Wasp Cocoons Found in Dinosaur Egg Fossil

Posted on July 16, 2011

Researchers in Argentina have found well preserved fossils of insect cocoons inside 70 million year old fossils of titanosaur sauropod eggs. The research was published in the scientific journal Palaeontology.

The eggs were discovered in 1989 in the Patagonia region of Argentina. Recently it was discovered that one of the broken eggs contains tiny sausage-shaped structures, 2-3cm long and 1cm wide. The structures closely resemble fossilized insect cocoons. They are similar in size and shape to the cocoons of some species of modern wasp.

The sceintists say the results indicates that "wasps probably participated in the food web, mostly composed of scavenging insects, which developed on the rotten egg." The researchers believe the egg was broken by force. Fractures in the egg shell enabled scavenging creatures to feed upon its contents. The large dinosaurs eggs would have supported plenty of insect scavengers. The wasps could have been feeding on insects that were gorging on rotting egg contents.

The palaeontologists believe the insect scavengers played an important role in helping clean up nest sites. Some dinosaurs revisited nest sites each year to lay new eggs, so the insect communities were essential to removing decaying material ahead of the nesting season.

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