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151.
Sex-specific nest defense in house sparrows (Passer domesticus) varies with badge size of males 总被引:2,自引:0,他引:2
Heinz-Ulrich Reyer Wiltrud Fischer Pascale Steck Thomas Nabulon Philip Kessler 《Behavioral ecology and sociobiology》1998,42(2):93-99
According to indicator models of sexual selection, females can benefit from choosing males with above average epigamic traits,
but empirical evidence for such benefits is scarce. Here, we report results from an experiment with 29 pairs of house sparrows
(Passer domesticus) where the intensity of nest defense against a mounted mustelid predator was related to the size of the black throat and
breast patch (“badge”) in males. Using principal components analysis (PCA), original response variables of both sexes were
reduced to two factors: “Approach” to the predator and “Distant warning”. “Approach”, the more risky behavior, increased from
small- through medium- to large-badged males and decreased in their females. Since large-badged males have a higher certainty
of paternity (i.e. greater benefits from defense) and may be older and more experienced (i.e. incur lower costs), the most
likely explanation for male defense intensity increasing with badge size is an improving benefit/cost ratio. The resulting
optimal response of their females and evolutionarily stable participation in joint parental care is illustrated by a graphical
model. It shows that females would, indeed, benefit directly from choosing large-badged males. This, however, is no proof
of a direct evolutionary tie between badge size and paternal behavior, as assumed by indicator models of sexual selection.
It may simply represent a spurious relationship, originating from the correlation of badge size and defense with confidence
of paternity.
Received: 22 September 1997 / Accepted after revision: 3 November 1997 相似文献