Root-maggot Fly

Fucellia rufitibia





F. rufitibia is a sandy beach root-maggot fly species associated with kelp wrack. F. rufitibia is easily recognized by its rufous or amber tibia, by which it is named for. These flies have yellow cheeks and red eyes that are longer than they are wide. Unlike C. vanduzeei, these flies have uniform hairs on their thorax along with putter stripes. Their body length ranges from 3.5mm to 7.5mm. Perhaps the most common kelp fly across all beaches, F. rufitibia is seen in groups throughout the year, particularly in spring and summer months. They have moderate sized larvae that act as a significant source of nutrients for predatory arthropods and shore birds that occupy and forage kelp wrack. Like C. vanduzeei, their larvae are also a significant source of kelp removal. Their pupae are known to be parasitized by both the parasitoid beetle A. sulcicollis (Schooler et al. 2012), and parasitoid wasps that occupy the sandy beach. As adults, these short-lived flies are a resource for arthropods that can either capture them alive, or scavenge their decaying bodies. Their adult diet is suspected to be fluids or bacteria from kelp or bird feces, but has not been confirmed