@article{616,
  abstract     = {Social insects protect their colonies from infectious disease through collective defences that result in social immunity. In ants, workers first try to prevent infection of colony members. Here, we show that if this fails and a pathogen establishes an infection, ants employ an efficient multicomponent behaviour − "destructive disinfection" − to prevent further spread of disease through the colony. Ants specifically target infected pupae during the pathogen's non-contagious incubation period, relying on chemical 'sickness cues' emitted by pupae. They then remove the pupal cocoon, perforate its cuticle and administer antimicrobial poison, which enters the body and prevents pathogen replication from the inside out. Like the immune system of a body that specifically targets and eliminates infected cells, this social immunity measure sacrifices infected brood to stop the pathogen completing its lifecycle, thus protecting the rest of the colony. Hence, the same principles of disease defence apply at different levels of biological organisation.},
  author       = {Pull, Christopher and Ugelvig, Line V and Wiesenhofer, Florian and Grasse, Anna V and Tragust, Simon and Schmitt, Thomas and Brown, Mark and Cremer, Sylvia},
  journal      = {eLife},
  publisher    = {eLife Sciences Publications},
  title        = {{Destructive disinfection of infected brood prevents systemic disease spread in ant colonies}},
  doi          = {10.7554/eLife.32073},
  volume       = {7},
  year         = {2018},
}

@article{1830,
  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.},
  author       = {Theis, Fabian and Ugelvig, Line V and Marr, Carsten and Cremer, Sylvia},
  issn         = {1471-2970},
  journal      = {Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences},
  number       = {1669},
  publisher    = {Royal Society},
  title        = {{Opposing effects of allogrooming on disease transmission in ant societies}},
  doi          = {10.1098/rstb.2014.0108},
  volume       = {370},
  year         = {2015},
}

@article{2926,
  abstract     = {To fight infectious diseases, host immune defenses are employed at multiple levels. Sanitary behavior, such as pathogen avoidance and removal, acts as a first line of defense to prevent infection [1] before activation of the physiological immune system. Insect societies have evolved a wide range of collective hygiene measures and intensive health care toward pathogen-exposed group members [2]. One of the most common behaviors is allogrooming, in which nestmates remove infectious particles from the body surfaces of exposed individuals [3]. Here we show that, in invasive garden ants, grooming of fungus-exposed brood is effective beyond the sheer mechanical removal of fungal conidiospores; it also includes chemical disinfection through the application of poison produced by the ants themselves. Formic acid is the main active component of the poison. It inhibits fungal growth of conidiospores remaining on the brood surface after grooming and also those collected in the mouth of the grooming ant. This dual function is achieved by uptake of the poison droplet into the mouth through acidopore self-grooming and subsequent application onto the infectious brood via brood grooming. This extraordinary behavior extends the current understanding of grooming and the establishment of social immunity in insect societies.},
  author       = {Tragust, Simon and Mitteregger, Barbara and Barone, Vanessa and Konrad, Matthias and Ugelvig, Line V and Cremer, Sylvia},
  journal      = {Current Biology},
  number       = {1},
  pages        = {76 -- 82},
  publisher    = {Cell Press},
  title        = {{Ants disinfect fungus-exposed brood by oral uptake and spread of their poison}},
  doi          = {10.1016/j.cub.2012.11.034},
  volume       = {23},
  year         = {2013},
}

@article{2284,
  abstract     = {Background: The brood of ants and other social insects is highly susceptible to pathogens, particularly those that penetrate the soft larval and pupal cuticle. We here test whether the presence of a pupal cocoon, which occurs in some ant species but not in others, affects the sanitary brood care and fungal infection patterns after exposure to the entomopathogenic fungus Metarhizium brunneum. We use a) a comparative approach analysing four species with either naked or cocooned pupae and b) a within-species analysis of a single ant species, in which both pupal types co-exist in the same colony. Results: We found that the presence of a cocoon did not compromise fungal pathogen detection by the ants and that species with cocooned pupae increased brood grooming after pathogen exposure. All tested ant species further removed brood from their nests, which was predominantly expressed towards larvae and naked pupae treated with the live fungal pathogen. In contrast, cocooned pupae exposed to live fungus were not removed at higher rates than cocooned pupae exposed to dead fungus or a sham control. Consistent with this, exposure to the live fungus caused high numbers of infections and fungal outgrowth in larvae and naked pupae, but not in cocooned pupae. Moreover, the ants consistently removed the brood prior to fungal outgrowth, ensuring a clean brood chamber. Conclusion: Our study suggests that the pupal cocoon has a protective effect against fungal infection, causing an adaptive change in sanitary behaviours by the ants. It further demonstrates that brood removal-originally described for honeybees as "hygienic behaviour"-is a widespread sanitary behaviour in ants, which likely has important implications on disease dynamics in social insect colonies.},
  author       = {Tragust, Simon and Ugelvig, Line V and Chapuisat, Michel and Heinze, Jürgen and Cremer, Sylvia},
  journal      = {BMC Evolutionary Biology},
  number       = {1},
  publisher    = {BioMed Central},
  title        = {{Pupal cocoons affect sanitary brood care and limit fungal infections in ant colonies}},
  doi          = {10.1186/1471-2148-13-225},
  volume       = {13},
  year         = {2013},
}