This video about red ants is called Myrmica rubra.
From British daily The Independent:
The butterfly, the ant, and other natural mimics
By Steve Connor, Science Editor
Published: 04 January 2008
It sounds like one of Aesop’s fables but the story of the blue butterfly and the red ant is probably not one you would like to send your children off to sleep with. The caterpillar of the blue butterfly is “adopted” by the red ant which takes the butterfly larva back to its nest where it treats it like one of its own brood – feeding it until it is old enough to turn into an adult butterfly.
The caterpillar, however, repays the ant’s generous hospitality by greedily eating as much food as it can and gobbling up the ant’s offspring as a tasty side dish. …
All five species of large blue butterflies in Europe engage in this form of parasitism on red ants and now scientists have worked out the trick that allows them to do it – the caterpillars cover themselves in a chemical that makes them smell like orphaned baby ants. …
David Nash of the University of Copenhagen, who led the study published in the journal Science, said the results were a vivid demonstration of the evolutionary “arms race” that can escalate between parasites and their hosts.
See also here.