The limits to cost-free signalling of need between relatives

Ben O. Brilot, Rufus A. Johnstone

Research output: Contribution to journalJournal Articlepeer-review

24 Citations (Scopus)


Theoretical models have demonstrated the possibility of stable cost-free signalling of need between relatives. The stability of these cost-free equilibria depends on the indirect fitness cost of cheating and deceiving a donor into giving away resources. We show that this stability is highly sensitive to the distribution of need among signallers and receivers. In particular, cost-free signalling is likely to prove stable only if there is very large variation in need (such that the least-needy individuals stand to gain much less than the most-needy individuals from additional resources). We discuss whether these conditions are likely to be found in altricial avian breeding systems - the most intensively studied instance of signalling of need between relatives. We suggest that cost-free signalling is more likely to prove stable and will provide parents with more information during the earlier phases of chick growth, when parents can more easily meet the demands of a brood (and chicks are more likely to reach satiation). Later, informative yet costfree signalling is unlikely to persist.
Original languageEnglish
Pages (from-to)1055-1060
Number of pages6
JournalPhilosophical Transactions of the Royal Society B: Biological Sciences
Issue number1519
Publication statusPublished - 22 May 2003
Externally publishedYes


  • Cost-free signalling
  • Information
  • Pooling equilibria
  • Signalling of need


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