School of Mathematics, University of Bristol, University Walk, Bristol BS8 1TW, UK.
Ecol Lett. 2011 Mar;14(3):237-43. doi: 10.1111/j.1461-0248.2010.01576.x. Epub 2011 Jan 19.
Ostensibly, it makes sense in a changeable world to condition behaviour and development on information when it is available. Nevertheless, unconditional behavioural and life history strategies are widespread. Here, we show how intergenerational effects can limit the evolutionary value of responding to reliable environmental cues, and thus favour the evolutionary persistence of otherwise paradoxical unconditional strategies. While cue-ignoring genotypes do poorly in the wrong environments, in the right environment they will leave many copies of themselves, which will themselves leave many copies, and so on, leading genotypes to accumulate in habitats in which they do well. We call this 'The Multiplier Effect'. We explore the consequences of the multiplier effect by focussing on the ecologically important phenomenon of natal philopatry. We model the environment as a large number of temporally varying breeding sites connected by natal dispersal between sites. Our aim is to identify which aspects of an environment promote the multiplier effect. We show, if sites remain connected through some background level of 'accidental' dispersal, unconditional natal philopatry can evolve even when there is density dependence (with its accompanying kin competition effects), and cues that are only mildly erroneous. Thus, the multiplier effect may underpin the evolution and maintenance of unconditional strategies such as natal philopatry in many biological systems.
从表面上看，在一个多变的世界中，根据可用信息来调节行为和发展是有意义的。然而，无条件的行为和生活史策略是广泛存在的。在这里，我们展示了世代间效应如何限制对可靠环境线索做出反应的进化价值，从而有利于无条件策略的进化持久性，尽管这些策略在其他方面看起来是矛盾的。虽然忽略线索的基因型在错误的环境中表现不佳，但在正确的环境中，它们会留下大量的自身副本，这些副本本身又会留下大量的副本，以此类推，导致基因型在它们表现良好的栖息地中积累。我们称这种现象为“倍增效应”。我们通过关注生态上重要的出生地亲代保护现象来探索倍增效应的后果。我们将环境建模为大量随时间变化的繁殖地点，通过地点之间的出生地扩散来连接。我们的目标是确定环境的哪些方面促进了倍增效应。我们表明，如果站点通过某种背景水平的“偶然”扩散保持连接，即使存在密度依赖性（及其伴随的亲缘竞争效应）和仅略微错误的线索，无条件的出生地亲代保护也可以进化。因此，倍增效应可能是许多生物系统中无条件策略（如出生地亲代保护）进化和维持的基础。
