September 27, 2003

A Dung Beetle Story

Find out how female dung beetles lay their eggs on this Moment of Science.

When a female dung beetle find a nice piece of dung, she digs a tunnel through it and down into the earth below. Next, she pulls small pieces of dung into the tunnel with her, making it into little balls that she can lay her eggs in. She lays one egg into each ball of dung. And when the eggs hatch, each larva feeds on its ball of dung in peace.

The amount of food does affect the size of the dung beetles. In fact, if a male larva gets plenty of food early on he will grow big in size, and he will grow horns to match. But if a male larva gets little food he will grow to be small, and he will grow either very small horns or no horns at all.

In mating, females don’t have a specific preference for either the big horned male of the smaller hornless males. About half the population of male dung beetles are big and horned, about half small.