Data from: Nonlinear scaling of foraging contacts with rodent population density

Density-dependent shifts in population processes like territoriality, reproduction, dispersal, and parasite transmission are driven by changes in contacts between individuals. Despite this, surprisingly little is known about how contacts change with density, and thus the mechanisms driving density-dependent processes. A simple linear contact-density function is often assumed, but this is not based on a sound basis of empirical data. We addressed this question using a replicated, semi-natural experiment in which we measured contacts at feeding stations between multimammate mice, Mastomys natalensis, across ten distinct, linearly increasing densities between 10 and 272 animals/ha. Unexpectedly, unique contacts increased not linearly but sigmoidally with density, which we attribute to the species’ scramble competition mating system, small-scale dominance/avoidance and absence of territoriality. These results provide new insights into how species’ characteristics can relate to density-dependent changes in contacts, and the unexpected shape of the contact-density function warrants that density-dependence in ecological models, such as parasite transmission models, must be parameterized with care.种群过程（如领域行为、繁殖、扩散以及寄生虫传播）的密度依赖型变化，由个体间接触模式的改变所驱动。尽管如此，学界对接触模式如何随种群密度变化的认知仍十分有限，因此驱动密度依赖型过程的具体机制也尚未得到充分阐释。现有研究常假设接触频次与种群密度呈简单线性函数关系，但这一假设并未获得可靠实证数据的支撑。为此，我们开展了可重复的半自然实验，以多乳鼠（Mastomys natalensis）为研究对象，在饲喂站处记录个体间的接触行为，实验设置了10至272只/公顷的10个梯度递增的种群密度处理组。令人意外的是，独特接触频次并未随种群密度呈线性增长，而是呈现出S型变化趋势。我们将该现象归因于该物种的争夺式交配系统、小规模优势等级与避让行为，以及其缺乏领域行为的特性。本研究结果为理解物种特性与接触行为的密度依赖型变化之间的关联提供了全新视角；同时，接触频次-密度函数的意外形态也提示，在寄生虫传播模型等生态模型中，密度依赖项的参数化过程需格外审慎。