Ants behavior exemplary in infections

Exemplary behavior of ants in infections

04/13/2015

Ants are pursuing a relatively simple strategy to prevent the spread of infectious diseases within their populations. They pay more attention to their own hygienic care and try to avoid the transmission of pathogens to other ants, according to a joint study by researchers from the Institute of Science and Technology Austria and the Helmholtz Zentrum München.

The scientists around Professor Sylvia Cremer of the Institute of Science and Technology Austria and Professor Fabian Theis of the Helmholtz Zentrum München examined in their study on the basis of an epidemiological model, how the cleaning behavior influences the spread of diseases in an ant population. The researchers have published their results in a special issue of the „Philosophical Transactions of the Royal Society B“ released.

Strategies against the spread of infections
„Caring for yourself and trying not to infect others“, According to information from the Institute of Science and Technology Austria „a good strategy to prevent the spread of disease - not only as a considerate colleague, but also as an ant, meerkat, or other social animal.“ Proof of this is provided by the research of the research team headed by Professor Theis and Professor Cremer. Without countermeasures, infectious diseases can spread rapidly in societies, both for humans and for animals living in larger populations. Mutual hygienic care or the care of sick individuals is therefore not limited to human societies, according to the scientists, „but also occurs in other groups of social animals, such as primates and social insects.“

Changed brushing behavior of the ants
For their study, the researchers use „Ant societies as a model system to monitor the hygienic response of ants to pathogen hazards in the laboratory and to determine their impact on disease progression with epidemiological models“, This is the message of the Institute of Science and Technology Austria. Using garden ants (Lasius neglectus), they analyzed how the cleaning behavior of animals changes when they come into contact with pathogenic fungal spores (metarhizium). It was already known from previous studies that the infected ants are apparently cleaned much more frequently than the other animals, which was attributed to increased care by the healthy nest members. The scientists come in their current investigation, however, to the conclusion that „Ants, when exposed to the fungus, brush themselves more often, but drastically reduce the brushing of other, healthy nest members.“ This shift in brushing behavior leads to the social asymmetry of cleaning, in which infectious ants are cleaned much more often than they clean others.

Spread of the pathogens successfully contained
According to the researchers, the epidemiological models have also shown, „that the observed behavioral changes help stem the spread of the pathogen in the ant colony.“ To increase one's own care and limit contact with others, as long as one could pose a risk to their health, is a strategy helpful to all social animals. The healthy animals, however, continued to maintain their care for sick ants in the experiments, which in the opinion of the scientists also contributed to a social immunization within the colony. A complete avoidance of contact with the diseased animals would therefore have been rather counterproductive here. (Fp)