| Little is known about mutualistic relationships between extrafloral nectary (efn) plants and parasitoids. Here I asked if parasitoids act as mutualist protectors of efn plants. I studied and compared the general biology, life histories, and biological interactions of an efn plant Solanum adherens, a plant without efns, Solanum rudepanum, their shared herbivores, in particular Mechanitis polymnia (Nymphalidae), and the parasitoids of those herbivores. Egg parasitoids of M. polymnia were probably not mutualists but larval parasitoids were. Larval parasitoids parasitize individual Lepidoptera species and Lepidoptera in general significantly more often on the efn plant. In addition, because M. polymnia larval survival is significantly higher on the efn plant until mortality from parasitoids is factored in, parasitoids may prevent M. polymnia larvae from effectively using the ants visiting S. adherens as protection from predators. Because it receives protection from parasitoids and ants, Solanum adherens may be an insectary plant; effectively using both predators and parasitoids attracted to its extrafloral nectaries as protection from its insect herbivores. |
