A new study published in Nature Ecology & Evolution reveals the extraordinary impact of host-parasite interactions. Scientists from the Institute of Science and Technology Austria (ISTA) and chemical ecologists from the University of Würzburg, Germany took a close look at social ants and their response to pathogenic fungi. The results show that fungi reduce their chemical detection signals to outsmart social immunity, the collective hygiene and health care measures used by ants to avoid spreading infection throughout the community.
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The experiment involved Argentine ants infected with pathogenic Metarhizium fungi in the presence and absence of caregiving colony members. Over ten infection cycles, the fungi that experienced grooming by nestmate ants boosted their spore production and became more difficult to detect. The researchers found that the fungi reduced a fungal-specific compound called ergosterol, causing the ants to perceive them less strongly. This reduction in fungal signals allowed the pathogen to escape the social immunity of the colony.
The findings highlight the impact of social hosts on their pathogens and raises the question of how the ant colony will respond in turn. The study sheds light on the evasive strategies of pathogens and the significance of social immunity in fighting infections.