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Titolo:
Yellow-footed rock-wallaby group size effects reflect a trade-off.
Autore:
Blumstein, DT; Daniel, JC; Evans, CS;
Indirizzi:
Macquarie Univ, Dept Psychol, Anim Behav Lab, Sydney, NSW 2109, Australia Macquarie Univ Sydney NSW Australia 2109 Lab, Sydney, NSW 2109, Australia Macquarie Univ, Cooperat Res Ctr Conservat & Management Marsupial, Sydney,NSW 2109, Australia Macquarie Univ Sydney NSW Australia 2109 pial, Sydney,NSW 2109, Australia
Titolo Testata:
ETHOLOGY
fascicolo: 7, volume: 107, anno: 2001,
pagine: 655 - 664
SICI:
0179-1613(200107)107:7<655:YRGSER>2.0.ZU;2-C
Fonte:
ISI
Lingua:
ENG
Soggetto:
EASTERN GREY KANGAROOS; VIGILANCE; FLOCKING; ADVANTAGES; PREDATION; BEHAVIOR; MAMMALS; BIRDS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Life Sciences
Citazioni:
33
Recensione:
Indirizzi per estratti:
Indirizzo: Blumstein, DT Univ Calif Los Angeles, Dept Organism Biol Ecol & Evolut, 621 Charles E Young Dr S, Los Angeles, CA 90095 USA Univ Calif Los Angeles 621 Charles E Young Dr S Los Angeles CA USA 90095
Citazione:
D.T. Blumstein et al., "Yellow-footed rock-wallaby group size effects reflect a trade-off.", ETHOLOGY, 107(7), 2001, pp. 655-664

Abstract

As group size increases, individuals of many species modify the time allocated to anti-predator vigilance and foraging.. Group size effects can result from a reduction in predation risk or from an increase in competition as a function of aggregation. Anti-predator models of vigilance and foraging group size effects both predict a non-linear relationship between group sizeand time allocation. Linear relationships between group size and time allocation may reflect the modification of such relationships by intraspecific interference competition for limited resources, which would reveal a fundamental cost of sociality. We studied the degree to which group size effects in the yellow-footed rock-wallaby (Petrogale xanthopus, a macropodid marsupial) were non-linear. Like several other macropods, yellow-footed rock-wallabies foraged more and looked less as group size increased. Variation in vigilance was best explained by the number of conspecifics within 10 m-a distance substantially less than the 30-50 in often used to quantify group sizein macropodids. Linear regressions explained more variation than non-linear ones, suggesting that wallabies traded-off the benefits of aggregation with the costs of competition. Moreover, dominant yellow-foots looked less and tended to forage more than subordinate animals. We hypothesize that competition may be relatively more important in the life-histories of yellow-footed rock-wallabies than those of other macropodid marsupials.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 29/03/20 alle ore 11:51:34