High rates of shiny cowbird parasitism on the brown-and-yellow marsh bird select for complementary host defenses

Hosts of brood parasites may have not developed antiparasitic defenses either because host and parasite are recently sympatric or because costs of potential defenses outweigh their benefits. We studied antiparasitic defenses of the Brown-and-yellow Marshbird (Pseudoleistes virescens) against the Shi...

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Autores principales:	Mermoz, Myriam Emilia, Reboreda, Juan Carlos, Fernandez, Gustavo Javier
Publicado:	2013
Materias:	Brood parasitism Cowbird nest searches Egg rejection Enemy recognition Host defenses Nest attention
Acceso en línea:	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00105422_v115_n4_p910_Mermoz http://hdl.handle.net/20.500.12110/paper_00105422_v115_n4_p910_Mermoz
Aporte de:	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires

id	paper:paper_00105422_v115_n4_p910_Mermoz
record_format	dspace
spelling	paper:paper_00105422_v115_n4_p910_Mermoz2023-06-08T14:34:37Z High rates of shiny cowbird parasitism on the brown-and-yellow marsh bird select for complementary host defenses Mermoz, Myriam Emilia Reboreda, Juan Carlos Fernandez, Gustavo Javier Brood parasitism Cowbird nest searches Egg rejection Enemy recognition Host defenses Nest attention Hosts of brood parasites may have not developed antiparasitic defenses either because host and parasite are recently sympatric or because costs of potential defenses outweigh their benefits. We studied antiparasitic defenses of the Brown-and-yellow Marshbird (Pseudoleistes virescens) against the Shiny Cowbird (Molothrus bonariensis), evaluating recognition and aggression toward female and male Shiny Cowbirds, estimating rates of rejection of cowbird eggs of different colors, and testing the effect of the size of parasite eggs on host rejection. We also observed and video-recorded host nests to estimate hosts' nest attentiveness, frequency of cowbird visits, and interactions between marshbirds and cowbirds. When marshbirds were faced with dummy models, they attacked first and more intensively those of cowbirds (both sexes) than those of a control species. Frequency of egg ejection increased as differences between cowbird and spotted marshbird eggs increased (immaculate > intermediate > spotted), and spotted eggs were ejected more frequently when laid before than during or after the hosts' laying. Marshbirds ejected artificially added immaculate eggs independently of their size. Cowbirds visited marshbird nests only at the egg stage. Hosts' nest attention was low during egg laying and increased during incubation and after hatching, but aggressiveness against cowbirds was always high. Nest defense was inefficient, as losses due to egg pecking by cowbirds were high. Ejection of cowbird eggs avoided the cost of lower survival of marshbird nestlings in highly parasitized nests. As this defense is cost-free, this small benefit would be sufficient to select for the evolutionary maintenance of egg ejection. © 2013 by The Cooper Ornithological Society. Fil:Mermoz, M.E. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Reboreda, J.C. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Fernández, G.J. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 2013 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00105422_v115_n4_p910_Mermoz http://hdl.handle.net/20.500.12110/paper_00105422_v115_n4_p910_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	Brood parasitism Cowbird nest searches Egg rejection Enemy recognition Host defenses Nest attention
spellingShingle	Brood parasitism Cowbird nest searches Egg rejection Enemy recognition Host defenses Nest attention Mermoz, Myriam Emilia Reboreda, Juan Carlos Fernandez, Gustavo Javier High rates of shiny cowbird parasitism on the brown-and-yellow marsh bird select for complementary host defenses
topic_facet	Brood parasitism Cowbird nest searches Egg rejection Enemy recognition Host defenses Nest attention
description	Hosts of brood parasites may have not developed antiparasitic defenses either because host and parasite are recently sympatric or because costs of potential defenses outweigh their benefits. We studied antiparasitic defenses of the Brown-and-yellow Marshbird (Pseudoleistes virescens) against the Shiny Cowbird (Molothrus bonariensis), evaluating recognition and aggression toward female and male Shiny Cowbirds, estimating rates of rejection of cowbird eggs of different colors, and testing the effect of the size of parasite eggs on host rejection. We also observed and video-recorded host nests to estimate hosts' nest attentiveness, frequency of cowbird visits, and interactions between marshbirds and cowbirds. When marshbirds were faced with dummy models, they attacked first and more intensively those of cowbirds (both sexes) than those of a control species. Frequency of egg ejection increased as differences between cowbird and spotted marshbird eggs increased (immaculate > intermediate > spotted), and spotted eggs were ejected more frequently when laid before than during or after the hosts' laying. Marshbirds ejected artificially added immaculate eggs independently of their size. Cowbirds visited marshbird nests only at the egg stage. Hosts' nest attention was low during egg laying and increased during incubation and after hatching, but aggressiveness against cowbirds was always high. Nest defense was inefficient, as losses due to egg pecking by cowbirds were high. Ejection of cowbird eggs avoided the cost of lower survival of marshbird nestlings in highly parasitized nests. As this defense is cost-free, this small benefit would be sufficient to select for the evolutionary maintenance of egg ejection. © 2013 by The Cooper Ornithological Society.
author	Mermoz, Myriam Emilia Reboreda, Juan Carlos Fernandez, Gustavo Javier
author_facet	Mermoz, Myriam Emilia Reboreda, Juan Carlos Fernandez, Gustavo Javier
author_sort	Mermoz, Myriam Emilia
title	High rates of shiny cowbird parasitism on the brown-and-yellow marsh bird select for complementary host defenses
title_short	High rates of shiny cowbird parasitism on the brown-and-yellow marsh bird select for complementary host defenses
title_full	High rates of shiny cowbird parasitism on the brown-and-yellow marsh bird select for complementary host defenses
title_fullStr	High rates of shiny cowbird parasitism on the brown-and-yellow marsh bird select for complementary host defenses
title_full_unstemmed	High rates of shiny cowbird parasitism on the brown-and-yellow marsh bird select for complementary host defenses
title_sort	high rates of shiny cowbird parasitism on the brown-and-yellow marsh bird select for complementary host defenses
publishDate	2013
url	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00105422_v115_n4_p910_Mermoz http://hdl.handle.net/20.500.12110/paper_00105422_v115_n4_p910_Mermoz
work_keys_str_mv	AT mermozmyriamemilia highratesofshinycowbirdparasitismonthebrownandyellowmarshbirdselectforcomplementaryhostdefenses AT reboredajuancarlos highratesofshinycowbirdparasitismonthebrownandyellowmarshbirdselectforcomplementaryhostdefenses AT fernandezgustavojavier highratesofshinycowbirdparasitismonthebrownandyellowmarshbirdselectforcomplementaryhostdefenses
_version_	1768545033268494336

High rates of shiny cowbird parasitism on the brown-and-yellow marsh bird select for complementary host defenses

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