Ruusila V, PÖYSÄ H
Laboratory of Ecology and Animal Systematics, Department of Biology, University of Turku
Anim Behav. 1998 Feb;55(2):307-12. doi: 10.1006/anbe.1997.0630.
Lazarus & Inglis (Anim. Behav., 1986, 34, 1791-1804) introduced a model of the influence of brood size on the optimal level of parental investment and parent-offspring conflict and drew a distinction between shared and unshared types of parental investment. With respect to this division, we measured the parental costs in the goldeneye, Bucephala clangula, a precocial species with uniparental female care, in terms of time spent in vigilance and intraspecific aggression. We also compared levels of anti-predator vigilance and intraspecific aggression between females with and without broods. Females with broods spent considerably more time on both vigilance and intraspecific aggression, but anti-predator vigilance was independent of brood size. Furthermore, female behaviour was unaffected by brood reduction. Both these observations support the 'fixed-loss' model of unshared care, where the level of parental investment is predicted to be independent of brood size, since the predator is likely to take only a single offspring. In contrast, intraspecific aggression, mainly associated with defence of the brood's feeding area, increased with brood size. This supports the 'shared care' model where the level of parental investment increases with brood size, a type of care usually associated with altricial species. Copyright 1998 The Association for the Study of Animal Behaviour.
拉扎勒斯和英格利斯（《动物行为》，1986年，第34卷，1791 - 1804页）提出了一个关于窝卵数对亲代投资最优水平及亲代与子代冲突影响的模型，并区分了亲代投资的共享型和非共享型。关于这种分类，我们以警戒和种内攻击行为所花费的时间来衡量普通秋沙鸭（Bucephala clangula）这种单配制雌性育雏的早成鸟类的亲代成本。我们还比较了有雏和无雏雌性的反捕食警戒水平及种内攻击行为。有雏雌性在警戒和种内攻击行为上花费的时间都要多得多，但反捕食警戒与窝卵数无关。此外，雌性的行为不受雏鸟数量减少的影响。这两个观察结果都支持了非共享育雏的“固定损失”模型，在该模型中，亲代投资水平预计与窝卵数无关，因为捕食者可能只捕获一只雏鸟。相反，主要与雏鸟觅食区域防御相关的种内攻击行为随窝卵数增加。这支持了“共享育雏”模型，即亲代投资水平随窝卵数增加，这种育雏类型通常与晚成鸟类相关。版权所有1998年动物行为研究协会。
