Merodon equestris

[stuart]

Merodon equestris (Fabricius, 1794)

Identification ease/difficulty: 1

Sources of information

• Page 202, Pl. 12, fig 11 in Stubbs & Falk (1983)
• Larval plate Pl. 1b in Rotheray (1993)
• Map here and page 93 in Ball & Morris (2000)
• Page 304, Pl. 12, fig. 11 in Stubbs & Falk (2002)

Pictures:

[stuart]

Species account from Provisional atlas of British hoverflies, Ball & Morris, 2000.

Merodon equestris (Fabricius, 1794)

Biology: The larvae of this species (the “greater bulb fly”), tunnel 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 foodplants. Frequently settles on stones or patches of bare ground in the sunshine. A number of colour forms are recognised

Distribution: This species is widespread and common in gardens, and whilst the distribution shows a tendency to follow urban areas, this fly is by no means restricted to synanthropic habitats; wild bluebell bulbs, for example, provide an equally acceptable larval food. It is believed to have been accidentally introduced in imported bulbs some time towards the end of the last century; Bloomfield (1895) states that it “used to be considered a very rare British insect, but is now becoming common”. R.McLachlan, in a footnote to this paper, notes that a horticulturist friend introduced it to his garden by an “unlucky purchase” of a bag of imported bulbs from the south of Europe. It belongs to a large and diverse genus with many other European species, especially in the eastern Mediterranean, and it is quite possible that other species could arrive by a similar route (see Speight (1988a) for a discussion of the possibilities)