Earth Notes: Fireflies in Flagstaff

Jul 12, 2017

Jason Wilder was out looking for owls around Mount Elden one evening in June 2014. The Flagstaff biology professor noticed a tiny green light glowing on the forest floor, and in a careful search he found the light was coming from a flightless female firefly.

Mating fireflies
Credit Jason Wilder

Fireflies are true beetles, but many types of females don't grow wings or assume the form of  adult beetles when they mature—instead they look wormlike, thus their nickname “glowworm.” Fascinated by his find, Wilder took photos of the glowing female just as two non-glowing male fireflies dropped out of the air to mate with her.

Adult fireflies use bioluminescence to attract mates. But the ability to produce light originally evolved as a juvenile trait—possibly, scientists think, to warn predators not to eat them because of their foul taste.  

Wilder’s sighting was the first report since a 1959 paper listed specimens in several locations around northern Arizona. More fireflies were spotted on the grounds of the Museum of Northern Arizona in Flagstaff last summer. Museum entomologist Gary Alpert, and firefly scientist Joseph Cicero, believe they’re probably Microphotus pecosensis, a species originally found in Pecos, New Mexico, and described in 1912.

What many people fondly remember from Midwestern childhoods may become a delight of summers in the Southwest.