A bee and a flower are a timeless resource to explain sexual reproduction – and one with a solid theoretical basis, too. Pollination (what bees do in flowers) is, after all, one of the most effective strategies for plants to perpetuate themselves. Or it used to be, until now; the progressive decline of many pollinating insect species could jeopardize this successful evolutionary strategy.
“Those of us who work on this have been noticing for some time how in previous studies we used to find many more species, and in this century we have found fewer and fewer,” explains Concepción Ornosa, an entomologist and director of the Department of Biodiversity, Ecology and Evolution at Complutense University in Madrid, Spain. “In the United States they began to study it and discovered that between 2008 and 2013 wild bees had decreased by 23%, and all the alarms went off: the disappearance of 23% of the insects that pollinate crops is a very serious matter.”
The research warns both about the disappearance of species and about the decrease of individuals. Ornosa notes that a 2017 study on flying insects in protected areas in Germany found that, in relation to the previous 20 years, up to 75% of the biomass (the number of living organisms in an area at a given time) had disappeared. “The study was about flying insects in general, but most pollinating insects fly,” she adds.
The situation is so serious that many countries have been designing regulations for years to try to reverse the situation. The European Union launched the Pollinators Initiative in 2018
Pollination is the transfer of pollen from the male part of a flower to its female part. The result is its fertilization. The new ovule contains both the male and female genetic makeup, and it will give rise to a new generation of the plant. As the flowers cannot move from their spot, they need an agent to transport that pollen. It can be the wind or the water, but in most cases pollination is carried out by animals, particularly insects. Bees are the best pollinators and, among them, the most effective are bumblebees, because they have a lot of hair. When they feed on a flower, part of the pollen sticks to that hair and then falls on the next flowers they visit.
There is a wonderful book devoted precisely to bumblebees and written by one of the world’s leading experts: A Sting in the Tale: My Adventures with Bumblebees, by British conservationist Dave Goulson. In his book, Goulson warns of the disappearance of many species of bumblebees in the United Kingdom and the rest of the world, and explains how serious this fact is for our own survival.
The decrease in pollinating insects is no laughing matter. According to the Food and Agriculture Organization of the United Nations (FAO), about 35% of invertebrate pollinators, particularly bees and butterflies, and about 17% of vertebrates, such as bats, are endangered. And when the FAO – and many other international institutions – warn of this danger, they are literally alluding to the threat to global food production. According to the organization, more than 75% of the world’s food crops depend on pollination in some way.
The situation is so serious that many countries have been designing regulations for years to try to reverse the situation. The European Union launched the Pollinators Initiative in 2018, and Spain approved the National Strategy for the Conservation of Pollinators in 2020.
“The state of pollinating insects, and in particular bumblebees, is dramatic. In 2018, we published a study we did in the Spanish Pyrenees in which we compared the data we had from previous research with the populations we found. Of the 36 species that had been described, we only found 27. And, in addition, the ones we found were located at higher altitudes,” says Ornosa. The causes of this situation are varied: changes in land use, fertilizers in the soil, the introduction of invasive species, global warming… It is a series of alterations in the ecosystems that, together, have become a time bomb.
Insects need flowers because without them they don’t have food, and if they don’t visit flowers to feed, pollination doesn’t take place. And while some solutions could be difficult to implement, others are not: “There is one very easy thing that can be done. Right now, as soon as what we call ‘weeds’ come out, they are uprooted from roads, gardens, parks… but that is a wonderful habitat for pollinating insects,” explains Ornosa. “It would be much more efficient to wait until they dry out to pull them out, so insects can feed on them. Or prune the trees and bushes in the fall, when they no longer have flowers.” The goal is to save pollinating insects because, as the last sentence of Dave Goulson’s book points out, maybe if we learn to save one bumblebee today, we can save the world tomorrow.