A study of more than 1,400 genes encoding armor has solved one of the longest-running mysteries in the evolution of insects, reorganized its placement in the tree of life, and determined who its closest relatives are.
The University of Bristol work, published in the journal Paleoentomology, drew the largest insect molecular data set available. The database was analyzed using new statistical methods, including more sophisticated algorithms, to test all historically proposed hypotheses regarding the placement of insects in a living insect tree and the search for new potential connections.
The findings overturned theories about fleas, which previously claimed to have escaped classification in terms of evolution due to their unusual anatomy. Contrary to popular belief, the study authors are technically scorpion-like, which develops when fleas start eating with the blood of Perm and some time ago vertebrates. Jurassic, 290 to 165 million years ago.
The closest relatives of the Bira are members of the scorpion fly family, a rare group of only seven species native to the southern hemisphere. Unlike bloodthirsty bees, adult nannochoristid scorpion flies give rise to a peaceful creature that feeds on nectar.
“Of all the parasites in the animal kingdom, the flea is one of the leading. Black Death, caused by a bacterium transmitted by fleas, was the deadliest pandemic in human history; In the 14th century, it claimed the lives of about 200 million people. ” Leading author and undergraduate student of the School of Earth Sciences Eric Tihelka.
“However, despite its medical importance, the placement of fleas in the tree of life represents one of the most enduring mysteries in the evolution of insects.”
Previously, it was thought that all blood-feeding parasitic insects began to live either as predators or in the nests of vertebrate hosts. In fact, blood feeding can develop in groups that feed primarily on nectar and other plant secretions.
Mattia Giacomelli, a doctoral student at the University of Bristol who participated in the study, said: “It seems that elongated oral cavities, which specialize in feeding nectar from flowers, may be common during the evolution of the blood-sucking course.”
Previous studies have suggested a link between fleas and anatomically unusual groups of scorpions, but their complete relationship remains unresolved. The mystery was extended by the rapid evolution of flea genomes, which made it difficult to link ancient evolution. Moreover, nanocoristids are a very new and little-studied group, occurring only in New Zealand, southeastern Australia, Tasmania, and Chile, so they are easy to ignore.
“The new results show that we need to rethink our entomology textbooks. “Fleas no longer deserve the status of a separate insect line, but should be classified into scorpion flies.” Mesozoic insects.
“We have exclusively preserved fleas and fish belonging to the Jurassic fossils Chalk. In particular, some Jurassic bears, about 165 million years old from China, are actually giant and measure up to two centimeters. It may have been fed by dinosaurs, but it is extremely difficult to say. What is even more interesting is that these ancient beers share important characters with modern scorpion flies. ”
Reference: “Lice parasitic scorpion breasts” by Eric Tihelka, Mattia Giacomelli, Di-Ying Huang, Davide Pisani, Philip CJ Donoghue and Chen-Yang Cai, December 2020, Paleoentomology.
DOI: 10.11646 / paleoentomology.3.6.16