Bees and other insects crucial to a diverse ecosystem experience a significant decline in performance after exposure to polluted air, according to a new study. The results indicate that increased ozone and other air pollutants are another stressor for pollinators, which play a crucial role in ensuring the global food supply.

Ozone, which occurs naturally in the upper atmosphere, develops harmfully at ground level due to chemical reactions resulting from human activities, such as the burning of fossil fuels.

Data from a study published in Nature Communication, which was collected on 40 different insect species in 19 countries, noted that pollinators and beneficial predator species experienced a nearly 40 percent drop in productivity, while pest insects were not significantly affected.

Robbie Girling, from the University of Southern Queensland, co-authored the study and said it was a double whammy for food security.

"The pests are acting basically as they normally would in an uncontaminated environment, so what we will see is that they will continue to be as harmful as they are now," he said.

"But as pollution levels increase, we see a reduction in natural enemies of pests, which will be a big concern for growers."

Professor Girling said the difference in impact was due to the beneficial insects' reliance on their sense of smell.

"What happens is that the odors of the flowers are degraded [by pollutants] and insects use these odors to locate them," he explained.

 "And if those flowers release chemicals... it is likely that the ozone will react with them, completely eliminating the substances or chemically modifying them, so that the insect can no longer react."

Many food crops grown in Australia, such as almonds, mangoes, avocados and berries, depend on pollinators for fruit set.

Farmers of self-pollinating crops, such as wheat and barley, also rely heavily on beneficial predatory insects, such as wasps, to naturally control insect pests, such as aphids.

What to do?

With the results of the latest study, Professor Girling highlighted the importance of farmers taking action.

"What we have to do is alleviate, even a little, the stress that these insects suffer," he said.

“[That could be] the ability to leave some land free for natural habitat to provide [beneficial insects] pollen and nectar nearby so they can keep going.”

It also recommended that farmers take local pollinator populations into account when choosing which insecticide treatments they use on their crops and when to apply those treatments.

'It just takes small steps on everyone's part to reduce as many stressors as possible,' Professor Girling said.

Australian farmers take the lead

With advances in agricultural research and generational knowledge, experienced field crop agronomist Paul McIntosh believes Australian farmers are already looking to help beneficial insects.

«We have not been left behind; "We are already providing good environmental conditions for our beneficial insects," he said.

«Farmers now know that bees are a great asset to our agricultural systems. “We are not in the 80s, we are in 2024 and we have learned a lot.”

He said the use of synthetic pyrethroids, which kill all insects in a crop, had declined sharply and farmers were turning to mild chemicals.

"As the years have gone by, we have developed chemicals that still work against pest insects but do not destroy populations of beneficial insects that might be in the crop," McIntosh said.

Is organic farming the answer?

While Mr McIntosh acknowledged the role of biological insecticides in organic farming, he does not believe it is possible to completely eliminate chemicals in large-scale Australian food and fiber production.

«I certainly think organic farmers are doing a good job. However, I think if we move away from that harsh chemistry and get more into gentler chemicals and strategic spraying, we are doing something good,” he said.

Professor Girling reiterated that it will come down to many achievable steps forward.

"It's about being able to farm sustainably both from an economic and environmental point of view," he said.

"We just have to all work together."