de Vega Clara, Arista Montserrat, Ortiz Pedro L, Herrera Carlos M, Talavera Salvador
Estación Biológica de Doñana, Consejo Superior de Investigaciones Científicas, Avenida de María Luisa, Seville, Spain.
Ann Bot. 2009 May;103(7):1065-75. doi: 10.1093/aob/mcp049. Epub 2009 Mar 3.
The genus Cytinus is composed of rootless, stemless and leafless parasites whose flowers are only visible during the reproductive period when they arise from the host tissues. Most of the taxa occur in Madagascar and South Africa, where mammal pollination has been suggested for one species. There is only one species in the Mediterranean region, and its pollination system has been unknown. Here, a long-term field observation study is combined with experimental pollination treatments in order to assess the pollination biology and reproductive system in the Mediterranean species Cytinus hypocistis.
Field studies were carried out in six populations in southern Spain over 4 years. Temporal and spatial patterns of variation in the composition and behaviour of floral visitors were characterized. Pollen loads and pollen viability were observed, and exclusion and controlled-pollination treatments were also conducted.
Cytinus hypocistis is a self-compatible monoecious species that relies on insects for seed production. Ants were the main visitors, accounting for 97.4 % of total floral visits, and exclusion experiments showed that they act as true pollinators. They consistently touched reproductive organs, carried large pollen loads and transported viable pollen, although the different ant species observed in the flowers differed in their pollination effectiveness. The abundance of flying visitors was surprisingly low, and only the fly Oplisa aterrima contributed to fruit production and cross-pollination.
Mutualistic services by ant are essential for the pollination of Cytinus hypocistis. Although this parasite does not exhibit typical features of the 'ant-pollination syndrome', many other characteristics indicate that it is evolving to a more specialized ant-pollination system. The striking interspecific differences in the pollination systems of Mediterranean Cytinus (ant-pollinated) and some South African Cytinus (mammal-pollinated) make this genus an excellent model to investigate the divergent evolution of pollination systems in broadly disjunct areas.
杯轴花属植物为无根、无茎、无叶的寄生植物，其花朵仅在繁殖期从寄主组织中长出时可见。该属大多数分类群分布于马达加斯加和南非，有一种植物被认为是由哺乳动物传粉。地中海地区仅有一个物种，其传粉系统尚不清楚。在此，通过长期的野外观察研究与实验性授粉处理相结合，以评估地中海物种杯轴花（Cytinus hypocistis）的传粉生物学和繁殖系统。
在西班牙南部的六个种群中进行了为期4年的野外研究。对访花者的组成和行为的时间和空间变化模式进行了表征。观察了花粉载量和花粉活力，并进行了隔离和控制授粉处理。
杯轴花是一种自交亲和的雌雄同株物种，依靠昆虫进行种子生产。蚂蚁是主要访花者，占总访花次数的97.4%，隔离实验表明它们是真正的传粉者。它们持续接触生殖器官，携带大量花粉载量并传播有活力的花粉，尽管在花朵中观察到的不同蚂蚁物种在传粉效率上有所不同。飞行访花者的数量出奇地少，只有黑腹寡毛蝇（Oplisa aterrima）有助于果实生产和异花授粉。
蚂蚁的互利服务对杯轴花的授粉至关重要。尽管这种寄生植物没有表现出“蚂蚁传粉综合征”的典型特征，但许多其他特征表明它正在进化为一种更特化的蚂蚁传粉系统。地中海杯轴花（由蚂蚁传粉）和一些南非杯轴花（由哺乳动物传粉）传粉系统中显著的种间差异，使该属成为研究广泛分隔地区传粉系统趋异进化的优秀模型。
