Tiger moth caterpillars have been seen medicating themselves to treat a nasty influx of parasites. Scientists found the caterpillars' sense of taste actually changed when they became infected with parasites. Instead of avoiding certain alkaloid plants, the caterpillars actually developed a fondness for them. This change in diet helps to beat the creatures' parasite infection, the researchers report in Nature. The finding is slightly unusual because often when animals change their behaviour following a parasitic infection, it is to the invaders' benefit. "It is a new and surprising kind of interaction between organisms," said Elizabeth Bernays, of the University of...