Individual Contributions To Cooperative Behaviour in the Acorn Woodpecker: Effects of Reproductive Status, Sex, and Group Size
Individual Contributions To Cooperative Behaviour in the Acorn Woodpecker: Effects of Reproductive Status, Sex, and Group Size
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橡子啄木鸟合作行为的个体贡献：生殖状态、性别和群体规模的影响
DOI：
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发表时间：
1985
期刊：
影响因子：
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通讯作者：
A. Queiroz
中科院分区：
文献类型：
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作者：
R. Mumme;A. Queiroz
橡子啄木鸟（学名：Melanerpes formicivorus）是一种群居的啄木鸟，生活在2-15只的永久领地家庭群体中。所有的群体成员都参与了几种形式的合作行为，我们将其定义为对其他群体成员共同利益的资源投资（CHASE，1980）。橡子啄木鸟群体的利益包括在专门的存储树（粮仓）中缓存橡子，维护粮仓，以及防御粮仓内和种间入侵者。由于存储橡子和组繁殖成功的可用性之间存在很强的正相关关系，橡子存储，粮仓维护和粮仓防御投资有直接的积极影响个体健身的育种。然而，非繁殖的帮手并没有实现直接的生殖回报，因此从这些合作行为的投资中直接获利较少。因此，我们预测繁殖者应该比助手更重视合作行为。这一预测得到了证实：对于所研究的几乎每一种形式的合作行为，饲养者的贡献都明显多于帮助者。另一方面，虽然已建立的繁殖者很少侵入邻近地区，但非生殖助手经常这样做。这些分散的“突袭”构成了帮手试图找到生态限制繁殖的空缺。群体规模对个人对合作行为的贡献的影响尚不清楚。橡子存储的个人利率显着降低，增加组的大小，但粮仓出席和粮仓维护不。男性和女性橡子啄木鸟没有不同的贡献橡子存储，粮仓维护，或种间防御。女性，但是，发挥更大的作用，在种内防御，因为女性偏见的入侵者的性别比例和性别特异性的防御行为。
Acorn woodpeckers (Melanerpes formicivorus) are communal breeders that live in permanently territorial family groups of 2-15 individuals. All group members participate in several forms of cooperative behaviour, which we define as the investment of resources in a common interest shared by other group members (CHASE, 1980). Acorn woodpecker group interests include the caching of acorns in a specialized storage tree (the granary), maintenance of the granary, and defence of the granary against intra- and interspecific intruders. Because of a strong positive relationship between the availability of stored acorns and group reproductive success, investments in acorn storage, granary maintenance, and granary defence have a direct positive effect on the individual fitness of breeders. Non-breeding helpers, however, do not realize a direct reproductive reward, and therefore profit less directly from investment in these forms of cooperative behaviour. Thus, we predicted that breeders should invest more heavily in cooperative behaviour than should helpers. The prediction was upheld: for nearly every form of cooperative behaviour examined, breeders contribute significantly more than do helpers. On the other hand, while established breeders only rarely intrude on neighbouring territories, nonreproductive helpers frequently do so. These dispersal "forays" constitute attempts by helpers to locate ecologically restricted breeding vacancies. The effect that group size has on individual contributions to cooperative behaviour is unclear. Individual rates of acorn storage decrease significantly with increasing group size, but granary attendance and granary maintenance do not. Male and female acorn woodpeckers do not differ in their contributions to acorn storage, granary maintenance, or interspecific defence. Females, however, play a significantly greater role in intraspecific defence because of a female-biased intruder sex ratio and sex-specific defensive behaviour.