The threat from infectious diseases is a major concern not only for humans but also for other highly social animals. Organisms that live in close quarters are particularly susceptible to infection because of the intrinsically favorable disease transmission dynamics; hence, systems that prevent or ameliorate the spread of disease are likely to be beneficial. Indeed, social insects have evolved a number of behaviors--for example, nursing sick individuals or excluding them from the nest--that help to limit the spread of infection. Uglevig and Cremer demonstrate that in small colonies of the garden ant Lasius neglectus, introducing workers infected with living fungal spores (but not dead spores) promptly produced two changes in behavior. First, the infected ants almost immediately reduced their interaction with ant larvae in the brood chamber, apparently helping to protect the most valuable or susceptible individuals in a colony. The absence of aggression by uninfected worker ants toward afflicted individuals suggests that such standoffishness may be due to self-restraint. Second, the uninfected workers increased their brood-care activities, primarily via grooming to remove spores from the infected individuals. Rather than increasing their own incidence of infection, the naïve ants acquired a higher level of resistance to the fungus--providing a form of "social prophylaxis." -- GR
Curr. Biol. 17, 1967 (2007).
