Scientists claim they have found the first pollen-carrying insect in a 100-million-year-old amber block in northern Spain.

The insects, called 'thrips' were found inside the amber tree resin covered in pollen grains from a gingko tree, suggesting they transported the tiny grains just as bees do.

"This is the oldest direct evidence for pollination, and the only one from the age of the dinosaurs," said study leader Carmen Soriano of the European Synchrotron Radiation Facility (ESRF), reported UPI.

"The co-evolution of flowering plants and insects, thanks to pollination, is a great evolutionary success story."

The six female thrips – also called thysanopterans – that were discovered were about 2mm (0.07 inches) thick.

The insects were covered with small hairs to which the pollen became attached.

Researchers used a synchrotron X-ray tomography in order to view the specimens at a very high resolution in order to see the individual pollen grains.

"At very high magnification, we can see that these hairs are mostly in the dorsal part of the thrips and that's also where we observe most of the attached pollen," said Soriano, according to the BBC.

"So, our theory is that these hairs would have been used by the female thrips to gather as much pollen as possible to take back to their larvae."

Pollination is essential for life on earth with most plants unable to reproduce without the help of insect transporters.

The study is found in the journal Proceedings of the National Academy of the Science (PNAS).