Syrphidae

hover flies, flower flies, syrphid flies, drone flies

Subfamily Guides

Eristalinae(Drone Flies and Allies)
Microdontinae(Ant Flies and Allies)
Pipizinae(Pitheads & Kin)
Syrphinae(Typical Hover Flies)

is a -rich of true flies comprising over 6,000 described species worldwide, with approximately 800 species in North America. are commonly known as hover flies, , or drone flies due to their characteristic hovering and frequent flower visitation. Many species exhibit of bees and , gaining protection from through their resemblance to stinging Hymenoptera. The family provides critical services: adults are significant second only to bees, especially in Arctic climates, while larvae display diverse ecological roles including on crop pests and nutrient cycling in aquatic .

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

Sericomyia flagrans by (c) mark-groeneveld, some rights reserved (CC BY), uploaded by mark-groeneveld. Used under a CC-BY license.

Sericomyia chrysotoxoides by no rights reserved, uploaded by Todd Eiben. Used under a CC0 license.

Pronunciation

How to pronounce Syrphidae: /ˈsɪr.fɪˌdiː/

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

Identification

Distinguished from bees and by having only one pair of wings (bees and wasps have two pairs) and the presence of . Spurious in the wing are characteristic of many syrphid . The combination of hovering , flower association, and mimicry coloration helps separate them from other fly . Some species require examination of wing venation, facial features, or male genitalia for precise identification. Tiny Toxomerus species are often mistaken for sweat bees (Halictidae) due to similar size and coloration.

Images

Habitat

Extremely diverse across the . frequent flowering plants in gardens, meadows, forests, and agricultural fields. Larval span terrestrial environments including leaf litter, soil, and rotting vegetation; aquatic and semi-aquatic habitats such as ponds, streams, drainage ditches, and manure lagoons; and specialized including tree-related microhabitats (dead wood, rot holes) for saproxylic , and nests of social insects for species.

Distribution

distribution with on every continent except Antarctica. Particularly diverse in temperate regions. Some species, such as Eristalis tenax, have become cosmopolitan through human activity. North America approximately 800 species. Colombia alone has documented 337 species across 57 .

Seasonality

activity generally coincides with flowering periods, with peak abundance in spring and summer in temperate regions. Some overwinter as adults in protected locations such as caves, emerging in spring to resume activity. Others overwinter as larvae or pupae. In warmer climates, some species may be active year-round.

Diet

feed primarily on nectar and pollen, with pollen serving as a protein source for development and nectar providing energy for . Some adults have been observed consuming honeydew and secretions. Larval diets are highly diverse: many are on soft-bodied insects such as aphids, with some consuming over 1,000 aphids during development; others are saprophages in decaying organic matter; aquatic filter-feeders in polluted waters; and some are specialized feeders in specific microhabitats.

Host Associations

Aphidoidea - Larvae of many are specialized , providing services
Asteraceae - pollination show particular affinity for daisies, zinnias, asters, and related flowering plants
Iridomyrmex humilis - inquilinismObserved in Mixogaster nesting in Argentina nests in Colombia
Apis mellifera - mimicry modelMany drone flies (Eristalis) are Batesian mimics of drones

Life Cycle

Complete with , larva, pupa, and stages. Females lay eggs near appropriate larval food sources: near colonies for predatory , in decaying matter or aquatic for saprophagous species, or in specialized microhabitats for other guilds. Larval development time varies by species and environmental conditions. Some species have multiple per year; others are . stage varies: some as adults in protected shelters, others as larvae or pupae in soil or aquatic substrates.

Behavior

are renowned for their ability to hover motionless in mid-air, a that aids in nectar feeding and mate location. Many males establish and defend territories around flowering plants, chasing away competing males and other insects. Some adults seek out human sweat to obtain salts and minerals. of stinging insects provides protection from visually hunting such as birds. Some aggregate in winter shelters such as cave pockets. Larval behavior varies: predatory species actively search for prey, while others are sedentary filter-feeders or saprophages.

Ecological Role

are among the most significant after bees, particularly important in Arctic climates and for agricultural crops. Larval on aphids provides natural in gardens and agricultural systems. Aquatic larvae contribute to nutrient cycling in polluted waters by processing decaying organic matter. Saproxylic contribute to decomposition processes in dead wood . The supports as prey for birds, spiders, and other .

Human Relevance

Beneficial insects providing services including crop pollination and of pests. Some used in programs and available commercially for release. Rat-tailed maggots (Eristalis tenax) have been investigated for waste management applications due to their ability to process organic waste. Occasional negative impacts: larvae may contaminate livestock feed or cause myiasis if ingested; large of larvae leaving aquatic have caused electrical shorts. Frequently mistaken for bees or due to mimicry, leading to unnecessary concern.

Similar Taxa

HalictidaeSweat bees, particularly tiny Lasioglossum , are often mistaken for syrphid flies; both visit flowers and may land on humans for sweat. Separated by wing number (two pairs in bees, one in flies) and present in flies.
BombyliidaeBee flies also mimic bees and hover at flowers; distinguished by longer , different wing venation, and more robust body form.
ConopidaeThick-headed flies share flower-visiting habits and some mimicry; distinguished by humpbacked and different shape.

Misconceptions

Frequently mistaken for bees or due to , leading to fear of stinging; syrphid flies are harmless and cannot sting. The 'drone fly' for Eristalis refers to resemblance to male honey bees (drones), not to unmanned aerial vehicles. Some species are incorrectly called 'sweat bees' in casual speech, though they are true flies, not bees.

More Details

Taxonomic diversity

The comprises over 6,200 described globally, with substantial undescribed diversity remaining. Recent work in Colombia documented 337 species across 57 , including multiple new country records. The Illinois Natural History Survey collection alone holds tens of thousands of specimens representing this diversity.

Research and conservation needs

A century of specimen accumulation combined with modern digitization and citizen science data (iNaturalist, GBIF) is revealing range expansions, contractions, and of conservation concern. However, larval remains unknown for many species; only three of 134 European saproxylic species have properly understood . Veteran tree protection and artificial breeding site creation are being explored for conservation of threatened saproxylic syrphids.