Myrmica hirsuta is a very rare social parasite of Myrmica sabuleti Meinert and M. lonae Finzi. Queens and males are very similar to M. sabuleti but smaller, more robust and hairier. Myrmica hirsuta queens can be separated from microgynes of their host by an enlarged post-petiole, wider frons and longer body hairs. Small numbers of M. hirsuta workers are sometimes present in nests. Parasitised nests produce alates of both parasite and host.