Parasites are ubiquitous and represent one of the most described symbiotic interactions in nature (Cavalier-Smith, 1993;Lafferty et al., 2006). They play significant roles in almost all environments by shaping the food-web structure, regulating the host population, facilitating energy transfer/nutrient flows and maintaining genetic polymorphism/diversity (Gsell, de Senerpont Domis, van Donk, &