Low frequency of Shiny Cowbird parasitism on Scarlet-headed Blackbirds: Anti-parasite adaptations or nonspecific host life-history traits?

Interspecific brood parasitism is a strong selective force that has favoured the evolution of anti-parasite strategies. The Shiny Cowbird Molothrus bonariensis is a generalist parasite that uses more than 200 species as hosts. Scarlet-headed Blackbirds Amblyramphus holosericeus are infrequently para...

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Autores principales: Mermoz, M.E., Fernández, G.J.
Formato: JOUR
Materias:
defense mechanism
parasitism
passerine
Agelaius thilius
Amblyramphus holosericeus
Gallus gallus
Molothrus bonariensis
Passeriformes
Pseudoleistes virescens
Turdus merula
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_09088857_v30_n1_p15_Mermoz
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id todo:paper_09088857_v30_n1_p15_Mermoz
record_format dspace
spelling todo:paper_09088857_v30_n1_p15_Mermoz2023-10-03T15:44:34Z Low frequency of Shiny Cowbird parasitism on Scarlet-headed Blackbirds: Anti-parasite adaptations or nonspecific host life-history traits? Mermoz, M.E. Fernández, G.J. defense mechanism parasitism passerine Agelaius thilius Agelaius thilius Amblyramphus holosericeus Amblyramphus holosericeus Gallus gallus Molothrus bonariensis Molothrus bonariensis Passeriformes Pseudoleistes virescens Turdus merula Interspecific brood parasitism is a strong selective force that has favoured the evolution of anti-parasite strategies. The Shiny Cowbird Molothrus bonariensis is a generalist parasite that uses more than 200 species as hosts. Scarlet-headed Blackbirds Amblyramphus holosericeus are infrequently parasitized by Shiny Cowbirds in contrast to other sympatric marshbird species that are heavily parasitized. In this paper, we attempted to identify specific anti-parasite defences of the Scarlet-headed Blackbird. Parasitism by Shiny Cowbirds of Scarlet-headed Blackbirds averaged 14.2%, whereas in Brown-and-yellow Marshbirds Pseudoleistes virescens, a sympatric marsh-nesting species, it was 52%. Both host species reared Shiny Cowbird chicks. Scarlet-headed Blackbird did not reject artificially added parasite eggs and did not respond more aggressively toward a female Shiny Cowbrid dummy model than to control species, the Yellow-winged Blackbird Agelaius thilius or the Brown-and-yellow Marshbird. However, high levels of nest attentiveness were recorded during nest-building, egg-laying and incubation stages. About 95-98% of the time at least one parent remained less than 20 m from the nest. Our results show that the low frequency of parasitism on the Scarlet-headed Blackbird may be better explained by life-history traits such as territorial defence, rather than by evolved anti-parasite strategies. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_09088857_v30_n1_p15_Mermoz
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic defense mechanism
parasitism
passerine
Agelaius thilius
Agelaius thilius
Amblyramphus holosericeus
Amblyramphus holosericeus
Gallus gallus
Molothrus bonariensis
Molothrus bonariensis
Passeriformes
Pseudoleistes virescens
Turdus merula
spellingShingle defense mechanism
parasitism
passerine
Agelaius thilius
Agelaius thilius
Amblyramphus holosericeus
Amblyramphus holosericeus
Gallus gallus
Molothrus bonariensis
Molothrus bonariensis
Passeriformes
Pseudoleistes virescens
Turdus merula
Mermoz, M.E.
Fernández, G.J.
Low frequency of Shiny Cowbird parasitism on Scarlet-headed Blackbirds: Anti-parasite adaptations or nonspecific host life-history traits?
topic_facet defense mechanism
parasitism
passerine
Agelaius thilius
Agelaius thilius
Amblyramphus holosericeus
Amblyramphus holosericeus
Gallus gallus
Molothrus bonariensis
Molothrus bonariensis
Passeriformes
Pseudoleistes virescens
Turdus merula
description Interspecific brood parasitism is a strong selective force that has favoured the evolution of anti-parasite strategies. The Shiny Cowbird Molothrus bonariensis is a generalist parasite that uses more than 200 species as hosts. Scarlet-headed Blackbirds Amblyramphus holosericeus are infrequently parasitized by Shiny Cowbirds in contrast to other sympatric marshbird species that are heavily parasitized. In this paper, we attempted to identify specific anti-parasite defences of the Scarlet-headed Blackbird. Parasitism by Shiny Cowbirds of Scarlet-headed Blackbirds averaged 14.2%, whereas in Brown-and-yellow Marshbirds Pseudoleistes virescens, a sympatric marsh-nesting species, it was 52%. Both host species reared Shiny Cowbird chicks. Scarlet-headed Blackbird did not reject artificially added parasite eggs and did not respond more aggressively toward a female Shiny Cowbrid dummy model than to control species, the Yellow-winged Blackbird Agelaius thilius or the Brown-and-yellow Marshbird. However, high levels of nest attentiveness were recorded during nest-building, egg-laying and incubation stages. About 95-98% of the time at least one parent remained less than 20 m from the nest. Our results show that the low frequency of parasitism on the Scarlet-headed Blackbird may be better explained by life-history traits such as territorial defence, rather than by evolved anti-parasite strategies.
format JOUR
author Mermoz, M.E.
Fernández, G.J.
author_facet Mermoz, M.E.
Fernández, G.J.
author_sort Mermoz, M.E.
title Low frequency of Shiny Cowbird parasitism on Scarlet-headed Blackbirds: Anti-parasite adaptations or nonspecific host life-history traits?
title_short Low frequency of Shiny Cowbird parasitism on Scarlet-headed Blackbirds: Anti-parasite adaptations or nonspecific host life-history traits?
title_full Low frequency of Shiny Cowbird parasitism on Scarlet-headed Blackbirds: Anti-parasite adaptations or nonspecific host life-history traits?
title_fullStr Low frequency of Shiny Cowbird parasitism on Scarlet-headed Blackbirds: Anti-parasite adaptations or nonspecific host life-history traits?
title_full_unstemmed Low frequency of Shiny Cowbird parasitism on Scarlet-headed Blackbirds: Anti-parasite adaptations or nonspecific host life-history traits?
title_sort low frequency of shiny cowbird parasitism on scarlet-headed blackbirds: anti-parasite adaptations or nonspecific host life-history traits?
url http://hdl.handle.net/20.500.12110/paper_09088857_v30_n1_p15_Mermoz
work_keys_str_mv AT mermozme lowfrequencyofshinycowbirdparasitismonscarletheadedblackbirdsantiparasiteadaptationsornonspecifichostlifehistorytraits
AT fernandezgj lowfrequencyofshinycowbirdparasitismonscarletheadedblackbirdsantiparasiteadaptationsornonspecifichostlifehistorytraits
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