有花植物展现多样的花信号吸引传粉者，也会对第三方类群产生吸引；研究表明食花者与微生物在植物-传粉者互作中普遍存在，但其共同影响虫媒传粉的模式及机理，仍未见报道。我们前期大范围居群调查显示，花蜜微生物存在于西南鸢尾（Iris bulleyana）的所有居群，而食花者的发生率却存在着居群间差异。基于以上结果，本项目拟选择横断山区西南鸢尾的食花与非食花居群各两个，深入研究食花者和花蜜微生物在其虫媒传粉中的作用。计划通过多年多居群调查，明确食花者、花蜜微生物和传粉者的多样性及丰度；运用食花者控制和微生物接种的多重组合实验，检验两者各自及共同对西南鸢尾虫媒传粉和生殖适合度的影响；定量测定花信号并开展关键花信号的人工操作，结合昆虫行为实验，解析食花者和微生物介导的花信号改变对虫媒传粉的影响机制。项目的实施将加深对生物间多营养级互作模式的理解，也将有助于探索食花者、微生物和传粉者共同选择下的花信号演化。

Flowering plants produce diverse floral signals to attract pollinators, yet these signals may also attract third-party organisms. Previous studies have shown that florivore and microbe are widespread in plant-pollinator interactions, however, the pattern and mechanism of their joint influences on insect pollination are still unknown. Our previous large-scale survey indicates that nectar microbes are existed in all populations of Iris bulleyana, whereas the incidences of florivores show among-population variance. Based on these preliminary results, two florivore populations and two non-florivore populations in the Hengduan Mountains will be chosen to conduct studies on the influences of florivore and nectar microbe on insect pollination of I. bulleyana. We will carry out multi-population and multi-year investigations on the diversity and abundance of pollinators, florivores and nectar microbes. Combinations of florivore-control and microbe-inoculation experiments will be conducted to determine their separate and joint effects on insect pollination and plant reproductive fitness. In addition, quantitative measurement of floral signals, manipulations of key signals and insect behaviour bioassays will be conducted to explore the mechanisms underlying the influences of florivore- and/or microbe-induced changes in floral signals on insect pollination. The project aims to reveal the patterns of multitrophic interactions among organisms. Furthermore, relevant results will be useful to understand the evolution of floral signals under joint selections by florivore, microbe and pollinator.