there is a relaxation of reproductive suppression at any point in the year in non-breeding animals. The pattern of reproductive relaxation during the wetter months is similar to other Af rican mole-rat species. Interestingly, births and pregnant breeding females were recorded throughout the year, thus indicating an aseasonal breeding strategy, despite inhabiting a region that experiences seasonal rainfall. However, there were periods of the year favouring increased reproduction to e nable an increased likelihood of off...
Source: Canadian Journal of Zoology - August 28, 2021 Category: Zoology Authors: D.W. Hart K. Medger B. van Jaarsveld N.C. Bennett Source Type: research
Staying warm is not always the norm: behavioural differences in thermoregulation of two snake species
Canadian Journal of Zoology, Ahead of Print. Thermal biology research compares field with laboratory data to elucidate the evolution of temperature-sensitive traits in ectotherms. The hidden challenge of many of these studies is discerning whether animals actively thermoregulate, since motivation is not typically assessed. By studying the behaviours involved in thermoregulation, we can better understand the mechanisms underlying body temperature control. Using an integrative approach, we assessed the thermoregulatory and thermotactic behaviours of two sympatric snake species with contrasting life histories: the generalist ...
Source: Canadian Journal of Zoology - August 26, 2021 Category: Zoology Authors: Danilo Giacometti Katharine T. Yagi Curtis R. Abney Matthew P. Jung Glenn J. Tattersall Source Type: research
Growth, feed conversion, sexual maturation, and cataract formation in coho (Oncorhynchus kisutch) and Atlantic (Salmo salar) salmon post-smolts reared at different salinities in recirculating aquaculture systems for over one year
Canadian Journal of Zoology, Ahead of Print. There is increasing interest in defining optimal conditions for rearing salmon to market size in recirculating aquaculture systems (RAS). Salinity, however, as a parameter that can be potentially manipulated, has been poorly studied. To address this knowledge gap, we reared coho (Oncorhynchus kisutch (Walbaum, 1792)) and Atlantic (Salmo salar Linnaeus, 1758) salmon from smolt to market size over ∼460 days at five different salinities (0, 5, 10, 20, and 30 ppt) and examined their growth performance. We found that both species reared at intermediate salinities (5–10 ppt) star...
Source: Canadian Journal of Zoology - August 17, 2021 Category: Zoology Authors: Yuanchang Fang Joshua D. Emerman Victor K.S. Chan Kevin T. Stiller Colin J. Brauner Jeffrey G. Richards Source Type: research
Two new species of encrusting sponge (Porifera, family Crellidae) from eastern Canada
Canadian Journal of Zoology, Ahead of Print. Two new species of Crellidae Dendy, 1922 from the east coast of Canada are described. The first is Crella (Pytheas) cutis sp. nov., a massively encrusting species of Crella (Pytheas) collected from depths of 84 to 249 m in the Gulf of St. Lawrence and on the Scotian Shelf. The second is Crellomima mehqisinpekonuta sp. nov., a thinly encrusting sponge found at diving depths in the Bay of Fundy. We also report the first records of Crellomima derma Hentschel, 1929 from outside the type locality (Barents Sea). All known species of Crellomima are reviewed based on type material. (S...
Source: Canadian Journal of Zoology - August 17, 2021 Category: Zoology Authors: Claire Goodwin Curtis Dinn Ekaterina Nefedova Frauke Nijhof Francisco Javier Murillo Claude Noz ères Source Type: research
Sexual dimorphism in bat wing morphology — variation among foraging styles
Canadian Journal of Zoology, Ahead of Print. Sexual dimorphism can lead to differences in foraging style among conspecifics due to morphological differences. Within bats, maneuverability and speed of flight are influenced by wing shape and size, which may differ between sexes. Female bats gain about 30% of their body mass during pregnancy, affecting their agility and flight efficiency. To fill the same foraging niche as males, pregnant female bats would require wing size and (or) shape modifications to maintain maneuverability. We investigated sexual dimorphism in bat wing morphology and how it varies among foraging guil...
Source: Canadian Journal of Zoology - August 14, 2021 Category: Zoology Authors: D.G. Maucieri A.J. Ashbaugh J.M. Theodor Source Type: research
