Saturday, 1 December 2012

Ancient Insect Camouflage

The moth I chanced upon in Ecuador
In 2012, I visited the Amazon Rainforest. The group I was with stretched into two: faster ones in  front, stragglers behind. I was between the two and briefly found myself alone on the trail. In that instant something fluttered down. I saw that it was a brown moth and it looked exactly like a couple of dead leaves. Its camouflage was so perfect.
A sketch of the 165 million year old fossil insect Juracimbrophlebia,
a comparison between the ginkgo leaf and the wings in the top right
and a  small  specimen of the ginkgo specie sin the bottom right

There are many arthropods which disguise themselves as objects in their environment. Yet recent fossil evidence has shown that this evolutionary behaviour has been around for hundreds of millions of years. Palaeontologists working in China have found that a once overlooked fossil of what was originally thought to have been a five leafed extinct form of ginkgo plant was actually an insect similar in shape to a dragonfly.

The fossil fly itself
The creature (Juracimbrophlebia ginkgofolia) was an ancient form of hanging fly, so named on account that it hung from a tree branch, waiting for prey.

It is likely that it evolved its incredible mimicking abilities in order to simultaneously hide from its predators. The perfect nature of its camouflage provided by its four wings and abdomen were so similar to the leaves of the ginkgo Yimaia capituliformis that it managed to fool experts after 165 million years.

It is possible that the two species co-evolved in a mutually beneficial relationship. The relationships between plants and insects are some of the most fundamental in the biological world, having driven the evolution of not just the two dependent parties, but that of mammals, birds and even reptiles.

This tiny, 165 million year old fossil fly, shows just how ingenious nature can be, engineering solutions to problems which have stumped many. Big changes such as the Cambrian Explosion can result in the rise of new animal groups, but such events are rare. It is the smaller relationships and adaptations which create the diversity of life. The moth in the Amazon Rainforest was one small part of this.