title: Brood Parasitism Is Linked to Egg Pattern Diversity within and among Species of Australian Passerines.
abstract: Bird eggs show striking diversity in color and pattern. One explanation for this is that interactions between avian brood parasites and their hosts drive egg phenotype evolution. Brood parasites lay their eggs in the nests of other species, their hosts. Many hosts defend their nests against parasitism by rejecting foreign eggs, which selects for parasite eggs that mimic those of the host. In theory, this may in turn select for changes in host egg phenotypes over time to facilitate discrimination of parasite eggs. Here, we test for the first time whether parasitism by brood parasites has led to increased divergence in egg phenotype among host species. Using Australian host and nonhost species and objective measures of egg color and pattern, we show that (i) hosts of brood parasites have higher within-species variation in egg pattern than nonhosts, supporting previous findings in other systems, and (ii) host species have diverged more in their egg patterns than nonhost species after controlling for divergence time. Overall, our results suggest that brood parasitism has played a significant role in the evolution of egg diversity and that these effects are evident, not only within species, but also among species.
authors.forename: Iliana
authors.initials: I
authors.lastname: Medina
authors.forename: Jolyon
authors.initials: J
authors.lastname: Troscianko
authors.forename: Martin
authors.initials: M
authors.lastname: Stevens
authors.forename: Naomi E
authors.initials: NE
authors.lastname: Langmore
mesh_terms: D000818:Animals; D001315:Australia; D001717:Birds / Q000469:parasitology* / Q000502:physiology*; D003116:Color; D006790:Host-Parasite Interactions; D009425:Nesting Behavior; D010063:Ovum / Q000502:physiology; D046109:Passeriformes / Q000469:parasitology / Q000502:physiology; D010641:Phenotype; D010858:Pigmentation
keywords: Cuculidae; brood parasitism; diversity; egg phenotype; variability