wormhole art woodblock print dating beetle species




Hedges has nicknamed these telltale traces the "wormhole record," faint trails of these centuries-old animals—all told in hundreds of elegant prints.

wormhole art woodblock print dating beetle species

Diagram showing beetle larva and exiting adult courtesy of Blair Hedges


For a biological purpose, however, "these tiny errors or interruptions in the print serve as 'trace fossils,'" Hedges said in a prepared statement. "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."

The prints actually offer a more precise record of these invasions than the pieces of wood themselves. A beetle can lay eggs on a piece of wood at any point in time, whereas the marks from the woodblock on the paper print offer an indelible clue that the wood was infected before a particular print was made. "Because most prints, including those in books, have publication dates, we know that the wormholes in question were made very close to that date," Hedges said. "It's an almost perfect biological timestamp. And in most cases, we also know where the book was printed. So wormholes can tell us when and where a species existed with fairly good accuracy, more than 500 years ago, and that is amazing."

wormhole art woodblock print dating beetle species



He was then able to deduce the species of each beetle. "The size of the beetle closely matches the size of the hold made, and most species have preferences for the wood they eat," Hedges said. "This left two species as the probable hole-makers": the common furniture beetle (Anobium punctatum) in the northeast and the Mediterranean furniture beetle (Oligomerus ptilinoides) in the southwest. Other types of wood-boring insects don't share the same preference for dry, smooth-grained woods (such as apple, pear and box) that were used for woodblocks—instead targeting rotting, damp woods or those that are either extremely soft or extremely hard.

The line between these two beetles seemed to be surprisingly steady throughout the study period. "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," Hedges said. Local competition and climate differences might have kept these two species apart for centuries, if not millennia.

wormhole art woodblock print dating beetle species

Map of historic beetle species distribution courtesy of Blair Hedges

The discovery of historical separation is new. "Today and for the past 100 years, because travel, shipping and furniture transport tends to spread insects around, we find both species all over northern and southern Europe and elsewhere in the world," Hedges said. Indoor controlled climates might have also helped the beetles colonize new ranges.


The wormhole technique might also help solve some questions in art history as well. "There are some situations in which a book or print's origin is unknown," Hedges said. "Now that we know that different species of beetles existed in different locations in Europe, art historians can determine whether a book was from northern or southern Europe simply by measuring the wormholes."

The findings were described online November 20 in Biology Letters.