Gilbert Francis, Willmer Pat, Semida Fayez, Ghazoul Jaboury, Zalat Samy
Department of Life Science, Nottingham University, NG7 2RD, Nottingham, UK.
School of Biological and Medical Sciences, St Andrews University, KY16 9TS, St Andrews, UK.
Oecologia. 1996 Nov;108(3):479-487. doi: 10.1007/BF00333724.
We studied an insect-plant pollination system in adjacent steep-sided wadis and a connecting plain in the mountains of southern Sinai (Egypt): this environment creates a strongly divided habitat, which may promote the local differentiation of sub-populations. We tested for spatial differences in phenotypic reproductive characters of the only plant flowering abundantly in early spring, Alkanna orientalis (Boraginaceae), and its major pollinator at that time of year, Anthophora pauperata (Apoidea, Anthophoridae). There were significant morphological differences between sub-populations of Alkanna, mainly between plants from the narrower wadis and those on the interconnecting plain. Flowers on the plain were larger, with wider corollas and more nectar standing crop; these plants retained more flowers on the inflorescence, but received many fewer visits to flowers. There was a significant selection gradient between flower size and maternal fitness (seed set) in the plain, but not elsewhere. Natural selection may have increased resources devoted to attracting insect visitors in response to fewer pollinating visits in the plain. Consistent with this explanation, by experimentally manipulating flower number per plant, we showed that within a wadi having more flowers on a plant secured more visits.
我们研究了埃及西奈半岛南部山区相邻的陡峭河谷及相连平原中的一种昆虫-植物授粉系统：这种环境形成了一个高度分隔的栖息地，这可能会促进亚种群的局部分化。我们测试了早春时节唯一大量开花的植物东方紫朱草（紫草科）及其当时的主要传粉者贫花地花蜂（地花蜂科，地花蜂属）表型繁殖特征的空间差异。紫朱草亚种群之间存在显著的形态差异，主要体现在较窄河谷中的植株与相连平原上的植株之间。平原上的花朵更大，花冠更宽，花蜜存量更多；这些植株在花序上保留的花朵更多，但花朵接受的访花次数却少得多。在平原地区，花朵大小与母体适合度（结实率）之间存在显著的选择梯度，而在其他地方则不存在。由于平原地区传粉访花次数较少，自然选择可能增加了用于吸引昆虫访客的资源。与此解释一致的是，通过实验操纵单株花朵数量，我们发现，在一个河谷内，植株上花朵较多的能获得更多访花。
