Long-tongued fly pollination and evolution of floral spur length in the Disa draconis complex (Orchidaceae)
Long-tongued fly pollination and evolution of floral spur length in the Disa draconis complex (Orchidaceae)
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DOI：
10.1111/j.1558-5646.1997.tb02387.x
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发表时间：
1997-02-01
期刊：
影响因子：
3.3
通讯作者：
Steiner, KE
中科院分区：
文献类型：
--
作者：
Johnson, SD;Steiner, KE
南非的实地研究表明，在南部山区（平均值= 32-38毫米），低地砂原（平均值= 48毫米）和北方山区（平均值= 57-72毫米）的种群之间，Disa draconis复合体（兰科）的花距长度变化很大。我们测试了这一假设，即在距长度分歧，导致通过传粉者长鼻子长度施加选择。短距植物在几个南部山区人口，以及长距植物在一个北方山区人口，授粉的马蝇，Philoliche rostrata（虻科），与不同的网站之间的吻长度从22至35毫米。长距植物在沙地上授粉的缠结翅苍蝇，Moegistorynchus longirostris（Nemestrinidae），它有一个非常长的喙（平均= 57毫米）。选择显然有利于长距在沙坪植物，作为人工缩短距导致在花粉接收和坐果显着下降，虽然花粉囊去除没有显着影响。研究种群中的坐果受到花粉可用性的限制，这进一步表明对距长的选择主要通过生殖成功的雌性成分来进行。
Field studies in South Africa showed that floral spur length in the Disa draconis complex (Orchidaceae) varies enormously between populations in the southern mountains (means = 32-38 mm), lowland sandplain (mean = 48 mm), and northern mountains (means = 57-72 mm). We tested the hypothesis that divergence in spur length has resulted from selection exerted through pollinator proboscis length. Short-spurred plants in several southern mountain populations, as well as long-spurred plants in one northern mountain population, were pollinated by a horsefly, Philoliche rostrata (Tabanidae), with a proboscis length that varied from 22 to 35 mm among sites. Long-spurred plants on the sandplain were pollinated by the tanglewing fly, Moegistorynchus longirostris (Nemestrinidae), which has a very long proboscis (mean = 57 mm). Selection apparently favors long spurs in sandplain plants, as artificial shortening of spurs resulted in a significant decline in pollen receipt and fruit set, although pollinaria removal was not significantly affected. Fruit set in the study populations was limited by pollen availability, which further suggests that selection on spur length occurs mainly through the female component of reproductive success.