New DNA research into 100-year-old bees and their pollen
Associate Professor Philip Francis Thomsen has just received the prestigious Sapere Aude grant of DKK 6 million from the Independent Research Foundation. Based on DNA traces on insects up to 100 years old, he will investigate how the decline in flowers may have affected bees and butterflies.
A quick look at the Danish Red List shows that many insect species are in decline, but we still lack knowledge about patterns and causes. Now, Philip Francis Thomsen will make a valuable contribution to the research area. He has just received a Sapere Aude grant of DKK 6 million for his project about the connections between the population of plants and pollinating insects such as butterflies and bees.
The eDNA method offers new possibilities
In his project, he will use a special method that he has invented together with collaborators. The method is called environmental DNA (eDNA), and with it he can find DNA traces all over the world. It allows him to map out which flowers the insects have visited.
"We all deposit a small piece of DNA when we move around the landscape. So do the insects. When a bee flies around, it deposits small pieces of DNA every time it visits a flower. So, we can take a flower and uncover, which insects have visited it. We can also find DNA from the pollen of the flowers on the bees' legs and hairs," says Philip Francis Thomsen.
DNA traces on insects at museums
Many specimens of extinct and endangered insect species have been preserved in Danish museums, where they have been catalogued with important information about where and when they were collected. Also, pollen is still attached to these insects - pollen that originates from flower visits made before the animals were collected. Using the eDNA method, he will examine DNA traces on these pollen that are up to 100 years old. By studying several individuals of the same insect species collected over many years, he gains important knowledge about which flowers the insects have visited and whether their foraging has changed over time.
The endangerment of species of insects could be caused by the decline of plants
After the analysis of the DNA traces, he will make a mapping of how the distribution of certain plant species has changed and compare it with the pollinators' use of flowers over time. In this way, he can investigate how changes in the flora have potentially contributed to the decline of the insects.
The eDNA method in the modern landscape
The last part of the project will investigate the flower visits of different insects in today's habitats. By choosing habitats with different compositions of plant species, it is possible to study the interaction between the many different insects and the plants.
"There has been a lot of focus on bees as pollinators, but there are indications that many other insects such as flies and beetles are able to transport pollen around, and here the eDNA method is obvious to apply" says Philip Francis Thomsen, who expects the project in the long term could also contribute with some better methods to nature monitoring.