In avian host-brood parasite co-evolution, hosts develop antiparasite defence mechanisms against the brood parasite. Great reed warblers (Acrocephalus arundinaceus) exhibit intensive nest defence against common cuckoos (Cuculus canorus) and moderate egg rejection. Rejection of model cuckoo eggs is about two times greater than real eggs. Great reed warblers attacked a mounted cuckoo at nests in similarly high frequencies over the breeding cycle (86%-93%), but rejection rates of non-mimetic model cuckoo eggs increased from laying until early incubation from 69% to 92%, then decreased to 44% in late incubation. Temporal changes in the risk of parasitism were followed by the changes in egg rejection suggesting that egg rejection behaviour is primarily a risk-sensitive adaptation to brood parasitism, although hosts were not able to switch off egg rejection totally in the risk-free periods. In contrast, nest defence seems to be the compound effect of antiparasite defence and predator avoidance.
|Number of pages||8|
|Journal||Annales Zoologici Fennici|
|Publication status||Published - Dec 1 2005|
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics
- Animal Science and Zoology
- Nature and Landscape Conservation