At night in the Cerrado, Brazil’s savanna and second-largest biome, larvae of the click beetle Pyrearinus termitilluminans, which live in termite mounds, display green lanterns to capture prey attracted by the bright light.

In more than 30 years of expeditions with his students to Emas National Park and farms around the conservation unit in Goiás state to collect specimens, the phenomenon has never been so rare, said Vadim Viviani, a professor at the Federal University of São Carlos’s Science and Technology for Sustainability Center (CCTS-UFSCar) in Sorocaba, São Paulo state.

“In the 1990s, we would see many of these termite mounds full of fireflies and other bioluminescent insects, even in pasture areas. Now, sugarcane is grown in most of the areas, and we hardly see any,” he noted.

The dearth was one of the main findings of a study published in Annals of the Entomological Society of America.