Episyrphus

Matsumura, 1917

Aphid Hover Flies

Species Guides

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Episyrphus is a of hoverflies in the Syrphinae, commonly known as hover flies. The genus contains two recognized subgenera: Episyrphus and Asiobaccha, with the latter distinguished by a . Larvae are predatory, frequently preying on aphids. The most widely distributed , E. balteatus, exhibits migratory and has been extensively studied for its role in . Taxonomic classification within the genus requires revision due to unclear species boundaries and environmentally variable diagnostic characters.

Episyrphus balteatus by (c) Michael Knapp, some rights reserved (CC BY), uploaded by Michael Knapp. Used under a CC-BY license.Episyrphus by (c) Michael Knapp, some rights reserved (CC BY). Used under a CC-BY license.Episyrphus by (c) Rafael Carbonell Font, some rights reserved (CC BY), uploaded by Rafael Carbonell Font. Used under a CC-BY license.

Pronunciation

How to pronounce Episyrphus: //ˌɛpɪˈsɪrfəs//

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Identification

of subgenus Asiobaccha are distinguished from Episyrphus by a (stalked) . Identification of species within the is complicated by diagnostic characters that vary with environmental conditions; for example, abdominal coloration and pile coloration on the and scutellum in E. viridaureus have been shown to depend on temperature.

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Distribution

The has a broad distribution including Europe, northern India (Rohilkhand region of Uttar Pradesh), and Australia. E. balteatus has a distribution. The distribution of E. viridaureus has been extended to include Australia based on recent taxonomic revision.

Diet

Larvae are predatory, often on aphids. E. balteatus is described as aphidophagous, with larvae actively preying on including aphids such as Aphis craccivora and Aphis gossypii.

Life Cycle

Development from to averages 21.5 days under greenhouse conditions. Total mortality reaches approximately 70%, with 66% occurring in the egg stage, 23% in the larval stage, and 11% in the pupal stage. Females can enter a facultative reproductive as adults; diapause is induced during the second and third larval instars with a critical between 11.8 and 11.9 hours. Some females may live up to 100 days and continue producing fertile eggs.

Behavior

females select oviposition sites based on colony presence and size, with preference for larger colonies. Honeydew attracts females via olfaction and elicits oviposition. Females detect and avoid ovipositing in colonies containing through olfactory cues. E. balteatus exhibits seasonal , with autumn movement southward to grounds around the Mediterranean and beyond. Spring in Western France appear to comprise mainly local individuals with some immigration from southern regions.

Ecological Role

Important agents of in agricultural and nursery settings. The aphidophagous feeding of larvae contributes to natural pest suppression. flower flies serve as of flowering plants.

Human Relevance

Widely utilized in programs for management in greenhouses and agricultural fields. The E. balteatus has been extensively studied for its reproductive capacity and as a natural enemy of crop pests.

Similar Taxa

  • EristalisBoth are hoverfly with similar appearance; Eristalis are generally larger and exhibit different larval (rat-tailed maggots in aquatic or decaying organic matter rather than ).
  • MetasyrphusBoth are aphidophagous syrphid with predatory larvae; Metasyrphus confrater has been recorded sympatrically with E. balteatus in northern India.

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