Reproductive ecology and isolation of Psittacanthus calyculatus and P. auriculatus mistletoes (Loranthaceae)

Background: Relationships between floral biology and pollinator behavior are important to understanding species diversity of hemiparasitic Psittacanthus mistletoes (c. 120 species). We aimed to investigate trait divergence linked to pollinator attraction and reproductive isolation (RI) in two hummingbird-pollinated and bird-dispersed Psittacanthus species with range overlap. Methods: We investigated the phylogenetic relationships, floral biology, pollinator assemblages, seed dispersers and host usage, and the breeding system and female reproductive success of two sympatric populations of P. calyculatus and P. auriculatus, and one allopatric population of P. calyculatus. Flowers in sympatry were also reciprocally pollinated to assess a post-mating component of RI. Results: Hummingbird assemblages differed between calyculatus populations, while allopatric plants of calyculatus opened more but smaller flowers with longer lifespans and produced less nectar than those in sympatry. Baye...背景：花部生物学与传粉者行为之间的关联，对于理解半寄生性拟鹦鹉桑寄生属（Psittacanthus，约120种）槲寄生的物种多样性具有重要意义。本研究旨在探究两类分布区重叠的蜂鸟传粉、鸟类传播的拟鹦鹉桑寄生属物种中，与传粉者吸引及生殖隔离（Reproductive Isolation, RI）相关的性状分化。 方法：本研究针对两种同域分布的花萼拟鹦鹉桑寄生（P. calyculatus）、耳叶拟鹦鹉桑寄生（P. auriculatus）种群，以及一个异域分布的花萼拟鹦鹉桑寄生种群，开展了系统发育关系、花部生物学特征、传粉者类群组成、种子传播者与宿主利用情况、繁育系统及雌性生殖成功的调查。同时对同域分布的两种植物的花朵进行相互授粉实验，以评估生殖隔离的交配后组分。 结果：不同种群的花萼拟鹦鹉桑寄生的传粉者类群存在差异；与同域分布的花萼拟鹦鹉桑寄生相比，异域分布的该物种植株开放的花朵数量更多但单花更小、花期更长，且分泌的花蜜更少。贝叶斯...