DISSERTATION RESEARCH: Can indirect interactions arise from sharing mutualists? Detecting competition or facilitation for mutualist ants among plants with extrafloral nectaries

蚂蚁经常与植物进行互利的互动。许多植物在叶子或茎上的花外蜜腺中产生花蜜。一旦被蜜腺吸引，蚂蚁就会捕食植物的食草动物。这个项目将研究不同植物之间的相互作用是如何产生于共享相同的共生蚂蚁的花外蜜腺。如果蚂蚁保护是有价值的，并且蚂蚁的数量有限，那么植物可能会竞争蚂蚁。相反，在一个特定地区，许多提供花蜜的植物可能有助于吸引蚂蚁，这样附近的植物就可以相互受益。将对蚂蚁、植物和花蜜进行实验操作，以量化共享蚂蚁如何影响哥斯达黎加热带雨林中一种林下树种的种群增长。这项研究在寻找共享蚂蚁互惠主义者的短期和长期影响方面将是独一无二的。此外，由于具有花外蜜腺的植物在物种丰富的热带雨林中非常常见，因此了解这些植物之间的相互作用有助于解释热带树木的高度多样性。更一般地说，了解物种之间的相互作用对于预测物种损失对生物多样性的影响至关重要，例如当入侵的外来蚂蚁取代本地蚂蚁时，可能会影响本地的蜜腺植物。该项目还将为杜克大学的本科生和哥斯达黎加大学的学生提供国际实地经验。

Ants often engage in mutually beneficial interactions with plants. Many plants produce nectar in extrafloral nectaries on their leaves or stems. Once attracted to the nectaries, the ants then prey on the plant's herbivores. This project will investigate how interactions among different plants bearing extrafloral nectaries might arise from sharing the same mutualist ants. If ant protection is valuable, and there are a limited number of ants, then plants may compete for ants. Conversely, many plants providing nectar in a given area may help to attract ants, so that nearby plants may benefit one another. Experimental manipulation of ants, plants, and nectar will be performed to quantify how sharing ants might affect the population growth of an understory tree species in a Costa Rican tropical rainforest. This study will be unique in looking for both short- and long-term effects of sharing ant mutualists. Furthermore, as plants with extrafloral nectaries are very common in species-rich tropical rainforests, understanding interactions among these plants could help to explain high tropical tree diversity. More generally, understanding interactions among species is essential in predicting biodiversity effects of species losses, such as those that occur when invading exotic ants displace native ants, potentially affecting native nectary-bearing plants. This project will also provide international field experience for undergraduate students from Duke University, and for University of Costa Rica students.