title: Nestling polymorphism in a cuckoo-host system.
abstract: Virulence of avian brood parasites can trigger a coevolutionary arms race, which favours rejection of parasitic eggs or chicks by host parents, and in turn leads to mimicry in parasite eggs or chicks [1-7]. The appearance of host offspring is critical to enable host parents to detect parasites. Thus, increasing accuracy of parasites' mimicry can favour a newly emerged host morph to escape parasites' mimicry. If parasites catch up with the hosts with a newly acquired mimetic morph, host polymorphism should be maintained through apostatic (negative frequency-dependent) selection, which favours hosts rarer morphs [1-3,7]. Among population-wide polymorphism, uniformity of respective host morphs in single host nests stochastically prevents parasites from targeting any specific morph of hosts and thus helps parents detect parasitism. Polymorphism in such a state is well-known in egg appearances of hosts of brood parasitic birds [2,3,7], which might also occur in chick appearances when arms races escalate. Here, we present evidence of polymorphism in chick skin coloration in a cuckoo-host system: the fan-tailed gerygone Gerygone flavolateralis and its specialist brood parasite, the shining bronze-cuckoo Chalcites lucidus in New Caledonia (Figure 1A-C).
authors.affiliation: School of Science, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima, Tokyo 171-8501, Japan; Museum and Institute for Zoology, Polish Academy of Sciences, 00-679 Warsaw, Poland.
authors.forename: Nozomu J
authors.initials: NJ
authors.lastname: Sato
authors.affiliation: School of Science, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima, Tokyo 171-8501, Japan. Electronic address: keita.d.tanaka@gmail.com.
authors.forename: Keita D
authors.initials: KD
authors.lastname: Tanaka
authors.affiliation: School of Science, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima, Tokyo 171-8501, Japan; Japan Wildlife Research Center 3-3-7 Kotobashi, Sumida, Tokyo 130-8606, Japan (current address).
authors.forename: Yuji
authors.initials: Y
authors.lastname: Okahisa
authors.affiliation: Hakubi Center for Advanced Research, Kyoto University, Yoshida-Ushinomiya-cho, Sakyo, Kyoto 606-8501, Japan; Center for Ecological Research, Kyoto University, 2-509-3 Hirano, Otsu, Shiga 520-2113, Japan.
authors.forename: Masato
authors.initials: M
authors.lastname: Yamamichi
authors.affiliation: Unit of Molecular Zoology, Chair of Zoology, Department of Animal Science, Technische Universität München, 85354 Freising, Germany; Department of Fish, Wildlife and Conservation Ecology, New Mexico State University, Las Cruces, NM 88003-8003, USA.
authors.forename: Ralph
authors.initials: R
authors.lastname: Kuehn
authors.affiliation: Museum and Institute for Zoology, Polish Academy of Sciences, 00-679 Warsaw, Poland.
authors.forename: Roman
authors.initials: R
authors.lastname: Gula
authors.affiliation: School of Science, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima, Tokyo 171-8501, Japan.
authors.forename: Keisuke
authors.initials: K
authors.lastname: Ueda
authors.affiliation: Museum and Institute for Zoology, Polish Academy of Sciences, 00-679 Warsaw, Poland.
authors.forename: Jörn
authors.initials: J
authors.lastname: Theuerkauf
mesh_terms: D000220:Adaptation, Biological; D000818:Animals; D001717:Birds / Q000235:genetics*; D009425:Nesting Behavior; D011110:Polymorphism, Genetic; D012880:Skin Pigmentation / Q000235:genetics*