Many ant species show dramatic shifts in behaviour when infected with parasites, but the molecular basis of these behavioural changes is not well understood. An example is the wood ant, Formica aserva , which serves as an intermediate host for the lancet liver fluke, Dicrocoelium dendriticum . Infected ants leave their nests during the cool hours of the day, ascend a flower and then attach themselves to a petal with their mand...