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The parasitic Nematomorph hairworm (Spinochordodes tellinii) develops inside land-dwelling grasshoppers and crickets until the time comes for the worm to transform into an aquatic adult. At this time the worm brainwashes the grasshopper by producing proteins which directly and indirectly affect the grasshopper’s central nervous system, causing the host to seek out and plunge into water.

Once in the water the mature hairworms – which are three to four times longer that their hosts when extended – emerge and swim away to find a mate, leaving their host dead or dying in the water.

This is just one of many parasites that can manipulate their hosts’ behaviour: “’Enslaver’ fungi, for example, make their insect hosts die perched in a position that favours the dispersal of spores by the wind.”