Dolichopodidae

Latreille, 1809

long-legged flies, longlegged flies

Genus Guides

, the long-legged flies, is a large of true flies (Diptera) comprising over 8,000 described in approximately 250 . Members are typically small (1–10 mm), often metallic green, blue, or bronze, with characteristically long and slender legs. are predominantly predatory on small . The family is particularly diverse in North America, with nearly 60 genera and about 1,300 species. Many species inhabit moist environments near water margins, though others occupy terrestrial including tree trunks and foliage.

Tachytrechus moechus by (c) Owen Strickland, some rights reserved (CC BY), uploaded by Owen Strickland. Used under a CC-BY license.

Diaphorus by (c) portioid, some rights reserved (CC BY), uploaded by portioid. Used under a CC-BY license.

Dolichopus brevimanus by (c) Bernie Paquette, some rights reserved (CC BY), uploaded by Bernie Paquette. Used under a CC-BY license.

Pronunciation

How to pronounce Dolichopodidae: //ˌdɒlɪkoʊˈpɒdɪdiː//

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

Identification

can be distinguished from the similar Hybotidae by the of the male genitalia (90–180° dextral rotation of segments 7–8). Within Empidoidea, they are recognized by the combination of long legs, metallic coloration, and wing venation with basal and discoidal wing . -level identification typically requires examination of male genitalia; the claspers and associated structures are visible as forward-projecting appendages at the abdominal tip. Some are -specific: Hydrophorus species occur on water surfaces, Medetera on tree trunks, and Dolichopus in diverse terrestrial habitats.

Images

Appearance

Small to minute flies ranging from 1 mm to 10 mm in body length. Most exhibit a metallic green, blue, , or bronze lustre, though some are dull yellow, brown, or black. The legs are characteristically long and slender, giving a stilt-like posture with the body held nearly erect. The are large and prominent, separated on the in males (except in some ). The third antennal segment is largest and bears a long . Wings are typically clear or tinged, occasionally patterned with spots or strong colours; venation includes three radial with characteristic wing fusion. Male genitalia are often prominent, free, and borne on a petiole, frequently rotated 90–180° dextrally.

Habitat

occupy diverse including grassy places, shrubbery, woodland edges, gardens, and meadows. Many groups are confined to wet or semi-aquatic environments: margins of lakes, ponds, streams, and intermittent water bodies; some occur on saline inland shores or intertidal zones. such as Porphyrops, Tachytrechus, Campsicnemus, and Teuchophorus are strongly associated with water margins. Others, including Medetera, inhabit tree trunks damaged by bark beetles. Hydrophorus skate across the surface film of still water. No truly aquatic species are known, but many are semi-aquatic. Larvae occupy moist substrates: soil, moist sand, rotting organic matter, or under bark.

Distribution

distribution with representation on all continents except Antarctica. The is well-represented in amber deposits globally since at least the Cretaceous. North America north of Mexico contains approximately 1,300 in nearly 60 . The genus Dolichopus is the most speciose globally with approximately 600 species. Individual species distributions vary: some are widespread (e.g., across Europe to the Urals), others restricted to specific regions or types.

Seasonality

are active primarily during warmer months. In temperate regions, activity peaks from late spring through summer; for example, Neurigona quadrifasciata is active mainly from May to September. Specific timing varies by and latitude. occurs as larvae or subadults in many species.

Diet

are predatory, feeding on small including Collembola, aphids, Oligochaeta larvae, and other tiny arthropods. of Dolichopus commonly prey on mosquito larvae. Some observations document on typhlocybine leafhoppers. A minority of adults may scavenge or act as kleptoparasites of spiders or other . Larvae are also predatory: most feed on small invertebrates in their respective substrates; Medetera larvae prey on bark beetle in tunnels; Thrypticus larvae are exceptional in being phytophagous, feeding within stems of reeds and monocots near water.

Life Cycle

Complete with , larva, pupa, and stages. Larval are diverse and often moisture-dependent: soil, moist sand, rotting organic matter, under tree bark, in bark beetle galleries, or within aquatic/semi-aquatic substrates. Larval development duration varies by and environmental conditions. occurs in the larval substrate. Adults emerge and disperse to feeding and mating habitats. time varies; many species likely have one or more generations per year depending on climate.

Behavior

are agile, fast-moving that rarely remain stationary. Many assume a characteristic predatory posture standing high on their legs on ground, vegetation, tree trunks, rocks, or water surfaces. Some species walk on the surface film of still water. Courtship involves visual displays rather than chemical signals: males of many species perform elaborate dances using modified fore , flattened , or other secondary sexual structures. Male Neurigona fly in zig-zag patterns up tree trunks during courtship. Some species form sleeping clusters. Females of some (e.g., Bembecinus) practice of larvae, though this belongs to a different ; within , parental care details are poorly documented.

Ecological Role

of small in diverse terrestrial and semi-aquatic . Contribute to regulation of of Collembola, aphids, and other microarthropods. Some (e.g., Dolichopus) prey on mosquito larvae, potentially contributing to mosquito population control. Larvae of Medetera are predators of bark beetle , possibly providing of forest pests. Thrypticus larvae, being phytophagous, occupy a different trophic position as herbivores. flies serve as prey for spiders (including orbweavers that capture them at foliage edges) and other .

Human Relevance

Generally beneficial as of pest insects including aphids and mosquito larvae. Some have been investigated for potential in agricultural systems. The has been documented in hospital environments where flying insects may carry bacteria, though their role in transmission appears minimal compared to other fly families. No significant economic damage is attributed to the family. Research interest is high due to diversity, complex courtship , and potential as bioindicators of quality.

Similar Taxa

HybotidaeSimilar body plan and metallic coloration; distinguished by male genitalia orientation (not rotated dextrally as in ) and other subtle morphological differences
EmpididaeRelated within Empidoidea; generally lack the extreme leg elongation and metallic coloration typical of ; different wing venation and genitalic structure
SyrphidaeSome small metallic syrphids may resemble dolichopodids, but have shorter legs, different wing venation with spurious , and often mimic bees or

More Details

Taxonomic Complexity

-level identification within is notoriously difficult and generally requires microscopic examination of male genitalia. The is undergoing active taxonomic revision, with many relationships unresolved. An expanded concept (Dolichopodidae sensu lato) includes former families Microphoridae and Parathalassiinae as subfamilies.

Genomic Resources

The first -level assembly for the was completed for Neurigona quadrifasciata (582.53 Mb, 6 chromosomal pseudomolecules) as part of the Darwin Tree of Life project, providing foundational resources for future research.

Research Challenges

Larvae of most remain undescribed or poorly known, limiting understanding of and ecological roles. Basic biological data including associations, seasonality, and requirements are lacking for the majority of species.