A novel pesticide made from spider venom has been found to be safe for honeybees despite being highly toxic to a number of key insect pests. Its creators think it could be an alternative to the neonicotinoid pesticides linked to declines in pollinator populations.
Researchers at the UK universities of Newcastle and Durham studied bees fed varying concentrations of the pesticide for seven days. They found it had only a very slight effect on the bees’ survival and no measurable effect on their learning and memory. This is important because foraging honeybees learn and remember floral traits associated with food. If this ability is disrupted, they struggle to find food or return to their hives, so it can have profound implications for the survival of a bee colony.
In 2013, research by Newcastle University’s Geraldine Wright – also involved in this study – highlighted how neonicotinoids can potentially damage bees’ ability to learn, remember and communicate with their hive mates.
The new pesticide consists of a natural toxin from the venom of an Australian funnel web spider linked with lectin taken from snowdrops. The spider protein blocks calcium channels in an insect’s brain which are associated with learning and memory. The snowdrop lectin acts as a ‘carrier’ protein, and is an effective oral biopesticide for various insect pests.
Although the pesticide was carried to the bees’ brains, it did not appear to affect their learning or memory (Proc. R. Soc. B; doi:10.1098/rspb.2014.0619). The larvae were also unaffected, suggesting they could break it down in their gut. But it was toxic to other ‘agronomically important’ insect pests.
It is unlikely to have any detrimental effects on honeybees, says Angharad Gatehouse of Newcastle University, UK. ‘Previous studies have already shown that it is safe for higher animals, which means it has real potential as a pesticide and offers us a safe alternative to some of those currently on the market.’ The team now wants to double-check its safety against bumblebees and parasitoid wasps.
This is an interesting and promising start to the development of pollinator-friendly pesticides, says Christopher Connolly of the University of Dundee, UK, as it appears to target the pest but not honeybees.
One advantage of this approach is that it would be less likely to persist in the environment. He points out that a follow-up study on toxicity to key pollinators and a long-term study to investigate any chronic effects on whole colonies and insect reproduction are needed. The most efficient delivery system for the pesticide may be to use GM crops expressing a protein toxin, ‘but that’s a whole new area of controversy,’ he adds.