Look what's for dinner! - facts about dung beetles

Ranger Rick, August, 1995 by Deborah Churchman

POOP HAPPENS--over and over, all around the world. For example, cows in the United States drop more than one billion cow patties each day!

With all these droppings dropping, why aren't we up to our ears in doo-doo? Because lots of insects and worms dine on droppings--or dung or feces (FEE-seez) or whatever you want to call it. And some of the best diners are dung beetles.

So far, scientists have found 6000 species (kinds) of dung beetles. Some specialize in one type of animal droppings. For example, one species stays on a sloth's rear end. When the sloth's droppings drop, so does the beetle--onto the dung.

But most dung beetles go for almost any kind of dung. What they do with it depends on which species they are.

Some species live in a pile of droppings while they eat it. Others tunnel below the pile. From there they pull bits of poop underground.

Then there are the rollers--beetles that form wads of dung into balls. They usually roll these balls away from the pile, bury them, and dine in safety--away from their enemies. Turn the page to see them go!

It's MY Ball!

Sometimes beetles get their dung by snitching it from other beetles. Look out--here comes a robber! (1) It scrambles up the side of a ball to challenge the ball's maker on top. The robber starts whacking the other beetle with its feet. The battle of the beetles is on!

But the maker is still the master. It throws the robber onto its back (2). The robber squirms around, desperately trying to turn over. And that gives the roller time to get the ball away from its enemy. (Sometimes a third beetle will sneak over during a fight and steal the ball from both of the beetles!)

Now the roller goes back to rolling (3). It uses its long, curved hind legs to kick the ball backward. The beetle will probably move that big, heavy ball only a few inches from the dung pile. But if it has to, it can move the ball as far as 10 feet (3 m). Where's it going? To a place where the soil is soft and easy to dig. (Find out why on the next page.)

Going, Going, Gone!

Other dung beetles aren't the only robbers that the ball makers have to look out for. Some other kinds of insects also would like to get a big, juicy ball of dung. And animals such as mice and mongooses would like to get a big, juicy dung beetle. So what's the poor beetle to do?

Dig and bury. That's what rollers like this one usually do with their dung balls. (See photos at left.) Using its head as a shovel and its front feet as rakes, this beetle digs soil from beneath its ball. Slowly the ball drops down. When the beetle has finished, it will have buried the ball an inch or two below the surface. (Some beetles bury balls as far as six feet under!)

Once its ball is safely buried, the beetle starts eating its yummy scoop of poop. Any leftover dung helps to fertilize the soil. And all that digging the beetle has done breaks apart the soil and lets in air. The loose, airy soil is good for plants to grow in.

Rock-a-bye, Beetle

When it's mating time, a male roller uses a dung ball to attract a female. If she accepts, she helps the male roll the ball to a spot where they bury it.

When they've found a good place, the two work together until the ball is buried. (Photo 1 shows a cutaway view.) They mate, and then the male digs his way out. (Some kinds of dung beetle males stay to help make a nest.)

Next the female pushes and packs the ball until it's shaped like a pear (2). See her there, working on the ball? Then she carefully lays an egg near the top (3). (The photographer took a ball out of the soil to take some of these pictures.) The female may stick around for a few days to keep mold and other fungi from growing on the ball. Finally she leaves to start another nest.

Later, the egg hatches. The new beetle larva (young) finds itself surrounded by its dinner (4). It eats and grows, and grows and eats.

Follow That Smell!

The beetle larva keeps eating and growing until it changes into a pupa (below). Then the pupa changes into an adult beetle. The adult chews its way out of its dung ball and digs up through the soil.

Using its sensitive antennas, the dung beetle checks the air for odors. It's hunting for the special smell of droppings. There--a whiff of a fresh meal!

The beetle spreads its new wings and takes off (right). When it reaches the dung pile, it'll roll a ball and eat it.

If enough dung beetles show up, the whole pile may disappear in just a few hours. And that's good. Because right now, while you're reading this, poop is happening all over the world. Hey, dung beetles--come and get it!