fireflies

Pyractomena is a species of bioluminescent fireflies. There are at least 25 species of Pyractomena in North and Central America, 18 species in North America north of Mexico, and 5 species in Minnesota. Pyractomena occur across North America but are most common in the United States and southern Canada east of the Great Plains.

Pyractomena adults are active at night. When seeking a mate, males flash while in flight. Females flash while remaining stationery of vegetation.

Bioluminescence is though to have evolved as a warning to predators. Some fireflies contain steroidal chemicals called lucibufagins. At least one species contains enough of the toxin to kill a lizard.

The larvae, called a glowworm, is also bioluminescent. It is amphibious, preying mostly on snails, both in the water and on vegetation out of the water. Unlike other firefly species, who pupate underground, the Pyractomena larva undergoes aerial pupation. When it is ready to pupate, it leaves the water and crawls up the trunk of a large tree. There it nestles into a crevice in the bark in a sunny spot, glues the tip of its abdomen to the bark, and hangs head downward. Over the next two to three weeks it transforms into an adult firefly.

Adults are active at night.

The exoskeletal plate covering the thorax (pronotum) has a distinct ridge down the middle and a black stripe down the middle. The light organs are well developed on both sexes. On the male, they occupy the entire fifth and sixth abdominal segments. On the female they occupy just the sides of the segments, with the middle of the segments being dark.

The male flash pattern consists of four or five bursts. The flash is often amber-colored, and is compared to an ember from a campfire.

Sources

24, 27, 29, 30, 82.

This genus has no common name. The common name of the family Lampyridae is fireflies and is used here for convenience.

Location: Orléans Island, Quebec

Location: Woodbury, Minnesota