Celebrating bees: understanding the role of pollinators and why they are at risk

World Bee Day is celebrated on May 20 – the birthday of Anton Janša, one of the founders of modern beekeeping. The purpose of this day is to highlight the importance of pollinators for our planet. Bees have long been recognized as one of the most beneficial insects. What is their role in agricultural landscapes and how do insecticides endanger them? The original article was published in A / Magazine, the quarterly of the Czech Academy of Sciences.

If bees disappeared off the face of our planet, the human race would have only four years left to live. This alarming statement is attributed to Albert Einstein. But what did the famous physicist actually know about these insect pollinators? And did he ever really say a thing like that? We can’t provide a satisfactory answer to either question – there is no actual evidence that Einstein made this claim. What we do know, however, is that the assertion has no basis in truth, and whoever its author is, they have greatly overestimated the role of bees in agriculture (and, subsequently, the survival of humankind).

“This claim, while famous, is unfounded. Not to mention that it is often exploited by various beekeeper lobbies to promote their own interests and manipulate public opinion, giving the issue at hand a different weight than it should have,” says Radmila Čapková Frydrychová from the Biology Centre of the Czech Academy of Sciences (CAS). In her opinion, the issue has to be considered in its entirety.

We could ask a similar question as in the intro – just how much can a Czech scientist know about insect pollinators? Much more than Albert Einstein, that’s for sure! Frydrychová works as the head of the Laboratory of Telomere Research at the Institute of Entomology, where she is mainly involved in researching telomers in insects – i.e., DNA sequences located at chromosome ends that form a kind of defence mechanism for the integrity of genetic information in each cell. In addition, she is the principal investigator of a project called “Pollinators in Agricultural Landscapes”, which is part of the Strategy AV21 research programme, Land Conservation and Restoration. The Institute of Microbiology of the CAS is also working on this project.

Since ancient times, the bee has been a symbol of diligence, skill, orderliness, and purity. However, according to authors in antiquity, the greatest miracle of bees was the production of honey, which is beneficial for both humans and gods.

Bees as a harbinger of environmental pollution
The bee is the main pollinator of agricultural crops and, due to its interrelationship with the surrounding environment, it is also directly indicative of chemical pollution in the region. The goal of the “Pollinators…” project, then, is to develop procedures to demonstrate bee intoxication by insecticides. Currently, pesticides are the main cause of bee poisoning. Though pesticides play an indispensable role in agricultural production, their use is often disproportionate, leading to excessive environmental pollution, reduction of biodiversity, and intoxication of non-target organisms – such as honey bees.

Chemical methods, known as chemical pesticides, are among the most widely used methods for protecting crops from harmful organisms. They can protect agricultural crops from almost all disease pathogens, pests, and weeds, and their role in efficient agriculture is crucial. The problem is their overuse and the associated disproportionate burden they inflict upon the ecosystem. However, there is some good news. According to information from the Czech Ministry of Agriculture, in the European Union, the Czech Republic in its use of pesticides ranks below average.

According to the Food and Agriculture Organization of the UN, Czech farmers currently use an average of 1.39 kilograms of active pesticide substance per hectare. To compare: the Netherlands uses 10.82 kilograms, Cyprus 9.24 kilograms, and Austria 4.03 kilograms. Data from Eurostat, the European statistical office, shows that pesticide sales in the Czech Republic decreased the most between 2011 and 2020 – by 38%. Looking at other European countries: in Latvia, sales increased by 77% over the same period and in Austria by 61%. A comparison across EU countries therefore suggests that the application of chemical pesticides in agriculture is being overvalued, which is one of the reasons why European officials have decided to regulate their use more vigorously.

Modern agriculture increasingly uses new technologies that protect the environment and contribute to higher yields. One of these technologies is drones. They help detect overfertilized or dried-out areas in the fields, and their application of sprays can be more accurately targeted than when heavy machinery is used.

Harmful pesticides
What is their danger? The biggest problem lies in the accumulation of pesticides and their metabolites in the environment and their transfer throughout the entire ecosystem – for example, through the food chain, as well as chronic exposure of organisms to very low, so-called subthreshold doses of these substances. “The presence of pesticides at subthreshold concentrations may not be apparent at first glance. According to current legislation, it may even be tolerated. However, even subthreshold concentrations, if the organism is chronically exposed to the substance, can have a negative impact, including on human health or reproduction,” Frydrychová explains.

In humans, exposure to excessive amounts of chemical pesticides can cause various neurodegenerative diseases (such as Parkinson’s and Alzheimer’s), cancer, as well as hormonal imbalance. They have also been attributed to playing a role in high blood pressure, diabetes, reproductive issues, mood disorders, anxiety, and depression.

Due to the close connection of honey bees with agricultural areas, the overuse of chemical pesticides or failure to follow proper procedures during their application endangers the health of bee colonies. Direct poisonings result in the death of individual bees or even fatal collapses of entire colonies. However, sublethal effects are also a problem. These manifest in the reduced health condition of the affected bees and their diminished development.

What we must also consider is the chronic accumulation of pesticides not only in bee colonies, but also in hives and bee products such as honey and wax. When bees are exposed to lower doses of pesticides or chronic stress, they undergo a series of physiological changes – in behavior, movement activity, metabolism, and communication. “Since bees are eusocial organisms, meaning they are existentially linked to their community, changes at the individual level affect their collective behavior throughout their community, significantly influencing the setting and functioning of the colony as a whole,” Frydrychová adds.

It is the honey be that the “Pollinators in Agricultural Landscapes” project uses as a monitor for pesticide pollution in the environment, employing several markers that reflect sublethal effects at the physiological or biochemical level. “It involves a combination of several approaches. Firstly, using special sensors installed in hives, we monitor vibroacoustic (sound) signals in the colonies and look for any links in the variations of these signals in light of stress factors, such as pesticides,” the researcher explains.

As pilot experiments, researchers use laboratory experiments in which they apply low doses of pesticides to bees, and their vibroacoustic response is monitored. Biochemical methods are used to measure the dose of the pesticide in bees as well as levels of stress markers, such as adipokinetic hormone (an insect stress hormone) or levels of oxidative stress markers.

And what will the results of the research project be used for in the future? “We want to develop a new approach for intelligent monitoring of bee colonies. Some beekeepers already use it. Using a mobile application on their phone or computer, they can remotely and continuously monitor the status of their bee colonies,” Frydrychová sums up the research intentions of the ongoing project. The technology could also be useful in detecting suspected cases of pesticide intoxication in bee colonies, which could be utilized, for instance, by government authorities. However, the most significant idea of the entire project is to employ an ecosystem-wide monitoring approach, where – metaphorically speaking – the bee colony will act as a reporter on the health status of the overall landscape.

The wind also helps with pollination
Globally, more than three thousand plant species are used as food, of which only three hundred are specifically cultivated as agricultural crops. Out of these three hundred, only twelve crops provide around 90% of the world’s food supply. These include rice, wheat, corn, sorghum, millet, rye, barley, potatoes, sweet potatoes, cassava, bananas, and coconuts. “Cereals are either wind-pollinated or self-pollinated, coconuts are partly pollinated by wind and partly by insects, and the rest reproduce asexually,” Frydrychová explains, adding that for two-thirds of the world’s population (especially in Southeast Asia), rice is the staple diet.

Grasses, which form the basic diet for livestock, are also wind-pollinated. “On the other hand, seventy-five percent of agricultural crop species are at least partially dependent on animal pollinators, such as insect pollinators, bats, and birds,” the researcher says. Their economic contribution to global agricultural production is estimated at 235 to 577 billion USD per year.

Bumblebees are among the most common insect pollinators.

The vast majority of pollinators are insects – mainly sawflies, wasps, bees, moths, butterflies, beetles, and thrips. The main group of insect pollinators consists of various bee species, of which there are approximately twenty thousand, contributing to one-third of plant production. “The honey bee is merely one of these species. Moreover, the actual role of individual animal pollinators in agricultural production is still largely unclear,” Frydrychová notes.

Another unknown is the role of the honey bee in pollinating natural ecosystems and its impact on maintaining biodiversity. Its significance for pollination in nature in general is roughly similar to that of other insect pollinators, the researcher believes: “From an overall perspective, I wouldn’t put particular emphasis on the honey bee in its role in maintaining the landscape or nature. It might even be the opposite – that excessive numbers of honey bee colonies, artificially maintained by humans, could in fact theoretically reduce the biodiversity of insect pollinators such as various species of bees, bumblebees, other Hymenoptera, but also butterflies, flies, and beetles.”

Although the validity of the claim of the importance of bees for the existence of humanity, as allegedly stated by the famous physicist, is highly debatable, it does not diminish the benefits and usefulness that bees provide to humankind and the respect that a cultivated human society should have – not only for bees but for all of nature. The goal of the research programs of the Strategy AV21 of the CAS is also to focus on the protection of the environment. In light of the public debate about the use of pesticides in agricultural practices, their impact on the environment and human health, comprehensive monitoring of pesticide contamination in both bees and the entire landscape is highly desirable.

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The original article was published in A / Magazine, the quarterly of the Czech Academy of Sciences:

4/2023 (version for browsing)
4/2023 (version for download)

Written and prepared by: Markéta Wernerová
Translated by: Tereza Novická
Photo: Shutterstock

The text is released for use under the Creative Commons licence.

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