Microdon devius (Linnaeus, 1761)
Biology & ecology:
In southern England, M. devius is closely associated with short turfed Chalk downland, but in East Anglia and Oxfordshire the records are from fens. The larva is a predator of ant broods within nests of the yellow ant Lasius flavus. Adults rarely stray far from their parental ant nests and may be found sitting on vegetation close to ant hills. They are not usually known as flower visitors, but have been reported from flowers of Ox-eye Daisy Leucanthemum vulgare.
This is mainly a species of southern England but there are outlying populations in West Norfolk and East Suffolk, and from Meirionnydd and old records from Oxfordshire and from the Wyre Forest. There are post-1990 records from Buckinghamshire, North Hampshire, West Sussex, and Meirionnydd but the majority of modern localities lie on the North Downs of Surrey.
Status & conservation:
This is a very localised species that has been It is extremely vulnerable to loss of grassland sites because its adaptation to colonising ant colonies means that it is unlikely to expand its distribution once sites have been lost although occurrence appears to be increasing.