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Do animals living in larger groups experience greater parasitism? A meta-analysis.

Publication ,  Journal Article
Rifkin, JL; Nunn, CL; Garamszegi, LZ
Published in: The American naturalist
July 2012

Parasitism is widely viewed as the primary cost of sociality and a constraint on group size, yet studies report varied associations between group size and parasitism. Using the largest database of its kind, we performed a meta-analysis of 69 studies of the relationship between group size and parasite risk, as measured by parasitism and immune defenses. We predicted a positive correlation between group size and parasitism with organisms that show contagious and environmental transmission and a negative correlation for searching parasites, parasitoids, and possibly vector-borne parasites (on the basis of the encounter-dilution effect). Overall, we found a positive effect of group size (r = 0.187) that varied in magnitude across transmission modes and measures of parasite risk, with only weak indications of publication bias. Among different groups of hosts, we found a stronger relationship between group size and parasite risk in birds than in mammals, which may be driven by ecological and social factors. A metaregression showed that effect sizes increased with maximum group size. Phylogenetic meta-analyses revealed no evidence for phylogenetic signal in the strength of the group size-parasitism relationship. We conclude that group size is a weak predictor of parasite risk except in species that live in large aggregations, such as colonial birds, in which effect sizes are larger.

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Published In

The American naturalist

DOI

EISSN

1537-5323

ISSN

0003-0147

Publication Date

July 2012

Volume

180

Issue

1

Start / End Page

70 / 82

Related Subject Headings

  • Spiders
  • Risk
  • Population Density
  • Phylogeny
  • Parasitic Diseases, Animal
  • Mammals
  • Lizards
  • Insecta
  • Host-Parasite Interactions
  • Fishes
 

Citation

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Rifkin, J. L., Nunn, C. L., & Garamszegi, L. Z. (2012). Do animals living in larger groups experience greater parasitism? A meta-analysis. The American Naturalist, 180(1), 70–82. https://doi.org/10.1086/666081
Rifkin, Joanna L., Charles L. Nunn, and László Z. Garamszegi. “Do animals living in larger groups experience greater parasitism? A meta-analysis.The American Naturalist 180, no. 1 (July 2012): 70–82. https://doi.org/10.1086/666081.
Rifkin JL, Nunn CL, Garamszegi LZ. Do animals living in larger groups experience greater parasitism? A meta-analysis. The American naturalist. 2012 Jul;180(1):70–82.
Rifkin, Joanna L., et al. “Do animals living in larger groups experience greater parasitism? A meta-analysis.The American Naturalist, vol. 180, no. 1, July 2012, pp. 70–82. Epmc, doi:10.1086/666081.
Rifkin JL, Nunn CL, Garamszegi LZ. Do animals living in larger groups experience greater parasitism? A meta-analysis. The American naturalist. 2012 Jul;180(1):70–82.
Journal cover image

Published In

The American naturalist

DOI

EISSN

1537-5323

ISSN

0003-0147

Publication Date

July 2012

Volume

180

Issue

1

Start / End Page

70 / 82

Related Subject Headings

  • Spiders
  • Risk
  • Population Density
  • Phylogeny
  • Parasitic Diseases, Animal
  • Mammals
  • Lizards
  • Insecta
  • Host-Parasite Interactions
  • Fishes