Marsh flies

Definition

Common name for the family Sciomyzidae, a group of brachyceran Diptera whose larvae are predominantly aquatic or semiaquatic predators and parasitoids of freshwater and terrestrial mollusks. Adults frequent marshy vegetation, wet meadows, and riparian margins. The family is notable for its specialized larval ecology: most species prey on or parasitize snails and slugs, with some taxa targeting bivalves or fingernail clams, making them subjects of study for biological control of pest mollusks and as indicators of wetland habitat quality.

Etymology

From the association of adults with marshy, wetland habitats; 'snail-killing flies' refers to larval predation on gastropods.

Example

Larvae of the genus Tetanocera penetrate the shells of aquatic snails to feed, while Sepedon species are used in biocontrol programs against Lymnaea snails that vector liver flukes.

Synonyms

• snail-killing flies

Related Terms

• Sciomyzidae
• Diptera
• Brachycera
• Biological control
• wetland ecology
• gastropod parasitoids
• aquatic insects

Usage Notes

The term is sometimes restricted to the more conspicuous wetland-dwelling species, though the family occurs in diverse moist habitats; 'snail-killing flies' emphasizes function over habitat and is preferred in parasitology and biocontrol literature. Not to be confused with shore flies (Ephydridae) or other semi-aquatic Diptera families.