A study of more than 1,400 red protein-coding genes has uncovered one of the longest-running mysteries of insect evolution, rearranging their place in the tree of life and identifying which relatives are most they are closer.
A Bristol University study, published in the journal Palaeoentomology, drew on the largest available molecular database. The data were analyzed using new statistical methods, including more sophisticated algorithms, to test all historically suggested hypotheses about placing fleas on a tree. insect life and finding potential relationships.
The previously reversed conclusions hold theories about fleas, and the unusual anatomy has meant that they have eliminated classification in evolutionary terms. According to the authors of the study, contrary to popular belief, berries are technically like scorpionflies, which arose when they began feeding on vertebrate blood sometime between the Permian and Jurassic, between 290 and 165 million years ago.
The closest relatives to fleas are members of the scorpionfly family Nannochoristidae, a rare group with only seven species native to the southern hemisphere. Unlike the blood-thirsty lice, adult nannochoristid scorpionflies lead a peaceful nectar-eating life.
“Of all the parasites in the animal kingdom, berries have a special place. The Black Death, caused by a flea-transmitted bacterium, was the deadliest pandemic in recorded human history; it claimed the lives of up to 200 million people in the 14th century, ”said lead author and undergraduate student Erik Tihelka of the School of Earth Sciences.
“But despite their medical significance, the presence of fleas on the tree of life represents one of the most enduring enigmas in insect evolution.”
It used to be thought that all parasitic beasts that fed blood as predators or by living with vertebra hosts in their nests originated. In fact, blood feeding can occur in groups that were initially feeding on nectar and other plant secrets.
“It seems that the long mouth groups that are specialized in feeding nectar from flowers can be co-opted during the evolution of the course to draw blood,” says Mattia Giacomelli, a PhD student at Bristol University participated in the study.
Previous studies had suggested linking lice and anatomically abnormal groups of scorpionflies, but their exact relationships were still unresolved. The mystery was amplified by the fact that flea genomes have undergone rapid evolution, which makes the reconstruction of old evolutionary relationships challenging. Moreover, the nannochoristids are a very rare and little-studied group that occurs only in New Zealand, southeastern Australia, Tasmania, and Chile, so they are easily overlooked.
“The new findings indicate that we may need to review our entomology textbooks. Grooves no longer deserve the order of individual insect orders, but they should be classified within scorpionflies, ”said Chenyang Cai, associate professor at the Nanjing Institute of Geology and Palaeontology (NIGP) and researcher at Bristol University specializing in Mesozoic Insects.
“We have preserved fossil fuels from the Jurassic and Cretaceous. In particular, some Jurassic reds from China, around 165 million years old, are very large and measure up to two centimeters. They may have fed dinosaurs, but that’s very hard to say. What is more interesting is that these ancient fleas have important characters with scorpionflies. “