Ambrosia Seed Maggot Fly
Euaresta stigmatica
This adult female Euaresta stigmatica was observed on foliage of Canyon Ragweed (Ambrosia ambrosioides). 22 Dec 2021. Phoenix, Arizona.
Tephritidae -- Fruit Fly Family
Canyon Ragweed (Ambrosia ambrosioides) has thick, broad leaves and copious aromatic compounds that for many herbivores are a deterrent to feeding. Nonetheless Euaresta crawls about on the leaves without any difficulty. These little flies are true fruit flies that develop in the flower heads and developing fruits of ragweeds. Ragweeds in the Sonoran Desert are also known as bursages for the bur-like fruit. I hope to learn whether the larvae feeding reduces the amount of viable seed produced.