Butterfly experts have been angered by the appearance in a top journal of a paper they say is bizarre and unsupported by evidence, claiming it was published only because it was ushered in by a “bigwig” in the field.

The paper, by Donald Williamson, a retired academic from the University of Liverpool, was published in advance online late last month in the Proceedings of the National Academy of Sciences of the United States of America (PNAS).

Its publication was via a special “communication” mechanism understood to be unique to PNAS. This allows national academy members to bypass normal editorial procedures and submit papers that they consider to be of particular importance without the normal peer-review requirements, although they must obtain two referees.

Dr Williamson’s article was communicated by Lynn Margulis, a well-known professor in the department of geosciences at the University of Massachusetts Amherst.

It makes the extraordinary claim that caterpillars and butterflies have different evolutionary histories – that rather than being a single lineage that evolved through two different life stages, they are a hybrid that resulted from the accidental mating of a flying insect with a worm-like species.

But butterfly experts say the idea is unsubstantiated and have called into question the method by which such a seemingly unsupportable theory could end up in one of the world’s most prestigious journals.

In a posting called “Worst paper of the year?” on his blog “Why Evolution Is True”, Jerry Coyne, a professor of biology at the University of Chicago, says the paper’s appearance is an example of a “bigwig” exercising undue influence.

Max Telford, a reader in zoology at University College London, told Times Higher Education that “clearly something has gone wrong”.

“There is no science in it. I don’t think it could possibly have got through on a normal peer-review process,” he said. “It is unique to PNAS that they have got this back-door way of getting things through.”

He added that Professor Margulis was an “incredibly important and highly respected” scientist in evolutionary circles, having come up with the idea, considered dubious at the time but now textbook science, that cell organelles originated as bacteria that were subsequently absorbed by the cell. But extrapolating that thinking to butterflies went too far, he said.

“Maybe there needs to be a forum for off-the-wall ideas, but at the same time, this was not reviewed to the standard that one would expect in PNAS,” he said.

Chris Jiggins, who leads the Butterfly Genetics Group at the University of Cambridge, also rubbished the paper and labelled the PNAS system “quite nepotistic”.

“I think it’s nonsense – there is no data in the paper. It claims to use molecular biology evidence in the abstract, but there isn’t actually anything in there,” he said.

Professor Margulis did not respond to a request from Times Higher Education to comment.

Dr Williamson described Professor Margulis as a “good friend” who had been an “enthusiastic supporter” of his hypothesis over the years.

Saying that he had been studying larvae “considerably longer” than any of his detractors, he challenged the sceptics to refute the hypothesis by DNA analysis. He did note, however, that the paper in question, “Caterpillars evolved from onychophorans by hybridogenesis”, had been rejected by seven journals before being published in PNAS.

Meanwhile, in a September editorial, PNAS announced plans to scrap the communication submission process from June next year.

zoe.corbyn@tsleducation.com