Auteurs: Elin P. Pierce, Lewis W. Oring, Eivin Røskaft, Jan T. Lifjeld
Bron: BEHAVIORAL ECOLOGY, Volume 21, Number 2, p. 275-283
Abstract: In most monogamous sandpiper species, females share parental care
but leave the brood earlier than males, a feature unusual among
birds in general. In the purple sandpiper (Calidris maritima),
females almost always leave the brood at hatching and never share
brood care. Males perform uniparental brood care from hatching
until well after fledging. In this paper, we report the
results of a mate-removal experiment conducted on the purple sandpiper
in high Arctic Svalbard and discuss the implications for the
evolution of their mate desertion strategy. By removing males
from nests near hatching, we tested 2 hypotheses: 1) Males assume
brood care because females, who always have a net benefit from
deserting, have a fixed brood desertion strategy, whereas males
do not; 2) females desert the brood because they cannot perform
uniparental brood care as well as males and/or because they
are under physiological stress at hatching due to egg laying and
incubation activities hypothesis). We found that when experimentally
deserted, most female purple sandpipers assumed brood care. Parental
behavior and the growth and survival of the chicks suggested
that the attending females were not under physiological stress
after hatching and did not seem less able than males to
perform brood care. Thus, we found no support for either hypothesis.
We suggest that uniparental brood desertion is a consequence
of strong selection for uniparental brood care in this
species and that the actual sex roles may result from rather marginal
differences between the sexes in the fitness consequences of
care and desertion.
Bron: BEHAVIORAL ECOLOGY, Volume 21, Number 2, p. 275-283
Abstract: In most monogamous sandpiper species, females share parental care
but leave the brood earlier than males, a feature unusual among
birds in general. In the purple sandpiper (Calidris maritima),
females almost always leave the brood at hatching and never share
brood care. Males perform uniparental brood care from hatching
until well after fledging. In this paper, we report the
results of a mate-removal experiment conducted on the purple sandpiper
in high Arctic Svalbard and discuss the implications for the
evolution of their mate desertion strategy. By removing males
from nests near hatching, we tested 2 hypotheses: 1) Males assume
brood care because females, who always have a net benefit from
deserting, have a fixed brood desertion strategy, whereas males
do not; 2) females desert the brood because they cannot perform
uniparental brood care as well as males and/or because they
are under physiological stress at hatching due to egg laying and
incubation activities hypothesis). We found that when experimentally
deserted, most female purple sandpipers assumed brood care. Parental
behavior and the growth and survival of the chicks suggested
that the attending females were not under physiological stress
after hatching and did not seem less able than males to
perform brood care. Thus, we found no support for either hypothesis.
We suggest that uniparental brood desertion is a consequence
of strong selection for uniparental brood care in this
species and that the actual sex roles may result from rather marginal
differences between the sexes in the fitness consequences of
care and desertion.
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