Merodon equestris (Narcissus bulb fly, greater bulb fly, large bulb fly, large Narcissus fly) is a European species of hoverfly (Family Syrphidae). Like other hoverflies it displays a colouration pattern similar to a stinging insect (a bumblebee in this case) as an evolutionary defense mechanism.
M. equestris is a species native to Europe and namely the British Isles. It has been documented in North America, where it may have been introduced.
The larvae of these flies are known pests found on the bulbs of these flowers, leading to the names bulb fly and Narcissus fly. This is unlike most other members of the family, which predate on aphids.
M. equestris is on average 12 millimetres (0.47 in) in length and is orange, black and yellow in colour.
The legs of this species are always black. Patterns of venation on the wings can be used to identify the species.
Mimicry of bees
This hoverfly has taken on characteristics of the bumblebee, including colouration and a hairy carapace. This can be misleading to birds and other animals who may try to eat it or interfere with its feeding.
Males and females display a body dimorphism common among hoverflies. The eyes of the male are larger and almost touch along the top of the head, whereas females have smaller eyes which are placed farther apart. Females also have a pointed abdomen with inconspicuous genitalia while males have curved asymmetrical genitals.
- "Hoverflies". Retrieved 2009-12-12.
- Stubbs, Alan E. and Falk, Steven J. (1983). British Hoverflies: An Illustrated Identification Guide. British Entomological & Natural History Society. pp. 253, xvpp.
- "Narcissus Bulb Fly". Retrieved March 3, 2010.
- "Hoverflies (Syphidae), tribe Merodontini". Retrieved March 3, 2010.[dead link]
- "All about Hover Flies". Retrieved March 3, 2010.