Fossils show parental care in beetles

Helicopter parenting may be a modern invention, but parenting overall is nothing special. After all, beetles have been doing it for some 125 million years. Today’s Nicrophorus burying beetles are known for the care of their young. A male and female pair buries the carcass of a small vertebrate, such as a rodent or bird, removing the fur or feathers in the process; the female then

lays 20 to 40 eggs around it. After they hatch, about 5 days later, the larvae crawl toward the carcass nest, where the parents regurgitate partially digested carrion for them. To help the larvae find the nest, the parents make audible raspy sounds by rubbing the edge of their wing covers over raised ridges, or files, on the dorsal side of their abdomen, an action known as stridulating. The beetles also stridulate to alert their young to predators. To find out when the Nicrophorus beetles first began parenting, the scientists studied 44 exceptionally well preserved fossils of the ancestral beetles. They found that specimens dating to 165 million years ago from Inner Mongolia in China don’t have the requisite files. But the ridges are present on other fossils (pictured above) dating to 125 million years ago from Liaoning province and Inner Mongolia,suggesting some early form of parental care in the Nicrophorus lineage, the scientists report online today in the Proceedings of the National Academy of Sciences. Animals are thought to evolve parental care as a response to predators and competition for resources. And although the scientists could not identify the ancient beetles’ competitors, they did see an increase in the diversity of their predators during this same time period—leading them to target predation as the driving force behind their parental musicmaking.

Posted in Paleontology, Plants & Animals