CAUSES AND CONSEQUENCES OF WITHIN‐TREE PHENOLOGICAL PATTERNS IN THE FLORIDA STRANGLING FIG, FICUS AUREA (MORACEAE)
CAUSES AND CONSEQUENCES OF WITHIN‐TREE PHENOLOGICAL PATTERNS IN THE FLORIDA STRANGLING FIG, FICUS AUREA (MORACEAE)
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佛罗里达无花果榕（桑科）树内物候模式的原因和后果
DOI：
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发表时间：
1992
期刊：
影响因子：
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通讯作者：
Aviva Patel
中科院分区：
文献类型：
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作者：
J. Bronstein;Aviva Patel
无花果的专性传粉者(无花果属，桑科)，物种特有的无花果黄蜂，只通过在树之间传递花粉来使无花果受益；幼虫是种子捕食者。但考虑到在树间飞行死亡的高风险，成年黄蜂应该更喜欢在它们发育的同一棵树上的花序内授粉和产卵。在大多数物种中，个体内的开花是紧密同步的，而不同的树木彼此开花不同步，这表明无花果物候已经进化到确保异交。然而，一些无花果树种表现出明显的树内开花异步性。有人提出，这种异步性是一种适应，季节环境中的无花果可以通过允许黄蜂在不可能飞行的时候在个别树上存活来降低传粉者的死亡率。我们已经评估并拒绝了这种季节性假说对佛罗里达无花果北部范围界限附近的无花果的有效性。在两年中最冷、最干燥的几个月里，个别树木的作物最同步，尤其是最不同步。最大的异步性出现在可能最有利于黄蜂在树间转移的季节。然而，允许黄蜂留在出生树上的物候阶段的时间重叠总是非常罕见的，这意味着发育中的聚球果的连续队列可能在时间上间隔开，以限制这种发生。我们建议这些物候特征的替代成本和收益，以及可能产生它们的最接近的机制。
The obligate pollinators of figs (Ficus, Moraceae), species-specific agaonid wasps, benefit figs only by transporting pollen between trees; larvae are seed predators. But given the high risk of mortality in flight between trees, adult wasps should prefer to pollinate and oviposit within inflorescences (syconia) at the same tree at which they developed. Flowering within individuals is tightly synchronous in most species, while different trees flower out of phase with each other, suggesting that fig phenology has evolved to assure outcrossing. However, some fig species show distinct within-tree flowering asynchrony. It has been suggested that such asynchrony is an adaptation by which figs in seasonal environments can reduce pollinator mortality, by permitting wasps to persist on individual trees at times when flight would be impossible. We have evaluated and rejected the validity of this Seasonality Hypothesis for the Florida strangling fig, Ficus aurea, near its northern range limit. Crops of individual trees were most, not least, synchronous during the coldest, driest months of 2 years. Maximum asynchrony occurred in seasons that were probably most favorable for wasp transit between trees. However, temporal overlap of the phenological stages that permit wasps to remain on their natal trees was always very rare, implying that consecutive cohorts of developing syconia may be spaced in time to limit this occurrence. We suggest alternative costs and benefits for these phenological traits, as well as the proximate mechanisms that might produce them.