16-Million-Year-Old Hitchhiker Found: A Springtail Riding A Mayfly

We may associate hitchhiking with older times, but the truth is that it may have been an older practice than we can possibly imagine. Using an incredible composition of scans that resulted in a 3D image, scientists have identified a springtail on an adult mayfly's back - from 16 million years ago. 

"I had initially thought the creature on the mayfly may have been a tiny nymphal pseudoscorpion, as they are known to use other creatures for transport, and this behaviour is not uncommon to see in amber. I was interested in the fact that this was the first time a creature had been found on an adult mayfly but I didn't truly appreciate the significance of my find until I used the CT scanner and was able to identify the animal as a springtail," said lead author of the study Dr. David Penney from the Faculty of Life Sciences and the School of Materials at the University of Manchester. 

The springtail was hooked on to the adult mayfly with its prehensile antennae in the depression at the base of one of the mayfly's wings. Oddly enough a quick zoom in on the 3D image shows that the springtail was around 50 micrometers off the mayfly, indicating it might have tried to jump away just as it was entombed in amber.

The find is one of the first pieces of evidence that we have of any creature using the adult mayfly for transport. The first instance was discovered back in 2010, when scientists found five springtails hanging on to the leg of a harvestman arachnid. 

Phoresy, the transportation of one organism by another, can tell a lot about a creature's behaviour, and the scientists hope to learn more about the springtail and mayfly by analyzing their relationship with each other.

The fossil is not only useful to scientists because of its unique snapshot in time, but also because of the nature of the two creatures. The springtail is the nervous, jumping insect-like creature you see hopping around disturbed soil, and is incredibly hard to study. The adult mayfly cannot eat and only lives to reproduce with a lifespan ranging from one hour to a couple days. 

To create the 3D image, the scientists took over 3,000 X-Rays from various angles using a high resolution CT scanner.