Phylum Arthropoda (Arthropods) ➔ Subphylum Hexapoda (Hexapods) ➔ Class Insecta (Insects) ➔ Order Diptera (True flies) ➔ Family Syrphidae (Hoverflies)

Merodon equestris (Fabricius, 1794)

Gemeine Narzissenschwebfliege Large Narcissus Fly

Synonyms and other combinations:

Eristalis ferrugineus Fabricius, 1805 | Eristalis narcissi Fabricius, 1805 | Merodon bulborum Rondani, 1845 | Merodon constans Wiedemann, 1822 | Merodon nigrithorax Bezzi, 1900 | Merodon nobilis Meigen, 1822 | Merodon transversalis Wiedemann, 1822 | Merodon tuberculatus Rondani, 1845 | Merodon validus Wiedemann, 1822 | Musca bombyliformis Geoffroy, 1785 | Syrphus flavicans Fabricius, 1794 |

  • Merodon equestris, male  493
    Merodon equestris (Fabricius, 1794)  Gemeine Narzissenschwebfliege  Large Narcissus Fly 
    Merodon equestris, male
    DE, Chemnitz, Zeisigwald; 2006-06-10 09:51:10
    Image number: 493
    male
    DE, Chemnitz, Zeisigwald
    2006-06-10 09:51:10

  • Merodon equestris, male  495
    Merodon equestris (Fabricius, 1794)  Gemeine Narzissenschwebfliege  Large Narcissus Fly 
    Merodon equestris, male
    DE, Chemnitz, Harthwald; 2008-06-01 10:45:26
    Image number: 495
    male
    DE, Chemnitz, Harthwald
    2008-06-01 10:45:26

  • Merodon equestris  494
    Merodon equestris (Fabricius, 1794)  Gemeine Narzissenschwebfliege  Large Narcissus Fly 
    Merodon equestris
    DE, Chemnitz, Hutholz; 2005-05-29 11:12:40
    Image number: 494

    DE, Chemnitz, Hutholz
    2005-05-29 11:12:40

  • Merodon equestris var. validus, female  489
    Merodon equestris (Fabricius, 1794)  Gemeine Narzissenschwebfliege  Large Narcissus Fly 
    Merodon equestris var. validus, female
    DE, Chemnitz, Hutholz; 2005-05-29 13:02:58
    Image number: 489
    female
    DE, Chemnitz, Hutholz
    2005-05-29 13:02:58

  • Merodon equestris, male  701
    Merodon equestris (Fabricius, 1794)  Gemeine Narzissenschwebfliege  Large Narcissus Fly 
    Merodon equestris, male
    DE, Chemnitz, Hutholz; 2009-05-03 11:48:17
    Image number: 701
    male
    DE, Chemnitz, Hutholz
    2009-05-03 11:48:17

  • Merodon equestris, male  4803
    Merodon equestris (Fabricius, 1794)  Gemeine Narzissenschwebfliege  Large Narcissus Fly 
    Merodon equestris, male
    DE, Chemnitz, Zeisigwald; 2011-05-21 09:34:37
    Image number: 4803
    male
    DE, Chemnitz, Zeisigwald
    2011-05-21 09:34:37

  • Merodon equestris, female  4182
    Merodon equestris (Fabricius, 1794)  Gemeine Narzissenschwebfliege  Large Narcissus Fly 
    Merodon equestris, female
    DE, Chemnitz, Zeisigwald; 2010-06-20 11:50:09
    Image number: 4182
    female
    DE, Chemnitz, Zeisigwald
    2010-06-20 11:50:09

  • Merodon equestris, female  4183
    Merodon equestris (Fabricius, 1794)  Gemeine Narzissenschwebfliege  Large Narcissus Fly 
    Merodon equestris, female
    DE, Chemnitz, Zeisigwald; 2010-06-20 11:50:17
    Image number: 4183
    female
    DE, Chemnitz, Zeisigwald
    2010-06-20 11:50:17

  • Merodon equestris, male  9485
    Merodon equestris (Fabricius, 1794)  Gemeine Narzissenschwebfliege  Large Narcissus Fly 
    Merodon equestris, male
    DE, Chemnitz, Morgenleite; 2020-06-01 11:17:16
    Image number: 9485
    male
    DE, Chemnitz, Morgenleite
    2020-06-01 11:17:16

  • Merodon equestris, male  9486
    Merodon equestris (Fabricius, 1794)  Gemeine Narzissenschwebfliege  Large Narcissus Fly 
    Merodon equestris, male
    DE, Chemnitz, Morgenleite; 2020-06-01 11:17:29
    Image number: 9486
    male
    DE, Chemnitz, Morgenleite
    2020-06-01 11:17:29

  • Merodon equestris, male  9487
    Merodon equestris (Fabricius, 1794)  Gemeine Narzissenschwebfliege  Large Narcissus Fly 
    Merodon equestris, male
    DE, Chemnitz, Morgenleite; 2020-06-01 11:17:41
    Image number: 9487
    male
    DE, Chemnitz, Morgenleite
    2020-06-01 11:17:41

  • Merodon equestris, male  9488
    Merodon equestris (Fabricius, 1794)  Gemeine Narzissenschwebfliege  Large Narcissus Fly 
    Merodon equestris, male
    DE, Chemnitz, Morgenleite; 2020-06-01 11:18:14
    Image number: 9488
    male
    DE, Chemnitz, Morgenleite
    2020-06-01 11:18:14

  • Merodon equestris, male  9408
    Merodon equestris (Fabricius, 1794)  Gemeine Narzissenschwebfliege  Large Narcissus Fly 
    Merodon equestris, male
    DE, Chemnitz, Stadtpark; 2020-06-16 17:29:33
    Image number: 9408
    male
    DE, Chemnitz, Stadtpark
    2020-06-16 17:29:33

  • Merodon equestris, male  9409
    Merodon equestris (Fabricius, 1794)  Gemeine Narzissenschwebfliege  Large Narcissus Fly 
    Merodon equestris, male
    DE, Chemnitz, Stadtpark; 2020-06-16 17:29:47
    Image number: 9409
    male
    DE, Chemnitz, Stadtpark
    2020-06-16 17:29:47


Further vernacular names:
Narcissus Bulb Fly
Classification:
Merodon equestris belongs to the subfamily Eristalinae, tribe Merodontini (=Eumerini).
Distribution:
Fennoscandia south to Iberia and the Mediterranean, including North Africa; from Ireland eastwards through much of Europe into European parts of Russia; also in Japan; in North America from British Colombia south to California.
As a result of the international trade in flower bulbs, the species has spread across much of the world, including New Zealand.
Habitat:
Deciduous forest/open ground; open areas in moist deciduous forests, also in gardens and horticultural land, at higher altitudes up to the subalpine zone.
Description:
Body length 12 - 15 mm; appearance bumblebee-like; body strong, stocky, dense and long-haired; legs completely black, hind tibia of the males with 2 humps and 1 spur.
The coloration of the hair of Merodon equestris is extremely variable. There are various genetically determined color forms. The forms bulborum, equestris, flavicans and transversalis occur in both sexes, nobilis and validus only in the females.
Biology:
The Large Narcissus Fly Merodon equestris flies in one generation from May to July (in southern Europe already in April and at higher altitudes in August). The adults fly low and fast zigzagging. They visit various flowers from different plant families, such as umbellifers, Ajuga, Cirsium, Crepis, Hieracium, Knautia arvensis, Papaver, Ranunculus, Rubus idaeus and Senecio. Males exhibit territorial behaviour. They routinely patrol and defend their territories by repelling other insects away. The females start on average from the fourth day of life with the oviposition. The eggs, usually one egg per plant, are placed at the base of the leaves of a suited host plant or in the adjacent soil. Known hostplants of the larvae are daffodil, hyacinth, amaryllis, ismene and snowdrop. After about 10 to 12 days, the larvae hatch. The larvae feed and develop for about 4 months in the bulbs. The adult 3rd instar larvae overwinter in the bulbs. At the end of winter, the larvae leave the bulbs to pupate in the soil litter. The pupal stage lasts about 3 - 4 weeks. The adults hatch in May or June.
Merodon equestris can cause considerable damage in commercial flower bulb cultivation and is therefore controlled.
Predators:
Rhembobius abdominalis (Provancher, 1874) from the parasitic wasp family (Ichneumonidae).

References, further reading, links:
  1. Pape T. & Thompson F.C. (eds) (2017). Systema Dipterorum (version 2.0, Jan 2011). In: Species 2000 & ITIS Catalogue of Life, 2017 Annual Checklist (Roskov Y., Abucay L., Orrell T., Nicolson D., Bailly N., Kirk P.M., Bourgoin T., DeWalt R.E., Decock W., De Wever A., Nieukerken E. van, Zarucchi J., Penev L., eds.). Digital resource at www.catalogueoflife.org/annual-checklist/2017. Species 2000: Naturalis, Leiden, the Netherlands. ISSN 2405-884X.
  2. Gerald Bothe: Bestimmungsschl├╝ssel f├╝r die Schwebfliegen (Diptera, Syrphidae) Deutschlands und der Niederlande, DJN, 1984, ISBN 3-923376-07-3
  3. M.C.D.Speight: Species Accounts of European Syrphidae (Diptera), Glasgow 2011, Syrph the Net, the database of European Syrphidae, vol. 65, 285 pp., Syrph the Net publications, Dublin.
  4. Menno Reemer, Willem Renema, Wouter van Steenis, Theo Zeegers, Aat Barendregt, John T. Smit, Mark P. van Veen, Jeroen van Steenis, Laurens van der Leij: De Nederlandse Zweefvliegen (Diptera: Syrphidae), Nederlandse Fauna 8, 2009.