Pfennig David W
Department of Zoology, University of Texas, Austin, TX, 78712-1064, USA.
Evolution. 1990 Jul;44(4):785-798. doi: 10.1111/j.1558-5646.1990.tb03805.x.
Many animals modify their behavior toward unfamiliar conspecifics as a function of their genetic relatedness. A fundamental problem of any kin recognition study is determining what is being recognized and why. For anuran tadpoles, the predominant view is that associating with relatives is kin-selected because these relatives may thereby accrue benefits through increased growth or predation avoidance. An alternative view is that kin associations are simply a side-effect of habitat selection and thus do not represent attempts to identify kin per se. In the laboratory, spadefoot toad tadpoles (Scaphiopus multiplicatus) preferentially associated with unfamiliar siblings over unfamiliar nonsiblings, as do other anurans. However, same age tadpoles also were more likely to orient toward unfamiliar nonsiblings reared on the same food (familiar food) than toward unfamiliar siblings that were reared on unfamiliar food. These results, together with the results of previous tadpole kin recognition studies, suggest that tadpoles orient toward cues learned early in ontogeny, regardless of the cues' source. Tadpoles that preferentially associated with cues learned from their environment at birth would tend to be philopatric. Censuses of 14 natural ponds revealed that tadpole density remained greatest near oviposition sites until four days before metamorphosis. Tadpole philopatry may be advantageous: tadpoles restricted to their natal site had greater growth and survivorship than did their siblings restricted to randomly selected sites elsewhere within the same pond. Thus kin affiliative tendency observed in the laboratory in this and perhaps other species of anurans may be a byproduct of habitat selection. Since kin discrimination in animals is most commonly assayed as orientation toward kin, it follows that many examples of "kin recognition" may not represent true attempts to identify kin as such, but rather may reflect some other recognition system that is under entirely different selective pressures.
许多动物会根据与陌生同种个体的基因亲缘关系来改变自己的行为。任何亲缘识别研究的一个基本问题是确定被识别的是什么以及为什么。对于无尾两栖类蝌蚪来说，主流观点是与亲属交往是亲缘选择的结果，因为这些亲属可能会通过加快生长或避免被捕食而获得好处。另一种观点是，亲缘交往仅仅是栖息地选择的一个副作用，因此本身并不代表识别亲属的尝试。在实验室中，锄足蟾蝌蚪（Scaphiopus multiplicatus）与陌生的兄弟姐妹相比，更倾向于与陌生的非兄弟姐妹交往，其他无尾两栖类也是如此。然而，相同年龄的蝌蚪也更有可能朝向以相同食物（熟悉的食物）饲养的陌生非兄弟姐妹，而不是以陌生食物饲养的陌生兄弟姐妹。这些结果，连同之前蝌蚪亲缘识别研究的结果表明，蝌蚪会朝向个体发育早期学到的线索，而不管这些线索的来源如何。优先与出生时从环境中学到的线索交往的蝌蚪往往会有留居习性。对14个天然池塘的普查显示，直到变态前四天，蝌蚪密度在产卵地附近一直最大。蝌蚪的留居习性可能是有利的：局限于出生地的蝌蚪比局限于同一池塘其他随机选择地点的兄弟姐妹有更大的生长和存活率。因此，在实验室中观察到的这种以及其他一些无尾两栖类物种的亲缘亲近倾向可能是栖息地选择的一个副产品。由于动物中的亲缘识别最常见的检测方式是对亲属的朝向，因此可以推断，许多“亲缘识别”的例子可能并不代表真正识别亲属的尝试，而可能反映了一些其他的识别系统，这些系统受到完全不同的选择压力。
