Wild plants 'abandon' pollinators and move towards self-fertilization

Pollinators like bees, butterflies, wasps, birds, bats, and other insects are crucial for maintaining healthy ecosystems worldwide. They help plants reproduce by moving pollen from one flower to another. But, there’s been a worrying drop in the number of pollinators in recent years. This decline threatens not just wildlife diversity, but also our food supply.

As the number of insects decreases, wild flowering plants that grow in farming areas are adapting. A study in the ‘New Phytologist’ journal found that as it gets harder for these plants to reproduce because there are fewer pollinators, the plants are evolving to fertilize themselves.

The research team compared current plants in the Paris region with flowers of the same species grown in a lab from seeds collected between 1990 and 2000. They found that today’s flowers are 10% smaller, make 20% less nectar, and get fewer visits from pollinators than the flowers from the past.

Analysis in population genetics indicates a 27% surge in self-fertilization rates in the field over the past three decades. This suggests that plant reproductive systems can swiftly adapt in natural populations amidst continuous environmental changes.

Scientists theorize that these quick progressions are a result of dwindling pollinator populations. Supporting this, a study conducted in Germany reveals a staggering loss of over 75% of flying insect biomass from protected regions in the last 30 years.

Cascade effects

The study highlights a vicious cycle where pollinators' decline leads to a reduction in flowers' nectar production, which could subsequently exacerbate the decline of these insects by being unable to find enough food.

Therefore, environmental changes can present a double danger to pollinator populations as both those changes and the evolution of plant traits victimize them. This may then generate a positive eco-evolutionary feedback loop that encourages the decline of pollinators, thereby strengthening the plants' evolution towards a self-fertilization syndrome.

"The report states that the degradation of the plant-pollinator network, as documented in a previous study, may explain this. It also raises the worrying prospect of cascading effects on food webs in general, beyond plant-pollinator interactions,"

"There is an urgent need to investigate whether these results are symptomatic of a broader pattern between angiosperms and their pollinators and, if so, understand whether there is a possibility of reversing this process and breaking this positive eco-evolutionary feedback loop," adds the document.

The authors emphasize that we should implement measures to stop this phenomenon as quickly as possible and to maintain interactions between plants and pollinators, which have existed for several million years.

A serious threat

Animals are responsible for the pollination of more than 80% of existing angiosperms. Habitat destruction, land use changes – primarily grazing, fertilizers, and monoculture – along with the widespread use of pesticides, are the three main causes of pollinator loss.

Among the impacts of the decline of pollinators are the decrease in biodiversity, the threat to food security (a large percentage of food crops depends on pollination) and the destabilization of ecosystems.

For the preservation of pollinators, scientists suggest several measures. These include conserving and restoring natural habitats to offer appropriate locations for pollinators’ reproduction and nourishment. Implementing sustainable farming practices that reduce pesticide usage and promote crop diversity can also aid in preserving pollinators.

Additionally, education, awareness, and sensitization about the significance of pollinators and the risks they encounter are crucial. Research into the reasons behind the decline of pollinators and monitoring their populations can help devise effective conservation strategies.

Experts warn that the decrease in pollinator populations is a “grave threat” that necessitates “immediate attention and collective efforts on a global scale.” They emphasize that safeguarding these biodiversity custodians not only protects nature but also bolsters food security and planetary health.

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