Plecia longiforceps
Mating pairs of this small fly stay physically joined together even in flight, forming the dense swarms that have recently spread into the Seoul area.
| Where | Urban areas and farmland, East Asia |
|---|---|
| Size | 6 to 8 mm body length |
| When | April and June to July |
A small fly with a black body and a distinctive reddish thorax; mating pairs fly about while still joined end to end, a habit shared with other lovebug flies.
Soil dwelling larvae break down dead plant matter, while the short lived adults form large seasonal swarms around buildings and vehicles, a range expansion first noticed in Korea in the 2010s and 2020s.
Traits
Habitat
Towns
Colour
Black, Red
Active
Day and night
To people
Does not bite or sting people; large swarms are only a seasonal nuisance around lights and buildings.
Activity through the year
Often confused with
A similarly built March fly with a uniformly black body, lacking the reddish thorax of this species, and it does not fly joined in mating pairs.
Questions
Is Plecia longiforceps dangerous to people?
Does not bite or sting people; large swarms are only a seasonal nuisance around lights and buildings.
When can you see Plecia longiforceps?
Plecia longiforceps can be seen from April and June to July, by day and at night.
Plate retouched from a photo by mister_bumble, CC BY 4.0, iNaturalist Licence
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Last updated 2026-09-27. Every entry is checked against published sources.