Species details

Merodon equestris (Fabricius, 1794)


The larva of this species (the 'Greater bulb fly'), tunnels in the bulbs of many plants, especially cultivated daffodils Narcissus, and are regarded as a pest by some gardeners. Adults visit flowers close to breeding sites and can often be seen resting and mating on the leaves of larval food plants. They frequently settle on stones, dead vegetation or patches of bare ground in the sunshine. The general shape and colour patterns of the adult mimic those of bumblebees and a number of colour forms occur, mimicking a variety of bumblebee species.


Most records lie south of a line between the Ribble and the Humber but Merodon equestris has been recorded as far north as the Moray Firth and Sutherland. Whilst its distribution shows a tendency to follow urban areas, this species is by no means restricted to synanthropic habitats; wild Bluebell Hyacinthoides non-scripta bulbs, for example, provide an equally acceptable larval food.


Believed to have been accidentally introduced to Britain in imported Daffodil bulbs in the late 19th Century.