Chrysosyrphus

Sedman, 1965

wrinklehead flies, High-horned Wrinkleheads, LBFs (Little Black Flies)

Species Guides

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Chrysosyrphus is a of small, dark-colored hoverflies in the Syrphidae, commonly known as wrinklehead flies or High-horned Wrinkleheads. Native to the Holarctic region, these flies are characterized by distinctive facial modifications including a or projecting lower margin. feed on nectar and pollen, while larval remains unknown.

Pronunciation

How to pronounce Chrysosyrphus: /ˌkrɪsoʊˈsɪrfəs/

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Identification

Distinguished from similar hoverfly by the combination of: bare medial with distinct or projecting lower margin; absence of orbital strip; positioned above upper third of ; scutellum without bristles but with subscutellar fringe of pile; and M1 forming acute angle with R4+5. The facial tubercle or modified lower margin is particularly diagnostic. Males further identified by bare .

Appearance

Small, predominantly black hoverflies. The is entirely black or partly yellow, bare medially, with either a distinct clearly separated from the oral margin or a straight face with a projecting lower margin. The face is haired with only a stripe that is bare; hairs extend from just below the to the subcranial margin. No orbital strip present. Antennae located above the upper third of the . Scutellum lacks bristles but has a subscutellar fringe of pile. Wing with cross- (M1) forming an acute angle with the third vein (R4+5). Males have bare .

Habitat

Arctic and subarctic environments of the Holarctic region. Specific microhabitat preferences are not documented.

Distribution

Holarctic region. Documented from Norway (NO) and Sweden (SE) based on distribution records. Native range includes arctic and subarctic zones of the Nearctic and Palearctic.

Diet

feed on nectar and pollen, using these as sources of energy and protein respectively. Larval diet unknown.

Life Cycle

Larval stages unknown. stage documented feeding on floral resources.

Behavior

visit flowers to feed on nectar and pollen. Other , including mating, territoriality, and larval habits, are not documented.

Ecological Role

function as through nectar and pollen feeding. Other roles, including any larval contributions, are unknown.

Human Relevance

No documented direct interactions with humans. Of interest to entomologists studying arctic hoverfly diversity.

Similar Taxa

  • Other Brachyopini generaShare Eristalinae and tribe Brachyopini, but differ in facial structure—Chrysosyrphus has the diagnostic or projecting lower margin on the , bare medial face with bare stripe, and specific wing venation (acute M1-R4+5 angle)
  • Other small black hoverflies (LBFs)Similar size and coloration, but Chrysosyrphus is distinguished by the unique facial modifications and specific antennal placement above the upper third of the

More Details

Larval biology

The larval of Chrysosyrphus remains completely unknown. This represents a significant gap in understanding for this , as hoverfly larvae typically occupy diverse ecological roles including saprophagy, , and .

Taxonomic history

established by Sedman in 1965. Contains eight recognized , including C. nasuta, C. niger, C. latus, C. frontosus, C. nigripennis, C. alaskensis, C. montanus, and C. tundrarum.

Diagnostic resources

Identification relies on Speight's key to and associated glossary for morphological terminology.

Sources and further reading