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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todo:paper_00105422_v115_n4_p910_Mermoz2023-10-03T14:09:25Z High rates of shiny cowbird parasitism on the brown-and-yellow marsh bird select for complementary host defenses Mermoz, M.E. Reboreda, J.C. Fernández, G.J. 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. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar 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, M.E. Reboreda, J.C. Fernández, G.J. 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. |
| format |
JOUR |
| author |
Mermoz, M.E. Reboreda, J.C. Fernández, G.J. |
| author_facet |
Mermoz, M.E. Reboreda, J.C. Fernández, G.J. |
| author_sort |
Mermoz, M.E. |
| 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 |
| url |
http://hdl.handle.net/20.500.12110/paper_00105422_v115_n4_p910_Mermoz |
| work_keys_str_mv |
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| _version_ |
1807322509367836672 |