The disappearance of bioluminescent beetles from the Brazilian Cerrado: a loss for biodiversity and technology
In the darkness of the Cerrado, the savannah of Brazil and its second largest biome, the larvae of the beetle Pyrearinus termitilluminans, which live in termite mounds, display green lanterns to capture prey attracted to the bright light. This phenomenon is becoming increasingly rare, signaling a loss not only of biodiversity, but also of technological and economic opportunities.
An alarming decrease
Professor Vadim Viviani, from the Federal University of São Carlos, noted a significant decrease in this phenomenon over the last 30 years.
“ In the 1990s, we were seeing a lot of these termite mounds full of fireflies and other bioluminescent insects, even in grazing areas. Now sugarcane is grown in most areas and we hardly see any “, he explained.
This decrease was one of the main conclusions of a study supported by FAPESP, as reported in an article by Professor Viviani and his collaborators published in the Annals of the Entomological Society of America.
The other co-authors of the article are Cleide Costa, researcher at the Zoology Museum of the University of São Paulo, and Simone P. Rosa, entomologist at the Federal University of Itajubá. Both are authorities on the taxonomy of the beetle superfamily Elateroidea.
The results of the study
The study identified 51 species, most of which are fireflies (Lampyridae). The others are beetles (Elateridae), which have two lanterns on their back, and glowworms, also known as glowworms (Phengodidae), which can produce light of different colors at the same time.
The researchers noted a sharp decrease in the diversity of these beetles in the remains of the Cerrado and farms neighboring the park over the past three decades, alongside the substitution of soybean and sugar cane plantations with pastures, as well as a reduction in the Cerrado as a whole, and more specifically in forest areas dense dry weather known as cerradão.
Threats to bioluminescent beetles
Pesticides and artificial lighting are also enemies of bioluminescent beetles. The bright light produced by humans prevents them from being located by their partners and from reproducing.
In particular, researchers noted the absence of glow worm larvae during recent expeditions. These insects can emit red and green light at the same time and have significant biotechnological potential.
Bioluminescence, a process widely used in research
Bioluminescence – the production and emission of cold visible light by living beings – is useful for many analytical processes deployed in scientific research, medicine, industry and environmental management. Cold light means that less than 20% of the light generates thermal radiation (i.e. heat).
Bioluminescence comes from the oxidation of luciferin, a compound found in these insects and other animals, as well as some fungi. The oxidation process is catalyzed by enzymes called luciferases.
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Over the years, the group led by Prof. Viviani has isolated and cloned the largest number of luciferases in the world. THE luciferases come from different insects, including flies that produce blue light.
Luminescent beetles produce colors such as green, yellow, orange and red. Their luciferases are used to mark cells and proteins, for example.
“ It is important to understand that the Cerrado is not just scrub or bush. It is a reservoir of water in the ground, a source of evaporation that generates rain, and also an immense reserve of exclusive species. We can learn a lot from all these riches », concluded Professor Viviani.
Synthetic
The extinction of bioluminescent species is not only a loss to the biodiversity and ecosystem services provided by these animals, but also represents lost technological and economic opportunities. Bioluminescence, which is useful for many analytical processes deployed in scientific research, medicine, industry and environmental management, is in decline.
For a better understanding
What is bioluminescence?
Bioluminescence is the production and emission of cold visible light by living beings. It is useful for many analytical processes deployed in scientific research, medicine, industry and environmental management.
What is causing the decline in bioluminescent beetles?
The decrease is due to several factors, including the substitution of soybean and sugarcane plantations with pastures, the reduction of the Cerrado as a whole, the use of pesticides and artificial lighting.
What are the consequences of this reduction?
The extinction of bioluminescent species is not only a loss to the biodiversity and ecosystem services provided by these animals, but also represents lost technological and economic opportunities.
What is the Cerrado?
The Cerrado is Brazil’s savannah and its second largest biome. It is currently threatened by intensive agriculture and deforestation.
What is Pyrearinus termitilluminans?
The Pyrearinus termitilluminans is a species of beetle that lives in termite mounds in the Cerrado. Its larvae display green lanterns to capture prey attracted to bright light.
References
Article: “Inventory and ecological aspects of bioluminescent beetles in the Cerrado ecosystem and its decline around Emas National Park” – DOI: 10.1093/aesa/saad029