Parasite-induced alteration of odour responses in an amphipod-acanthocephalan system

- We tested amphipods for responses to alarm pheromones and predator kairomones.
- Uninfected amphipods reduced activity and increased refuge when either chemical was present.
- Infected amphipods failed to change behaviour in the presence of alarm pheromones or predator kairomones.
- Infected amphipods acted similarly to amphipods exposed to no chemical cue.
- This is the first known demonstration of parasitic modification of these responses to alarm pheromones.