Data from: Preference of an insular flying fox for seed figs enhances seed dispersal of a dioecious species

Interactions among multiple species form complex networks of interdependences and are considered primary factors in the generation and maintenance of biodiversity. Pteropodid bats are keystone species that provide important ecosystem services of pollination and seed dispersal in the tropics and subtropics. In this study, we investigated the utilization and preference of food resources by the insular frugivorous flying fox Pteropus dasymallus. We found that fig species constituted the major portion of the diet of the flying fox (94.6%). When foraging, the flying fox preferred seed figs from female trees over gall figs from male trees in functionally dioecious fig species. Germination experiments showed a significantly higher percentage of germination for fig seeds in feces than those from pellets and ripe figs (feces: 80.2%, pellets: 23.4%, ripe figs: 32.9%). Considering the active selection of seed figs and avoidance of gall figs by foraging flying foxes, we suggest that the abundance of seed figs accurately represents food availability for dioecy. This preference for seed figs or viable seeds can effectively promote the survival of pollinating wasps and might reinforce the evolution of dioecism in figs. In addition, the effects of gut passage on seed germination, in combination with the capacity of flying foxes to travel long distances, may substantially contribute to the efficiency of flying foxes as seed dispersers.

多物种间的相互作用构成复杂的依存网络，被认为是生物多样性产生与维持的核心驱动因素。狐蝠科蝙蝠（Pteropodidae）属于关键种，在热带与亚热带地区提供授粉和种子传播等重要生态系统服务。本研究针对岛屿食果狐蝠——琉球狐蝠（Pteropus dasymallus）的食物资源利用与取食偏好展开调查。研究发现，无花果属植物占该狐蝠食物组成的94.6%，为其主要食物来源。在觅食过程中，该狐蝠会优先取食功能雌雄异株无花果物种中雌树结的可育无花果，而非雄树产生的虫瘿无花果。萌发实验结果显示，狐蝠粪便中的无花果种子萌发率显著高于食丸及成熟无花果中的种子（粪便组：80.2%，食丸组：23.4%，成熟无花果组：32.9%）。结合觅食狐蝠主动偏好可育无花果、规避虫瘿无花果的行为特征，本研究认为可育无花果的丰度可准确反映功能雌雄异株无花果系统的食物可获得性。这种对可育无花果或有活力种子的取食偏好，可有效提升传粉榕小蜂的存活率，并可能推动无花果属植物雌雄异株性状的演化。此外，肠道转运过程对种子萌发的影响，结合狐蝠的长距离飞行能力，可显著提升狐蝠作为种子传播者的传播效率。