We use a variety of methods to understand the impact of parasites on trophic interactions across food webs. Parasites are best known for causing mortality, but they can have a range of other impacts on their hosts, such as changing their behavior or decreasing fecundity. For each of these impacts, there are potential implications for the food web – host death provides food for scavengers, such as blue crabs, or releasing nutrients for bacteria; reducing fecundity can decrease the population, meaning less food for predators; and changes in host behavior often increase the likelihood of a host being consumed by a predator, meaning an increase in food availability for predators. Parasites can also be an important food source for some aquatic organisms.
We are using field surveys along with field and lab experiments to understand how changes in host behavior impact food availability. This includes using genetic methods to understand parasite diversity and impacts in phytoplankton and zooplankton assemblages (a vital food source for many important fish and bivalve species) and gut contents of commercially important crustaceans and fishes (e.g., blue crabs, striped bass, menhaden).