About the Authors

Knut Helge Jensen

To whom correspondence should be addressed. E-mail: knut.jensen@bio.uib.no

Affiliations Department of Biology, University of Fribourg, Fribourg, Switzerland , Department of Biology, University of Bergen, Bergen, Norway

Tom Little

Affiliation The School of Biological Sciences, University of Edinburgh, Edinburgh, Scotland, United Kingdom

Arne Skorping

Affiliation Department of Biology, University of Bergen, Bergen, Norway

Dieter Ebert

Affiliations Department of Biology, University of Fribourg, Fribourg, Switzerland , Zoologisches Institut, University of Basel, Basel, Switzerland

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

KHJ, TL, AS, and DE conceived and designed the experiments. KHJ performed the experiment that tested spore production versus host longevity, and TL performed the experiment that tested the genetic basis for parasite virulence. KHJ and TL analysed the data. TL, AS, and DE contributed reagents/materials/analysis tools. KHJ, TL, AS, and DE wrote the paper.