A 16 million year old mayfly tells us how animals behave today

Scans of a 16-million-year old fossil in amber have revealed the first example of any animal using an adult mayfly for transport, shedding light on a phenomenon that has never been observed, though in all likelihood still happens today.

Amber is tree resin, which hardens to the valued gemstone we all know.  Animals and plants can get caught in amber as it runs down the tree, and it preserves them almost perfectly.  16 million years ago a mayfly got caught in a piece of amber.  It was amazingly preserved but otherwise unremarkable.  But when Dr David Penney and colleagues at the University of Manchester took 3000 X-rays of this specimen with a computer tomographic (CT) scanner, they discovered something amazing.

The mayfly in the amber had a passenger: a tiny springtail can be seen secured in a depression by the mayfly’s wings.  Springtails are 1-2mm long creatures, related to true insects.  They easily colonise islands, but until now it was unclear how they travelled there.  This is the first time anyone has seen a creature using an adult mayfly for transport, and only the second time springtails have been seen hitchhiking on another animal (the first time was also in amber), even though insects today probably behave this way.

If the image is magnified, you can see that the springtail is slightly apart from the mayfly (by 50 micrometres), so was just about to jump off.  The amber managed to trap these creatures at a fascinating moment in time, that no-one has been able to record from live insects.  CT scanning technology is beginning to be widely used in palaeontology, as it allows researchers to see more detail in a fossil without damaging it.

This is a link to the article, with some images of the scans: http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0047651&imageURI=info%3Adoi%2F10.1371%2Fjournal.pone.0047651.g001;jsessionid=08EDCA340A31DD078FBB7B2C36AF9FF3