INVESTIGADORES
FERNANDEZ Gustavo Javier
artículos
Título:
Costs of large communal clutches for males and females Greater Rheas
Autor/es:
FERNANDEZ, GUSTAVO J.; REBOREDA, JUAN C.
Revista:
IBIS
Editorial:
WILEY-BLACKWELL PUBLISHING, INC
Referencias:
Año: 2007 vol. 149 p. 215 - 222
ISSN:
0019-1019
Resumen:
The breeding system of the Greater Rhea Rhea americana is almost unique among birds as
it combines harem polygyny and sequential polyandry, with communal egg-laying and
uniparental male care. In this species, large communal clutches (more than 30 eggs) are rare
and have a lower hatching success than smaller clutches. Here we analyse the proximate
causes of hatching failures and the costs of large communal clutches (and therefore the costs
of extensive polygyny) for males and females. We evaluated if length of the nesting period,
egg viability, egg losses during incubation and male parental activity at the nest were affected
by clutch size. We also evaluated if chicks hatched from large clutches have a lower survival
during the first 2 months after hatching. Large clutches had longer nesting period and lower
hatching success, mainly as a result of bacterial contamination of the eggs and increased
hatching asynchrony. In addition, large clutches tended to lose more eggs as a result of accidental
breakage or predation. Male activity at the nest and chick survival were not related
to clutch size. Low hatching success, nest predation risk and energetic costs associated with
large clutches penalize females that join large harems and males that accept additional eggs
into the nest.
it combines harem polygyny and sequential polyandry, with communal egg-laying and
uniparental male care. In this species, large communal clutches (more than 30 eggs) are rare
and have a lower hatching success than smaller clutches. Here we analyse the proximate
causes of hatching failures and the costs of large communal clutches (and therefore the costs
of extensive polygyny) for males and females. We evaluated if length of the nesting period,
egg viability, egg losses during incubation and male parental activity at the nest were affected
by clutch size. We also evaluated if chicks hatched from large clutches have a lower survival
during the first 2 months after hatching. Large clutches had longer nesting period and lower
hatching success, mainly as a result of bacterial contamination of the eggs and increased
hatching asynchrony. In addition, large clutches tended to lose more eggs as a result of accidental
breakage or predation. Male activity at the nest and chick survival were not related
to clutch size. Low hatching success, nest predation risk and energetic costs associated with
large clutches penalize females that join large harems and males that accept additional eggs
into the nest.
Rhea americana is almost unique among birds as
it combines harem polygyny and sequential polyandry, with communal egg-laying and
uniparental male care. In this species, large communal clutches (more than 30 eggs) are rare
and have a lower hatching success than smaller clutches. Here we analyse the proximate
causes of hatching failures and the costs of large communal clutches (and therefore the costs
of extensive polygyny) for males and females. We evaluated if length of the nesting period,
egg viability, egg losses during incubation and male parental activity at the nest were affected
by clutch size. We also evaluated if chicks hatched from large clutches have a lower survival
during the first 2 months after hatching. Large clutches had longer nesting period and lower
hatching success, mainly as a result of bacterial contamination of the eggs and increased
hatching asynchrony. In addition, large clutches tended to lose more eggs as a result of accidental
breakage or predation. Male activity at the nest and chick survival were not related
to clutch size. Low hatching success, nest predation risk and energetic costs associated with
large clutches penalize females that join large harems and males that accept additional eggs
into the nest.