When a colony member dies, surviving ants go out of their way to remove the lifeless body from the colony. It isn't yet known what sorts of bacteria, viruses, or fungi grow on the bodies of dead ants, but biologists have long thought that corpse removal was a behaviour that evolved to keep the colony healthy, because the deceased individual could have been, or could become, infected. But it had never been proven, until now.
Earlier this year, Belgian researcher Lise Diez and colleagues finally found concrete evidence to bolster the hypothesis. The researchers maintained several colonies of common red ants, Myrmica rubra in their laboratory for 50 days. Half of the colonies were free to dispose of their corpses as they naturally would, but the others were blocked from doing so. Starting from the eighth day, adult workers from colonies that were permitted to remove corpses naturally were significantly more likely to survive than adults from the restricted ones. Impressively, the ants in the restricted colonies found alternative mechanisms for reducing their exposure to corpses. The dead ants were moved to the corners and the colony to reduce the number of individuals who could pass near them, and especially to keep them away from the developing larvae. Some restricted colonies also managed to "bury" their dead under some cotton wool they had removed from artificial water dispensers.
Behaviours that reduce an animal's exposure to infectious parasites, from hiring cleaner fish to hiding dead corpses, probably evolved to combat the deadly pressure of disease, just as animals evolved camouflage to escape being gobbled up by toothy predators.
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Earlier this year, Belgian researcher Lise Diez and colleagues finally found concrete evidence to bolster the hypothesis. The researchers maintained several colonies of common red ants, Myrmica rubra in their laboratory for 50 days. Half of the colonies were free to dispose of their corpses as they naturally would, but the others were blocked from doing so. Starting from the eighth day, adult workers from colonies that were permitted to remove corpses naturally were significantly more likely to survive than adults from the restricted ones. Impressively, the ants in the restricted colonies found alternative mechanisms for reducing their exposure to corpses. The dead ants were moved to the corners and the colony to reduce the number of individuals who could pass near them, and especially to keep them away from the developing larvae. Some restricted colonies also managed to "bury" their dead under some cotton wool they had removed from artificial water dispensers.
Behaviours that reduce an animal's exposure to infectious parasites, from hiring cleaner fish to hiding dead corpses, probably evolved to combat the deadly pressure of disease, just as animals evolved camouflage to escape being gobbled up by toothy predators.
- More Here
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