Tiny yellow lights hover in the backyard. Kids squeal and clasp their hands around winking insects, hoping to capture their glow in a glass jar.
Central Indiana is blinking to life from lightning bug season -- a time when porch dwellers and third-graders share a common wonder for a bug that can produce light from its body.
That talent is inspiring cancer research and treatment, and the entomology department at Purdue University is leading a campaign to make lightning bugs the official insect of Indiana.
But Indiana's favorite beetle may be in danger.
Pesticides, habitat loss and dry weather all pose threats to lightning bugs. It's those factors that make Tom Turpin, an entomology professor at Purdue, think the population of some firefly species is dropping.
It's difficult to say for sure, though.
Unlike other insects, lightning bugs aren't studied much by entomologists. That means no one is really counting those that show up in Hoosier backyards this summer.
"We don't really have a scientific survey," Turpin said. "We don't have anyone going out to study them. There's just personal observations."
In southern Ohio, drought is putting fireflies in danger, said Barbara Bloetscher, an entomologist at Ohio State University. The larvae survive best in wetter conditions, since their soft bodies lose water easily to dry soil.
The folks at the nonprofit preservation organization firefly.org worry that lawn pesticides harm the beetles, too. Patio lights might confuse the bugs, and even mowing the lawn too often might harm them.
Though Turpin thinks the general population is decreasing, he said fireflies seem plentiful in Central Indiana.
"There's fairly consistent displays of firefly flashing by the later part of June and July," he said.
Lightning bugs seem to be thriving in central Illinois, too, said University of Illinois entomologist Phil Nixon.
Though its future might be unclear, the insect's impact on science and medicine is coming into focus. The reason? Its intriguing bioluminescence, the glow created by a chemical reaction within the firefly's body.
"Every time you see them, you see the light and wonder, 'What makes a firefly tick?' " said Evan Horn, 8, Indianapolis. "It couldn't be like someone glued a light bulb to its back."
That chemical reaction might help track the effectiveness of cancer drugs, scientists think.
Last year, scientists at the University of Texas Southwestern Medical Center altered human breast cancer tumors to carry the firefly gene. Implanted in mice, the tumors emitted light. By tracking how much light is emitted, scientists can track the size of the tumor. The procedure will allow scientists to be more efficient in preclinical experiments.
The firefly gene might also help attack cancer cells directly. Scientists have used it to make cancer cells sensitive to light and then used laser lights to try to eliminate them.
The procedure is still in the early stages. The greatest challenge is refining the laser's ability to distinguish cancer cells from healthy cells.
They may be assisting in sophisticated medical procedures, but fireflies' simple, backyard appeal remains timeless.
Izzy Pippen, 8, Indianapolis, might sum it up best.
"They're cool because their butts glow," Izzy said.