Parasitic Infections Compel Infected Grasshoppers To What?
Answer: Drown Themselves
Several parasites have mechanisms for influencing the behavior of their host in a way that is beneficial to the parasitic freeloader. In the case of Spinochordodes tellinii, a nematomorph hairworm from the nematode family that infects grasshoppers, the behavior alteration for the host is fatal.
Spinochordodes tellinii both begins and ends its life cycle in large bodies of water: it needs to return to water to reproduce. In order to get there, it compels its host grasshopper to seek out nearby bodies of water. Upon reaching the water, the grasshopper jumps right in, a fatal move, and provides the parasite with an escape route back into the water. Scientists are unclear on the exact mechanism by which the parasite drives the grasshopper into the water.
Image by D. Andreas Schmidt-Rhaesa.