This odd little bug was spotted on some mint flowers growing near hot springs in Buena Vista, Colo., Aug. 27, 2011. It’s a red fly of the family Tachinidae and the species Adejeania vexatrix. The species is noted for its greatly elongated palpi, located under the fly’s head. This adaptation allows them to drink nectar buried in a variety of species of flowers.
It’s bright, orange abdomen and black bristles help it blend into colorful flowers, where it finds its food. If it were black, like the common house fly, predators would quickly see it resting on brightly-colored peddles or pollen. Birds, lizards and amphibians would have gobbled them up quickly, due to their alerting color.
Tachinid flies vary in colors; most are dull like house flies. Speciation may have led to the unique appearance of the Adejeania vexatrix, as a method to evade extinction. They’re found in the warm mountainous Western regions of the United States, where blooming plants are common. Had the fly not evolved the long mouth parts for feeding on flowers — instead relying on flesh and feces — it seems likely that the color variation wouldn’t have survived the process of natural selection.