Holen Ø H, Johnstone R A
Centre for Ecological and Evolutionary Synthesis, Department of Biology, University of Oslo, Oslo, Norway.
J Evol Biol. 2007 Nov;20(6):2165-72. doi: 10.1111/j.1420-9101.2007.01426.x. Epub 2007 Sep 7.
When a parent's parentage differs across breeding attempts, established theory predicts that the parent should invest more in a brood when perceived parentage is high. We present a model of parental investment in which offspring unrelated to the parent have a competitive advantage over the parent's own offspring and take a larger share of investment. We show that this can weaken or, if the competitive advantage is great, reverse the predicted relationship between perceived parentage and parental investment. A moderate competitive advantage of extra-pair young over within-pair young could partly explain the lack of any clear relationship between paternal care and paternity in many studies, and could easily arise if females choose extra-pair partners for good genes. Our results are also relevant to interspecific avian brood parasitism. As parasites reared together with host offspring are often superior competitors, their hosts could benefit from increasing investment in response to suspected parasitism.
当亲本在不同繁殖尝试中的亲本身份不同时，既定理论预测，当感知到的亲本身份较高时，亲本应该对一窝幼崽投入更多。我们提出了一个亲本投资模型，在该模型中，与亲本无关的后代比亲本自己的后代具有竞争优势，并获得更大份额的投资。我们表明，这可能会削弱预测的感知亲本身份与亲本投资之间的关系，或者，如果竞争优势很大，则会逆转这种关系。异窝幼雏相对于同窝幼雏的适度竞争优势可以部分解释许多研究中父性照料与父权之间缺乏任何明确关系的现象，并且如果雌性为了优良基因而选择异窝配偶，这种情况很容易出现。我们的结果也与种间鸟类巢寄生有关。由于与宿主后代一起饲养的寄生虫通常是更强的竞争者，它们的宿主可能会因怀疑寄生而增加投资从而受益。
