title: Evidence for aggressive mimicry in an adult brood parasitic bird, and generalized defences in its host.
abstract: Mimicry of a harmless model (aggressive mimicry) is used by egg, chick and fledgling brood parasites that resemble the host's own eggs, chicks and fledglings. However, aggressive mimicry may also evolve in adult brood parasites, to avoid attack from hosts and/or manipulate their perception of parasitism risk. We tested the hypothesis that female cuckoo finches (Anomalospiza imberbis) are aggressive mimics of female Euplectes weavers, such as the harmless, abundant and sympatric southern red bishop (Euplectes orix). We show that female cuckoo finch plumage colour and pattern more closely resembled those of Euplectes weavers (putative models) than Vidua finches (closest relatives); that their tawny-flanked prinia (Prinia subflava) hosts were equally aggressive towards female cuckoo finches and southern red bishops, and more aggressive to both than to their male counterparts; and that prinias were equally likely to reject an egg after seeing a female cuckoo finch or bishop, and more likely to do so than after seeing a male bishop near their nest. This is, to our knowledge, the first quantitative evidence for aggressive mimicry in an adult bird, and suggests that host-parasite coevolution can select for aggressive mimicry by avian brood parasites, and counter-defences by hosts, at all stages of the reproductive cycle.
authors.affiliation: Research School of Biology, The Australian National University, Canberra, Australian Capital Territory, Australia Department of Zoology, University of Cambridge, Cambridge, UK william.e.feeney@gmail.com.
authors.forename: W E
authors.initials: WE
authors.lastname: Feeney
authors.affiliation: Centre for Ecology and Conservation, University of Exeter, Penryn, UK.
authors.forename: J
authors.initials: J
authors.lastname: Troscianko
authors.affiliation: Research School of Biology, The Australian National University, Canberra, Australian Capital Territory, Australia.
authors.forename: N E
authors.initials: NE
authors.lastname: Langmore
authors.affiliation: Department of Zoology, University of Cambridge, Cambridge, UK DST-NRF Centre of Excellence at the Percy FitzPatrick Institute, University of Cape Town, Cape Town, South Africa.
authors.forename: C N
authors.initials: CN
authors.lastname: Spottiswoode
mesh_terms: D000374:Aggression; D000818:Animals; D005075:Biological Evolution; D000067558:Biological Mimicry; D009425:Nesting Behavior; D020308:Songbirds / Q000469:parasitology* / Q000502:physiology*
keywords: brood parasite; coevolution; cuckoo finch; egg rejection; evolution; plumage mimicry