Vanessa Poirier, Barbara Frei, Mathilde Lefvert, Ana Morales, Kyle Hamish Elliott
Stopovers are the most energy- and time-consuming events during avian migration, yet individuals of certain species make long stopovers to moult (‘moult migration’). Requiring abundant energy and a prolonged stay, moult migrants should occupy small stopover home ranges in resource-rich habitats. Understanding migrant behaviour at their stopovers is critical for implementing conservation efforts for declining Neotropical passerines. To examine the stopover timing and habitat use of one such moult migrating passerine, we radio-tagged 18 moulting and 4 post-moult Tennessee Warblers (Leiothlypis peregrina A. Wilson, 1811) at an autumn stopover site. Although our data were biased towards one sampling year, moult migrants generally arrived at the stopover site earlier (average = 2 August) than post-moult migrants (average = 12 September). Moult migrants also stayed longer (46 ± 5 days) than post-moult migrants (8 ± 6 days) and had large overlapping stopover home ranges (~15 ha) that were dependent on high abundance of forest (%) and forest edge (m). We conclude that Tennessee Warblers occupied forested stopover sites within a peri-urban landscape where they successfully moulted before continuing migration. This study illustrates the importance of including stopover sites in conservation plans, particularly in cities where quality habitats are scarce.
中途停留是鸟类迁徙过程中最耗费精力和时间的事情，但某些物种的个体会在中途停留很长时间来换羽(“换羽迁徙”)。换毛候鸟需要充足的能量和长时间的停留，它们应该在资源丰富的栖息地占据一小块中途停留的范围。了解候鸟在中途停留地的行为对于实施保护日益减少的新热带雀形目动物的努力至关重要。为了研究一种这样的换羽迁徙雀鸟的中途停留时间和栖息地利用，我们在一个秋季中途停留点对18只换羽的田纳西林莺和4只换羽后的田纳西林莺(leiothlyypis peregrina A. Wilson, 1811)进行了无线电标记。虽然我们的数据偏向于一个采样年，但蜕皮候鸟通常比蜕皮后候鸟(平均= 9月12日)更早到达中途停留点(平均= 8月2日)。换毛候鸟停留的时间(46±5天)也比换毛后候鸟停留的时间(8±6天)更长，并且有很大的重叠的中途停留范围(~15公顷)，这取决于森林的丰度(%)和森林边缘(m)。我们得出结论，田纳西林莺占据了城郊景观中有森林的中途停留点，在那里它们成功地换毛，然后继续迁徙。这项研究说明了在保护计划中包括中途停留点的重要性，特别是在高质量栖息地稀缺的城市。
{"title":"Moult migrant Tennessee Warblers undergo extensive stopover in peri-urban forests of southern Quebec","authors":"Vanessa Poirier, Barbara Frei, Mathilde Lefvert, Ana Morales, Kyle Hamish Elliott","doi":"10.1139/cjz-2023-0109","DOIUrl":"https://doi.org/10.1139/cjz-2023-0109","url":null,"abstract":"Stopovers are the most energy- and time-consuming events during avian migration, yet individuals of certain species make long stopovers to moult (‘moult migration’). Requiring abundant energy and a prolonged stay, moult migrants should occupy small stopover home ranges in resource-rich habitats. Understanding migrant behaviour at their stopovers is critical for implementing conservation efforts for declining Neotropical passerines. To examine the stopover timing and habitat use of one such moult migrating passerine, we radio-tagged 18 moulting and 4 post-moult Tennessee Warblers (Leiothlypis peregrina A. Wilson, 1811) at an autumn stopover site. Although our data were biased towards one sampling year, moult migrants generally arrived at the stopover site earlier (average = 2 August) than post-moult migrants (average = 12 September). Moult migrants also stayed longer (46 ± 5 days) than post-moult migrants (8 ± 6 days) and had large overlapping stopover home ranges (~15 ha) that were dependent on high abundance of forest (%) and forest edge (m). We conclude that Tennessee Warblers occupied forested stopover sites within a peri-urban landscape where they successfully moulted before continuing migration. This study illustrates the importance of including stopover sites in conservation plans, particularly in cities where quality habitats are scarce.","PeriodicalId":9484,"journal":{"name":"Canadian Journal of Zoology","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135728937","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jason Thomas Fisher, Melanie Dickie, Joanna Burgar, Cole Burton, Robert D Serrouya
Density estimation is a key goal in ecology, but accurate estimates for unmarked animals remain elusive. Camera-trap data can bridge this gap, but accuracy, precision, and concordance varies among estimators. We compared estimates from unmarked spatial capture-recapture (spatial count, SC) models, and Time In Front of Camera (TIFC) models, for four large mammal species in boreal Canada. Species differed in movement rates, behaviours, and sociality – traits related to model assumptions. TIFC densities typically exceeded SC model estimates for all species. Two- to five-fold differences between estimators were common. SC estimates were annually stable for moose and caribou, but not for white-tailed deer. TIFC estimates showed high annual variation in some species, sites, and years, and consistency in others. Both models often produced imprecise estimates. Estimates varied from DNA- and aerial survey-based estimates. We contend models diverge, or implausibly vary, due to violations of model assumptions incurred by animal behavior. Gregarious animals pose challenges to SC whereas curious animals pose challenges for TIFC models. Simulations can help unravel the role of assumption violations in affecting accuracy of estimates, but field applications across species and landscapes help interpret the outcomes of estimating density from simulated data.
{"title":"Density estimates of unmarked mammals: Comparing two models and assumptions across multiple species and years.","authors":"Jason Thomas Fisher, Melanie Dickie, Joanna Burgar, Cole Burton, Robert D Serrouya","doi":"10.1139/cjz-2023-0055","DOIUrl":"https://doi.org/10.1139/cjz-2023-0055","url":null,"abstract":"Density estimation is a key goal in ecology, but accurate estimates for unmarked animals remain elusive. Camera-trap data can bridge this gap, but accuracy, precision, and concordance varies among estimators. We compared estimates from unmarked spatial capture-recapture (spatial count, SC) models, and Time In Front of Camera (TIFC) models, for four large mammal species in boreal Canada. Species differed in movement rates, behaviours, and sociality – traits related to model assumptions. TIFC densities typically exceeded SC model estimates for all species. Two- to five-fold differences between estimators were common. SC estimates were annually stable for moose and caribou, but not for white-tailed deer. TIFC estimates showed high annual variation in some species, sites, and years, and consistency in others. Both models often produced imprecise estimates. Estimates varied from DNA- and aerial survey-based estimates. We contend models diverge, or implausibly vary, due to violations of model assumptions incurred by animal behavior. Gregarious animals pose challenges to SC whereas curious animals pose challenges for TIFC models. Simulations can help unravel the role of assumption violations in affecting accuracy of estimates, but field applications across species and landscapes help interpret the outcomes of estimating density from simulated data.","PeriodicalId":9484,"journal":{"name":"Canadian Journal of Zoology","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135729344","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Luísa de Paula Reis, Jessica Fratani, María Laura Ponssa
Many species of anurans display special mechanical abilities, such as excavation and climbing. The aim of this study is to investigate the development of traits that are associated with these special mechanical abilities, under the hypothesis that these structures attain their configuration during the juvenile stages of development. We examined specimens from four different species of Leptodactylidae and six species of Hylidae. For the digging behavior, we evaluated the progress of calcification in the anterior region of the skulls, as well as the development of the snout-ridge. To assess climbing ability, we examined the ossification rate, the variation in the shape of the phalanx, the progress of the offset angle, and the distance between the terminal phalanx and the penultimate phalange of finger IV. The ossification of the skull and phalanges, along with the development of the snout-ridge, progresses and reaches completion during the juvenile phase of ontogeny, suggesting that at the time of metamorphosis, individuals are not yet full-scale replicas of the adults. The shape and the mechanical characteristics of terminal phalanges are already established by the conclusion of metamorphosis, revealing intriguing distinctions among arboreal species with walking and jumping locomotion.
{"title":"Are juveniles full-scale replicas of adults? Evaluation of anuran special locomotion and digging adaptations during and after metamorphosis","authors":"Luísa de Paula Reis, Jessica Fratani, María Laura Ponssa","doi":"10.1139/cjz-2023-0077","DOIUrl":"https://doi.org/10.1139/cjz-2023-0077","url":null,"abstract":"Many species of anurans display special mechanical abilities, such as excavation and climbing. The aim of this study is to investigate the development of traits that are associated with these special mechanical abilities, under the hypothesis that these structures attain their configuration during the juvenile stages of development. We examined specimens from four different species of Leptodactylidae and six species of Hylidae. For the digging behavior, we evaluated the progress of calcification in the anterior region of the skulls, as well as the development of the snout-ridge. To assess climbing ability, we examined the ossification rate, the variation in the shape of the phalanx, the progress of the offset angle, and the distance between the terminal phalanx and the penultimate phalange of finger IV. The ossification of the skull and phalanges, along with the development of the snout-ridge, progresses and reaches completion during the juvenile phase of ontogeny, suggesting that at the time of metamorphosis, individuals are not yet full-scale replicas of the adults. The shape and the mechanical characteristics of terminal phalanges are already established by the conclusion of metamorphosis, revealing intriguing distinctions among arboreal species with walking and jumping locomotion.","PeriodicalId":9484,"journal":{"name":"Canadian Journal of Zoology","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135480887","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nematode communities in natural pristine forests composed of trees aged over a thousand years have not been thoroughly studied. Old-growth forests can provide diverse microhabitats for nematodes such as fallen trees with mossy conditions. This study aimed to characterize the community and trophic compositions of nematodes in relation to different microhabitats in old-growth Japanese cedar (Cryptomeria japonica (Lf) D.Don) forests in Yakushima Island, Japan. To this aim, nematodes retrieved from four different types of microhabitats were morphologically identified at the family/genus level and divided into five trophic groups. A non-metric multidimensional scaling scatterplot showed that nematode communities clustered significantly in each microhabitat and their community compositions were significantly affected by C/N ratio. With respect to nematode trophic composition, bacterivorous nematodes dominated decaying barks of fallen trees, with a relative abundance of 45%, while fungivorous nematodes were dominant in living barks of cedar trunks (61%). Predatory-omnivorous nematodes predominated in mosses of fallen trees (51%). These results showed that nematode community and trophic composition were different among microhabitats characterized by nutrient conditions. The predatory-omnivorous nematodes were abundant in mosses with N-rich conditions. In contrast, fungivorous nematodes were abundant in cedar trunks with high C/N conditions. Thus, old-growth natural forests can provide diverse microhabitats where various nematode taxa coexist due to the presence of fallen trees and mosses.
{"title":"Distribution and characterization of nematodes in above-ground microhabitats on a natural pristine cedar forest in Yakushima Island, Japan","authors":"Yudai Kitagami, Yosuke Matsuda","doi":"10.1139/cjz-2023-0107","DOIUrl":"https://doi.org/10.1139/cjz-2023-0107","url":null,"abstract":"Nematode communities in natural pristine forests composed of trees aged over a thousand years have not been thoroughly studied. Old-growth forests can provide diverse microhabitats for nematodes such as fallen trees with mossy conditions. This study aimed to characterize the community and trophic compositions of nematodes in relation to different microhabitats in old-growth Japanese cedar (Cryptomeria japonica (Lf) D.Don) forests in Yakushima Island, Japan. To this aim, nematodes retrieved from four different types of microhabitats were morphologically identified at the family/genus level and divided into five trophic groups. A non-metric multidimensional scaling scatterplot showed that nematode communities clustered significantly in each microhabitat and their community compositions were significantly affected by C/N ratio. With respect to nematode trophic composition, bacterivorous nematodes dominated decaying barks of fallen trees, with a relative abundance of 45%, while fungivorous nematodes were dominant in living barks of cedar trunks (61%). Predatory-omnivorous nematodes predominated in mosses of fallen trees (51%). These results showed that nematode community and trophic composition were different among microhabitats characterized by nutrient conditions. The predatory-omnivorous nematodes were abundant in mosses with N-rich conditions. In contrast, fungivorous nematodes were abundant in cedar trunks with high C/N conditions. Thus, old-growth natural forests can provide diverse microhabitats where various nematode taxa coexist due to the presence of fallen trees and mosses.","PeriodicalId":9484,"journal":{"name":"Canadian Journal of Zoology","volume":"166 3-4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135549011","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
John M. Green, Dustin Schornagel, Khanh Nguyen, Curtis Pennell, Corey Morris
Atlantic cod (Gadus morhua Linnaeus, 1758) can experience mortality at sub-zero (<0°C) temperatures in ice-infested waters, and many populations migrate to deeper and warmer areas during winter. An exception is the resident population in Gilbert Bay, Labrador, which annually experiences six months of sub-zero temperatures. We used the VEMCO Positioning System (VPS) to estimate fish locations to determine depth utilization, and seasonal movements of tagged Gilbert Bay cod ranging in size from 43 to 75 cm. This is the first study to directly monitor the movements of adult Atlantic cod for extended periods (months) in sub-zero temperatures. Gilbert Bay cod remained active under an ice-covered surface during the six months of sub-zero temperatures. During both warm (>0°C) and cold (≤0°C) periods, fish spent similar amounts of time not moving, moving slowly, and moving at medium and fast rates. They tended to utilize shallow depths, <10 m, beneath surface ice during winter, while utilizing deeper depths as well during other times of the year. Surprisingly, fish that resided within our tracking array year-round had greater cumulative swimming distances during sub-zero periods compared to warmer periods. No tracked fish died during winter further highlighting the cold-adaptiveness of this population, and its importance to biodiversity conservation.
{"title":"Field observations of the movements of locally adapted Atlantic cod (Gadus morhua) living in zero and sub-zero centigrade temperatures for half the year","authors":"John M. Green, Dustin Schornagel, Khanh Nguyen, Curtis Pennell, Corey Morris","doi":"10.1139/cjz-2023-0067","DOIUrl":"https://doi.org/10.1139/cjz-2023-0067","url":null,"abstract":"Atlantic cod (Gadus morhua Linnaeus, 1758) can experience mortality at sub-zero (<0°C) temperatures in ice-infested waters, and many populations migrate to deeper and warmer areas during winter. An exception is the resident population in Gilbert Bay, Labrador, which annually experiences six months of sub-zero temperatures. We used the VEMCO Positioning System (VPS) to estimate fish locations to determine depth utilization, and seasonal movements of tagged Gilbert Bay cod ranging in size from 43 to 75 cm. This is the first study to directly monitor the movements of adult Atlantic cod for extended periods (months) in sub-zero temperatures. Gilbert Bay cod remained active under an ice-covered surface during the six months of sub-zero temperatures. During both warm (>0°C) and cold (≤0°C) periods, fish spent similar amounts of time not moving, moving slowly, and moving at medium and fast rates. They tended to utilize shallow depths, <10 m, beneath surface ice during winter, while utilizing deeper depths as well during other times of the year. Surprisingly, fish that resided within our tracking array year-round had greater cumulative swimming distances during sub-zero periods compared to warmer periods. No tracked fish died during winter further highlighting the cold-adaptiveness of this population, and its importance to biodiversity conservation.","PeriodicalId":9484,"journal":{"name":"Canadian Journal of Zoology","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135385676","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Emily Wright, Jacob Bayouth, Joseph Bayouth, Asha Worsham, Grant McDaniel, Tess Hollinger, Vivienne Lacy, Emma Johnston, David Pipkin, Emma Roberts, Robert D. Bradley
Introgressive hybridization between members of Odocoileus was examined using the mitochondrial cytochrome-b (maternal marker) and paternal sex-determining region Y ( Sry) genes. Eight out of 130 free-ranging individuals from the Panhandle and Trans-Pecos regions of Texas were determined to possess the mitochondrial haplotype of mule deer ( Odocoileus hemionus (Rafinesque, 1817)) and the paternal haplotype of white-tailed deer ( Odocoileus virginianus Rafinesque, 1832). Results indicated that hybridization between deer species in Texas (6.15%) was more broadly distributed than previously reported. Previous studies demonstrated that ancient hybridization events (1.32 mya) involved the capture of the white-tailed deer mitochondrial genome by mule deer, indicating a male mule deer × a female white-tailed deer directionality relevant to hybridization. Alternatively, contemporary hybridization events indicated a reversal in directionality and suggested a cross between a female mule deer × a male white-tailed deer. The Sry gene and species assignment based on morphological characters consistently were in agreement. Further, phylogenetic relationships between Odocoileus virginianus couesi and Odocoileus hemionus eremicus warrant additional investigation as recent hybridization (>200 years) may be a mechanism that allowed these two subspecies to evolve a unique evolutionary trajectory.
{"title":"Contemporary hybridization between female mule deer and male white-tailed deer in west Texas differs from the hypothesized sex mating patterns recovered from ancient hybridization events","authors":"Emily Wright, Jacob Bayouth, Joseph Bayouth, Asha Worsham, Grant McDaniel, Tess Hollinger, Vivienne Lacy, Emma Johnston, David Pipkin, Emma Roberts, Robert D. Bradley","doi":"10.1139/cjz-2023-0082","DOIUrl":"https://doi.org/10.1139/cjz-2023-0082","url":null,"abstract":"Introgressive hybridization between members of Odocoileus was examined using the mitochondrial cytochrome-b (maternal marker) and paternal sex-determining region Y ( Sry) genes. Eight out of 130 free-ranging individuals from the Panhandle and Trans-Pecos regions of Texas were determined to possess the mitochondrial haplotype of mule deer ( Odocoileus hemionus (Rafinesque, 1817)) and the paternal haplotype of white-tailed deer ( Odocoileus virginianus Rafinesque, 1832). Results indicated that hybridization between deer species in Texas (6.15%) was more broadly distributed than previously reported. Previous studies demonstrated that ancient hybridization events (1.32 mya) involved the capture of the white-tailed deer mitochondrial genome by mule deer, indicating a male mule deer × a female white-tailed deer directionality relevant to hybridization. Alternatively, contemporary hybridization events indicated a reversal in directionality and suggested a cross between a female mule deer × a male white-tailed deer. The Sry gene and species assignment based on morphological characters consistently were in agreement. Further, phylogenetic relationships between Odocoileus virginianus couesi and Odocoileus hemionus eremicus warrant additional investigation as recent hybridization (>200 years) may be a mechanism that allowed these two subspecies to evolve a unique evolutionary trajectory.","PeriodicalId":9484,"journal":{"name":"Canadian Journal of Zoology","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135535169","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Travis Durhack, Melanie Aminot, Jason Treberg, Eva Enders
Understanding how metabolic costs change in relation to increasing temperature under future climate changes is important to predict how ectotherms will be affected across the globe. In fish, whole body respiration is traditionally used to estimate aerobic performance via an organism’s minimum and maximum oxygen consumption rates. However, mitochondria play a crucial role in the aerobic cascade and may be a useful surrogate of aerobic performance. To test whether whole body oxygen consumption and mitochondrial capacity are correlated, we estimated whole body metabolic and mitochondrial respiration rates (using permeabilized red muscle fibres) in brook trout ( Salvelinus fontinalis (Mitchill, 1814)) at 10, 15, and 20 °C. Standard metabolic rate increased with acclimation temperature, while maximum rates were less sensitive. All mitochondrial respiration rates increased with acclimation temperature, suggesting that red muscle mitochondrial preparations may correlate to the minimal metabolic demands in this species. When expressed as relative rates of electron flow, the red muscle fibres showed no effect of temperature on mitochondrial coupling efficiency. However, there was a pattern of declining capacity to augment respiration via complex II with increasing temperature with a concomitant increase in the capacity of the phosphorylating system relative to maximal rates of mitochondrial electron flow.
{"title":"Comparing whole body and red muscle mitochondrial respiration in an active teleost fish, Brook Trout (Salvelinus fontinalis)","authors":"Travis Durhack, Melanie Aminot, Jason Treberg, Eva Enders","doi":"10.1139/cjz-2023-0045","DOIUrl":"https://doi.org/10.1139/cjz-2023-0045","url":null,"abstract":"Understanding how metabolic costs change in relation to increasing temperature under future climate changes is important to predict how ectotherms will be affected across the globe. In fish, whole body respiration is traditionally used to estimate aerobic performance via an organism’s minimum and maximum oxygen consumption rates. However, mitochondria play a crucial role in the aerobic cascade and may be a useful surrogate of aerobic performance. To test whether whole body oxygen consumption and mitochondrial capacity are correlated, we estimated whole body metabolic and mitochondrial respiration rates (using permeabilized red muscle fibres) in brook trout ( Salvelinus fontinalis (Mitchill, 1814)) at 10, 15, and 20 °C. Standard metabolic rate increased with acclimation temperature, while maximum rates were less sensitive. All mitochondrial respiration rates increased with acclimation temperature, suggesting that red muscle mitochondrial preparations may correlate to the minimal metabolic demands in this species. When expressed as relative rates of electron flow, the red muscle fibres showed no effect of temperature on mitochondrial coupling efficiency. However, there was a pattern of declining capacity to augment respiration via complex II with increasing temperature with a concomitant increase in the capacity of the phosphorylating system relative to maximal rates of mitochondrial electron flow.","PeriodicalId":9484,"journal":{"name":"Canadian Journal of Zoology","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135534634","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
F. Stephen Dobson, Claire Saraux, Vincent A. Viblanc
Phenotypic plasticity of life-history traits is well known among vertebrate species. We estimated reproductive and somatic efforts of female Columbian ground squirrels ( Urocitellus columbianus (Ord, 1815)) to test for plasticity of these important resource allocations. We examined a 27-year dataset of life-history traits on these long-living (8–10 years), hibernating, montane-living mammals. Environmental variation was estimated from two important traits of mothers, their relative timing of breeding and spring maternal body mass (initial “capital” for use in subsequent reproduction). Results from 183 known-aged mothers and 508 litters revealed considerable variation in the relative timing of breeding, initial maternal mass, and reproductive and somatic efforts, as well as significant variation among ages and years. Results from 125 mothers that reproduced more than once (and 450 litters) revealed significant plasticity of reproductive and somatic efforts with respect to relative timing of breeding and spring maternal mass. A within-subject centering statistical approach showed that phenotypically plastic reproductive and somatic efforts were due to variation within individuals, but were not always reflected by the pattern of responses among individuals in the population. The plastic responses of different mothers appeared to be similar in strength.
{"title":"PHENOTYPIC PLASTICITY IN REPRODUCTIVE AND SOMATIC EFFORTS OF FEMALE COLUMBIAN GROUND SQUIRRELS","authors":"F. Stephen Dobson, Claire Saraux, Vincent A. Viblanc","doi":"10.1139/cjz-2023-0108","DOIUrl":"https://doi.org/10.1139/cjz-2023-0108","url":null,"abstract":"Phenotypic plasticity of life-history traits is well known among vertebrate species. We estimated reproductive and somatic efforts of female Columbian ground squirrels ( Urocitellus columbianus (Ord, 1815)) to test for plasticity of these important resource allocations. We examined a 27-year dataset of life-history traits on these long-living (8–10 years), hibernating, montane-living mammals. Environmental variation was estimated from two important traits of mothers, their relative timing of breeding and spring maternal body mass (initial “capital” for use in subsequent reproduction). Results from 183 known-aged mothers and 508 litters revealed considerable variation in the relative timing of breeding, initial maternal mass, and reproductive and somatic efforts, as well as significant variation among ages and years. Results from 125 mothers that reproduced more than once (and 450 litters) revealed significant plasticity of reproductive and somatic efforts with respect to relative timing of breeding and spring maternal mass. A within-subject centering statistical approach showed that phenotypically plastic reproductive and somatic efforts were due to variation within individuals, but were not always reflected by the pattern of responses among individuals in the population. The plastic responses of different mothers appeared to be similar in strength.","PeriodicalId":9484,"journal":{"name":"Canadian Journal of Zoology","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135534946","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jacob L. Seguin, Melanie R. Boudreau, Sophia Lavergne, Ryan Lamoureux, Charles J. Krebs, Rudy Boonstra
Perceived predation risk alters prey behaviour and physiology, but few studies have examined downstream consequences on prey demography in wild populations. Perceived predation risk could alter adult reproductive performance via reduced investment in offspring quality and post-birth care. We manipulated perceived predation risk in snowshoe hare ( Lepus americanus Erxleben, 1777) by exposing pregnant mothers to chases by a domestic dog ( Canis familiaris Linnaeus, 1758). Litter size was comparable between risk-augmented and control groups, but treated females had more stillbirths and gave birth to leverets of lower body condition. Leverets from risk-augmented females had 88% higher 40-day mortality rate. Maternally preventable causes of death like starvation or predation by red squirrel ( Tamiasciurus hudsonicus (Erxleben, 1777)) caused this difference, particularly during the nursing period. Risk-augmented mothers were always more active than controls, but the difference was greatest during the nursing period. We found that perceived predation risk reduces maternal productivity pre- and post-partum, implying downstream consequences to populations. Because our treatment ended before parturition, we can link offspring performance such as survival and behaviour specifically to maternal life-history trade-offs, which has not been shown in a wild mammal.
感知到的捕食风险会改变猎物的行为和生理，但很少有研究调查野生种群对猎物数量的下游影响。感知到的捕食风险可以通过减少对后代质量和产后护理的投资来改变成人的生殖表现。我们通过将怀孕的雪鞋兔暴露于家犬(Canis familiaris Linnaeus, 1758)的追逐中，来操纵雪鞋兔(Lepus americanus Erxleben, 1777)的感知捕食风险。产仔数在风险增加组和对照组之间是相当的，但治疗过的雌性有更多的死产，产下的小白鼠身体状况较低。来自风险增强雌性的小杠杆40天死亡率高出88%。母亲可预防的死亡原因，如饥饿或被红松鼠(Tamiasciurus hudsonicus (Erxleben, 1777))捕食造成了这种差异，特别是在哺乳期。风险增加的母亲总是比对照组更活跃，但在哺乳期间差异最大。我们发现，感知到的捕食风险降低了产前和产后的孕产妇生产力，这意味着对种群的下游后果。因为我们的治疗在分娩前就结束了，我们可以将后代的表现，如生存和行为，具体地与母亲的生活史权衡联系起来，这在野生哺乳动物中还没有显示出来。
{"title":"Experimental manipulation of perceived predation risk alters survival, cause of death, and demographic patterns in juvenile snowshoe hares","authors":"Jacob L. Seguin, Melanie R. Boudreau, Sophia Lavergne, Ryan Lamoureux, Charles J. Krebs, Rudy Boonstra","doi":"10.1139/cjz-2023-0046","DOIUrl":"https://doi.org/10.1139/cjz-2023-0046","url":null,"abstract":"Perceived predation risk alters prey behaviour and physiology, but few studies have examined downstream consequences on prey demography in wild populations. Perceived predation risk could alter adult reproductive performance via reduced investment in offspring quality and post-birth care. We manipulated perceived predation risk in snowshoe hare ( Lepus americanus Erxleben, 1777) by exposing pregnant mothers to chases by a domestic dog ( Canis familiaris Linnaeus, 1758). Litter size was comparable between risk-augmented and control groups, but treated females had more stillbirths and gave birth to leverets of lower body condition. Leverets from risk-augmented females had 88% higher 40-day mortality rate. Maternally preventable causes of death like starvation or predation by red squirrel ( Tamiasciurus hudsonicus (Erxleben, 1777)) caused this difference, particularly during the nursing period. Risk-augmented mothers were always more active than controls, but the difference was greatest during the nursing period. We found that perceived predation risk reduces maternal productivity pre- and post-partum, implying downstream consequences to populations. Because our treatment ended before parturition, we can link offspring performance such as survival and behaviour specifically to maternal life-history trade-offs, which has not been shown in a wild mammal.","PeriodicalId":9484,"journal":{"name":"Canadian Journal of Zoology","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134886639","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
C. Dinn, Bruce Ott, Mariève Bouchard Marmen, Royce Steeves, Geneviève Côté, Vonda Hayes, C. Nozères, Meredith V. Everett, Abigail Powell, Jackson W.F. Chu
Mycale ( Mycale) loveni (Fristedt, 1887) is a very large structure-forming sponge that has previously been reported in the North Pacific, North Atlantic, and Arctic oceans. Through morphological and molecular examination, North Atlantic and Eastern Canadian Arctic specimens are now described as a new species, Mycale ( Mycale) lorea sp. nov. The two species have similar external morphology; however, the spicules that make up their skeletons differ in size and shape, and the species are also separated phylogenetically by multiple genetic markers.
{"title":"Two large structure-forming sponges from opposite North American coasts: a taxonomic review of Arctic–Pacific Mycale (Mycale) loveni and the description of a new Arctic–Atlantic Mycale","authors":"C. Dinn, Bruce Ott, Mariève Bouchard Marmen, Royce Steeves, Geneviève Côté, Vonda Hayes, C. Nozères, Meredith V. Everett, Abigail Powell, Jackson W.F. Chu","doi":"10.1139/cjz-2023-0011","DOIUrl":"https://doi.org/10.1139/cjz-2023-0011","url":null,"abstract":"Mycale ( Mycale) loveni (Fristedt, 1887) is a very large structure-forming sponge that has previously been reported in the North Pacific, North Atlantic, and Arctic oceans. Through morphological and molecular examination, North Atlantic and Eastern Canadian Arctic specimens are now described as a new species, Mycale ( Mycale) lorea sp. nov. The two species have similar external morphology; however, the spicules that make up their skeletons differ in size and shape, and the species are also separated phylogenetically by multiple genetic markers.","PeriodicalId":9484,"journal":{"name":"Canadian Journal of Zoology","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45275781","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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