Behavioural manipulation: 10 bedtime stories!

Behavioural manipulation is one of the most impressive consequences of parasitic infections. In order to increase their transmission rate, some parasites alter the behaviour of their host, sometimes leading to its death.

Suicides of hairwom-infected crickets (Thomas et al. 2002) and of mice infected with protozoa (Berdoy et al. 2000) are among the best-documented examples where host death is necessary for parasite reproduction or transmission. Such manipulations can be very simple, such as for the eye fluke Diplostomum pseudospathaceum, which encysts in the eyes of its fish host to cause blindness and increase predation by the fish-eating bird final host (Karvonen et al. 2003). Other parasites, such as the trematode Schistosoma mansoni (Kavaliers et al. 1999), use more sophisticated manipulation by secreting of neuroactive substances to alter host behaviours.   

Ten bedtime stories of behavioural manipulation by parasites. 

Among these is notably mentioned the tapeworm Schistocephalus solidus, which is known to deeply affect the behaviour of its secondary intermediate host - the threespine stickleback Gasterosteus aculeatus. More about this parasite here!