Microdon mutabilis (Linnaeus, 1758)
The 'Microdon mutabilis' of earlier works (e.g. Stubbs & Falk 1983) was split by Schonrogge et al. 2002, into two species M. mutabilis and M. myrmicae and most of the records formerly ascribed to M. mutabilis are believed to relate to M. myrmicae.
Biology & ecology:
The larva is associated with ant nests, and at the moment the principal host appears to be Formica lemani which is widespread in northern and western Britain. There is some evidence that adult Microdon from particular ant nests may stand the greatest prospect of breeding successfully if they lay their eggs in association with the original host colony, thereby suggesting a degree of sub-speciation linked to the characteristics of individual ant colonies.
As yet the true M. mutabilis has been confirmed from only two areas in Scotland (Mull and near Inverness), and six sites in south-west Ireland (mainly the famous limestone district of The Burren).