Fruit and seed set.csv

PREMISE OF THE STUDY: On islands, flowering plants tend to be more generalist in their pollination needs, as insects (the main pollinators of flowering plants) are under-represented in these ecosystems compared to the mainland. In addition, some vertebrate species that are typically insectivorous or granivorous on the mainland are forced to broaden their diet and consume other resources such as nectar or pollen on the islands. The shrub Malva arborea L., with its large and colourful flowers, attracts different groups of potential pollinators. This study aimed to compare the effectiveness of vertebrates vs insects in an insular population of M. arborea and to investigate its reproductive system.METHODS: For three groups of taxa (insects, birds and lizards), we assessed the two components of pollination effectiveness: (i) the quantitative component (i.e. number of visits and number of flower contacted) through direct observations of flowers; and (ii) the qualitative component (fruit and seed set, number and size of seeds, and proportion of seedling emergence) through pollinator exclusion experiments.KEY RESULTS: Vertebrates (birds and lizards) were quantitatively the most effective pollinators, followed by insects. However, when all three groups visited the flowers, fruit and seed set were higher than when any of them were excluded. We also found that M. arborea has hermaphrodite flowers and is able to reproduce by autogamy, although less efficiently than when pollinated by animals.CONCLUSIONS: Both, vertebrates and insects play an important role in the reproduction of M. arborea. Although the plant does not need pollinators to produce seeds, its reproductive success increases when all pollinators are allowed to visit the flowers. Besides providing new information on M. arborea, these findings may help to better understand the role of different pollinator groups in the reproduction of other plant species, especially on islands where the co-occurrence of vertebrate and invertebrate pollination in the same plant species is usual.研究前提：岛屿生态系统中，作为显花植物主要传粉者的昆虫种群丰度相较于大陆更为匮乏，因此岛屿上的显花植物往往具有更泛化的传粉需求。此外，部分原本在大陆以食虫或食谷为生的脊椎动物类群，在岛屿上被迫拓宽食谱，转而取食花蜜或花粉等其他资源。花大色艳的树锦葵（Malva arborea L.）会吸引多类潜在传粉者。本研究旨在对比脊椎动物与昆虫在树锦葵（Malva arborea L.）岛屿种群中的传粉有效性（pollination effectiveness），并探究其生殖系统。 研究方法：针对昆虫、鸟类与蜥蜴三大类群，我们评估了传粉有效性的两个组分：(i) 定量组分，即通过对花朵进行直接观察，记录访花次数与接触花朵的数量；(ii) 定性组分，即通过传粉者排除实验，统计坐果与结籽率、种子数量与大小，以及幼苗出苗比例。 主要结果：脊椎动物（鸟类与蜥蜴）是定量传粉效率最高的传粉者，其次为昆虫。但当三类传粉者均可访花时，坐果与结籽率高于排除任意一类传粉者后的水平。本研究同时发现，树锦葵（Malva arborea L.）具两性花，可通过自花授粉（autogamy）繁殖，但效率低于动物介导的授粉。 结论：脊椎动物与昆虫均在树锦葵（Malva arborea L.）的生殖过程中发挥重要作用。尽管该植物无需传粉者即可产生种子，但当所有传粉者均可访花时，其生殖成功率会显著提升。本研究不仅为树锦葵（Malva arborea L.）的相关研究提供了新数据，其研究结果还有助于更深入地理解不同传粉类群在其他植物物种生殖过程中的作用，尤其在脊椎动物与无脊椎动物传粉在同一植物物种中共存较为普遍的岛屿生态系统中。