Data from: Cascading reproductive isolation: plant phenology drives temporal isolation among populations of a host-specific herbivore

All organisms exist within a complex network of interacting species, thus evolutionary change may have reciprocal effects on multiple taxa. Here, we demonstrate "cascading reproductive isolation," whereby ecological differences that reduce gene flow between populations at one trophic level affect reproductive isolation (RI) among interacting species at the next trophic level. Using a combination of field, laboratory and common-garden studies and long-term herbaria records, we estimate and evaluate the relative contribution of temporal RI to overall prezygotic RI between populations of Belonocnema treatae, a specialist gall-forming wasp adapted to sister species of live oak (Quercus virginiana and Q. geminata). We link strong temporal RI between host-associated insect populations to differences between host plant budbreak phenology. Budbreak initiates flowering and the production of new leaves, which are an ephemeral resource critical to insect reproduction. As flowering time is implicated in RI between plant species, budbreak acts as a "multitrophic multi-effect trait," whereby differences in budbreak phenology contribute to RI in plants and insects. These sister oak species share a diverse community of host-specific gall-formers and insect natural enemies similarly dependent on ephemeral plant tissues. Thus, our results set the stage for testing for parallelism in a role of plant phenology in driving temporal cascading RI across multiple species and trophic levels.所有生物均处于由相互作用物种构成的复杂网络之中，因此演化改变可能对多个类群产生双向相互效应。本研究阐明了级联生殖隔离（"cascading reproductive isolation"）这一现象：即某一营养级种群间降低基因流的生态差异，会影响下一营养级相互作用物种间的生殖隔离（Reproductive Isolation，简称RI）。 本研究结合野外调查、实验室实验与同质园（common garden）实验数据，以及长期植物标本馆馆藏记录，对专性造瘿蜂*Belonocnema treatae*的种群间合子前生殖隔离总水平中，时间型RI的相对贡献进行了估算与评估；该造瘿蜂寄主为栎属姊妹种——弗吉尼亚栎（*Quercus virginiana*）与宝石栎（*Q. geminata*）。我们将寄主关联昆虫种群间显著的时间型RI，与寄主植物的芽萌物候差异联系起来。芽萌会启动开花与新叶生成，而新叶是对昆虫繁殖至关重要的暂时性资源。 由于开花时间与植物物种间的RI相关，芽萌可作为一种多营养级多效应性状：芽萌物候的差异同时促成了植物与昆虫的RI。这两种栎树姊妹种共同拥有多样的专性造瘿昆虫群落，以及同样依赖植物暂时性组织的昆虫天敌类群。因此，本研究结果为验证植物物候在多物种、多营养级层面驱动时间型级联RI的作用是否具有平行性奠定了基础。