Plant-defense mimicry facilitates rapid dispersal of short-lived seeds by hornets

Abstract

Rates of seed dispersal have rarely been considered important. 

种子散布中速度的重要性很少有人研究。（rate可以有很多种意思，从下一句的rapid可以看出这里是说速度而不是概率）。

Here, we demonstrate through field observations and experiments that rapid dispersal is essential for the unusually short-lived seeds of Aquilaria sinensis (agarwood; Thymelaeaceae), 

我们进行了野外观察，也结合了实验，发现瑞香科的一种叫土沉香的植物的种子很短命，所以必须要快速的被散布出去，

which desiccate and die within hours of exposure by fruit dehiscence in the hot, dry forest canopy in tropical southwest China.

不然这些种子在果荚开裂（dehiscence）后，暴露在中国西南亚热带地区炎热又干旱的林冠，几个小时就干死了。

 We show that three species of Vespa hornets remove most seeds within minutes of exposure. 

我们发现，大多数的种子在果荚开裂几分钟后就被来自虎头蜂属的三种胡蜂搬走了。

The hornets consume only the fleshy elaiosomes and deposit most seeds in damp shade, 

胡蜂把种子上面的脂质体（？）吃了，种子就被扔到了阴暗潮湿处，

where they can germinate, 

方便他们萌发，

a mean of 166 m from the parent tree. 

平均能被搬运166米远。

那胡蜂为何能如此迅速的赶到现场呢？

Electrophysiological assays and field experiments demonstrate that the hornets are attracted by highly volatile short-carbon-chain (C5–C9) compounds, 

电生理检测和野外试验证明，胡蜂是被果荚开裂时释放的极易挥发的短碳链化合物（5到9个碳原子）所吸引，

including aldehydes, ketones, alcohols, and acids, emitted from the dehiscent fruit capsule. 

包括醛类（aldehydes, 碳氧双键，碳氢键和碳碳键）、酮类（ketones， 碳氧双键和两个碳碳键）、醇类（alcohols, -C-OH), 和酸类(acids, 如-COOH)。

These attractive fruit volatiles share 14 of 17 major electrophysiologically active compounds with those emitted from herbivore-damaged leaves, 

17种能让胡蜂产生电生理反应的果实挥发物里，有14种在土沉香的叶片被昆虫取食时也会释放，

which attract predators, including hornets. 

以吸引这些植食性昆虫（如黄野螟，沉香属植物专性取食者）的捕食者，其中就包括胡蜂（之前还记录有一种stinkbug）。

Rapid seed dispersal thus appears to have been achieved in this species by the re-purposing of a rapid indirect defense mechanism. 

所以还真不知道这些胡蜂过来到底是为了吃种子上面的脂质体呢，还是吃取食沉香的植食性昆虫（作者认为是果实模拟叶子）。不管怎样，种子传播的目的达到了。

We predict that rapid seed dispersal by various mechanisms will be more widespread than currently documented and suggest that volatile attractants are more effective in facilitating this than visual signals, which are blocked by vegetation.

作者推测，种子快速传播可能比我们想象的更普遍，而且通过气味来吸引传播者在密林里确实比通过视觉更有效。

In brief 总结起来

Qin et al. demonstrate that rapid seed dispersal by hornets is essential for shortlived seeds of an agarwood plant. 

1. 土沉香种子短命，果荚打开后必须靠胡蜂快速传播到适宜种子萌发的地方。

Hornets are attracted rapidly by highly volatile fruit chemicals, which appear to have been achieved by re-purposing of volatiles utilized in plant defense. 

2. 胡蜂是被果实释放的高挥发性的化合物吸引的，这些化合物同时也被植物用来吸引其取食者的天敌，从而实现间接防御。

Rapid seed dispersal seems widespread, and volatiles are effective signals.

3. 作者还讨论了在其他系统中的种子快速散布以及以气味作为吸引散布者的优势，预测其普遍性。

最后恭喜陈进老师及其团队！

原文链接：https://doi.org/10.1016/j.cub.2022.06.034