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Chimpanzee (Pan troglodytes schweinfurthii) Group Sleep and Pathogen-Vector Avoidance: Experimental Support for the Encounter-Dilution Effect

Publication ,  Journal Article
Samson, DR; Louden, LA; Gerstner, K; Wylie, S; Lake, B; White, BJ; Nunn, CL; Hunt, KD
Published in: International Journal of Primatology
December 1, 2019

Sleep is essential for survival, yet it represents a time of extreme vulnerability, including through exposure to parasites and pathogens transmitted by biting insects. To reduce the risks of exposure to vector-borne disease, the encounter-dilution hypothesis proposes that the formation of groups at sleep sites is influenced by a “selfish herd” behavior, where individuals dilute risk by sleeping with other group members. To investigate this hypothesis in the context of chimpanzee (Pan troglodytes schweinfurthii) sleep site selection, we employed four light traps that we also baited with nontoxic chemical attractants to capture insects throughout the night. Across 74 nights with 294 traps set, we collected 66,545 individual insects. Consistent with the encounter-dilution hypothesis, we found that insect exposure, inferred by absolute numbers of insects caught in nighttime traps, was strongly influenced by the grouping of traps. Specifically, single traps caught more insects—including vector transmitting female mosquitoes—than grouped traps, and the number of insects caught increased with increasing distance between grouped traps. Moreover, ground sleep sites caught fewer insects than arboreal sleep sites. In addition, traps associated with Cynometra alexandri trees resulted in significantly lower catch rates than Pseudospondias microcarpa–associated traps. Our results suggest wild chimpanzees use group sleep as a strategy to avoid biting insects that serve as hosts for vector-borne diseases.

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Published In

International Journal of Primatology

DOI

EISSN

1573-8604

ISSN

0164-0291

Publication Date

December 1, 2019

Volume

40

Issue

6

Start / End Page

647 / 659

Related Subject Headings

  • Behavioral Science & Comparative Psychology
  • 3109 Zoology
  • 0608 Zoology
 

Citation

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ICMJE
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Samson, D. R., Louden, L. A., Gerstner, K., Wylie, S., Lake, B., White, B. J., … Hunt, K. D. (2019). Chimpanzee (Pan troglodytes schweinfurthii) Group Sleep and Pathogen-Vector Avoidance: Experimental Support for the Encounter-Dilution Effect. International Journal of Primatology, 40(6), 647–659. https://doi.org/10.1007/s10764-019-00111-z
Samson, D. R., L. A. Louden, K. Gerstner, S. Wylie, B. Lake, B. J. White, C. L. Nunn, and K. D. Hunt. “Chimpanzee (Pan troglodytes schweinfurthii) Group Sleep and Pathogen-Vector Avoidance: Experimental Support for the Encounter-Dilution Effect.” International Journal of Primatology 40, no. 6 (December 1, 2019): 647–59. https://doi.org/10.1007/s10764-019-00111-z.
Samson DR, Louden LA, Gerstner K, Wylie S, Lake B, White BJ, et al. Chimpanzee (Pan troglodytes schweinfurthii) Group Sleep and Pathogen-Vector Avoidance: Experimental Support for the Encounter-Dilution Effect. International Journal of Primatology. 2019 Dec 1;40(6):647–59.
Samson, D. R., et al. “Chimpanzee (Pan troglodytes schweinfurthii) Group Sleep and Pathogen-Vector Avoidance: Experimental Support for the Encounter-Dilution Effect.” International Journal of Primatology, vol. 40, no. 6, Dec. 2019, pp. 647–59. Scopus, doi:10.1007/s10764-019-00111-z.
Samson DR, Louden LA, Gerstner K, Wylie S, Lake B, White BJ, Nunn CL, Hunt KD. Chimpanzee (Pan troglodytes schweinfurthii) Group Sleep and Pathogen-Vector Avoidance: Experimental Support for the Encounter-Dilution Effect. International Journal of Primatology. 2019 Dec 1;40(6):647–659.
Journal cover image

Published In

International Journal of Primatology

DOI

EISSN

1573-8604

ISSN

0164-0291

Publication Date

December 1, 2019

Volume

40

Issue

6

Start / End Page

647 / 659

Related Subject Headings

  • Behavioral Science & Comparative Psychology
  • 3109 Zoology
  • 0608 Zoology