Eristalini

Rat-tail Maggot Flies

Tribe Guides

Eristalina
Helophilina(rat-tail maggot flies)
Sericomyiina

Eristalini is a tribe of hoverflies (Syrphidae) characterized by larvae known as "rat-tailed maggots," which possess a telescopic breathing siphon. Several are notable hymenopteran mimics: Eristalis species resemble honeybees, while Helophilus and Parhelophilus display -like yellow and black striping. function as , while larvae inhabit aquatic or semi-aquatic environments rich in decaying organic matter.

Eristalis rupium by (c) Michael Knapp, some rights reserved (CC BY), uploaded by Michael Knapp. Used under a CC-BY license.

Pronunciation

How to pronounce Eristalini: /ˌɛrɪˈstælɪnaɪ/

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Identification

identified by combination of mimicry type (honeybee vs. -like) and wing venation with dip in R4+5. Larvae identified by presence of long, telescopic siphon for breathing while submerged. Distinguished from Sericomyiini by the wing dip in R4+5 (Sericomyiini share rat-tailed larvae but lack this venation feature).

Images

Habitat

Larvae inhabit decaying organic materials in aquatic or semi-aquatic environments: manure run-offs and heaps (Eristalis), ponds and ditches (Anasimyia, Helophilus), wet rotting tree stumps and rot holes (Myathropa, Mallota), bog mat pools (Sericomyia), and rain gutters. frequent flowering vegetation in urban, suburban, and rural areas.

Distribution

Widespread across North America, Europe, and other regions; individual vary in range. Eristalis tenax is established throughout North America following introduction from Europe.

Diet

Larvae filter bacteria and microbes from decaying organic matter in water or saturated substrates. nectar on flowers including lavender, catmint, daisies, sunflowers, yarrow, and orchard blossoms.

Life Cycle

laid in decaying organic substrates. Larvae (rat-tailed maggots) develop through multiple instars; first instar has highest mortality. Mature larvae seek dry land to pupate; pupal capsule is hard and mouse-shaped. follows. Total duration approximately 46–65 days in studied (Eristalis tenax: ~46 days; Eristalinus aeneus: ~65 days under laboratory conditions).

Behavior

Larvae remain submerged, extending breathing siphon to water surface. are flower visitors. Mimicry of stinging hymenopterans () reduces by visual such as birds.

Ecological Role

serve as of wildflowers and agricultural crops. Larvae contribute to decomposition and nutrient cycling in aquatic and semi-aquatic rich in organic matter. Larval filter-feeding on microbes may influence microbial dynamics in their habitats.

Human Relevance

are beneficial in natural and agricultural systems. Larvae occasionally encountered in water gardens, compost, and rain gutters, sometimes causing concern; Eristalis tenax historically speculated as source of biblical accounts of spontaneous from rotting carcasses. Sometimes misidentified as bees or in popular media and stock photography.

Similar Taxa

SericomyiiniShares rat-tailed maggot larvae with breathing siphon, but lacks the characteristic dip in wing R4+5 present in Eristalini. Some authorities treat Sericomyiini as a subtribe of Eristalini.

Misconceptions

frequently misidentified as honeybees (Eristalis) or (Helophilus, Parhelophilus) due to convergent mimicry; distinguished by single pair of wings (Diptera) versus two pairs in Hymenoptera.

More Details

Wing Venation

The dip in wing R4+5 is a diagnostic feature of Eristalini, separating it from Sericomyiini despite shared larval .

Siphon Variation

Length of larval breathing siphon varies by : very long in Eristalis, short in Chrysogaster, reflecting to different aquatic and water depths.