Effect of mutualist partner identity on plant demography

Mutualisms play a central role in the origin and maintenance of biodiversity. Because many mutualisms have strong demographic effects, interspecific variation in partner quality could have important consequences for population dynamics. Nevertheless, few studies have quantified how a mutualist partner influences population growth rates, and still fewer have compared the demographic impacts of multiple partner species. We used integral projection models parameterized with three years of census data to compare the demographic effects of two ant species - Crematogaster laevis and Pheidole minutula - on populations of the Amazonian ant-plant Maieta guianensis. Estimated population growth rates were positive (i.e., λ>1) for all ant-plant combinations. However, populations with only Pheidole minutula had the highest asymptotic growth rate (λ=1.23), followed by those colonized by Crematogaster laevis (λ=1.16), and in which the partner ant alternated between C. laevis and P. minutula at leas...互利共生（Mutualism）在生物多样性的起源与维持中发挥核心作用。由于多数互利共生作用具有显著的种群统计效应，共生伙伴质量的种间差异可能对种群动态产生重要影响。然而，目前鲜有研究量化共生伙伴如何影响种群增长率，且直接比较多种共生伙伴物种种群统计效应的研究更为匮乏。本研究采用基于三年种群普查数据参数化的积分投影模型（Integral Projection Model），对比两种蚂蚁——光腰举腹蚁（Crematogaster laevis）和小大头蚁（Pheidole minutula）——对亚马逊蚁栖植物圭亚那麦塔草（Maieta guianensis）种群的统计效应。所有蚁植共生组合的种群增长率估计值均为正值（即λ>1）。不过，仅由小大头蚁共生的种群渐近增长率最高（λ=1.23），其次为被光腰举腹蚁定植的种群（λ=1.16），以及共生蚂蚁至少在……