Why Dung Beetles Are Always 'Reaching For The Stars'
It is a known fact that some species of the lowly dung beetle that feed off animal droppings, first form their finds into little balls and roll them away to a safe distance. However, what the scientists had never been able to figure out is how the beetle is able to navigate itself and its tasty little morsel in a straight line, away from the pile of droppings where they are likely to encounter competitors. Now, thanks to a team of Swedish researchers the mystery has been at least partially solved and the answer, is causing quite a stir amongst the scientific community.
The research into these dung beetles often referred to as 'rollers' began last year, when Emily Baird at Sweden's Lund University and her colleagues observed a strange phenomenon - Every time these little insects created a mound of animal droppings, they first climbed atop and danced around in circles as if, celebrating. But upon closer observation, they realized that the little insect was not being jubilant, but instead, looking at the skies to get its bearings.
Turns out that the upper part of the dung beetle's eyes has the capability to ascertain the direction the light vibrates from - So, when it looks up to the skies it is getting its current bearings in relation to the celestial bodies, so that it can then decide what direction to move in, to get away from the dung pile.
However, the one thing that still remained a mystery was how the beetles could continue walking in a straight line even on moonless nights, especially given that they are doing so moving backward, with their heads on the ground - The scientists began to wonder if just like birds, seals and humans, these insects too, had the capability of using stars to navigate their way.
But given that they have really tiny eyes, the researchers knew that they could not be using individual stars - So what stars were these tiny insects seeking out? To try extract their secret, they placed the beetles inside a planetarium and conducted several different scenarios - like beaming only the brightest stars, the complete starry sky and even, just the Milky Way. What they discovered was that the beetles responded best when the sky was either full of stars or when it contained just the Milky Way.
This along with previous experiments conducted on another species of the dung beetle which showed similar results has convinced the researchers that this tiny beetle whose brains have 0.0001% of the neurons found in a human brain, navigates its way around using the Milky Way as its guide - Making it the first animal or insect found with this capability.
This report which was published on January 24th edition of Current Biology, doesn't explain what the beetles in the Northern Hemisphere that don't have access to the full array of the Milky Way do. Another thing the scientists are still curious about is what cues the beetles consider most important when they are faced with a sky full of the celestial lights - The moon, polarized lights and the Milky Way!
Dung beetles, that all belong to the super family Scarabaeoidea, can be found in almost any habitat unless it has extreme hot or cold weather. While all of them feed exclusively on feces, the way each species does it, is different. Some, are like the rollers that were researched above, others known as tunnelers, bury their treasure wherever they find it. A third group is even smarter - They just live inside the manure! And while their choice of food may sound gross, what they do helps keep our food sources healthy. By burying and consuming the dung, they not only help the soil structure, but also, protect livestock. That's because dung left lying around attracts pests like flies. The American Institute of Biological Sciences estimate that the feces burying habits of these tiny beetles save the US cattle industry an estimated $380 million USD annually!
Resources: livescience.com,foxnews.com,dailymail.co.uk, wikipedia.org