A caterpillar of the small moor blue is carried into the nest by a knot ant. Photo: David Nash
The larvae of the small moor-blue flower imitate the skin of larvae of the knot ant so skillfully that the growing butterflies are taken into the ant-state. There they are fed by the workers and even receive a preferential treatment. This endangers the young apes and leads to a reduction of the colony. The Moorbläuling lays its eggs on the peat plant lungenzian, from which they fall after several molts. Some larvae are picked up by workers of the ant genus Myrmica and taken to the anthill, where the larvae develop until they pupate. The ants feed the parasites during this time and neglect their own offspring. The butterfly larvae deceive the ants by the chemical surface structure of their outer skin, which is modeled on the skin of the host larvae. The closer she gets to the original, the sooner the host ants are deceived and the butterfly larvae picked up by them.

One of the two host species, the node ant Myrmica rubra, encounters this danger with its own evolutionary adaptation, the researchers found: In infected colonies, the ant larvae change the surface of their outer skin until it can be distinguished again from the parasite. The resulting co-evolution of host and parasite leads to alienation between colonies of this ant species, the scientists explain. This development even goes so far that they can no longer breed with each other.

The second species of ants, Myrmica ruginodis, which is affected by the parasite infestation, on the other hand, does not change its surface structure at all and thus allows small moor-blue to survive in phases of poor adaptation to Myrmica rubra.

David Nash (Institute of Genetics and Ecology, Copenhagen): Science, Volume 319, p. 88 ddp / science.de? Livia Rasche advertisement

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