Experimental Shifts in Intraclutch Egg Color Variation Do Not Affect Egg Rejection in a Host of a Non-Egg-Mimetic Avian Brood Parasite

摘要: Avian brood parasites lay their eggs in the nests of other birds, and impose costs associated with rearing parasitic young onto these hosts. Many hosts defend against parasitism by removing foreign from nest. In systems where mimic host coloration patterning, extensive intraclutch variation egg appearances may impair host’s ability to recognize reject eggs, but experimental investigation this effect has produced conflicting results. The cognitive mechanism which vary across parasite hosts, explain outcome studies investigating rejection egg-mimicking parasites. contrast, for non-egg-mimetic parasites, color is not predicted co-vary rejection, irrespective mechanism. Here we tested effects a nonmimetic manipulating American robins (Turdus migratorius), brown-headed cowbirds (Molothrus ater). We recorded robins’ behavioral responses simulated cowbird was artificially enhanced or reduced. also quantified within between unmanipulated robin clutches as perceived themselves using spectrophotometric measures avian visual modeling. nests, varied more than clutches. As predicted, however, manipulation did affect rates. Overall, our results best support scenario wherein selective pressure parasite, because are efficient rejecters own clutch.