Bug FAQBull Thistle Gall Fly
Urophora stylata · Order: Diptera · Family: Tephritidae
Also called: Fruit fly
Its larvae develop inside the flower heads of thistles such as Cirsium and Carduus. It is native across Europe to Japan and has been introduced to several other regions, including North America for biocontrol of invasive thistles.
Source: Wikipedia
Where it lives
The larvae live on thistles of the genera Cirsium or Carduus. It has been released in North America to control the invasive thistle Cirsium vulgare.
Source: Wikipedia
What it eats
Larvae feed on thistles in the genera Cirsium and Carduus.
Source: Wikipedia
Life cycle
Urophora stylata is a tephritid fruit fly species in the genus Urophora.
Source: Wikipedia
Where it comes from
It occurs naturally throughout Europe eastward to Japan. It has been introduced to India, Pakistan, Australia, and North America.
Source: Wikipedia
Where it is found in the US
Recorded in 4 of 51 states and DC. Most records: Washington, New Hampshire, Oregon, Vermont.
Darker = more records. Counts are museum and citizen-science records, not population size.
Source: GBIF
Status: introduced in United States. Source: iNaturalist
Months it is reported in the US
Source: GBIF
More photos
Questions people ask
What plants do the larvae of Bull thistle gall fly use?
The larvae develop inside thistles of the genera Cirsium and Carduus.
Source: Wikipedia
Where is Bull thistle gall fly originally from?
It is native across Europe to Japan.
Source: Wikipedia
Has Bull thistle gall fly been introduced elsewhere?
Yes, it has been introduced to India, Pakistan, Australia, and North America for biocontrol of invasive thistles.
Source: Wikipedia
Same family (Tephritidae)
Goldenrod Gall FlyEurosta solidaginis
Thistle Stem Gall FlyUrophora cardui
Goldenrod Brussels Sprout Gall FlyProcecidochares atra
Mediterranean Fruit FlyCeratitis capitataDamages trees, gardens or crops
Cotton-gall TephritidAciurina bigeloviae
Oriental Fruit FlyBactrocera dorsalisDamages trees, gardens or cropsSources
- Wikipedia: https://en.wikipedia.org/wiki/Urophora_stylata
Look it up elsewhere: GBIF · iNaturalist · BugGuide · ITIS · Wikipedia
Text written 2026-10-23 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-23.