Numerous prey species exhibit inducible changes in traits such as morphology and chemistry in response to consumers. Such inducible defenses are thought to be adaptive because they reduce the vulnerability of the responding species to consumption. Although we appreciate the taxonomic ubiquity of inducible defenses, we have a poor sense of the variation in inducible defenses within a species. This is problematic because interactions involving the same prey-consumer species pair often occur over broad geographic ranges and the dynamics of these interactions may strongly depend on the local environmental context. Attention to this issue is critical if we are to better understand the role that inducible defenses play in structuring natural communities.
This project examines large-scale variation in the inducible defenses of two seaweeds (Ascophyllum nodosum, Fucus vesiculosus) in response to grazer cues from two herbivorous snails (Littorina littorea, Littorina obtusata) that are common on the rocky intertidal shores of the Gulf of Maine. Both seaweeds provide essential thermal buffering for the intertidal community during low tides and both of their primary consumers play a key role in rocky shore community dynamics. Hence, by focusing on these seaweed-herbivore interactions, the investigators expect to obtain considerable insight into the role that inducible defenses have in structuring rocky shore communities and how this role may vary geographically. Indeed, their previous work with Gulf of Maine seaweed populations, and that of others on European populations, suggests that there are considerable differences in the capacity of these seaweeds to exhibit inducible defenses. This project will combine laboratory and field approaches to address the following questions: 1. Do seaweeds display geographic variation in inducible defenses in response to herbivores? 2. Does the degree of seaweed inducible defense correlate with overall grazing intensity or grazing variability? 3. How are the costs and benefits of seaweed inducible defenses shaped by herbivore tolerance?
The research will make significant novel intellectual contributions to community ecology and the evolutionary ecology of inducible defenses by exploring the nature of seaweed-herbivore interactions across an unusually broad spatial scale.
This project will significantly enhance the research and educational opportunities of undergraduate, and junior high school students. Graduate students will participate directly in all aspects of this research, including experimental maintenance, data analysis, and manuscript development. The principal investigators will continue a strong commitment to undergraduate education by having undergraduate students (via the Three Seas Program assist with the execution of our experiments. The project will also involve junior high students in the research by interacting with the Marine Science Center's Outreach Program. This program targets Boston Public Schools where the majority of students are from under-represented groups. In collaboration with the Outreach Program, the investigators will design new lesson plans that align with the Massachusetts Life Science Standards. By developing lesson plans with outreach, the investigators have the ability to educate a broad and diverse group of students. Interactions with Outreach students will further enhance their enthusiasm for marine science as well as the teaching and research experience offered by the MSC's Outreach Program.
