Beetles Keep Their Cool With Dung
October 23, 2012

Feeling Hot – Grab Some Dung And Cool Off Beetle Style

Lee Rannals for - Your Universe Online

The next time the thermostat hits the triple digits outside, instead of paying a high electric bill for the month, take a page out of the dung beetle's playbook and try cooling off with some fresh feces instead.

Researchers have discovered that dung beetles use their dung balls to keep themselves cool as they push a weight of up to 50 times heavier than their own bodies across the hot sand.

"Like an air conditioning unit, the moist ball is cooled by evaporative cooling," said Jochen Smolka of Lund University.

Experiments showed that this only held true when the beetles were crossing hot ground, and that the insects even climb on their balls seven times as often than those on cooler ground.

"The beetles climb on top of their moist balls whenever their front legs and heads overheat," writes Prof. Marcus Byrne from University of the Witwatersrand. "We stumbled upon this behavior by accident while watching for an 'orientation dance' which the beetles perform on top of their balls to work out where they're going. We noticed that they climbed their balls much more often in the heat of the midday sun."

This is the first time scientists have observed insects using feces as an air conditioning method.

The team stumbled upon the behavior by accident, while watching the beetles perform an "orientation dance."

Dung beetles perform these dances to work out where they are going. As the team was watching for the dancing, they noticed that the beetles climbed on top of their balls of dung much more often in the heat of the midday sun.

Once on top of the ball at midday, the beetles were seen "wiping their faces," which is a behavior that they suspect is spreading regurgitated liquid onto their legs and head to cool them down further.

In order to prove it was because they were hot that they climb on the balls, the team applied some cool silicone boots to the front of their legs as alternative protection from the heat.

"To our great surprise, this actually worked, and beetles with boots on climbed their balls less often," Smolka said.

The findings could be considered a reminder of the creative solutions nature has found over time.

"Evolution has an astonishing ability to make use of existing structures for new purposes — in this case using a food resource for thermoregulation," Smolka concluded.

The researchers published their findings recently in the journal Current Biology.

Image 2 (below): Researchers from South African and Sweden applied silicone boots to the front legs of dung beetles as alternative protection from the heat to prove their theory that dung beetles climb their dung balls to cool down. Credit: Wits University