Eristalinae

Drone Flies and Allies

Tribe Guides

8

Eristalinae is a of hoverflies (Syrphidae) comprising approximately nine tribes and notable for exceptional of bees and . are important , while larvae exhibit the greatest diversity among hoverflies, occupying aquatic environments, decaying organic matter, sap runs, and even wasp nests. The subfamily includes the well-known drone fly (Eristalis tenax), whose larvae—called rat-tailed maggots—possess an extendable breathing siphon.

Eristalis hirta by (c) dloarie, some rights reserved (CC BY), uploaded by dloarie. Used under a CC-BY license.Sericomyia chrysotoxoides by (c) christine123, some rights reserved (CC BY), uploaded by christine123. Used under a CC-BY license.Sericomyia nigra by (c) dschigel, some rights reserved (CC BY), uploaded by dschigel. Used under a CC-BY license.

Pronunciation

How to pronounce Eristalinae: /ɛrɪˈstælɪnaɪ/

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Identification

distinguished from actual bees and (Hymenoptera) by dipteran features: single pair of functional wings with hindwings reduced to , large that often meet dorsally in males, and short . Many have broad, flattened with yellow-and-black banding mimicking Apidae. Wing venation includes a characteristic 'false ' (spurious vein) typical of Syrphidae. Larvae identified by the spiracular lobes into an elongated, often extensible breathing tube—the 'rat-tail' structure most pronounced in Eristalis.

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Habitat

frequent flowers in diverse terrestrial . Larvae occupy the broadest range of microhabitats among hoverflies: shallow aquatic environments including ponds, ditches, drains, bog pools, and tree-hole water; decaying organic matter such as , compost, and rotting vegetation; sap runs and cavities under bark; and some inhabit or nests as or scavengers.

Distribution

distribution with documented across all major biogeographic regions. Notable records include widespread occurrence in North America, Europe, Afrotropical Region (South Africa, Zimbabwe), and Serbia. Individual species vary in range: Eristalis tenax is established across the entire North American continent; Meromacroides meromacriformis is to Africa; Syrittosyrphus opacea occurs in South Africa and Zimbabwe.

Diet

Larvae are predominantly saprophagous , consuming microorganisms and detritus from decomposing organic matter and stagnant water. Some feed on plant bulbs and may damage garden plants. A few species are scavengers in insect remains, and some are in or nests. feed on nectar and pollen.

Life Cycle

Complete with , larva, pupa, and stages. Larvae are aquatic or semi-aquatic, respiring through spiracular lobes into a single elongated tube that functions as a snorkel connecting to the surface. Larval duration varies by . Mature larvae seek dry land to pupate; the pupal capsule is hard and compact. Adult follows pupal development.

Behavior

males employ dual mate-seeking strategies: patrolling flowers and waiting near potential oviposition sites where females may appear. Adults are and frequent blossoms for nectar. Larvae remain submerged or buried in substrate, extending the breathing siphon to the surface to access atmospheric oxygen while feeding below.

Ecological Role

serve as of wildflowers, orchard trees, and landscape plants. Larval filter feeding helps purify water by removing microorganisms and detritus. Decomposer larvae contribute to nutrient cycling in aquatic and terrestrial . Some regulate and through or scavenger .

Human Relevance

are beneficial often mistaken for bees. Larvae may be perceived as pests when occurring in water features, compost, or garden settings; some damage plant bulbs. The drone fly (Eristalis tenax) is a well-known mimic of the and has been suggested as the biological basis for biblical accounts of bees emerging from rotting animal carcasses.

Similar Taxa

  • SyrphinaeOther hoverfly ; distinguished by larval —Syrphinae larvae are predominantly rather than saprophagous , and lack the elongated breathing tube characteristic of Eristalinae.
  • MicrodontinaeThird hoverfly ; larvae are myrmecophilous (associated with ants), a stark contrast to the free-living aquatic and saprophagous larvae of Eristalinae.
  • Apidae (honey bees)Frequent misidentification due to ; distinguished by four wings (vs. two in flies), elbowed , and constricted waist in Hymenoptera.

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Sources and further reading