An enigmatic glowing worm discovered in a Peruvian rainforest puts on a light show not for fun but probably for food, researchers say.
Believed to be the larvae of an as-yet-unidentified beetle species, or possibly a new subspecies of an already known species, the glow worms may be using their phosphorescence trick to attract unsuspecting smaller insets to their gaping, waiting jaws, they say.
Termites or a will "fly right into their jaws, and then they'll just clamp shut and that's their meal," says entomologist Aaron Pomerantz, who collaborates with a rain forest expedition outfit near the Tambopata Research Center in Peru.
The larvae can control when they glow, he says, turning it on and off at will, suggesting they've evolved to ability for use as a kind of lure, attracting prey in the dark night of the rain forest.
"These larvae may glow using a chemical known as luciferin, which is the same chemical found in many firefly species," Pomerantz says.
Once the prey is within range, the half-inch larva will erupt from its burrow to fasten onto its victim, like something out of the camp 1990 horror movie "Tremors."
"They're underground, and they burst from the earth," Pomerantz says.
The researchers say the creatures are the larval stage of an unknown species of click beetle, so named for their fast "clicking" or popping motion used to escape predators.
While adult click beetles seem to feed on nectar and flowers, the larvae are most likely predatory, Pomerantz says.
Wildlife photographer Jeff Cremet was the first person to find the glowing larvae, and in an attempt to secure some help in identifying them he posted pictures to an online "whatsthisbug" forum where wildlife enthusiasts and entomologists work together to identify newly discovered insects.
That led to Pomerantz and colleagues from the University of Florida contacting him to arrange an expedition in October to seek out more of the glowing larvae.
They found numbers of them embedded in a wall of dirt, with just their glowing heads -- and their fierce mandibles -- sticking out, a sure sign of a sit-and-wait, or ambush, strategy or predation, the researchers say.
Of more than 10,000 click beetle species, around 200 are bioluminescent, or able to give off light.
The most common use of bioluminescence in animals is to either lure prey within range or to warn off predators by signaling that they contain noxious chemicals, the researchers said.