Reproductive Delay in Female Cape Ground Squirrels (Xerus Inauris) PDF Download
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Author: Beth A. Pettitt
Publisher:
ISBN:
Category :
Languages : en
Pages : 80
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Book Description
Prior to the start of the field season, I conducted an initial experiment to determine the best alternative form of fecal storage if freezing was unavailable. I found that drying feces provides a more reliable method for long-term preservation of fecal steroid concentrations when compared to storing fecal samples in alcohol. Data associated with each of the seven parameters was analyzed using model selection to simultaneously measure the ability of different combinations of parameters to explain the observed variation in female age of sexual maturity. I found that an increase in the number of adult breeding female group mates and related adult male group mates resulted in a substantial inhibition of female reproductive maturity. I concluded that, while female Cape ground squirrels gain many advantages from group living, their sexual maturity is primarily influenced by a tug-of-war among social parameters, with minimal direct influence by environmental ones.
Author: Beth A. Pettitt
Publisher:
ISBN:
Category :
Languages : en
Pages : 80
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Book Description
Prior to the start of the field season, I conducted an initial experiment to determine the best alternative form of fecal storage if freezing was unavailable. I found that drying feces provides a more reliable method for long-term preservation of fecal steroid concentrations when compared to storing fecal samples in alcohol. Data associated with each of the seven parameters was analyzed using model selection to simultaneously measure the ability of different combinations of parameters to explain the observed variation in female age of sexual maturity. I found that an increase in the number of adult breeding female group mates and related adult male group mates resulted in a substantial inhibition of female reproductive maturity. I concluded that, while female Cape ground squirrels gain many advantages from group living, their sexual maturity is primarily influenced by a tug-of-war among social parameters, with minimal direct influence by environmental ones.
Author: Jane Margaret Waterman
Publisher:
ISBN:
Category : Animal societies
Languages : en
Pages : 378
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Book Description
Author: Philip Shimel
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
Sociality - or living in groups among members of the same species - can have both costs and benefits for survival and reproductive success. Inclusive fitness theory suggests organisms might behaviourally favour closer kin if they can identify and act to benefit them. In promiscuous social species, average relatedness may be too low to maintain costly social behaviours like cooperative breeding without kin discrimination. Animals that are more central in social networks may gain fitness benefits and costs similar to those of sociality generally, but particularly those effects that arise from indirect social connections. Increased social network centrality is often linked to improved fitness, but also greater ectoparasite abundance. Exploring whether fitness correlates to social network position under low rates of aggression or hierarchy remains a key challenge for comparative evolutionary ecology. Cape ground squirrels (Xerus inauris) are facultatively cooperative breeders with high promiscuity. They are a social species that rarely exhibit aggressive behaviours towards conspecifics and show no evidence of dominance hierarchies. A previous study that removed their parasites dramatically increased female reproductive success. Our objective was to examine whether kinship influences social structure and whether ectoparasite abundance and centrality influence survival and reproductive success in adult female Cape ground squirrels. We predicted kinship increases affiliative and decreases agonistic interactions, that centrality increases ectoparasites, and that ectoparasites and centrality reduce reproductive success but not survival. We studied Cape ground squirrels on S.A. Lombard Nature Reserve, South Africa in 2017. We followed 14 social groups, collected interaction data through all-occurrence sampling, and collected ectoparasite abundance data from trapping. We found that kinship increased both affiliative and agonistic interactions. Since agonistic interactions are relatively mild in this species, greater agonistic interaction frequencies with closer kin may have insignificant fitness costs. More central adult females had more ectoparasites, but eigenvector centrality and ectoparasite abundance did not affect survival or reproductive success. Our study shows that Cape ground squirrels are nepotistic with their interactions within their social groups, and that the costs and benefits of group living in species with low rates of aggression can have novel implications for the relationships between fitness and sociality.
Author: Mary Beth Manjerovic
Publisher:
ISBN:
Category : Ground squirrels
Languages : en
Pages : 114
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Book Description
Sexual selection is considered a powerful evolutionary force responsible for the enormous diversity found in reproductive morphology, physiology, and behavior. I addressed questions related to selection in the Cape ground squirrel (Xerus inauris), a species characterized as highly social and promiscuous. These attributes often are responsible for variance in male reproductive success and as such, sexual selection theory predicts increased opportunity for sexual selection. I confirm that the predominant mechanism underlying genital evolution and competition for paternity in X. inauris is sperm competition. I find evidence that investment in sperm competition is costly and may reflect immunocompetence. I quantify reproductive success as it relates to alternative male tactics and female resource distribution. I find that male X. inauris alternative reproductive tactics differ within and across populations most likely due to differences in female resource distribution. In areas where females are evenly distributed, dispersed males encounter more estrous females, and therefore have increased breeding opportunities. However, the decision to remain natal does not preclude reproduction. I determine that these tactics are most likely conditional with equal fitness payoffs. Males, regardless of tactic, invest more in post-copulatory competition (e.g. sperm competition, copulatory plugs) than males within a population with a clustered distribution of breeding females. In the latter area, males form dominance hierarchies that affect copulatory success and lead to greater skews in reproduction among males. Both sites have evidence of a highly skewed variance in reproduction and intense sexual selective pressure. My results suggest these populations have increased opportunities for selection but that different mechanisms of intrasexual competition may result in rapid evolutionary change within this species.
Author: Jonathan Kingdon
Publisher: A&C Black
ISBN: 1408189968
Category : Nature
Languages : en
Pages : 3500
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Book Description
Mammals of Africa (MoA) is a series of six volumes which describes, in detail, every currently recognized species of African land mammal. This is the first time that such extensive coverage has ever been attempted, and the volumes incorporate the very latest information and detailed discussion of the morphology, distribution, biology and evolution (including reference to fossil and molecular data) of Africa's mammals. With 1,160 species and 16 orders, Africa has the greatest diversity and abundance of mammals in the world. The reasons for this and the mechanisms behind their evolution are given special attention in the series. Each volume follows the same format, with detailed profiles of every species and higher taxa. The series includes some 660 colour illustrations by Jonathan Kingdon and his many drawings highlight details of morphology and behaviour of the species concerned. Diagrams, schematic details and line drawings of skulls and jaws are by Jonathan Kingdon and Meredith Happold. Every species also includes a detailed distribution map. Extensive references alert readers to more detailed information. Volume I: Introductory Chapters and Afrotheria (352 pages) Volume II: Primates (560 pages) Volume III: Rodents, Hares and Rabbits (784 pages) Volume IV: Hedgehogs, Shrews and Bats (800 pages) Volume V: Carnivores, Pangolins, Equids and Rhinoceroses (560 pages) Volume VI: Pigs, Hippopotamuses, Chevrotain, Giraffes, Deer and Bovids (704 pages)
Author: Jonathan Kingdon
Publisher: A&C Black
ISBN: 1408189925
Category : Nature
Languages : en
Pages : 785
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Book Description
Mammals of Africa (MoA) is a series of six volumes which describes, in detail, every currently recognized species of African land mammal. This is the first time that such extensive coverage has ever been attempted, and the volumes incorporate the very latest information and detailed discussion of the morphology, distribution, biology and evolution (including reference to fossil and molecular data) of Africa's mammals. With more than 1,160 species and 16-18 orders, Africa has the greatest diversity and abundance of mammals in the world. The reasons for this and the mechanisms behind their evolution are given special attention in the series. Each volume follows the same format, with detailed profiles of every species and higher taxa. The series includes hundreds of colour illustrations and pencil drawings by Jonathan Kingdon highlighting the morphology and behaviour of the species concerned, as well as line drawings of skulls and jaws by Jonathan Kingdon and Meredith Happold. Every species also includes a detailed distribution map. Edited by Jonathan Kingdon, David Happold, Tom Butynski, Mike Hoffmann, Meredith Happold and Jan Kalina, and written by more than 350 authors, all experts in their fields, Mammals of Africa is as comprehensive a compendium of current knowledge as is possible. Extensive references alert readers to more detailed information. Volume III, edited by David Happold, has profiles of 395 species of rodents, comprising the squirrels, dormice, jerboas, blind mole-rats, African root-rats, pouched rats and mice, Swamp Mouse, climbing mice, fat mice, White-tailed Rat, rock mice, voles, Maned Rat, spiny mice, brush-furred mice, gerbils, jirds, taterils, African Forest Mouse, rats and mice, vlei rats, whistling rats, anomalures, springhares, gundis, African mole-rats, porcupines, Noki (Dassie Rat), cane rats and Coypu. The volume concludes with 13 species of hares and rabbits.
Author: Ara Monadjem
Publisher: Walter de Gruyter GmbH & Co KG
ISBN: 3110389231
Category : Nature
Languages : en
Pages : 1126
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Book Description
This comprehensive handbook covers all the rodents occurring in Southern, Central, East and West Africa, south of the Sahara. Genus and species accounts include diagnostic descriptions, systematics and taxonomy, biogeographical environment, fossil species, photographs of skull and mandible, illustrations of molar dentition, photographs of live animals, distribution maps and tables of standard museum measurements.
Author: Richard W. Thorington, Jr.
Publisher: JHU Press
ISBN: 1421404699
Category : Science
Languages : en
Pages : 470
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Book Description
Squirrels of the World, written by scientists with more than 100 years of collective experience studying these popular mammals, is the first comprehensive examination of all 285 species of squirrels worldwide. The authors reveal virtually every detail of the family Sciuridae, which includes ground squirrels, tree squirrels, flying squirrels, prairie dogs, and chipmunks. Each species—from the familiar gray squirrel of American backyards to the exotic and endangered woolly flying squirrel of Pakistan—is described in a detailed account that includes distinguishing characteristics, ecology, natural history, conservation status, and current threats to its existence. Squirrels of the World includes • stunning color photographs that document rare and unusual squirrels as well as common varieties• evolution, morphology, ecology, and conservation status• colorful range maps marking species distribution• images of the skull of each genus of squirrel• extensive references -- Lawrence Heaney, Curator and Head of the Division of Mammals, The Field Museum (Chicago)
Author: Nereida Bueno-Guerra
Publisher: Cambridge University Press
ISBN: 110842032X
Category : Medical
Languages : en
Pages : 459
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Book Description
Leading researchers present current methodological approaches and future directions for a less anthropocentric study of animal cognition.
Author: David Norris
Publisher: Academic Press
ISBN: 0080958044
Category : Technology & Engineering
Languages : en
Pages : 411
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Book Description
This series of volumes represents a comprehensive and integrated treatment of reproduction in vertebrates from fishes of all sorts through mammals. It is designed to provide a readable, coordinated description of reproductive basics in each group of vertebrates as well as an introduction to the latest trends in reproductive research and our understanding of reproductive events. Whereas each chapter and each volume is intended to stand alone as a review of that topic or vertebrate group, respectively, the volumes are prepared so as to provide a thorough topical treatment across the vertebrates. Terminology has been standardized across the volumes to reduce confusion where multiple names exist in the literature, and a comprehensive glossary of these terms and their alternative names is provided. A complete, essential and up to date reference for research scientists working on vertebrate hormones and reproduction - and on animlals as models in human reproductive research Covers the endocrinology, neuroendocrinology, physiology, behaviour and anatomy of vertebrate reproduction Structured coverage of the major themes for all five vertebrate groups allows a consistent treatment for all Special chapters elaborate on features specific to individual vertebrate groups and to comparative aspects, similarities and differences between them
