The Discovery of a New Species of Parasid Wasp in the Fruit Fly Drosophila melanogaster as a Signal from the Early Americas
All the ancient Rapanui carried Native American ancestry in their genomes, which the researchers determined had probably resulted from mixing dated to the fourteenth century. The lack of ancient and modern human genomes from the Americas makes it difficult to identify the people who the ancient Rapanui encountered. Still, the finding that Rapanui encountered Native Americans hundreds of years before Europeans arrived is “a banger result”, says Nägele. Where this happened and who traveled can be looked into by us.
Despite being a hugely studied model organism, it seems that there’s still more to find out about the fruit fly Drosophila melanogaster, as researchers have discovered a new species of parasitoid wasp that infects the species. Unlike other parasitic wasps, this one lays its eggs in adult flies, with the developing larva devouring its host from the inside. The minuscule wasp was discovered by chance in an infected fruit fly collected in a Mississippi backyard and analysis suggests that despite having never been previously identified, it is widespread across parts of North America.
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The Nature Podcast: Can ancient Rapanui DNA address the ecological ecology of the Polynesian islands? An archaeoeogeneticist’s perspective
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The latest analysis, published on 11 September in Nature1, “serves as the final nail in the coffin of this collapse narrative”, says Kathrin Nägele, an archaeogeneticist at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. There is an issue with the image of Indigenous people.
The study was endorsed by and input from officials and Indigenous community members. The study’s sample was collected in the 19 and 20th century and is currently sitting in a Paris museum.
The ancient Polynesians developed a flourishing culture famous for its many marble statues, called moai.
The landscape of the island was denuded of the palm trees when Europeans first arrived in 1722, estimating that the population was between 1,500 and 3,000. By the late 19th century the Indigenous population had dwindled to 110 people, due to an outbreak of diseases and the kidnapping of part of the inhabitants by slave traders.
The ‘ecocide’ theory, that a pre-contact population of 15,000 or more plundered the once-pristine island’s resources, has been challenged by researchers who have questioned humans’ role in deforestation and its effects on food production, as well as the large estimates for the population.
Anna-Sapfo Malaspinas, a population geneticist at the University of Lausanne, Switzerland, and Vctor Moreno-Mayar, an evolutionary geneticist at the University of Copenhagen, were hopeful that ancient Rapanui DNA could address the ecocide theory.
Both ancient and modern genomes carry information about how a population’s size has changed over time. The segments of DNA shared between individuals tend to have a longer and more abundant existence when there is a small population.
Translating these trajectories into actual population numbers is not straightforward, but further modelling suggested that the genetic data are not consistent with, for example, a drop from 15,000 to 3,000 people before the eighteenth century. “There’s no strong collapse,” says Malaspinas. We are pretty sure that it did not happen.
The finding of Rapanui in the Americas will not come as a surprise to the Polynesian people, according to Keolu Fox. “We’re confirming something we already knew,” he says. Do you think an area like Hawaii or a Polynesian island would miss a lot of people?
The researchers got a similar reaction when they presented their initial findings. Malaspinas recalls being told that ‘of course we went to the Americas’. She and other colleagues traveled to the island many times to meet with officials and residents.
Ngele, who is employed in Polynesia, thinks that the researchers did well engaging with people in Rapa Nui. She believes that scientists should be involved in returning Indigenous remains to where they came from.