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.
