French wild pansies are producing smaller flowers and less nectar than 20 to 30 years ago in ‘startling’ act of evolution, study shows

Flowers are “giving up on” pollinators and evolving to be less attractive to them as insect numbers decline, researchers have said.

A study has found the flowers of field pansies growing near Paris are 10% smaller and produce 20% less nectar than flowers growing in the same fields 20 to 30 years ago. They are also less frequently visited by insects.

“Our study shows that pansies are evolving to give up on their pollinators,” said Pierre-Olivier Cheptou, one of the study’s authors and a researcher at the French National Centre for Scientific Research. “They are evolving towards self-pollination, where each plant reproduces with itself, which works in the short term but may well limit their capacity to adapt to future environmental changes.”

Plants produce nectar for insects, and in return insects transport pollen between plants. This mutually beneficial relationship has formed over millions of years of coevolution. But pansies and pollinators may now be stuck in a vicious cycle: plants are producing less nectar and this means there will be less food available to insects, which will in turn accelerate declines.