SKEWED BROOD SEX-RATIO AND SEX-BIASED HATCHING SEQUENCE IN HARRIS HAWKS
SKEWED BROOD SEX-RATIO AND SEX-BIASED HATCHING SEQUENCE IN HARRIS HAWKS
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DOI：
10.1086/285149
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发表时间：
1991-01-01
影响因子：
2.9
通讯作者：
HAYDEN, TJ
中科院分区：
文献类型：
--
作者：
BEDNARZ, JC;HAYDEN, TJ
雏鸟的性别比在哈里斯的鹰显示出显着的偏见，男性在性别鉴定的年龄，费舍尔的平衡假说预测。然而，我们的数据并不支持目前的假设，即父母操纵后代的性别比例，以应对不同的环境或社会线索。后代性别比的总体偏差是由于一个非常显着的倾斜向男性首次孵化的雏鸟。我们建议，性别依赖孵化序列可能代表了一个近端的机制，维护一个自适应的性别比偏向男性，较便宜的性别。如果这种机制没有采用哈里斯的鹰，我们认为，雌性雏鸟的二型大小的优势，加上孵化的发展优势，第一可能会导致适应不良的育雏减少。我们的观察结果表明，巢中，男性首先孵化羽翼显着更年轻的巢中，女性首先孵化。因此，我们认为，女性育种者可能会提高他们的健身倾斜的性别比例的第一次孵化的后代向男性。
Nestling sex ratios in Harris's hawks show a significant bias toward males at the age of sexing, as predicted by Fisher's equilibrium hypothesis. Our data, however, do not support current hypotheses of parental manipulation of offspring sex ratios in response to varying environmental or social cues. The overall bias in offspring sex ratios was due to a highly significant skew toward males in first-hatched nestlings. We propose that sex-dependent hatching sequence may represent a proximal mechanism that upholds an adaptive sex-ratio skew toward males, the less expensive sex. If this mechanism were not employed by Harris's hawks, we submit that the dimorphic-size advantage of female nestlings added to the developmental advantage of hatching first might result in maladaptive brood reduction. Our observations show that nests in which males hatch first fledged significantly more young than nests in which females hatch first. Therefore, we suggest that female breeders may enhance their fitness by skewing the sex ratio of the first-hatched offspring toward males.