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New Mexico State University

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Glowworms Sighted in Southern New Mexico

Las Cruces -- People who have noticed eerie, blue-green lights the size of pinpoints in the grass at night may have witnessed a rare sighting of New Mexico glowworms, said an entomologist with New Mexico State University.


The glowworms have mainly been sighted in Las Cruces, Alamogordo and Lincoln from August through October.

"Glowworms are insects -- a very unusual group of beetles that are native to this area," said Carol Sutherland with NMSU's Cooperative Extension Service. "They're luminescent. They produce light biologically."

Electric light bulbs produce almost 90 percent heat and 10 percent light when they are lit, she said. But luminescent insects like glowworms produce almost no heat and nearly 100 percent light. Their bodies produce luciferin, a substance that combines with an enzyme plus oxygen to produce the light.

A healthy, active glowworm can glow during the day, but its light is only visible in the dark, Sutherland explained. The beetles seem to be most active at night, while they hide in grass, mulches and leaf litter and under logs and dead bark during the day.

The adult female glowworm is tan, wingless, flat and elongated. During the day, it can easily be mistaken for a dried fir needle or grass clipping. Two specimens collected in Alamogordo were about five-eighths of an inch long, but some of the larger species can exceed an inch in length as adults. Male glowworms are small, winged beetles.

"For all of their interesting features and behavior, very little is known about these odd little beetles," Sutherland said. Glowworms are part of the few native insects to the area that light up. Entomologists like Sutherland have been trying to collect the insects for their records.

To help, amateur collectors should look at night in grassy or weedy areas. Once glowworms have been spotted, collectors just have to pick them up, Sutherland said.

"Glowworms are too tiny to bite humans and they are harmless to handle," she added.

Live specimens are preferred. Once caught, the insects should be put in a small container with a piece of paper towel that has a drop of water on it. If dead specimens are collected, they should be placed in a small container of rubbing alcohol.

Collected glowworms can be sent to Sutherland at the Extension Plant Sciences Department, Box 30003, MSC 3AE, Las Cruces, NM 88003-8003, or delivered to room 130 Gerald Thomas Hall on the NMSU campus.