Do gorilla females join males to avoid infanticide? A quantitative model
Do gorilla females join males to avoid infanticide? A quantitative model
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DOI：
10.1006/anbe.2001.1835
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发表时间：
2001-11-01
期刊：
影响因子：
2.5
通讯作者：
Greenberg, J
中科院分区：
文献类型：
--
作者：
Harcourt, AH;Greenberg, J
大猩猩，大猩猩大猩猩，雌性永远与雄性联系在一起。女性从协会中获得了什么好处？在雄性比雌性大的地方，比如大猩猩，保护自己不被捕食是长期以来的解决办法。然而，越来越多的人认为，保护非父亲的雄性动物是一个更好的假设。考虑到雌性的替代策略是独自活动并与许多雄性交配，反杀雄假说中迄今被忽视的问题是，雌性加入单个雄性必然会使种群中能够使用杀雄策略的雄性比例最大化。要问是否孤独的大猩猩女性可以与足够的男性交配，以减少在野外观察到的以下的概率杀猩猩，我们使用新的修改的气体分子方程模型遇到率的孤独的女性与男性。这些修改包括在生育期从那些在哺乳期，重要的是，一个下降的功能，将cardiocidal男性noncardiocidal，交配的遭遇率分离。参数包括雄性的密度、移动速度以及生育期和哺乳期的持续时间。在另外两种类人猿中（黑猩猩Pan和猩猩Pongo），雌性或多或少都是独居的，并且捕杀率非常低（小于或等于5%）。利用模型中的这些物种的值，产生了相当低的杀藻剂比率。因此，该模型似乎是有效的。对于大猩猩来说，模型表明，在大多数现实条件下，孤独的雌性与如此少的雄性交配，以至于杀死率是观察到的14%的出生率的三倍多。因此，与男性交往会降低杀婴的可能性。因此，支持分组的反种族灭绝假说。但是，反捕食假说并没有因此而被否定，而且仍然是一个强有力的假说，因为捕食者对雌性和她的婴儿都是危险的。(C)2001年，动物行为研究协会。
Gorilla, Gorilla gorilla, females associate permanently with males. What benefit do the females obtain from the association? Where males are larger than females, as in the gorilla, protection from predation is the long-standing answer. However, protection from infanticidal nonfather males is increasingly suggested as a better hypothesis. Given that a female's alternative strategy is to range alone and mate with many males, a hitherto ignored problem of the anti-infanticide hypothesis is that a female's joining a single male necessarily maximizes the proportion of males in the population who can use the infanticidal strategy. To ask whether lone gorilla females could mate with enough males to decrease the probability of infanticide below that observed in the wild, we use novel modifications of a gas molecule equation to model encounter rates of a lone female with males. The modifications include separation of encounter rates in fertile periods from those in nursing periods and, importantly, a decline function that converts infanticidal males to noninfanticidal, on mating. Parameters include density of males, speed of travel, and duration of fertile and nursing periods. In two other great apes (chimpanzee Pan, orang-utan Pongo), females are more or less solitary, and infanticide rates are very low (less than or equal to5%). With these species' values in the model, equivalently low infanticide rates result. Thus, the model appears valid. For the gorilla, the model indicates that under most realistic conditions, solitary females mate with so few males that infanticide rates are more than three times the observed rate of 14% of births. Association with a male thus decreases the probability of infanticide. The anti-infanticide hypothesis for grouping is thus supported. But the antipredation hypothesis is not thereby negated, and remains a powerful hypothesis, given that predators are a danger to the female, as well as her infant. (C) 2001 The Association for the Study of Animal Behaviour.