Populations of pollinating insects are declining significantly in many parts of the planet. The problems affecting honey bees (Apis mellifera) are just one example of a crisis that, in some cases, experts do not hesitate to consider an episode of mass extinction.
In the absence of natural pollinator populations, some farmers are forced to use methods or agents specifically designed or transported to their crops to enable optimal fertilization of vegetables and fruit production, for example.
In plants with flowers without commercial value (not cultivated), the crisis of pollinating insects has a different dimension and a scientific team led by French experts has now shown that in some cases an adaptive phenomenon is occurring that makes the lack of pollinators, plants with wild flowers increase their capacity to reproduce by self-fertilization.
The results of this research, published in the journal New Phytologist (December 20, 2023), indicate that scientists from the French National Council for Scientific Research (CNRS) and the University of Montpellier 1 (France) have discovered that flowering plants such as wild pansy (Viola arvensis) that grow on agricultural land increasingly survive without the need for pollination through the action of insects.
"As reproduction becomes more difficult for them in an environment impoverished in pollinating insects, plants are evolving towards self-fertilization," indicates the CNRS in a note disclosing these results.
By comparing wild pansies growing today in the Paris region with pansies from the same localities grown in the laboratory from seeds collected between 1992 and 2001, the research team found that today's flowers are 10% smaller, produce 20% less nectar and are less visited by pollinators than their ancestors.
This rapid evolutionary adaptation is thought to be due to declining pollinator populations in Europe. In fact, a study carried out in Germany showed that more than 75% of the biomass of flying insects has disappeared from protected areas in the last thirty years.
The study identified a vicious cycle in which declines in pollinators lead to reduced nectar production from flowers, which in turn could exacerbate declines in these insects. It underlines the importance of implementing measures to counteract this phenomenon as quickly as possible and thus safeguard interactions between plants and pollinators, which have existed for millions of years.
