An amazing new study found something very interesting when fake caterpillars were placed on leaves throughout the world.
A remarkable new study that was just published in the journal Science has resulted in a groundbreaking discovery thanks to fake caterpillars glued to leaves. The study was trying to determine how much caterpillars were at risk depending on their location in the world, and interestingly enough, scientists found out that there’s a huge difference, not just with location but elevation.
Scientists used these fake caterpillars to accumulate bite marks, and then used those marks to determine what animal attacked the slug and how many times. Caterpillars near the equator were eight times more likely to get eaten than one nearer to the poles, according to the paper, which used 3,000 dummy caterpillars spread across 31 sites.
The sites were very diverse, ranging from the Arctic Circle all the way down to southern Australia. And it found out that elevation also had an impact in addition to location, with caterpillars at higher elevation being at a much lower risk than those at lower elevations.
“What was most fascinating was that the pattern was not only mirrored on both sides of the Equator, but also appeared across elevational gradients,” says Tomas Roslin, who led the analyses, in a statement from the Swedish Research Council. “Moving up a mountain slope, you find the same decrease in predation risk as when moving towards the poles. This suggests a common driver could be controlling species interactions at a global scale.”
“People often think of vertebrates as the most important predators in the tropics, but birds and mammals weren’t the groups responsible for the increase in predation risk towards the Equator. Instead tiny arthropod predators like ants drove the pattern”, explains Will Petry, who contributed data from California, and also helped analyze the data.
“The findings may also affect herbivore evolution”, says Petry. “Our results suggest that tropical caterpillars would do well to target their defenses and camouflage specifically against arthropod predators. Closer to the poles, lower predation may allow caterpillars to let their guard down.”