Ants avoid superinfections by performing risk-adjusted sanitary care Journal Article

Author(s): Konrad, Matthias; Pull, Christopher D; Metzler, Sina; Seif, Katharina; Naderlinger, Elisabeth; Grasse, Anna V; Cremer, Sylvia
Article Title: Ants avoid superinfections by performing risk-adjusted sanitary care
Affiliation IST Austria
Abstract: Being cared for when sick is a benefit of sociality that can reduce disease and improve survival of group members. However, individuals providing care risk contracting infectious diseases themselves. If they contract a low pathogen dose, they may develop low-level infections that do not cause disease but still affect host immunity by either decreasing or increasing the host’s vulnerability to subsequent infections. Caring for contagious individuals can thus significantly alter the future disease susceptibility of caregivers. Using ants and their fungal pathogens as a model system, we tested if the altered disease susceptibility of experienced caregivers, in turn, affects their expression of sanitary care behavior. We found that low-level infections contracted during sanitary care had protective or neutral effects on secondary exposure to the same (homologous) pathogen but consistently caused high mortality on superinfection with a different (heterologous) pathogen. In response to this risk, the ants selectively adjusted the expression of their sanitary care. Specifically, the ants performed less grooming and more antimicrobial disinfection when caring for nestmates contaminated with heterologous pathogens compared with homologous ones. By modulating the components of sanitary care in this way the ants acquired less infectious particles of the heterologous pathogens, resulting in reduced superinfection. The performance of risk-adjusted sanitary care reveals the remarkable capacity of ants to react to changes in their disease susceptibility, according to their own infection history and to flexibly adjust collective care to individual risk.
Keywords: social immunity; Host–pathogen interactions; behavioral plasticity
Journal Title: PNAS
Volume: 115
Issue 11
ISSN: 1091-6490
Publisher: National Academy of Sciences  
Date Published: 2018-03-13
Start Page: 2782
End Page: 2787
DOI: 10.1073/pnas.1713501115
Notes: We thank B. M. Steinwender and J. Eilenberg for the fungal strains and the entire Social Immunity Team at IST Austria for support and discussion throughout the project, particularly B. Milutinović, M. A. Fürst, B. Casillas-Pérez, and M. Iglesias. We also thank P. Schmid-Hempel, J. Kurtz, S. A. Frank, C. D. Nunn, M. Schaller, C. Russell, and F. Jephcott for discussion and R. M. Bush, L. V. Ugelvig, M. Sixt, and four anonymous reviewers for comments on the manuscript. This work was supported by European Research Council Starting Grant 240371 (to S.C.).
Open access: no
IST Austria Authors
  1. Sylvia Cremer
    52 Cremer
  2. Matthias Konrad
    6 Konrad
  3. Anna Grasse
    5 Grasse
  4. Christopher Pull
    9 Pull