How do fruit secondary metabolites shape the effectiveness of seed dispersal?
Fruits contain a wide diversity of secondary metabolites, and many of these compounds play a role in shaping interactions surrounding fruits. Because plants are rooted in place, they often rely on animals to help disperse their seeds. Yet, the effectiveness of seed dispersal depends on a variety of fruit traits, including secondary metabolites, which determine fruit taste, odor, and color. In a recent Ecology study, we found that toxic secondary metabolites in Piper fruits not only reduce the quantity of seed dispersal services (i.e., the number of seeds dispersed) provided by ants but also alter the quality of seed dispersal by influencing how ants handle and where they deposit seeds. This work demonstrates that fruit secondary metabolites have complex and multi-faceted effects on seed dispersal effectiveness and ultimately plant fitness. To learn more about this research, check out this recording of a recent seminar I gave at Chico State or this VT News article summarizing some of our recent findings!
To extend this work, we have provided a general guide in a recent TREE review for integrating fruit secondary metabolites into the Seed Dispersal Effectiveness conceptual framework, which is widely used for evaluating the outcome of animal-mediated seed dispersal. I have also begun to think about how we can take lessons from the chemical ecology of seed dispersal to understand the movement ecology of mutualisms more broadly, after participating in an organized session at the Ecological Society of America 2022 Annual Meeting on this topic.
Relevant publications:
To extend this work, we have provided a general guide in a recent TREE review for integrating fruit secondary metabolites into the Seed Dispersal Effectiveness conceptual framework, which is widely used for evaluating the outcome of animal-mediated seed dispersal. I have also begun to think about how we can take lessons from the chemical ecology of seed dispersal to understand the movement ecology of mutualisms more broadly, after participating in an organized session at the Ecological Society of America 2022 Annual Meeting on this topic.
Relevant publications:
How do plants balance trade-offs between seed dispersal and fruit defense?
Plants face contrasting selective pressures to attract mutualists but simultaneously defend themselves against antagonists. Although many plants produce fleshy fruits to attract animals to disperse their seeds, fruits are also vulnerable to attack by pre- and post-dispersal seed predators and pathogens. Fruits contain high concentrations and diversity of secondary metabolites that help mediate these interactions, but there are nonetheless often trade-offs between dispersal and defense. The same nutrients or chemical attractants that make fruits appealing to dispersers can also increase the attraction of seed predators, and vice versa, the same toxic or deterrent compounds that help defend fruits against seed predators and pathogens can also deter effective seed dispersers. Currently, I am investigating how plants minimize such trade-offs, through shifts in the allocation of attractive and defensive compounds in fruits across space and time. Using a series of field and lab experiments with bloodroot (Sanguinaria canadensis), a perennial plant that occurs in eastern U.S. deciduous forests, I have found that changes in secondary metabolite concentration and composition throughout fruit development play an adaptive role in mediating seed dispersal and fruit defense. Two manuscripts based on this work are currently in preparation!
Relevant publications:
Relevant publications: