A recognition-free mechanism for reliable rejection of brood parasites

Michael G. Anderson, Mark E. Hauber

Research output: Contribution to journalShort surveypeer-review


Hosts often discard eggs of avian brood parasites, whereas parasitic chicks are typically accepted. This can be explained theoretically by fitness losses associated with adults learning to recognize parasitic young and mistakenly rejecting their own young. A new experimental study confirms that rejection of parasitic chicks, without relying on memory to discriminate between foreign and own young, is a feasible and potentially cost-free mechanism used by reed warblers to reject common cuckoo chicks. By abandoning broods that are in the nest longer than is typical for their own young, parents can reliably reject parasite nestlings and reduce fitness losses owing to having to care for demanding parasitic young. Discrimination without recognition has important implications for the realized trajectories of host-parasite coevolutionary arms races.

Original languageEnglish (US)
Pages (from-to)283-286
Number of pages4
JournalTrends in Ecology and Evolution
Issue number6
StatePublished - Jun 2007
Externally publishedYes

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics


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