Closely related tree species support distinct communities of seed-associated fungi in a lowland tropical forest

Previous theoretical work has highlighted the potential for natural enemies to mediate the coexistence of species with similar life-histories via density-dependent effects on survivorship. For plant pathogens to play this role, they must differ in their ability to infect or induce disease in different host plant species. In tropical forests characterized by high diversity, these effects must extend to phylogenetically closely related species pairs. Mortality at the seed and seedling stage strongly influences the abundance and distribution of tropical tree species, but the host preferences and spatial distributions of fungi are rarely determined.

We examined how host species identity, relatedness, and seed viability influence the composition of fungal communities associated with seeds of four co-occurring pioneer trees (Cecropia insignis, C. longipes, C. peltata, and Jacaranda copaia). Seeds were buried in mesh bags in five common gardens in the understory of a lowland tropical forest...

过往的理论研究已指出，天敌可通过对宿主存活率产生密度依赖效应，介导具有相似生活史的物种种群共存。若植物病原菌要发挥这类调控作用，其对不同宿主植物的侵染或致病能力必须存在差异。在以高物种多样性为特征的热带森林中，这类效应还需延伸至系统发育关系紧密的物种种对。种子与幼苗阶段的死亡率对热带树木物种的丰度与分布具有显著调控作用，但目前学界对真菌的宿主偏好性及其空间分布的研究仍鲜有明确测定。

本研究探究了宿主物种身份、亲缘关系以及种子活力，如何影响四种共存先锋树种（号角树属 *Cecropia insignis*、*C. longipes*、*C. peltata* 以及蓝花楹 *Jacaranda copaia*）的种子关联真菌群落组成。研究人员将种子装入网袋，置于低地热带森林林下的5个同质种植园中……