Different organisms are capable of glowing for various reasons. Some do it for communication or to attract mates, while some glow to lure in prey. A group of researchers recently discovered a glowing larva in Peru that definitely fits into that last group. While it isn’t yet known exactly what species of beetle the larvae are, these little guys have some serious hunting prowess.
According to the Rainforest Expeditions blog, these larvae were first discovered a couple of years ago by wildlife photographer Jeff Cremer during a hike at night through the Peruvian Amazon rainforest. Looking at the face of a dirt wall, Cremer spotted small points of green light. Upon closer inspection, he saw the heads of bioluminescent larvae staring back at him. Cremer snapped some pictures of the larvae, and later sought the assistance of entomologists to identify them.
Cremer returned to the rainforest alongside three entomologists: Aaron Pomerantz of Rainforest Expeditions, along with Pomerantz’s colleagues from the University of Florida, Mike Bentley and Geoff Gallice. Upon seeing the glowing larvae up close, the first thing the scientists noticed were that their large mandibles were stretched wide and ready for action.
The scientists suspect that the larvae glow in order to draw in prey, then ambush them when they come close enough. In order to investigate whether or not the creature was predatory, they attached an ant to the end of a stick and offered it to a larva. As soon as the ant was close enough, the larva lurched out, chomped down, and attempted to drag the ant back into its hole. This simple experiment quickly validated the team’s prediction that the large mandibles allow the insect to be a fierce predator.
The larvae are about 12 millimeters (0.5 inches) long and burrow into dirt walls, like a creepy version of Whac-A-Mole. While other beetle larvae are known to burrow into termite mounds and dine on its inhabitants, there aren’t any species known to hunker down into a wall of dirt as is seen in this species.
The larvae are currently assumed to be a variety of click beetle, belonging to the family Elateridae. However, they still haven’t yet nailed down an exact species. There are 10,000 species of beetle within the family, and 200 of those exhibit bioluminescence. When viewing the larvae up close, it is possible to make out the glands responsible for the insect’s bioluminescence. It has not yet been confirmed, but the glowing is likely caused by the molecule luciferin.
Beyond the name of the species and what molecule they use to glow, Pomerantz writes that there is much to understand about these larvae and how they fit into their ecosystem. Future research will hopefully illuminate their evolutionary history and how they have helped shape the environment around them.