Fruit and seed secondary metabolites and animal seed handling: impacts on germination success and seedling survival

任何物种都不能孤立地生存。即使是可以自己制造食物的植物，也依赖动物给它们的花授粉，并将它们的种子传播到新的地点。随着我们星球上的生物多样性继续下降，了解我们希望保护的物种之间的相互依存关系变得越来越迫切。这项研究的目的是加深我们对植物和种子传播动物之间相互作用的理解，这些动物维持着热带森林的生物多样性。为了吸引动物，植物结出诱人又有营养的果实。然而，水果不仅仅是美味的奖赏。除了营养物质外，水果还会产生天然化合物，这些化合物会影响食用水果的动物的行为和生理。例如，水果中的某些化合物对动物有通便作用，这可能是植物影响种子从父母那里运输到多远的一种方式。这项研究将探讨果实和种子化学、动物行为和生理以及种子萌发和存活之间的关系。这些信息可以帮助科学家更好地保护热带森林的生物多样性，并以最大限度地促进种子萌发和存活的方式管理恢复区域。该项目将产生新的热带森林生态教育资源，这些资源将在当地的自然中心和弗吉尼亚州的科学节上广泛分享。此外，实地和实验室的多样化研究活动将有助于培训下一代科学家，包括拉美裔(A)学生，他们将成为中南美洲热带森林的未来管家。该项目将专注于热带植物中最丰富和最多样化的群体之一-胡椒属胡椒植物-与它们赖以传播种子的动物之间的相互作用。这些动物中最引人注目的是果蝠，它们会吃掉水果(和它们所含的种子)，然后在新的地点排泄种子。然而，还有另一类动物对散布蚂蚁至关重要。蚂蚁虽然很小，但它们是热带森林中数量最多的动物，它们很快就会到达蝙蝠掉下的部分吃掉的水果，或者蝙蝠粪便中沉积的种子。有些种子被蚂蚁吃掉，但许多种子和果肉一起被带走，短距离移动，然后丢弃。为了评估水果和种子化学在决定这些相互作用的结果方面的作用，研究人员将在哥斯达黎加的La Selva生物站进行三项实验。首先，由于对果实化学对散播种子的蚂蚁的影响一无所知，他们将测试水果化学如何影响被蚂蚁移走的种子的命运--即种子是被消耗、缓存还是丢弃。这将涉及圈养蚂蚁群体的实验，研究人员可以在其中跟踪单个种子的命运。其次，研究人员将调查蝙蝠、蚂蚁或蝙蝠和蚂蚁的结合如何影响种子的化学成分。第三，研究人员将在最后的实验中使用蝙蝠和蚂蚁不同处理的种子，以确定化学物质和动物处理如何影响种子萌发和存活的最终概率。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

No species can survive in isolation. Even plants, which can make their own food, depend on animals to pollinate their flowers and disperse their seeds to new sites. As the biological diversity on our planet continues to decline, it is becoming increasingly urgent to understand the interdependencies among the species that we hope to protect. The aim of this research is to deepen our understanding of interactions between plants and the seed-dispersing animals that sustain the biodiversity of tropical forests. To attract animals, plants produce fruits that are attractive and nutritious. However, fruits are much more than tasty rewards. In addition to nutrients, fruits produce natural chemical compounds that can influence the behavior and physiology of animals that consume them. For example, certain compounds in fruits have a laxative effect on animals, which could be a way for plants to influence how far the seed is transported from the parent. This research will investigate the relationships among fruit and seed chemistry, animal behavior and physiology, and seed germination and survival. This information can help scientists better protect the biodiversity of tropical forests and manage areas targeted for restoration in a way that will maximize seed germination and survival. The project will generate new educational resources on tropical forest ecology, which will be shared broadly at a local nature center and through science festivals in Virginia. Additionally, the diverse research activities in the field and lab will help train the next generation of scientists, including Latino(a) students who will be the future stewards of tropical forests in Central and South America. The project will focus on interactions between one of the most abundant and diverse groups of tropical plants - pepper plants in the genus Piper - and the animals they rely on to disperse their seeds. The most conspicuous of these animals are fruit bats, which consume fruits (and the seeds they contain) and later defecate the seeds in new sites. However, there is another group of animals that are critical to dispersal - ants. Although small, ants are the most abundant animals in tropical forests, and rapidly arrive at partially consumed fruits that are dropped by bats, or at seeds that are deposited in bat feces. Some seeds are consumed by ants, but many are removed along with pulp, moved short distances, and discarded. To assess the role of fruit and seed chemistry in determining the outcome of these interactions, researchers will conduct three experiments at La Selva Biological Station in Costa Rica. First, because nothing is known about the effects of fruit chemistry on seed-dispersing ants, they will test how fruit chemistry affects the fate of seeds removed by ants - that is, whether the seeds are consumed, cached, or discarded. This will involve experiments with captive ant colonies in which researchers can track the fate of individual seeds. Second, the researchers will investigate how handling by bats, ants, or the combination of bats and ants influences the chemistry of seeds. Third, the researchers will use seeds that have been differentially handled by bats and ants in a final experiment to determine how chemistry and animal handling influence the ultimate probability of seed germination and survival.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.