The killer neural wiring that links eyes and wings :

JEWEL wing damselflies live up their names : They dart through the filtered sunlight of ferny stream beds and forests like wands made of brilliantly colored gems.

''They fly around like little helicopters until they see prey,'' usually flying insects, said Paloma Gonzalez-Bellido, a biologist at the University of Minnesota. Then they lunge at their meals in a burst of speed.

You might mistake jewel wings for their colorful cousins, dragonflies. New research shows that these two predators share something very profound than their appearance, however.

In a paper in Current Biology, Dr. Gonzalez-Bellido and colleagues reveal that the neural systems behind jewels wings' vision are shared with dragonflies, with whom they share a common ancestor that lived before the dinosaurs.

But over the eons, the brain wiring has adapted itself in different ways in each creature, enabling a radically different strategies.

For flying creatures, instantaneous, highly accurate vision is crucial to survival. Recent research showed that birds of prey that fly faster also see changes in their field of vision more quickly demonstrating the link between speed on the wing and speed in the brain.

But the group of insects that includes jewel wings and dragonflies took to the air long before birds were even on the evolutionary horizon, and their vision is swifter than any vertebrate's studied thus far.

Researchers looking to understand how their vision, flight and hunting abilities are connected are thus particularly interested in the neurons that send visual information to the wings.

Jewel wings behavior involves attacking what's directly in front of them, the team found.

But recordings made in the lab by Dr. Gonzalez-Bellido's team confirmed that dragonflies rise up in a straight line to seize unsuspecting insects from below, successfully snugging their prey 97 percent of the time.

The difference in hunting behavior may be linked to the placement of the insects' eyes. Jewel wings eyes are on the other side of the head, facing forward. The dragonfly's eyes encase the top of the insect head in an iridescent dome.

The visual neurons that guide the dragonfly's wing muscles operate almost as if the creature had a singly eye.

To look more closely at the neurons linking vision and flight, the researchers equipped jewel wings with sensors and showed them a video of a moving dot., comparing it with earlier dragonfly research.

When a neuron fired, a popping sound filled the researchers' ears, allowing them to tell exactly which movements each neuron responded to. Jewel wings see best what's right in front of them, they found, while dragonflies' clearest vision is just above them.

The researchers were intrigued to find that while jewel king neurons didn't always respond like those in dragonflies, the number of neurons and and their organization were similar.

That suggests that the system that conveys the information from the eyes to the wing muscles has roots millions of years older than the older than the oldest dinosaurs.

In the intervening eons, the system evolved to to suit individual insect species. the most distinctive difference appeared when the researchers blocked the view of either of a jewel wing's eyes using a black eye patch. If either eye was covered, certain neurons fell silent. These neurons were getting messages from both eyes.

That suggests that jewel wings are summing up information from both eyes as they zip around, something dragonflies do not do.

Dragonflies hunt in the open, in the bright sunlight, said Dr. Gonzales-Bellido, where pinpoint accuracy is key. Jewel wings hunt in the mixed shadows and sunbeams of forest streams, where using vision from two separate eyes to avoid obstacles may be more important.

The World Students Society thanks The Science Lab : The New York Times 


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