Glowworm (Phengodes spp.)
Detailing the physical features, habits, territorial reach and other identifying qualities of the Glowworm.
Updated: 6/8/2018; Authored By Staff Writer; Content ©www.InsectIdentification.org
An unusual beetle, the bioluminescent and beloved Glowworm has delighted generations and inspired song.
The larval form of the Glowworm Beetle is called a Glowworm. The larva is long and tubular like a worm, and it emits a yellow, orange, or green light from its body using bioluminescence, not heat. Some species can emit a red light from their head. They eat mostly other crawling things like millipedes, slugs, snails, and even other insects. A toxic cocktail is injected into their prey as they bite it. This causes the internal parts of the prey to dissolve whereupon the Glowworm eats it. They are found in soil, leaf litter, grasslands, and even in caves, where they light up the roof like stars.
Adults look similar to lightning bugs, or fireflies. They are orange and black with large bulging eyes on the sides of the head. Glowworm Beetles have long antennae with wispy, feathery lashes. Males, not females, have wings. They do not have a hard wing covering (elytra) like other types of beetles. Larvae and females, not males, can glow. She looks somewhat like her larval form and somewhat like an adult. Her beacon of light is how she attracts a mate since she is not as mobile as the male.
Collecting Glowworms for captivity actually reduces their ability to successfully reproduce and maintain a population in a specific area. Admiring Glowworms in their habitat and allowing them to finish the mating process allows for an annual summertime display. Glowworms were the subject a fun tune sung by the Mills Brothers in the early 1950's. Their harmony and lyrics are still easy on the ears. Look for Glowworm Beetles day or night, but enjoy the illumination of their worms after the sun has set. It doesn't hurt to hum their song, too.