Ancient larvae built predator-thwarting mazes

BALTIMORE — Modern animals such as rodents and platypuses dig underground labyrinths to confound predators. So did ancient insect larvae, new research suggests.

Branching tunnels called Treptichnus embedded inside ancient rocks are among the oldest and most widespread preserved structures built by ancient animals, first appearing about 541 million years ago. The mazelike layout of these subterranean passageways was meant to frustrate unwanted intruders, paleontologist Patrick Getty of the University of Connecticut in Storrs proposed November 1 at the Geological Society of America’s annual meeting.

The burrows, possibly dug by fly larvae, are composed of short, forking passageways. Scientists commonly describe these structures as the trails left behind by hungry sediment-munching critters. But that explanation misses the bigger picture, Getty said. Constructing an underground maze requires extra work compared with the efficiency of a single, spiraling tunnel like those left behind by some other sediment eaters, he says.

Analyzing Treptichnus in nearly 200-million-year-old sedimentary rock, Getty and colleagues realized that the tunnels served two purposes: feeding and defense. An invading predator would probably take multiple wrong turns as it hunted for its next meal and eventually give up, Getty proposed.

Tracing the origins of this maze-building behavior will provide clues about how predation has changed over time, Getty said.