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Angelina Tittmann

Slowed down by parasites

Many prey animals react collectively to predators. They transmit information about potential predators in no time at all to trigger and coordinate escape behaviours. Jens Krause and IGB guest scientist Ralf Kuvers, together with colleagues, found out that parasite infections can disrupt this transmission in a swarm.

In their study, the scientists analysed the behaviour of infected sticklebacks. | Photo: David Ausserhofer

Group living has many advantages, for example it reduces the risk of being eaten. But some parasites can influence how animals react to attacks by predators. The researchers were therefore interested in whether infected, behaviourally altered individuals affect the spread of escape reactions within a swarm. They infected sticklebacks with the tapeworm Schistocephalus solidus, because this increases risk-taking behaviour and reduces the social responsiveness of its host. Then they confronted the sticklebacks with an artificial bird attack, with one group containing infected individuals and the other not.

With uninfected sticklebacks, the waves of escape quickly spread through the entire shoal and the fish sought shelter at depth for prolonged periods. With infected sticklebacks, the escape wave was interrupted and uninfected fish also returned to the water surface more quickly. They are thus exposed to a higher risk when they join infected individuals. The observed processes could also play a role in many other prey species and their parasites.

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Contact person

Jens Krause

Head of Department
Research group
Mechanisms and Functions of Group-Living

Ralf Kurvers

Guest Scientist
Research group
Behavioural Biology

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