Active pollination favours sexual dimorphism in floral scent
Active pollination favours sexual dimorphism in floral scent
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DOI：
10.1098/rspb.2013.2280
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发表时间：
2013-12-07
影响因子：
4.7
通讯作者：
Kato, Makoto
中科院分区：
文献类型：
--
作者：
Okamoto, Tomoko;Kawakita, Atsushi;Kato, Makoto
虫媒花经常传递嗅觉信号来吸引传粉者。在具有单性花的植物中，这种信号通常在性别之间是相似的，因为同一动物对雄花和雌花的吸引对于同种花粉转移至关重要。在这里，我们提出了一个显着的例子中观察到的生殖高度专业化的分支部落Phyllantheae（Phyllanthaceae）的花信号性二型。这些植物由种特异性的种子寄生的Epicephala蛾（Gracillariidae）授粉，它们积极地从雄花收集花粉并为它们产卵的雌花授粉;通过这样做，它们确保了它们的后代的种子。我们发现，Epicephala授粉Phyllanthaceae植物始终表现出雄性和雌性花之间的气味主要的质的差异，往往涉及来自不同的生物合成途径的化合物。在一个选择测试中，交配的雌性Epicephala蛾喜欢的气味雄花的雌花，这表明男性花的气味elaborate花粉收集行为。在余甘子亚科中，顶头花授粉经历了多次进化，至少有三次伴随着花香从性单态向二态的转变。这是第一个例子，在这个例子中，两性异形的花香已经进化成了每种性别提供的另一种奖励的信号，激发了传粉者的合法利他行为。
Zoophilous flowers often transmit olfactory signals to attract pollinators. In plants with unisexual flowers, such signals are usually similar between the sexes because attraction of the same animal to both male and female flowers is essential for conspecific pollen transfer. Here, we present a remarkable example of sexual dimorphism in floral signal observed in reproductively highly specialized clades of the tribe Phyllantheae (Phyllanthaceae). These plants are pollinated by species-specific, seed-parasitic Epicephala moths (Gracillariidae) that actively collect pollen from male flowers and pollinate the female flowers in which they oviposit; by doing so, they ensure seeds for their offspring. We found that Epicephala-pollinated Phyllanthaceae plants consistently exhibit major qualitative differences in scent between male and female flowers, often involving compounds derived from different biosynthetic pathways. In a choice test, mated female Epicephala moths preferred the scent of male flowers over that of female flowers, suggesting that male floral scent elicits pollen-collecting behaviour. Epicephala pollination evolved multiple times in Phyllantheae, at least thrice accompanied by transition from sexual monomorphism to dimorphism in floral scent. This is the first example in which sexually dimorphic floral scent has evolved to signal an alternative reward provided by each sex, provoking the pollinator's legitimate altruistic behaviour.