Merodon equestris (Fabricius, 1794)

Biology & ecology:

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 or patches of bare ground in the sunshine. A number of colour forms are recognised.

Distribution:

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.

Status & conservation:

This species is widespread and common in gardens. It was first noted in G.H. Verrall's brother's garden in Denmark Hill in South London in the 1870s and was likely to have been imported in bulbs from Holland. It evidently spread rapidly, as Bloomfield (1895) states that it 'used to be considered a very rare British insect, but is now becoming common'. Data suggests its occurrence is stable, possibly increasing. It has been