Tiny insect brains can solve big problems

Some bugs can recognize human faces, count and categorize, studies say

MSNBC

By Emily Sohn, Discovery News

Robber fly - Nature photographer Thomas Shahan specializes in amazing portraits of tiny insects. It isn't easy. Shahan says that this Robber Fly (Holcocephala fusca), for instance, is "skittish" and doesn't like its picture taken.

Eye-popping bug photos

Insects may have tiny brains, but they can perform some seriously impressive feats of mental gymnastics.

According to a growing number of studies, some insects can count, categorize objects, even recognize human faces — all with brains the size of pinheads.

Despite many attempts to link the volume of an animal's brain with the depth of its intelligence, scientists now propose that it's the complexity of connections between brain cells that matters most. Studying those connections — a more manageable task in a little brain than in a big one — could help researchers understand how bigger brains, including those of humans, work.

Figuring out how a relatively small number of cells work together to process complex concepts could also lead to "smarter" computers that do some of the same tasks.

"The question is: If these insects can do these things with such little brains, what does anything need a big brain for?" said Lars Chittka, who presented his arguments along with colleague Jeremy Niven in the journal Current Biology. "Bigger isn't necessarily better, and in some cases it could be quite the opposite."

Because we are intelligent animals with big brains, people have long assumed that big brains are smarter brains. Yet, scientists have found scant evidence to support that view, Chittka said. Studies that have made those connections are fraught with problems. "If you try many measurements," he said, "Eventually you will find one that shows a correlation."

There's a lot of evidence, on the other hand, that overall size is irrelevant when it comes to brain power. Among humans, individuals with larger noggins don't have higher IQs. Whales, with brains that weigh up to 20 pounds and have more than 200 billion neurons, are no smarter than people, with our measly 3-pound brains that have just 85 billion neurons.

Instead of contributing intelligence, big brains might just help support bigger bodies, which have larger muscles to coordinate and more sensory information coming in. Like computers, Chittka said, size might add storage capacity but necessarily speed or usefulness. At the same time, it takes a lot of energy to support a big brain.

On a smaller scale, scientists are finally moving past the idea that locusts, ants, bees and other insects are simple machines that respond to events in predictable ways, said Sarah Farris, an evolutionary neurobiologist at West Virginia University in Morgantown. Study after study now shows that insects can, in fact, change their behavior depending on the circumstances.

Honeybees, which have been the focus of Chittka's work, have tiny brains with fewer than a million neurons. Yet, the insects can classify shapes as symmetrical or asymmetrical. They can pick objects based on concepts like "same" or "different." They can also learn to stop flying after a prescribed number of landmarks rather than after a certain distance.

Ants and bees have notoriously complex social systems. Along with other insects, they can move in a surprising number of ways to communicate or get around.

Bees, for example, can sting, scout for food, guard the hive and fan their wings for ventilation, along with more than 50 other behaviors. The insect's behavioral repertoire, in fact, surpasses that of some vertebrates.”

"They are fantastically smart," Chittka said. "Perhaps we are only amazed by this because we think small brains shouldn't be able to do it."

In fact, scientists have calculated that a few hundred neurons should be enough to enable counting. A few thousand neurons could support consciousness. Engineers hope to use that kind of information to design programs that do things like recognize faces from a variety of angles, distances and emotional states. That's something bees can do, but computers still can't.

"Knowing how an insect functions and produces complex behaviors with a brain that's a million-fold smaller than ours makes it a little easier to envision that we might be able to model some of these behaviors," Farris said.

"It's wonderful to see that insects are finally being compared equally with vertebrate animals," she added. "They have smaller brains, but they still have complex enough brains to do these things."