Taborsky B, Guyer L, Demus P
Behavioural Ecology, Institute of Ecology and Evolution, University of Bern, Hinterkappelen, Switzerland.
J Evol Biol. 2014 Jun;27(6):1217-28. doi: 10.1111/jeb.12398. Epub 2014 May 6.
Assortative mating, an ubiquitous form of nonrandom mating, strongly impacts Darwinian fitness and can drive biological diversification. Despite its ecological and evolutionary importance, the behavioural processes underlying assortative mating are often unknown, and in particular, mechanisms not involving mate choice have been largely ignored so far. Here, we propose that assortative mating can arise from 'prudent habitat choice', a general mechanism that acts under natural selection, and that it can occur despite a complete mixing of phenotypes. We show that in the cichlid Eretmodus cyanostictus size-assortative mating ensues, because individuals of weaker competitive ability ignore high-quality but strongly competed habitat patches. Previous studies showed that in E. cyanostictus, size-based mate preferences are absent. By field and laboratory experiments, here we showed that (i) habitat quality and body size are correlated in this species; (ii) territories with more stone cover are preferred by both sexes in the absence of competition; and (iii) smaller fish prudently occupy vacant territories of worse quality than do larger fish. Prudent habitat choice is likely to be a widespread mechanism of assortative mating, as both preferences for and dominance-based access to high-quality habitats are generic phenomena in animals.
选型交配是一种普遍存在的非随机交配形式，对达尔文适应性有强烈影响，并能推动生物多样性的发展。尽管其在生态和进化方面具有重要意义，但选型交配背后的行为过程往往并不为人所知，尤其是到目前为止，不涉及配偶选择的机制在很大程度上被忽视了。在此，我们提出选型交配可能源于“谨慎的栖息地选择”，这是一种在自然选择作用下的普遍机制，并且即使表型完全混合也可能发生。我们表明，在丽鱼科的蓝点埃氏丽鱼中会出现体型选型交配，因为竞争能力较弱的个体会忽略高质量但竞争激烈的栖息地斑块。先前的研究表明，在蓝点埃氏丽鱼中不存在基于体型的配偶偏好。通过野外和实验室实验，我们在此表明：（i）该物种的栖息地质量与体型相关；（ii）在没有竞争的情况下，两性都更喜欢有更多石头覆盖的领地；（iii）较小的鱼会谨慎地占据质量比大鱼所占据的更差的空置领地。谨慎的栖息地选择可能是一种广泛存在的选型交配机制，因为对高质量栖息地的偏好以及基于优势地位获取高质量栖息地都是动物中的普遍现象。
