Urophora cardui · daginė margasparnė

EN · thistle gall fly, thistle stem gall Fly DE · Distelbohrfliege PL · wyroślówka ostowa

https://en.wikipedia.org/wiki/Urophora_cardui The fly starts life as an egg, one to thirty of which are laid on the stems of 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.