It may sound surprising, but parasitism is the most common lifestyle on the planet. Indeed, recent estimates suggest that parasites dramatically outnumber free-living biodiversity- by as much as 50 percent. Further, they are not only numerically important components of biodiversity, but have critical roles in maintaining functioning ecosystems. To celebrate parasite biodiversity around the world, Dr. Susan Perkins of the American Museum of Natural History hosts a blog featuring a parasite species every day of the year during 2010.