Opposing effects of allogrooming on disease transmission in ant societies Journal Article

Author(s): Theis, Fabian J; Ugelvig, Line V; Marr, Carsten; Cremer, Sylvia
Article Title: Opposing effects of allogrooming on disease transmission in ant societies
Affiliation IST Austria
Abstract: To prevent epidemics, insect societies have evolved collective disease defences that are highly effective at curing exposed individuals and limiting disease transmission to healthy group members. Grooming is an important sanitary behaviour—either performed towards oneself (self-grooming) or towards others (allogrooming)—to remove infectious agents from the body surface of exposed individuals, but at the risk of disease contraction by the groomer. We use garden ants (Lasius neglectus) and the fungal pathogen Metarhizium as a model system to study how pathogen presence affects self-grooming and allogrooming between exposed and healthy individuals. We develop an epidemiological SIS model to explore how experimentally observed grooming patterns affect disease spread within the colony, thereby providing a direct link between the expression and direction of sanitary behaviours, and their effects on colony-level epidemiology. We find that fungus-exposed ants increase self-grooming, while simultaneously decreasing allogrooming. This behavioural modulation seems universally adaptive and is predicted to contain disease spread in a great variety of host–pathogen systems. In contrast, allogrooming directed towards pathogen-exposed individuals might both increase and decrease disease risk. Our model reveals that the effect of allogrooming depends on the balance between pathogen infectiousness and efficiency of social host defences, which are likely to vary across host–pathogen systems.
Keywords: social immunity; SIS model; Epidemiology; Host–pathogen interactions; Sanitary behaviours; Social interaction patterns
Journal Title: Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences
Volume: 370
Issue 1669
ISSN: 0962-8436
Publisher: Royal Society, The  
Date Published: 2015-05-01
DOI: 10.1098/rstb.2014.0108
Notes: We thank Meghan L. Vyleta for the genetical fungal strain characterization and Eva Sixt for ant drawings, Matthias Konrad for discussion and Christopher D. Pull, Barbara Casillas-Peréz, Sebastian Novak, as well as three anonymous reviewers and the theme issue editors Peter Kappeler and Charlie Nunn for valuable comments on the manuscript.
Open access: yes (repository)
IST Austria Authors
  1. Sylvia Cremer
    52 Cremer
  2. Line Ugelvig
    15 Ugelvig