Fossil evidence recently found in Europe confirms that bumble bees were visiting linden flowers 24 million years ago. This surprising discovery provides an important look into the development of these key pollinators. In-depth studies unprecedented research into the sediments of a former volcanic crater lake near Enspel, Rhineland-Palatinate, Germany, yielded groundbreaking findings. Now for the first time, they’ve linked a fossil flower to its pollinating bees.
The fossilized linden flower, named Tilia magnasepala—meaning “linden tree with large sepals”—is part of a new understanding of ancient ecosystems. Bumble bees are one of the most primitive representatives of their genus. This study shows that only a single species is older than the bumble bees that we found. Among the notable finds are two new bumble bee species: Bombus (Kronobombus) messegus and Bombus (Timebombus) paleocrater.
The bumble bees, all the pollen, just left an incredible biopreservation. To study these grains, scientists illuminated them with ultraviolet and blue light in order to make the fluorescent fossil pollen visible. Scientists employed a new approach to pull pollen grains directly from preserved ancient bees and flowers. To make sure the procedure was as minimally invasive as possible, they used an extremely fine needle.
Geier, a member of the research team, called their findings both hopeful and urgent.
“This is the first time worldwide that a fossil flower and its pollinating bees have been described from the same sediments and directly linked to each other using pollen,” – Geier
This relationship between the bumble bees and linden flowers is a testimony to their long-standing importance as effective pollinators. Flower constancy is striking among bumble bees. This requires them to often fly to a single species of plant on each flight. Geier stated,
“In our study, we were able to identify a certain degree of flower constancy in the bumble bees we studied.”
This remarkable discovery sheds new light not only on ancient ecosystems, but gives 21st century scientists a better understanding of pollinators. These linden flowers that have been found are the first of their kind ever found recorded on the European continent based on palynological criteria.
According to Friðgeir Grímsson, another researcher participating in the study, this was the intention behind their work.
“We examined hundreds, even thousands, of fossil flowers and insects for pollen in the hope of gaining insight into the evolution of flowers, flower visitors and pollination,” – Friðgeir Grímsson
These results underscore the profound relationship between bumble bees and linden trees. For hundreds of millions of years, these insects have been important pollinators in this mutualistic relationship. As further research emerges, it holds great potential for expanding knowledge about ancient pollinators and their interactions with flowering plants.