Wasps in dinosaur eggs

Egg scavengers cleaned dino nesting sites

Biology News

Wasp cocoons in a fractured titanosaur egg

Well-preserved fossil insect cocoons have allowed researchers in Argentina to describe how wasps bred in rotting dinosaur eggs. The research is published today in the scientific journal Palaeontology. This new discovery provides an insight into the lives of the tiny creatures that lived at the feet of the dinosaurs.

Scientists found the 70-million-year-old titanosaur eggs in 1989 in southern Argentina, an area well known for yielding fossils of sauropod dinosaur eggs and even embryonic dinosaurs. They later saw that some of the broken eggs contained fossilized insect cocoons that were similar in size and shape to the cocoons of certain modern wasps.

There are many records of dinosaur eggs, and even several records of fossil cocoons. But author Jorge Genise of the Museo Argentino de Ciencias Naturales says "this is the first time that these cocoons are found closely associated with an egg."

The results indicate "that wasps probably participated in the food web, mostly composed of scavenging insects, which developed in the rotten egg."

Breakage of the eggs allowed scavenging creatures to feed on their contents. Wasps would probably have been feeding not on the eggs themselves, but on ants, spiders, beetles and other creatures that initially entered the rotting egg.

Palaeontologists think some dinosaurs revisited nest sites year after year to lay new clutches of eggs, so these scavengers would have been important in cleaning up for new nesting seasons.