Abe Tetsuto
Forestry and Forest Products Research Institute, Matsunosato 1, Tsukuba, Ibaraki 305-0903, Japan.
Ann Bot. 2006 Aug;98(2):317-34. doi: 10.1093/aob/mcl117. Epub 2006 Jun 21.
Various alien species have been introduced to the Ogasawara Islands (Japan). A survey was made investigating whether the native pollination systems fit an 'island syndrome' (biasing the flora to dioecy, with subdued, inconspicuous flowers) and whether alien species have disrupted the native pollination network.
Flower visitors and floral traits were determined in the field (12 islands) and from the literature. Associations among floral traits such as sexual expression, flower colour and flower shape were tested.
Among the 269 native flowering plants, 74.7 % are hermaphroditic, 13.0 % are dioecious and 7.1 % are monoecious. Classification by flower colour revealed that 36.0 % were white, 21.6 % green and 13.8 % yellow. Woody species (trees and shrubs) comprised 36.5 % of the flora and were associated with dioecy and white flowers. Solitary, endemic small bees were the dominant flower visitors and visited 66.7 % of the observed species on satellite islands where the native pollination networks are preserved. In contrast to the situation on the satellite islands, introduced honeybees were the most dominant pollinator (visiting 60.1 % of observed species) on the two main islands, Chichi-jima and Haha-jima, and had spread to satellite islands near Chichi-jima Island.
The island syndrome for pollination systems in the Ogasawara Islands was evident in a high percentage of dioecious species, the subdued colour of the native flora and solitary flower visitors on satellite islands. The shape and colour adaptations of several flowers suggested native pollination niches for long-proboscis moths and carpenter bees. However, the domination and expansion of introduced honeybees have the potential for disruption of the native pollination network in the two main, and several satellite, islands of the Ogasawara Islands.
多种外来物种已被引入小笠原群岛（日本）。开展了一项调查，以研究本地授粉系统是否符合“岛屿综合征”（使植物区系偏向雌雄异株，花朵不显眼），以及外来物种是否扰乱了本地授粉网络。
在实地（12个岛屿）并根据文献确定访花者和花部特征。测试了性表达、花色和花形等花部特征之间的关联。
在269种本地开花植物中，74.7%为雌雄同株，13.0%为雌雄异株，7.1%为雌雄同序。按花色分类显示，36.0%为白色，21.6%为绿色，13.8%为黄色。木本植物（乔木和灌木）占植物区系的36.5%，与雌雄异株和白色花朵相关。独居的本地小蜜蜂是主要的访花者，在本地授粉网络得以保留的卫星岛上，它们访问了66.7%的观察物种。与卫星岛的情况相反，在两个主要岛屿父岛和母岛，引入的蜜蜂是最主要的传粉者（访问了60.1%的观察物种），并且已经扩散到父岛附近的卫星岛。
小笠原群岛授粉系统的岛屿综合征在高比例的雌雄异株物种、本地植物区系不显眼的颜色以及卫星岛上独居的访花者中很明显。几种花朵的形状和颜色适应性表明，长喙蛾和木蜂存在本地授粉生态位。然而，引入蜜蜂的主导地位和扩散有可能扰乱小笠原群岛两个主要岛屿及几个卫星岛的本地授粉网络。
