Indirect effects of parasitism: costs of infection to other individuals can be greater than direct costs borne by the host

Granroth-Wilding, Hanna M. V.; Burthe, Sarah J.; Lewis, Sue; Herborn, Katherine A.; Takahashi, Emi A.; Daunt, Francis; Cunningham, Emma J. A.

Abstract

Parasitic infection has a direct physiological cost to hosts but may also alter how hosts interact with other individuals in their environment. Such indirect effects may alter both host fitness and the fitness of other individuals in the host's social network, yet the relative impact of direct and indirect effects of infection are rarely quantified. During reproduction, a host's social environment includes family members who may be in conflict over resource allocation. In such situations, infection may alter how resources are allocated, thereby redistributing the costs of parasitism between individuals. Here, we experimentally reduce parasite burdens of parent and/or nestling European shags (Phalacrocorax aristotelis) infected with Contracaecum nematodes in a factorial design, then simultaneously measure the impact of an individual's infection on all family members. We found no direct effect of infection on parent or offspring traits but indirect effects were detected in all group members, with both immediate effects (mass change and survival) and longer-term effects (timing of parents' subsequent breeding). Our results show that parasite infection can have a major impact on individuals other than the host, suggesting that the effect of parasites on population processes may be greater than previously thought.

Citation

Granroth-Wilding, H. M. V., Burthe, S. J., Lewis, S., Herborn, K. A., Takahashi, E. A., Daunt, F., & Cunningham, E. J. A. (2015). Indirect effects of parasitism: costs of infection to other individuals can be greater than direct costs borne by the host. Proceedings of the Royal Society B: Biological Sciences, 282(1811), Article 20150602. https://doi.org/10.1098/rspb.2015.0602

• Journal Article Type: Article
• Acceptance Date: Jun 5, 2015
• Online Publication Date: Jul 22, 2015
• Publication Date: Jul 22, 2015
• Deposit Date: Oct 6, 2021
• Journal: Proceedings of the Royal Society B: Biological Sciences
• Print ISSN: 0962-8452
• Electronic ISSN: 1471-2954
• Publisher: Royal Society
• Peer Reviewed: Peer Reviewed
• Volume: 282
• Issue: 1811
• Article Number: 20150602
• DOI: https://doi.org/10.1098/rspb.2015.0602
• Keywords: anisakid, trade-off, parent–offspring conflict, seabird, endoparasite, life-history decision
• Public URL: http://researchrepository.napier.ac.uk/Output/2810127