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Can’tget you
out of my
head
In one of the coolest interactions, is able to control the mind of its month has been hot for research, unravelling more of the mysteries zombifying fungus. Words by Dr Robbie Rae, images from the Hughes Lab, Penn State
P
arasites in nature abound - from festive mistletoes parasitising trees and shrubs, tounge-eating lice staking a plot in the mouth of unsuspecting fish to cuckoos placing cleverly designed eggs in the nests of birds that drop their guards. But parasites get much more clever than this and can, upon infection, manipulate the behaviour of their hosts. Snails casually grazing on bird droppings might inadvertantly eat the eggs of the parasitic flatworm Leucochloridium paradoxum. The flatworms that grow within manipulate the snail’s behaviour, causing them to venture into open, sunlit spaces - making them vulnerable to predation. This particular parasite is also able to induce morphological changes. The larval form of the flatworm develops into a sporocyst, and grows into long swollen brood sacs filled with the free swimming stage of the parasite. These broodsacs are forced into the snail’s eyestalks - transforming them into large, throbbing tentacles, that perfectly resemble juicy, wriggling caterpillars - or to a hungry garden bird - lunch. This is an example of ‘aggressive
34 BIOSPHERE - ECOLOGY
the cordyceps fungus chosen ant host. This with two new studies surrounding this