Environmental stability and the evolution of cooperative breeding in hornbills

Issue Date

8-2013

Abstract

Reproductive cooperation in social animals has been the focus of intensive research, yet the role of environmental factors in promoting such cooperation remains uncertain. A recent global analysis suggested that cooperative breeding in birds is a 'bet-hedging' strategy associated with climatic uncertainty, but it is unclear whether this mechanism applies generally or is restricted to the insectivorous passerines that predominate as cooperative breeders at the global scale. Here, we use a phylogenetic framework to assess the effect of climate on the evolution of cooperation in hornbills (Bucerotidae), an avian family characterized by frugivory and carnivory. We show that, in contrast to the global pattern, cooperative reproduction is positively associated with both inter- and intra-annual climatic stability. This reversed relationship implies that hornbills are relatively insensitive to climatic fluctuations, perhaps because of their dietary niche or increased body mass, both of which may remove the need for bet-hedging. We conclude that the relationship between climatic variability and cooperative breeding is inconsistent across taxa, and potentially mediated by life-history variation. These findings help to explain the mixed results of previous studies and highlight the likely shortcomings of global datasets inherently biased towards particular categories. © 2013 The Author(s) Published by the Royal Society. All rights reserved.

Source or Periodical Title

Proceedings of the Royal Society B: Biological Sciences

ISSN

0962-8452

Volume

280

Issue

1768

Page

1-9

Document Type

Article

Physical Description

illustrations, tables, graphs

Language

English

Subject

Climate, Comparative analysis, Cooperation, Ecological traits, Social behaviour

Identifier

doi:10.1098/rspb.2013.1297.

Digital Copy

yes

Link to Full Text

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