INVESTIGADORES
FIORINI Vanina Dafne
artículos
Título:
Shiny cowbirds share foster mothers but not true mothers in multiply parasitized mockingbird nests
Autor/es:
GLOAG R; FIORINI VD; REBOREDA JC; KACELNIK A
Revista:
BEHAVIORAL ECOLOGY AND SOCIOBIOLOGY
Editorial:
SPRINGER
Referencias:
Lugar: Berlin; Año: 2014 vol. 68 p. 681 - 689
ISSN:
0340-5443
Resumen:
Obligate brood parasitic birds, such as cowbirds,
evade parental care duties by laying their eggs in the nests of
other species. Cowbirds are assumed to avoid laying repeatedly
in the same nest so as to prevent intrabrood competition
between their offspring. However, because searching for host
nests requires time and energy, laying more than one egg per
nest might be favoured where hosts are large and can readily
rear multiple parasites per brood. Such repeat parasitism by
females would have important consequences for parasite evolution
because young parasites would then incur indirect
fitness costs from behaving selfishly. We investigated shiny
cowbird (Molothrus bonariensis) parasitism of a large host,
the chalk-browed mockingbird (Mimus saturninus), in a population
where over 70 % of the parasitized mockingbird nests
receive multiple cowbird eggs. We assessed egg maternity
directly, using cameras at nests to film the laying of
individually-marked females. We also supplemented video
data with evidence from egg morphology, after confirming
that each female lays eggs of a consistent appearance. From
133 eggs laid, we found that less than 5%were followed by the
same female visiting the nest to lay again or to puncture eggs.
Multiple eggs in mockingbird nests were instead the result of
different females, with up to eight individuals parasitizing a
single brood. Thus, while cowbird chicks regularly share
mockingbird nests with conspecifics, these are unlikely to be
their maternal siblings. Our results are consistent with shiny
cowbird females following a one-egg-per-nest rule, even
where hosts can rear multiple parasitic young.