A team from the Institut de Biologie du Développement de Marseille-Luminy (CNRS/Université Aix-Marseille 2) led by Nicolas Gompel and Benjamin Prud'homme has reported the discovery of the first three winged group of insects in the 250 million year evolutionary history of insects. The discovery was reported in the Journal nature on May 5, 2011, and was announced at the Alpha Galileo web site on the same day.
The subject insect species Membracidae (commonly called treehoppers) exist in a huge variety. The distinguishing characteristic of these insects is called a "helmet". The helmet covers the majority of the insect’s body and confers protection from predation due to the multiple colors and shapes the helmet exhibits.
The researchers have discovered that the helmet is actually a modified third wing. This is the first and only third winged insect known to date.
Microscopic and genetic examinations have shown that the helmet is attached to the thorax and has the articulation and musculature of a wing.
Genetic analysis indicates the same genes that are involved in the development of the two pair of wings in Membracidae are also responsible for the development of the helmet.
The development of a third wing is a unique evolutionary development that involves a protein (the Hox protein) that prevents wing development in insect bodies except on the thorax but in the case of Membracidae does not. The researchers think the wing forming genes became insensitive to the effect of the Hox protein at some time in the distant past.
This unique evolutionary development in Membracidae has been around for 40 million years.
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