Science reports:

From half-meter-long moths to fairy wasps smaller than sand grains, insects come in a stunning variety of shapes and sizes and constitute the most diverse animal group on Earth. But the insect species discovered so far may represent just a fraction of the total crawling, flying, and burrowing around the planet, according to a new study published today in the Proceedings of the National Academy of Sciences. Using statistical methods borrowed from another field, a team of entomologists estimates there may be as many as 20 million insect species on our planet—more than three times the previous estimate.

“Even though it’s a crazy large number, I believe their approach gives us the lower bounds of what insect diversity is in the world,” says Brian Fisher, curator of entomology at the California Academy of Sciences, who was not involved in the new study. “Whether it’s 14 million or 20 million, to me, is not the story here. The most important thing is that they’ve shown that our current estimate is a very low ball.”

Scientists have long debated exactly how many insect species there are, with the previous consensus being about 6 million. Over the past 3 centuries, entomologists have described about 1 million insect species, but finding and describing them all would be a daunting—if not impossible—task. “It’s not going to happen,” says Robert Colwell, an entomologist at the University of Connecticut and co-author of the new study. “There are not enough taxonomists to get anywhere near describing all the species.” [Continue reading…]