Luton Institute of Research in Applied Natural Sciences, University of Bedfordshire, Luton, United Kingdom.
PLoS One. 2011;6(7):e22743. doi: 10.1371/journal.pone.0022743. Epub 2011 Jul 28.
Group or population level self-organised systems comprise many individuals displaying group-level emergent properties. Current theory indicates that individual-level behaviours have an effect on the final group-level behaviour; that is, self-organised systems are sensitive to small changes in individual behaviour. Here we examine a self-organised behaviour in relation to environmentally-driven individual-level changes in behaviour, using both natural systems and computer simulations. We demonstrate that aggregations of intertidal snails slightly decrease in size when, owing to hotter and more desiccating conditions, individuals forage for shorter periods--a seemingly non-adaptive behaviour for the snails since aggregation reduces desiccation stress. This decrease, however, only occurs in simple experimental systems (and simulations of these systems). When studied in their natural and more complex environment, and simulations of such an environment, using the same reduced foraging time, no difference in aggregation behaviour was found between hot and cool days. These results give an indication of how robust self-organised systems are to changes in individual-level behaviour. The complexity of the natural environment and the interactions of individuals with this environment, therefore, can result in self-organised systems being more resilient to individual-level changes than previously assumed.
群体或群体水平的自组织系统由许多表现出群体水平突现属性的个体组成。目前的理论表明，个体水平的行为对最终的群体水平行为有影响；也就是说，自组织系统对个体行为的微小变化敏感。在这里，我们使用自然系统和计算机模拟来研究与环境驱动的个体行为变化有关的自组织行为。我们证明，当由于更热和更干燥的条件导致个体觅食时间缩短时，潮间带蜗牛的聚集体的大小会略有减小——这对蜗牛来说似乎是一种非适应性行为，因为聚集减少了干燥压力。然而，这种减少仅发生在简单的实验系统（以及这些系统的模拟）中。当在其自然和更复杂的环境中进行研究，并使用相同的缩短觅食时间对其进行模拟时，在炎热和凉爽的日子之间，聚集行为没有发现差异。这些结果表明了自组织系统对个体行为变化的稳健性。因此，自然环境的复杂性以及个体与该环境的相互作用，可能会导致自组织系统比之前假设的更能抵御个体水平的变化。
