Rants and Musings About Science

Friday, April 28, 2006

New Species of Insect? - Look At Its Genitals!


Walking through the tropics of Grande Terre, the largest island of New Caledonia, a group of islands in the South Pacific about 750 miles east of Australia, he cuts his way through brush looking for undiscovered treasure. However, the booty is not the Holy Grail or some other relic from ancient history promising eternal life or supernatural power – he is looking for new species of animals. He is sure they are around him – somewhere. It’s around 80 degrees F and very humid. Temperatures on the island only vary around 10 oF all year round – a perfect incubator – there’s a reason why the place is nicknamed “the eternal spring.” This is what Eden could have looked like – lush and peaceful – a place for life to be born and discovered. It’s around here somewhere – what he is looking for.

A flicker catches his eye. It could be what he has been searching for his whole life. The elusive beast he has sought for his entire career is within his grasp; he can feel it. This emotion – discovering the unknown – is what drives him.

There sitting on a leaf among the emerald labyrinth is what he has traveled across the globe to find: a new species of insect.

“Those of us that work on insects are kind of blasé about those kinds of things,” says entomologist Randall “Toby” Schuh, the George Willett Curator and Chair of the Division of Invertebrate Zoology at the American Museum of Natural History and head project instructor of the Plant-Bug Inventory, a project that’s focus is to collect and categorize insects from the family Miridae.

Dr. Schuh has found thousands of new insects from this family. The easiest way to know that he has found a new species is by looking at its genitals.

“You start with the genitalia first,” says Schuh, describing how he figures out if he has found a new species. The tiny differences in the shapes and structures of the genitalia of insects can tell entomologists if a species is different from another.

This is an easier and less costly way of figuring out if you have found a new BUG X or just another Honeybee. Compared to doing expensive DNA sequencing experiments (one insect’s DNA is sampled that is the closest relative to the unidentified bug, their genomes - their genetic fingerprint – are compared and if they are different, it is a definite new find), just taking a peak at an insect's penis is the easiest way to categorize them.

“I let one of my younger colleagues handle that,” says Schuh, regarding DNA sequencing techniques, “I stick to the gross anatomy.”

Here is a cool page that has a video of a scientist looking at an insect's erection to tell if it is a new species!