Mechanisms of egg recognition in brown-headed cowbird hosts: the role of ultraviolet reflectance

摘要: One of the most effective adaptations to counter avian brood parasitism is rejection parasitic egg, yet relatively few hosts reject eggs brown-headed cowbird, Molothrus ater. Studies have demonstrated that ultraviolet (UV; 300–400 nm) reflectance plays a role in egg by cuckoos Cuculus spp. Only two studies experimentally tested whether cowbird host utilizes UV light when making decisions, and those found no evidence was significant factor. We blocked one clutches three rejecter species: brown thrasher, Toxostoma rufum, American robin, Turdus migratorius, grey catbird, Dumetella carolinensis, determine they utilize rejecting eggs. also measured each species' All species rejected more their own UV-blocked than did control eggs, but thrashers were significantly likely robins catbirds. Brown thrasher reflected both robin catbird Our results coupled with from similar suggest brighter UV-reflecting should be duller This first study demonstrate parameter used further increases our understanding mechanisms recognition brood-parasitic hosts.