Butterfly larvae fool ants into mothering them

A female Maculinea alcon butterfly laying eggs on a flower head of the Marsh gentian, Gentiana pneumonanthe. (Image courtesy of David Nash)

Danish researchers have found that in some areas in their country, beautiful blue Alcon butterflies fool ants into raising the butterfly larvae instead of their own, a report explains. The reason? The butterflies have developed an outer coating that mimics that of the ants.

A caterpillar of Maculinea alcon, having recently emerged from a flower of Gentiana pneumonanthe is carried back to a nest of the ant Myrmica rubra by a foraging worker ant. (Image courtesy of David Nash)

These butterflies, Maculinea alcon, are parasites because they endanger the health of two species of Myrmica ants since the ants ignore their own young to care for the butterfly larvae.

David R. Nash and European coauthors studied several sites in Denmark where the Alcon caterpillars develop on a plant in the marshland before one of these two ant species -- Myrmica rubra and Myrmica ruginodis -- bring them into their nests.

The biologists learned that the more closely the butterfly mimics the ant’s exterior hydrocarbon chemistry, the more successful the butterfly is in attracting the ants, but this varies from place to place.

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