The diversity of bioluminescent beetles in the Brazilian savanna has declined dramatically in 30 years.

Newswise – At night in the Cerrado, Brazil's savannah and second largest biome, beetle larvae Pyrearinus termitilluminansLiving in termite mounds, they display green lanterns to catch prey that is attracted to the bright light.

In more than 30 years of expeditions with his students to collect specimens in the Emmaus National Park and the farms surrounding the Conservation Unit of the State of Goiás, this phenomenon has never been so rare. Vadim VivianProfessor at the Center for Sustainability of Science and Technology of the Federal University of São Carlos (CCTS-UFSCar) in Sorocaba, State of São Paulo.

“In the 1990s, we would see these termite mounds filled with fireflies and other bioluminescent insects, even in pastures. Now sugarcane is grown in most areas and we hardly see it,” he said.

Scarcity was one of the main findings of the study Supported by FAPESP through the Biodiversity Characterization, Conservation, Restoration and Sustainable Use Research Program (BIOTA-FAPESPAccording to the article by Vivian and colleagues was published in Annals of the Entomological Society of America.

last author of the article, Etelvino BecharaProfessor at the Institute of Chemistry of the University of São Paulo (IQ-USP), was Vivian's master's and doctoral thesis advisor in the 1990s and is also Supported by FAPESP.

There are other co-authors Clyde CostaResearcher at the Zoology Museum of the University of São Paulo (MZ-USP) and Simone P. Rosa, an entomologist at the Federal University of Itajuba (UNIFEI) in the state of Minas Gerais. Both are authorities on the taxonomy of the beetle superfamily Elateroidea.

The survey recorded 51 species, most of which are fireflies (Lampyridae). The others are click beetles (Elateridae), which have two lanterns on their backs, and railworms, also known as glowworms (Phengodidae), which can produce different colors of light simultaneously.

In addition to samples collected in Goiás, the municipality of Mineiros, Emasi National Park and nearby farms, the researchers collected samples in Perolandia and Campinorte. In the state of Mato Grosso, the study covered Chapada dos Guimaras National Park and three towns (Alto Garchas, Novo Santo Antonio and Rio Manso). In Costa Rica, in the state of Mato Grosso do Sul, they visited two farms and the Sucurio Falls Municipal Park. Emasi National Park was the most productive site with 35 species.

Researchers say the diversity of these beetles in remnants of the Cerrado and neighboring farms in the park has declined dramatically over the past three decades, paralleling the replacement of soybean and sugarcane plantations with pastures, as well as the shrinking of the Cerrado as a whole. More specifically in the dense dry forests within the Cerrado, known as cerradão.

This article reports for the first time the occurrence of luminous termite mounds in Chapada dos Guimaraes National Park. Many mounds full of firefly larvae are found in Emasi National Park and neighboring areas. A previous study by the same group demonstrated the phenomenon of bioluminescence in the Amazon rainforest (Read it More here: agencia.fapesp.br/23640).

Annals of the Entomological Society of America

Pesticides and artificial lighting are also enemies of bioluminescent beetles. The bright light produced by humans prevents them from being deployed and reproduced by their mates. In particular, the researchers noted the absence of railworm larvae in recent expeditions. These insects can simultaneously emit red and green light and have significant biotechnological potential (Read it More here: agencia.fapesp.br/31481).

“Reduction in this family [Phengodidae] It was particularly obvious. Adult males are no longer attracted to light traps on farms surrounded by sugar cane since 2010. In addition, increasing levels of artificial lighting coming from nearby urban centers at night may threaten several bioluminescent species in Emasi National Park. The problem deserves special attention and further study,” said Vivian.

Extinction of bioluminescent species is not only a loss for biodiversity and the ecosystem services provided by these animals, but also represents lost technological and economic opportunities.

Bioluminescence—the production and emission of cold visible light by living organisms—is useful for many analytical processes used in scientific research, medicine, industry, and environmental management. Cold light means that less than 20% of the light produces thermal radiation (ie heat).

Bioluminescence results from the oxidation of luciferin, a compound present in these insects and other animals as well as some fungi. The oxidation process is catalyzed by enzymes known as luciferases.

Over the years, the group led by Vivian isolated and cloned the largest amount of luciferase of any group in the world. Luciferases are various insects, including flies, that produce blue light (Read it More here: agencia.fapesp.br/34061 and agencia.fapesp.br/29066).

Luminous beetles produce colors such as green, yellow, orange and red. Their luciferases are used to label cells and proteins, for example (Read more here: agencia.fapesp.br/36427 and agencia.fapesp.br/20609).

Vivian is currently coordinating the project Supported by FAPESP Development of bioluminescent reagents for immunoassays, environmental analysis and bioimaging. Reagents will be based on luciferases of Brazilian species. Most of these materials are currently imported.

“It's important to understand the fact that the Cerrado is not just scrub or bush. It is a reservoir of water in the soil, a source of evaporation that produces rain, and also a huge stock of exclusive species. We can learn a tremendous amount from all these treasures,” said Vivian.

About the São Paulo Research Foundation (FAPESP).

The São Paulo Research Foundation (FAPESP) is a public institution with a mission to support scientific research in all fields of knowledge by awarding scholarships, fellowships and grants to investigators affiliated with higher education and research institutions in the state of São Paulo, Brazil. FAPESP knows that the best research can only be done by working with the best researchers internationally. Therefore, it has established partnerships with funding agencies, higher education, private companies and research organizations in other countries known for the quality of their research and encourages grant-funded scientists to develop their international collaborations. You can learn more about FAPESP here www.fapesp.br/en and visit the information agency FAPESP at www.agencia.fapesp.br/en Keeping up to date with the latest scientific advances, FAPESP helps achieve this through its many programs, awards and research centers. You can also subscribe to the news agency FAPESP at http://agencia.fapesp.br/subscribe.