November 21, 2012
Wormhole Impressions In Old Art Provide A Snapshot In Time
Brett Smith for redOrbit.com - Your Universe Online
European Renaissance printers probably knew they were recording history for future generations, but what they didn´t realize is that they were also recording events related to biological history.
"The so-called 'wormholes' found in wood -- including furniture, rafters, oak floors, and woodblocks that were used to print art in books -- are not made by worms as the word suggests; rather, most are 'exit holes' made by those newly transformed adult beetles boring up to the surface and flying away," Hedges said.
After landing on a piece of wood, these beetles would lay their eggs in its cracks and crevices. The larvae then spend up to four years burrowing inside the wood as they munched on its cellulose. Eventually the larvae would metamorphosize into adult beetles and burrow out of the surface of the wood, creating the so-called wormhole.
The wormholes created in printers wood blocks would eventually show up in the printed materials they were used to make.
"These tiny errors or interruptions in the print serve as 'trace fossils,'" Hedges said. "They aren't the animals themselves but they are evidence of the animal's existence. They show that beetles invaded a particular piece of wood, even if that wood no longer exists."
Hedges also said the printed material serves as a better record than the actual wood blocks because it provides a snapshot in time, while the wood could have wormholes that were made over the course of centuries.
"By studying printed wormholes, we are seeing only the wormholes that were made at a specific moment in history," Hedges said. "Because most prints, including those in books, have publication dates, we know that the wormholes in question were made very close to that date, or at least between that printing and the first printing.”
“It's an almost perfect biological timestamp,” he added. “And in most cases, we also know where the book was printed. For example, if printed wormholes appear on a print made in Bamberg, Germany in 1462, then we know that the beetles that made the wormholes in the corresponding woodblock must have lived in or around that place at that time. So wormholes can tell us when and where a species existed with fairly good accuracy, more than 500 years ago, and that is amazing."
After analyzing the size of over 3,000 printed wormholes in printed art and books from 1462 to 1899, Hedges found prints from northern Europe averaged 1.43 mm in width, while those from southern Europe averaged 2.30 mm in width. The difference in sizes along with the different types of wood that each species is known to prefer indicates that two distinct beetle species created the holes.
"The northern European wormholes most likely were made by the Common Furniture Beetle, Anobium punctatum. The wormholes in southern Europe most likely were made by the Mediterranean Furniture Beetle, Oligomerus ptilinoides,” Hedges said. "This is surprising because it means that the two species' ranges were in close contact but, oddly, did not overlap along a precise dividing line.”
The biologist said that this method, along with extracting insect DNA from wood blocks, can assist in studying the beetle populations from this historical period.
The research is published in the journal Biology Letters.