FLEXIBILITY AND DIVERSITY OF CO-EVOLVING COMMUNITIES

捕食者特定防御对生物多样性和群落复杂性的影响：猎物采用的反捕食者策略可能是特定的(仅对一种类型的捕食者有效)，也可能是非特定的(对所有捕食者有效)。为了考察捕食者行为的特殊性对生物多样性和群落复杂性的影响，我们分析了一个包含多个捕食者和多个捕食者的系统的进化和种群动力学的数学模型。该模型假设所有捕食者物种在其猎物选择上都会发生变化，并且所有被捕食者物种在进化过程中的反捕食者努力都会发生进化变化。每个物种的性状都是以一种适应性的方式变化的，其变化速度与其适应度函数的斜率成正比。我们计算了两种情况下的群落复杂性、捕食者之间的资源重叠、生物多样性指数和共同进化稳定群落的其他性质：(1)所有被捕食物种都有非特定的反捕食行为；(2)所有被捕食物种都有捕食者特有的防御。捕食者在防御中的专一性增加了群落的复杂性、捕食者之间的资源重叠、捕食者的总丰度以及捕食者与被捕食者的比率。特定的防御也减少了整个食物网中孤立的子网的数量。

Effects of predator-specific defense on biodeversity and community complexity in two-trophic-level communities : Antipredator strategies employed by prey may be specific (effective against only one type of predator) or non-specific (effective against all predators). To examine the effects of the specificity of antipredator bahavior on biodiversity and community complexity, we analyze mathematical models including both evolutionary and population dynamics of a system including multiple prey species and multiple predator species. The models assume that all predator species change in their prey choice and all prey species have evolutionary change in their antipredator effort in evolution. The traits of each species change in an adaptive manner, whose rate is proportional to the slope of their fitness function. We calculate community complexity, resource-overlap between predators, an index of biodiversity and other properties of the coevoltionarily stable community for two cases : (1) all prey species have non-specific antipredator behavior and (2) all prey species have predator-specific defense. Predator-specificity in defense increases community complexity, resource-overlap between predators, the total abundance of predators and the ratio of predator to prey abundance. Specific defense also decreases the number of isolated subwebs within the entire foodweb.