Bigger Body or More Sperm? A Dung Beetle Conundrum

By Julie Leibach
Reporter, 探花精选 magazine
Published April 07, 2010


A male dung beetle (Onthophagus taurus) Credit: Armin Moczek/National Science Foundation

If Franz Kafka were writing today, he might have chosen an insect other than the dung beetle to represent 鈥檚  despairing protagonist, Gregor Samsa. Dung beetles, it turns out, merit the title 鈥淲orld鈥檚 Strongest Insect,鈥 according to a recent study in . Had Gregor known his own strength, perhaps he could have gotten out of that apartment, if not his existential crisis. Then again, maybe he just didn鈥檛 have a sexual outlet to put his power to good use.

 
Researchers have found that certain males of the dung beetle species Onthophagus taurus can pull 1,141 times their own body weight鈥攖hat鈥檚 like a 154-pound human lifting six double-decker buses, according to the .
 
The strength has to do with sex (are we surprised?). Some males will fight each other for the right to mate with a female, locking horns and pushing, writes the . Smaller and weaker males, on the other hand, forgo pugilism, relying on other, ahem, assets鈥攕pecifically, "substantially bigger testicles,鈥 according to the Telegraph. "Instead of growing super strength to fight for a female, they grow lots more sperm to increase their chances of fertilizing her eggs and fathering the next generation," said researcher Rob Knell, in the AFP article. This suggests that when their beefy rivals aren鈥檛 looking, the underlings swoop in to romance the beetle babe on the sly, 鈥淸using] their higher sperm count to up their chances at impregnating her in their single shot,鈥 writes .

But honestly, didn鈥檛 we know it all along? What a male lacks in brawn, he makes up for in sperm.