My research is motivated by several general interests: (1) the evolution of chemical and structural resistance, (2) the developmental mechanisms that constrain the evolution of form and function, (3) the causes and consequences of phenotypic plasticity, and (4) the lifehistories, defenses, and biology of colonial marine invertebrates.

Our current research is focused on the form, function, and evolution of defenses of marine invertebrates against their predators and competitors. Using a primarily experimental approach, I and my students are working on projects in temperate and tropical oceans. Our current work is focussed on chemical and structural mechanisms of disease resistance in Caribbean gorgonian corals. These soft corals are heavily endowed with biologically active compounds that are anti-fungal, anti-bacterial and deterrent to fish and some invertebrate predators. My particular focus now is on mechanisms of disease resistance to a fungal pathogen of sea fans. The fungal pathogen Aspergillus sydowii is currently affecting sea fans (Gorgonia ventalina and G. flabellum) throughout the Caribbean. The disease causes variable-sized lesions and even colony death at some sites. In the Bahamas and Florida Keys, many monitored lesions enter long-term stasis (> 12 months) suggesting the possibility of effective resistance against the fungus within colonies. At some sites in the Florida Keys and San Salvador Bahamas colonies are undergoing substantial mortality from the disease. The chemical extracts of the two species of sea fan are fungi-static, leading us into an investigation of the chemical mechanisms of disease resistance.

Since 1981 I have also been studying inducible morphological defenses of a colonial marine invertebrate (bryozoan) to its predators and competitors. One inducible defense is spines, which are rapidly grown approximately 36 hours after the colony detects a waterborne cue from a molluscan predator. Stolons against competitors are also inducible structures which are produced aggressively against conspecifics. Thus the marine bryozoan, Membranipora membranacea simultaneously produces spines against predators and stolons against competitors. Such rapidly produced phenotypic shifts in morphology provide powerful tools for the study of costs and benefits of alternative defensive strategies. We are currently combining theoretical and empirical approaches to the study of inducible defenses and concentrating on the particular mechanisms by which colonial invertebrates integrate these defenses. I am also working on an editted book The Evolution of Inducible Defenses with Ralph Tollrian.