In the ranks of the Soldier Fly family, there are many species named for various roles in the armed forces. The various colors and stripes on these flies can look like military uniforms, so that’s the source of the common name of the family. There are also themed common names for many species, including Silver Colonel and Ornate Brigadier.
Today’s Mount Pisgah insect is a Twin-spot Centurion Soldier Fly (Sargus bipunctatus). Centurions were Roman soldiers, commanders of 100 legionaries. This Centurion is a European species that has set up base operations on the U.S. West Coast…likely not by marching. It’s distinguished by two white spots just above the antennae. (Sorry, I didn’t get any great photos of the twin spots).
In person, the fly flashes bright, metallic colors. In photos, the colors come across more subtly. Sources say the males are bronze on green, and the females are blue on red. I believe these are both males.
The life cycle of this fly has a poopy start, literally. Females lay eggs on fresh dung, or in nearby soil. Larvae may grow up on a diet of cow dung, compost, rotting vegetation or decaying fungi. The adults feed on pollen and nectar and may be pollinators. They’re on the wing until very late fall.
Stay curious!
P.S. Exciting news: Karen will share a different PNW insect every day in 2025. Visit The Daily Insect to see the featured creatures!
Sources:
The Bug Lady on Soldier Flies: https://uwm.edu/field-station/bug-of-the-week/soldier-fly/. Accessed 12/11/24.
Profile of the species from Great Britain: https://www.gedlingconservationtrust.org/species/diptera/twin-spot-centurian/. Accessed 12/11/24.
All photos by Karen Richards