fireflies

Photuris is a genus of bioluminescent fireflies. There at least 64 Photuris species currently recognized worldwide, 50 species in North America north of Mexico, and at least 1 species in Minnesota.

The larvae live on the ground, under bark, and in moist swampy places. They are also bioluminescent. They are predators of snails, slugs, earthworms, and small insects. They paralyze and kill their prey, then pump chemicals through their jaws (mandibles) into the victim. The chemicals liquefy the tissues, which are then consumed.

Adults are found in spring and early summer. They are active at dusk and at night. During the day they can be found resting on vegetation.

Each species has its own distinctive courtship signal, distinguished by the number of flashes, the duration of each flash, and the interval between flashes. The female of one species, Photuris fairchildi, answers the flashes of males of other species, especially Photinus. When a male is attracted, she subdues and eats the unfortunate suitor. This is known as aggressive mimicry.

Adults are soft-bodied, flattened, elongate, and 5 ⁄16″ to ¾″ (8 to 20 mm) in length. When viewed from above, the head is often partly exposed, but it can be retracted defensively. The antennae are slender and thread-like, not saw-toothed.

The forewings (elytra) are leathery and are folded over the body when at rest. When folded, a small portion of the abdomen in the shoulder (humeral) area is exposed. This is only visible when viewed from the side. Called an incomplete elytral fold, this feature, along with the partially exposed head, distinguishes Photuris from similar Photinus fireflies.

The legs are long and slender but not compressed. The last part of each leg (tarsus), corresponding to the foot, has five segments, but the fourth segment is minute and is concealed within the lobes of the heart-shaped third segment, making it appear that there are only four segments. There is a pair of claws at the end of the last segment. The front half of each claw is split (cleft).

Sources

7, 24, 27, 29, 30, 82.

Location: Woodbury, MN

Location: Woodbury, MN