Urophora cardui or the Canada thistle gall fly is a fruit fly which, contrary to its common name, is indigenous to Central Europe from the United Kingdom east to near the Crimea, and from Sweden south to the Mediterranean.

Urophora cardui
Urophora cardui
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Diptera
Family: Tephritidae
Subfamily: Tephritinae
Tribe: Myopitini
Genus: Urophora
Species:
U. cardui
Binomial name
Urophora cardui
Synonyms

Distribution

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The Canada thistle gall fly has been introduced to North America from Europe to control the population of its host plant, Canada, or creeping thistle, which is an invasive, introduced weed in North America.

 
Gall formed by U. cardui on Cirsium arvense

Life cycle

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The fly starts life as an egg, one to thirty of which are laid on the stems of its host plant, the Canada or creeping thistle (Cirsium arvense), during the host's growing season. After hatching, the larvae burrow into the stem and form a gall (or swelling). The larvae grow to reach 98% of their full adult body weight, and overwinter in the gall in the third larval stage (instar). They pupate in early spring for 24 to 35 days and appear reddish brown. The adult fly then chews a tunnel and escapes from the gall.

References

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  1. ^ a b Robineau-Desvoidy, André Jean Baptiste (1830). "Essai sur les myodaires". Mémoires presentés à l'Institut des Sciences, Lettres et Arts, par divers savants et lus dans ses assemblées: Sciences, Mathématiques et Physique. 2 (2): 1–813. Retrieved 15 July 2018.
  2. ^ Ahrens, A. (1814). "Fauna Insectorum Europae". Fasc. 2: 25.
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