Cannibalism, once viewed as a rare or aberrant behavior, is now recognized to be widespread and to contribute broadly to the self-regulation of many populations. Cannibalism can produce endogenous negative feedback on population growth because it is expressed as a conditional behavior, responding to the deteriorating ecological conditions that flow, directly or indirectly, from increasing densities of conspecifics. Thus, cannibalism emerges as a strongly density-dependent source of mortality. In this synthesis, we review recent research that has revealed a rich diversity of pathways through which rising density elicits increased cannibalism, including both factors that (a) elevate the rate of dangerous encounters between conspecifics and (b) enhance the likelihood that such encounters will lead to successful cannibalistic attacks. These pathways include both features of the autecology of cannibal populations and features of interactions with other species, including food resources and pathogens. Using mathematical models, we explore the consequences of including density-dependent cannibal attack rates on population dynamics. The conditional expression of cannibalism generally enhances stability and population regulation in single-species models but also may increase opportunities for alternative states and prey population escape from control by cannibalistic predators.

中文翻译：

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同类相食的密度依赖性表达途径，以及对受监管种群动态的影响

自相残杀曾经被视为一种罕见或反常的行为，现在被认为是普遍存在的，并且对许多人群的自我调节有广泛的贡献。自相残杀可以对人口增长产生内生性负反馈，因为它表现为一种条件行为，对直接或间接因同种密度增加而导致的生态条件恶化作出反应。因此，同类相食成为一种强烈依赖于密度的死亡率来源。在本综合报告中，我们回顾了最近的研究，这些研究揭示了密度上升导致自相残杀增加的多种途径，包括以下两个因素：(a) 提高同种动物之间危险相遇的频率，以及 (b) 增加此类相遇的可能性导致成功的同类相食攻击。这些途径既包括食人族群的进化生态学特征，也包括与其他物种相互作用的特征，包括食物资源和病原体。使用数学模型，我们探讨了包括密度依赖性食人族攻击率对种群动态的影响。同类相食的条件表达通常会增强单一物种模型中的稳定性和种群调节，但也可能增加替代状态和猎物种群逃脱同类相食捕食者控制的机会。