Callopistromyia

Hendel, 1907

Peacock flies

Species Guides

2

Callopistromyia is a of small picture-winged flies ( Ulidiidae) known for the distinctive of males, which hold their patterned wings perpendicular to the body while sidling along substrates. The genus contains two : C. annulipes (the peacock fly) and C. strigula. are typically 3.5–5.5 mm in length. C. annulipes has expanded from its native North American range to become an established species in Europe since 2007.

Callopistromyia strigula by (c) Katja Schulz, some rights reserved (CC BY). Used under a CC-BY license.Callopistromyia annulipes by (c) Toby, some rights reserved (CC BY), uploaded by Toby. Used under a CC-BY license.Callopistromyia annulipes 216149629 by Alexis. Used under a CC BY 4.0 license.

Pronunciation

How to pronounce Callopistromyia: //ˌkæloʊpɪˈstrɒmiə//

These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.

Identification

Distinguished from other Ulidiidae by small size (3.5–5.5 mm) and the characteristic male courtship of holding wings perpendicular to the body while sidling along fence rails or logs. C. annulipes and C. strigula can be separated by distribution: C. annulipes occurs throughout the northern U.S. south to northern Georgia, Louisiana, Oklahoma, northern Utah, and Washington state, while C. strigula is restricted to Canada and the northeastern U.S.

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Appearance

Small flies, 3.5–5.5 mm in length, with boldly patterned wings characteristic of the Ulidiidae. Wing patterns consist of dark spots, bars, or lines on a clear background. Body relatively compact for the family.

Habitat

found on fence rails, logs, and tree trunks that serve as display sites for courtship. Larvae develop under bark.

Distribution

Native to North America. C. annulipes: northern U.S. south to northern Georgia, Louisiana, Oklahoma, northern Utah, and Washington state; introduced and established in Europe since 2007 (more than ten countries including Croatia, Czech Republic, and Romania). C. strigula: Canada and northeastern U.S.

Seasonality

Active in spring and fall; may seek winter shelter in buildings in autumn (based on pattern, specifically noted for C. annulipes).

Life Cycle

Larvae develop under bark; specific diet of larvae unknown.

Behavior

Males perform elaborate on fence rails or logs, erecting their patterned wings perpendicular to the body and sidling back and forth. This has earned C. annulipes the 'peacock fly'.

Human Relevance

C. annulipes has become an established in Europe with expanding distribution; its spread has been documented through citizen science platforms including iNaturalist and Facebook. may enter buildings in autumn seeking winter shelter.

Similar Taxa

  • CeroxysSimilar size and wing patterning, but Ceroxys males do not hold wings perpendicular to body during courtship; wing bars less complete than in Callopistromyia.
  • PseudotephretinaSimilar size and appearance to Ceroxys, with more 'tiger-striped' and complete wing bars than Ceroxys, but lacks the perpendicular wing display of Callopistromyia males.

More Details

Citizen science documentation

The spread of C. annulipes in Europe has been tracked partly through social media posts, demonstrating the utility of citizen science for detecting expansions.

Larval biology gap

Despite detailed knowledge of , the larval diet remains unknown, representing a significant gap in the understanding of this .

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Sources and further reading