A bee and a flower are a timeless resource for explaining sexual reproduction – and one with a solid theoretical foundation too. Pollination (what bees do in flowers) is, after all, one of the most effective strategies for plants to perpetuate themselves. Or it was, until now; the progressive decline of many species of pollinating insects could jeopardize this successful evolutionary strategy.
“Those of us who work on this subject have noticed for some time how in previous studies we used to find many more species, and in this century we have found fewer. less,” says Concepción Ornosa, entomologist and director of the Department of Biodiversity, Ecology and Evolution at the Complutense University of Madrid, Spain. “In the United States, they started to study it and found that between 2008 and 2013 wild bees had decreased by 23%, and all the alarms went off: the disappearance of 23% of insects that pollinate crops is a very serious matter.”
The research warns of both the disappearance of species and the decrease of individuals. Ornosa notes that a 2017 study of flying insects in protected areas in Germany found that, compared to the previous 20 years, up to 75% of biomass (the number of living organisms in an area at a time given) had disappeared. “The study looked at flying insects in general, but most pollinating insects fly,” she adds.
The situation is so serious that many countries have been developing regulations for years in an attempt 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 ovum contains both male and female genetic makeup, and it will give rise to a new generation of the plant. Since the flowers cannot move from their location, they need an agent to transport this pollen. It can be wind or water, but in most cases pollination is carried out by animals, especially 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, some of the pollen sticks to that hair and then falls on the next flowers they visit.
There is a wonderful book dedicated specifically to bumblebees and written by one of the world’s leading experts: A Sting in the Tale: My Adventures with Bumblebees, by British environmentalist Dave Goulson. In his book, Goulson warns of the disappearance of many bumblebee species in the UK and the rest of the world, and explains how serious this fact is for our own survival.
The decline in pollinating insects is no joke. According to the Food and Agriculture Organization of the United Nations (FAO), about 35% of pollinating invertebrates, especially bees and butterflies, and about 17% of vertebrates, such as bats, are at risk. . And when the FAO – and many other international institutions – warn of this danger, they literally allude to the threat to global food production. According to the organization, more than 75% of the world’s food crops depend in one way or another on pollination.
The situation is so serious that many countries have been developing regulations for years in an attempt 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 situation of pollinating insects, and in particular bumblebees, is dramatic. In 2018 we published a study we did in the Spanish Pyrenees where 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, those that we found were located at higher altitudes,” explains Ornosa. The causes of this situation are varied: changes in land use, fertilizers in the soil, introduction of invasive species, global warming… It is a succession of ecosystem alterations which, together, have become a delay.
Insects need flowers because without them they have no food, and if they don’t visit the flowers to feed, pollination does not take place. And while some solutions may be difficult to implement, others are not: “There is one very easy thing to do. Right now, as soon as what we call ‘weeds’ come out, they are torn from roads, gardens, parks… but it’s a wonderful habitat for pollinating insects,” explains Ornosa. “It would be much more efficient to wait for them to dry out before pulling them out, so that the insects could feed on them. Or prune 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 how to save a bumblebee today, we can save the world tomorrow.