Buzzing bees, laden with golden grains and circling patches of flowers, are more than just a pretty sight. They are engaging in the important process of pollen collection, with each journey from plant to plant representing a dynamic interaction. But how does this intersect with air pollution? We investigate more here!

Crucial pollinators

Insects, bees especially, are crucial pollinators, acting as the main facilitators of plant reproduction and fertilisation. As they transfer pollen between flowers and individual flower parts, they require an attraction and potential floral reward (mainly pollen and nectar) to maintain a mutually symbiotic relationship. Such floral rewards can be consumed by the pollinating insect itself, or taken back to the colony. As a result of this system, 87.5% of the world’s flowering plants, 87 of the leading global food crops, and 35% of world’s food crops depend on animal pollinators to reproduce.

If major ecological changes were to disrupt this, the consequences would be highly detrimental. Without pollination services, an estimated 5-8% of global crop production would be lost. Malnutrition rates would skyrocket and humans would likely have to engineer dietary supplements, not to mention the requisite altering of longstanding cultural norms. Insects, as the most abundant and diverse pollinators, are necessary for biodiversity and act as ecological indicators - monitoring ecological stress and pollution so that scientists can make informed decisions on how best to manage environmental and human health.

Interactions with Pollutants and the Air

The detrimental effects of air pollution on humans and vegetation have long been studied and publicised, such as links to dementia, neonatal complications, and higher cancer rates. More recently, studies have been conducted looking at the effects of ozone (O3), nitrogen oxides (NOx), and particulate matter (PM) on insect pollination and reproduction. Even levels of O3 and NOx that are below current air quality standards have significantly reduced counts of insect pollinators and their flower visits by 62-70% and 83-90% respectively. These air pollutants can chemically alter flower odours - with the scent plumes actively shortening and narrowing upon exposure to O3 - as well as changing the chemistry of the foliage and flowers. Exposing insects such as bees and wasps to O3 directly alters the responsiveness of their odour-sensing organs, degrading their olfactory senses, vision, and long-distance signal following. Shockingly, O3 was found to reduce searching efficiency by 34% compared to control treatments.

Exposure to PM has also been shown to disrupt the olfactory senses of male and female houseflies in urban areas, especially as they relate to reproduction and feeding. PM2.5, which is also a major threat to human health, is indicated to be more harmful to houseflies than larger particles. After just 12 hours of exposure, the houseflies odour-sensing capabilities were severely hindered and PM was present on their antennae. O3 was also reported to alter the pheromones of male flies, making them smell more like females and confounding the reproductive process.

Future Considerations

Given how vital insect pollinators are for the health of our ecosystem, further research must be conducted to better understand how these pollutant interactions can be curbed. Increased knowledge on such phenomena will impact future regulatory action and influence the global agriculture sector as a whole. Particularly worrisome about O3 and PM are their direct effects on urban insect mortality. PM can be transported thousands of kilometres from its origin, leading to impacts in rural, remote areas.

Upholding stricter air quality standards, reducing diesel emissions, and prioritising green infrastructure are important priorities for a sustainable future. Promoting awareness of the necessity of pollinator insect protection is an actionable goal, especially in agricultural sectors where farmers tend to underestimate the importance of diverse crop pollination. The economic and health benefits vastly outweigh the costs of research and conservation.

Insects and Air Aware Labs

Air Aware Labs recognises the importance of safe air quality, not only for human health but for the countless organisms that sustain the ecosystems we rely on. We have made it our goal to minimise exposure to harmful pollutants such as NO2 and PM2.5 through the launch of AirTrack, and are committed to promoting sustainability and environmental awareness across all sectors. As the research becomes increasingly clear about the devastating impacts of even low-level air pollution on insect behaviour, physiology, and reproductive success, we are more determined than ever to raise awareness and support solutions that protect both biodiversity and public well-being.

Anika Pruntel overseen by Will Hicks

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