I define parasites as organisms that live in or on a host and cause that host a fitness class basically. They take energy from their host, and that means that the term parasite encompasses everything ...

Mark Forbes receives funding from Natural Sciences and Engineering Research Council of Canada (NSERC) and Environment and Climate Change Canada (ECCC) through their Grants and Contributions envelope.

Parasites. Cause of terrible diseases. Big on the yuck-factor. It’s easy to think of them as doing no good. “The public perception … when you use the word ‘parasite’ is that it’s bad,” says Nico Smit.