Group size adjustment to ecological demand in a cooperative breeder

Zöttl, Markus; Frommen, Joachim G.; Taborsky, Michael (2013). Group size adjustment to ecological demand in a cooperative breeder. Proceedings of the Royal Society B: Biological sciences, 280(1756), p. 20122772. The Royal Society 10.1098/rspb.2012.2772

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Environmental factors can determine which group size will maximize the fitness of group members. This is particularly important in cooperative breeders, where group members often serve different purposes. Experimental studies are yet lacking to check whether ecologically mediated need for help will change the propensity of dominant group members to accept immigrants. Here, we manipulated the perceived risk of predation for dominant breeders of the cooperatively breeding cichlid fish Neolamprologus pulcher to test their response to unrelated and previously unknown immigrants. Potential immigrants were more readily accepted if groups were exposed to fish predators or egg predators than to herbivorous fish or control situations lacking predation risk. Our data are consistent with both risk dilution and helping effects. Egg predators were presented before spawning, which might suggest that the fish adjust acceptance rates also to a potential future threat. Dominant group members of N. pulcher apparently consider both present and future need of help based on ecological demand. This suggests that acceptance of immigrants and, more generally, tolerance of group members on demand could be a widespread response to ecological conditions in cooperatively breeding animals.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Department of Biology > Institute of Ecology and Evolution (IEE) > Behavioural Ecology
08 Faculty of Science > Department of Biology > Institute of Ecology and Evolution (IEE)

UniBE Contributor:

Zöttl, Markus; Frommen, Joachim Gerhard and Taborsky, Michael

Subjects:

500 Science > 590 Animals (Zoology)
500 Science > 570 Life sciences; biology

ISSN:

1471-2954

Publisher:

The Royal Society

Language:

English

Submitter:

Joachim Gerhard Frommen

Date Deposited:

29 Apr 2014 09:47

Last Modified:

22 Dec 2016 12:01

Publisher DOI:

10.1098/rspb.2012.2772

BORIS DOI:

10.7892/boris.44789

URI:

https://boris.unibe.ch/id/eprint/44789

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