Living Reference Work Entry

Encyclopedia of Evolutionary Psychological Science

pp 1-3

Date: Latest Version

Rejection Thresholds

  • William E. FeeneyAffiliated withSchool of Biological Sciences, University of Queensland Email author 

Synonyms

Decision making; Egg recognition; Egg rejection

Definitions

The threshold at which hosts of avian brood parasites reject a foreign egg, which can be adjusted according to their perceived risk of parasitism.

Introduction

The interactions between avian brood parasites, such as cuckoos or cowbirds, and their hosts have emerged as model systems to study coevolutionary processes under natural conditions. Instead of building a nest and tending their offspring, brood parasites lay their eggs in the nests of other birds and abandon the care of their young to the host. Adult parasites tend to remove or damage host eggs when depositing their own and parasite chicks generally eliminate the rest of the host’s brood after hatching. Consequently, hosts evolve defenses against brood parasites, which select counteradaptations in parasites, further counteradaptations in hosts, and so on. While evidence of reciprocal adaptations and counteradaptations in hosts and brood parasites are evident at all ...

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