A yet unknown family of beetles was discovered in the Brazilian Atlantic Forest by an international team of entomologists including Robin Kundrata from the Department of Zoology at the UP Faculty of Science. This new evolutionary lineage of beetles is characterised with a unique body structure and genetic make-up. While males in this family have wings and the ability to fly, the wingless females are morphologically almost indistinguishable from their larvae. The results of the study dedicated to this new beetle family from one of the most endangered biomes in the world were published in the prestigious journal Scientific Reports.
Scientists have already been able to describe the majority of beetle families, therefore discoveries of new developmental lineages at this level are very exceptional today. The recent discovery of a completely new group of beetles from the Brazilian rainforest has thus aroused great interest, not only in academic circles. “These beetles have escaped the attention of scientists, mainly due to their small size and also their hidden lifestyle in the soil and forest floor. During the first expedition, only two larvae were discovered. Since no one could identify them, they were preserved in the laboratory until adulthood. Coincidentally, they were representatives of both sexes,” said Kundrat, who collaborated with colleagues from Brazil and Germany on the research of this group of beetles, about the unexpected discovery.
The surprise for entomologists was that the male had both pairs of wings, including the elytra, and was fully able to fly, while the female was wingless and resembled her own larva in appearance. “This phenomenon of an individual retaining some larval signs in adulthood is called neotenia. In beetles, it usually involves females much more noticeably,” said Kundrata.
Entomologists eventually discovered a total of three species of this unique line in Brazil and classified them into two genera. They called them Jurasai and Tujamita, which are terms derived from the local indigenous languages. A detailed study of the morphology of all developmental stages combined with the results of DNA analysis subsequently showed that it is a completely new independent developmental branch of beetles, which deserves the status of a family and was named Jurasaidae.
“The discovery of this family has brought a lot of new knowledge about the evolution of neotenia in beetles. It arose several times and may not be as pronounced in every group. Both genera of Jurasaidae are a shining example of this. While females of the genus Jurasai are at first sight almost indistinguishable from their larvae, females of the genus Tujamita have at least some parts of the head and chest partially similar to adult males,” said Kundrata in explanation of the interesting morphology of the newly discovered line.
Due to the fact that neotenic groups with non-flying females occupy relatively small areas due to their limited ability to spread and usually strong dependence on habitats with long-term stable climatic conditions, according to Kundrata they become excellent indicators of historical refuges of tropical rainforests in periods of drier climates.
The Atlantic Forest is the second largest tropical rainforest in Brazil. It covers an over 3,000 km long strip along the Atlantic coast. Due to excessive deforestation, approximately one tenth of the area of the original forest has been preserved, while only about a third falls under protected areas. Nevertheless, the area is characterised by its unique species diversity and a number of endemic taxa. “It is one of the most endangered biomes in the world,” pointed out the Olomouc entomologist, according to whom the remaining fragments of the original rainforest are home to one of the most diverse faunas on the planet.
The largest and best protected parts of the Brazilian Atlantic rainforest are now maintained in the mountain ranges in the south of the territory. This is exactly where all the representatives of the new family Jurasaidae were found. “The fact that this forest hosts beetles whose survival is bound to long-term stable forest habitats due to their cryptic lifestyle only further reinforces the importance of this region as a priority area for local nature protection,” added Kundrata.