Endocrine regulation of egg rejection in an avian brood parasite host

Mikus Abolins-Abols, Mark E. Hauber

Research output: Contribution to journalArticlepeer-review


Parasite-host coevolution can lead to novel behavioural adaptations in hosts to resist parasitism. In avian obligate brood parasite and host systems, many host species have evolved diverse cognitive and behavioural traits to recognize and reject parasitic eggs. Our understanding of the evolution and ecology of these defences hinges on identifying the mechanisms that regulate them. We hypothesized that corticosterone, a hormone linked to stress response, vigilance and the suppression of parental behaviour, stimulates the rejection of foreign eggs by brood parasite hosts. We experimentally reduced circulating glucocorticoid levels with mitotane injections in American robins Turdus migratorius and found that the mitotane-treated birds rejected foreign eggs at a lower frequency compared to the sham-treated subjects. This is the first study to causally identify a potential mechanism of a widespread defence behaviour, and it is consistent with egg rejection being mediated by stress physiology.

Original languageEnglish (US)
Article number20200225
JournalBiology Letters
Issue number6
StatePublished - Jun 1 2020


  • avian brood parasitism
  • corticosterone
  • egg rejection

ASJC Scopus subject areas

  • Agricultural and Biological Sciences (miscellaneous)
  • General Agricultural and Biological Sciences


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