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Costs of group size: Lower developmental and reproductive rates in larger groups of leaf monkeys

Publication ,  Journal Article
Borries, C; Larney, E; Lu, A; Ossi, K; Koenig, A
Published in: Behavioral Ecology
November 26, 2008

Feeding competition is suggested as a major factor constraining group size in social foragers. It has, however, been challenging to demonstrate consequences of reduced energy gain in terms of fitness, possibly because social foragers may compensate negative effects of scramble competition via adjustments in time budgets. Herbivorous animals are particularly interesting in this context because their fibrous diet and slow digestion process may make it difficult to adjust time budgets. Here we investigate infant development and reproductive rates in Phayre's leaf monkeys (Trachypithecus phayrei) at Phu Khieo Wildlife Sanctuary, Thailand. The diet of the species consists of 39.0% leaves (maximum 81.2% per month). Our analysis is based on data for 3 groups (185 group months) of different sizes (mean 11.4, 18.3, and 25.8 individuals, respectively). Infant development was significantly slower in the large group, in which infants changed to the adult coat later than in the medium-sized group (20.3 vs. 26.3 weeks) and were older when weaned (18.3, 19.7, and 21.4 months, respectively). The interbirth interval after a surviving infant significantly increased with group size (21.3, 22.8, and 24.5 months) while rearing success did not differ (77.8%, 76.5%, and 82.4%, survival to 2 years). Thus, infants in the large group developed more slowly were weaned later and females reproduced more slowly. With similar infant survival rates, these different reproductive rates indicate fitness differences across groups. As in other herbivores, these group-specific differences may reflect scramble competition for food or differences in habitat quality. © The Author 2008. Published by Oxford University Press on behalf of the International Society for Behavioral Ecology. All rights reserved.

Duke Scholars

Published In

Behavioral Ecology

DOI

EISSN

1465-7279

ISSN

1045-2249

Publication Date

November 26, 2008

Volume

19

Issue

6

Start / End Page

1186 / 1191

Related Subject Headings

  • Behavioral Science & Comparative Psychology
  • 3109 Zoology
  • 3104 Evolutionary biology
  • 3103 Ecology
  • 0608 Zoology
  • 0603 Evolutionary Biology
  • 0602 Ecology
 

Citation

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Borries, C., Larney, E., Lu, A., Ossi, K., & Koenig, A. (2008). Costs of group size: Lower developmental and reproductive rates in larger groups of leaf monkeys. Behavioral Ecology, 19(6), 1186–1191. https://doi.org/10.1093/beheco/arn088
Borries, C., E. Larney, A. Lu, K. Ossi, and A. Koenig. “Costs of group size: Lower developmental and reproductive rates in larger groups of leaf monkeys.” Behavioral Ecology 19, no. 6 (November 26, 2008): 1186–91. https://doi.org/10.1093/beheco/arn088.
Borries C, Larney E, Lu A, Ossi K, Koenig A. Costs of group size: Lower developmental and reproductive rates in larger groups of leaf monkeys. Behavioral Ecology. 2008 Nov 26;19(6):1186–91.
Borries, C., et al. “Costs of group size: Lower developmental and reproductive rates in larger groups of leaf monkeys.” Behavioral Ecology, vol. 19, no. 6, Nov. 2008, pp. 1186–91. Scopus, doi:10.1093/beheco/arn088.
Borries C, Larney E, Lu A, Ossi K, Koenig A. Costs of group size: Lower developmental and reproductive rates in larger groups of leaf monkeys. Behavioral Ecology. 2008 Nov 26;19(6):1186–1191.
Journal cover image

Published In

Behavioral Ecology

DOI

EISSN

1465-7279

ISSN

1045-2249

Publication Date

November 26, 2008

Volume

19

Issue

6

Start / End Page

1186 / 1191

Related Subject Headings

  • Behavioral Science & Comparative Psychology
  • 3109 Zoology
  • 3104 Evolutionary biology
  • 3103 Ecology
  • 0608 Zoology
  • 0603 Evolutionary Biology
  • 0602 Ecology