Effects of habitat quality on growth, age of first reproduction, and dispersal in Gunnison's prairie dogs (<i>Cynomys gunnisoni</i>)

Rayor, Linda S.

doi:10.1139/z85-423

Cited by 58 publications

(39 citation statements)

References 17 publications

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“…Social interactions among yellow-bellied marmots of areas with relatively short growing seasons are less agonistic and more friendly (ie socially tolerant) than those among marmots of areas with longer growing seasons (Barash 1973b(Barash , 1989. Similarly, Gunnison's prairie dogs reach sexual maturity more rapidly, and disperse at a younger age at sites with more extended growing seasons than prairie dogs of habitats with shorter growing seasons (Rayor 1985). Lastly, the rate of amicable interactions within groups (a measure of sociality) of Columbian ground squirrels Spermophilus columbianus decreases with the length of the plant (food) growing season (Ritchie and Belovsky 1990).…”

Section: The Parental Investment Hypothesismentioning

confidence: 99%

A review of the evolutionary causes of rodent group-living

Ebensperger

2001

Acta Theriol

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Ebensperger L. A. 2001. A review of the evolutionary causes of rodent group-living. Acta Theriologica 46: 115-144.I analyze and summarize the empirical evidence supporting alternative hypotheses posed to explain the evolution of rodent group-living. Eight hypotheses are considered: two rely on net fitness benefits to individuals, five rely on ecological and life-history constraints, and one uses elements of both. I expose the logic behind each hypothesis, identify its key predictions, examine how the available evidence on rodent socioecology supports or rejects its predictions, and identify some priorities for future research. I show that empirical support for most hypotheses is meager due to a lack of relevant studies. Also, empirical support for a particular hypothesis, when it exists, comes from studies of the same species used to formulate the original hypothesis. Two exceptions are the hypothesis that individual rodents live in groups to reduce their predation risk and the hypothesis that group-living was adopted by individuals to reduce their cost of thermoregulation. Finally, most hypotheses have been examined without regard to competing hypotheses and often in a restricted taxonomic context. This is clearly an unfortunate situation given that most competing hypotheses are not mutually exclusive. I suggest that in the future comparative approaches should be used. These studies should examine simultaneously the relevance of different benefits and constraints hypothesized to explain the evolution of rodent sociality.

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Section: The Parental Investment Hypothesismentioning

confidence: 99%

A review of the evolutionary causes of rodent group-living

Ebensperger

2001

Acta Theriol

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“…Yearlings of ground-dwelling sciurids do not reproduce, or reproduce at much lower rates, than older animals; examples include woodchucks (Snyder, 1962), Belding's ground squirrels Spermophilus beldingi (Sherman & Morton, 1984), Columbian ground squirrels (Festa-Bianchet, 1981;Dobson & Murie, 1987), Uinta ground squirrels Spermophilus armatus (Slade & Balph, 1974), thirteen-lined ground squirrels (McCarley, 1966), golden-mantled ground squirrels Spermophilus lateralis (Bronson, 1979), black-tailed prairie dogs (King, 1955;R. E. Smith, 1958;Hoogland, 1981Hoogland, , 1995), Gunnison's prairie dogs Cynomys gunnisoni (Rayor, 1985), Olympic marmots (Barash, 1973) and hoary marmots Marmota caligata (Barash, 1974a). Increased energy availability increased the frequency of reproduction in yearling black-tailed prairie dogs (Koford, 1958) and Gunnison's prairie dog yearlings bred only when food was more abundant (Rayor, 1985).…”

Section: Maternity Patterns and Comparisonsmentioning

confidence: 99%

“…E. Smith, 1958;Hoogland, 1981Hoogland, , 1995), Gunnison's prairie dogs Cynomys gunnisoni (Rayor, 1985), Olympic marmots (Barash, 1973) and hoary marmots Marmota caligata (Barash, 1974a). Increased energy availability increased the frequency of reproduction in yearling black-tailed prairie dogs (Koford, 1958) and Gunnison's prairie dog yearlings bred only when food was more abundant (Rayor, 1985). More yearling female Columbian ground squirrels reproduced on food-supplemented sites than on non-supplemented sites and in low-elevation habitats with a longer growing season (Dobson & Kjelgaard, 1985;Dobson, Zammuto & Murie, 1986;Dobson & Murie, 1987).…”

Section: Maternity Patterns and Comparisonsmentioning

confidence: 99%

A 32-year demography of yellow-bellied marmots (Marmota flaviventris)

Schwartz¹,

Armitage²,

Vuren³

1998

J. Zoology

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Yellow-bellied marmots Marmota¯aviventris in the East River Valley of Colorado were live-trapped and individually marked annually from 1962 through 1993. These pooled data were used to produce a demography and life table for these years. Females had signi®cantly better survivorship than males beyond the ®rst-year age class, and the sex ratio became progressively female biased. The major mortality factors of predation and unsuccessful hibernation acted evenly on all age classes as shown by the constant rates of survivorship. The rate of senescence indicated that the probability of mortality did not increase with age. Females produced litters from ages 2 to 10 years. Mean litter size was 4.1 and did not differ among age classes. The female generation length of 4.49 years was 2.4 times the life expectancy and the median survivorship. The net reproductive rate (R o ) was 0.67, yet the population did not continually decline; adjustments to these data increased R o to 0.85. Reproductive values (V x ) were approximately equal across the reproductive age classes. The polygynous mating system is both cause and effect of the demography. Marmot population size is affected by weather factors that in¯uence reproduction and survival, by predation, and by movement into and out of the study area.

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“…Similarly, the hypothesis that adult aggression actively promotes dispersal by young male conspecifics was rejected in studies of M.flaviventris (Armitage 1973, Armitage and Downhower 1974, Downhower and Armitage 1981, Brody and Armitage 1985, and S. beecheyi (Dobson 1979). Rayor (1985) concluded that natal dispersal by male Cynomys gunnisoni resulted from direct conflict with other males. However, predictions for the conspecific aggression hypothesis were violated in studies of dispersal in Cynomys ludovicianus (Z. Halpin, personal communication) and S. columbianus (Festa-Bianchet and King 1984).…”

Section: ) S Armatus (Slade and Balph 1974) Or S Tereticaudus (Dumentioning

confidence: 99%

“…However, as in the present study, earlier workers have attempted to examine effects on sciurid dis-persal of several independent variables concurrently. Exploratory excursions often precede dispersal in young male S. beldingi (Holekamp 1 984a), Cynomys gunnisoni (Rayor 1985), Castor canadensis (Svendsen 1980), and Odocoileus hemionus (McCullough 1985). Similarly Dunford (1977) found no significant relationship between dispersal and population density, food availability, or aggression in S. tereticaudus.…”

Section: ] Pygathrix Nemaeus [Lippold 1977])mentioning

confidence: 99%

Proximal Causes of Natal Dispersal in Belding's Ground Squirrels (Spermophilus Beldingi)

Holekamp¹

1986

Ecological Monographs

579

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JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. Ecological Society of America is collaborating with JSTOR to digitize, preserve and extend access to Ecological Monographs.Abstract. I studied the proximal factors influencing dispersal from the natal site in two free-living populations of Belding's ground squirrels (Spermophilus beldingi) in the Sierra Nevada of California. I tested 10 hypotheses, each suggesting a different social, ecological, or ontogenetic factor as a proximal cause of natal dispersal in this species. Using discriminant analysis I also examined effects on dispersal of several independent variables concurrently. Data from marking and live-trapping studies over three field seasons (1979)(1980)(1981) failed to support hypotheses suggesting resource shortage, ectoparasite load, social facilitation, conspecific aggression, or avoidance by conspecifics as proximal causes of natal dispersal in S. beldingi. Furthermore, dispersal is apparently not caused by changes in juveniles' response thresholds to conspecific aggression or by juveniles' attempts to avoid members of their family units, nearest neighbors, or other members of their local populations.My data supported an "ontogenetic switch" hypothesis that suggests natal dispersal by male S. beldingi is triggered by attainment of a particular body mass or body composition, or some combination of these two variables. Other data indicated that this ontogenetic switch initiates not only dispersal behavior per se, but also a larger syndrome of behaviors that appear to be functionally related to dispersal. Specifically, this syndrome involves changes in exploration, responses to frightening stimuli, and locomotor behavior exhibited by dispersers. I discuss possible relationships among variables operating at different proximal levels (sensu Tinbergen) to cause natal dispersal in S. beldingi and other mammals. I conclude that a complex suite of variables probably operates at genetic, physiological, and socioecological levels to proximally cause natal dispersal in each species. The ultimate (evolutionary) hypotheses most consistent with my data from S. beldingi are that dispersal: (1) reduces nuclear family incest, (2) optimizes inbreeding, and (3) improves access to mates.

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Effects of habitat quality on growth, age of first reproduction, and dispersal in Gunnison's prairie dogs (Cynomys gunnisoni)

Cited by 58 publications

References 17 publications

A review of the evolutionary causes of rodent group-living

A review of the evolutionary causes of rodent group-living

A 32-year demography of yellow-bellied marmots (Marmota flaviventris)

Proximal Causes of Natal Dispersal in Belding's Ground Squirrels (Spermophilus Beldingi)

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