Researchers have identified the biosynthetic process behind the natural production of a bee-friendly insecticide, potentially enabling its deployment at scale.
- The researchers believe that they will be able to increase the supply of azadarachtin, a plant-based insecticide that could serve as a replacement for harmful, synthetic formulations.
- Conventional insecticides are contributing to the decline of bee populations, with disastrous consequences for global well-being.
- As policymakers begin to accelerate their efforts to protect pollinating insects, we can hope that scientific contributions will receive the attention and support they deserve.
Researchers from the John Innes Centre and Stanford University have mapped the biosynthetic pathway through which plants produce valuable limonoid molecules, including a compound that can be used as a bee-friendly insecticide. Their work could enable the compound to be produced and deployed at scale, providing a useful solution to a number of the world’s greatest challenges.
Enabling the widescale production of bee-friendly insecticides
By combining genomic mapping tools with molecular analysis, the scientists have been able to identify the specific enzymes and processes that enable certain plant families to produce valuable limonoid molecules. Their initial research has focused on how a mahogany species, known as Chinaberry, produces a limonoid compound called azadirachtin.
Azadarachtin has already shown its potential as an organic insecticide that is far safer for humans, animals and pollinating insects. Research suggests that it could also boost crop yields while minimising the risk that the pests it discourages become resistant to insecticides.
Its deployment, however, has been limited by a lack of supplies. Until now, the only identified way to produce azadarachtin and other limonoids was through their extraction from the material of specific plant species. Having identified the biosynthetic pathway behind their natural production, the researchers say that they can now engineer commonly available host plants to make these limonoids available at scale.
“By finding the enzymes required to make limonoids, we have opened the door to an alternate production source of these valuable chemicals,” explained Dr Hannah Hodgson, co-first author of the study. “Their structures are too complicated to efficiently make by chemical synthesis. With the knowledge of the biosynthetic pathway, it is now possible to use a host organism to produce these compounds.”
Harmful pesticides contribute to pollinator decline
The excessive use of agricultural chemicals, such as insecticides, has been identified as one of the main drivers behind the rapid decline of bee populations. Despite global efforts to introduce safer and more sustainable alternatives, the issue continues to worsen as pesticides that are less toxic to people and animals can be even more deadly to pollinating insects.
This is particularly alarming, given the vital role that bees have to play in ensuring human well-being. Indeed, bees and other insects pollinate over 90% of the world’s most important crop types as well as a vast range of wild plant species.
Without their presence, research suggests that the world’s crop production would fall by as much as 8%. This would include a wide range of fruits, vegetables, nuts and legumes that provide vital nutrition to the global population and provide some protection from noncommunicable diseases such as heart disease, diabetes or certain types of cancer.
Already, there is research to suggest that the decline of pollinating insects is contributing to around 427,000 premature deaths per year due to the decreasing availability of nutritious food supplies. This highlights the dramatic influence of bee populations on human health, but it still does not paint the full picture of our dependence on insect pollinators.
As crop yields decline, a number of social and economic issues must also be acknowledged. To give just a couple of examples, those that rely on subsistence agriculture may suffer significant disruptions to their livelihoods and cultural values, while the global economy is likely to endure losses of up to $577 billion per year.
Taking action to protect the world’s bee populations
Given the numerous consequences of declining bee populations, there is an urgent need for effective solutions. Thankfully, the issue appears to have captured the attention of world leaders, who have begun to include pollinating insects within their broader focus on biodiversity.
In 2018, signatories to the COP14 Convention on Biological Diversity expressed their commitment to supporting pollinator conservation. This was followed by 2022’s COP15, which saw the agreement of a Global Biodiversity Framework that outlined four long-term goals and 23 targets for the protection and restoration of nature.
Among the targets, which are to be achieved by 2030, is a specific mention of the need to restore, maintain and enhance nature’s ability to provide vital ecosystem services including pollination. This raises some hope that policymakers worldwide will begin to explore possible solutions to the decline of bee populations.
Indeed, the acknowledgement of pollinating insects within the global agreement has already prompted some policy developments. The EU, which had previously implemented its 2018 Pollinators Initiative in recognition of COP14, has since revised its approach. Most recently, the Commission has presented a New Deal for Pollinators, which outlines a number of strategies to improve pollinator conservation and end the decline of their population by 2030.
Ultimately, it seems likely that various solutions will be needed. The contributions of researchers such as those behind the limonoid study could prove immensely valuable, so long as their work is supported and enabled by those with the power to do so.