An Itchy Time In The Trenches
Grey Squirrels in Britain
Fossilised Fleas
These creatures are small, wingless insect that has been around for millions of years. They are well known for their ability to feed on the blood of mammals and birds, and some species can transmit diseases to humans and other animals. But how did fleas evolve, and what can we learn from their fossilised remains?
The History Of Fleas
The oldest known flea fossil dates to the Late Cretaceous period, around 100 million years ago. This fossil belongs to a species called Pseudopulicidae, which is believed to have been a primitive form of flea that did not yet have the specialised adaptations seen in modern fleas for feeding on the blood of their hosts.
Over time, these pests evolved several unique adaptations to become specialised parasites. For example, their bodies became flattened and covered in spines that help them move through the fur or feathers of their hosts. Their legs became adapted for jumping, allowing them to move from one host to another quickly. And their mouthparts evolved into specialised structures that pierce the skin and suck blood.
Preserved Fleas
One particularly interesting fossil is that of a prehistoric flea preserved in amber. This fossil, which dates back to the mid-Tertiary period around 40-50 million years ago, shows a flea that is very similar in appearance to the modern ones. This suggests that many key adaptations seen in modern fleas have already evolved.