A bio-pesticide made from spider venom that kills pests but spares honeybees could help save the precious pollinators, scientists say.
Researchers have created a novel bio-pesticide using spider venom and a plant protein which is highly toxic to a number of key insect pests - but safe for honeybees.
The research led by Newcastle University, UK, has tested the insect-specific Hv1a/GNA fusion protein bio-pesticide - a combination of a natural toxin from the venom of an Australian funnel web spider and snowdrop lectin.
Feeding acute and chronic doses to honeybees - beyond the levels they would ever experience in the field - the team found it had only a very slight effect on the bees' survival and no measurable effect at all on their learning and memory.
Publishing their findings in the academic journal Proceedings of the Royal Society B, the authors said the insect-specific compound has huge potential as an environmentally-benign, 'bee-safe' bio-pesticide and an alternative to the chemical neonicotinoid pesticides which have been linked to declines in pollinator populations.
"Our findings suggest that Hv1a/GNA is unlikely to cause any detrimental effects on honeybees," said Professor Angharad Gatehouse, based in Newcastle University's School of Biology and one of the supervisors on the project.
"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," Gatehouse said.
During the study, the bees were exposed to varying concentrations of the spider/snowdrop bio-pesticide over a period of seven days.
Throughout the study period, the team carried out a series of memory tests and recorded any changes in behaviour.
"This is an oral pesticide so unlike some that get absorbed through the exoskeleton, the spider/snowdrop recombinant protein has to be ingested by the insects," said lead researcher Erich Nakasu, a PhD student at Newcastle University.
"Unlike other pesticides, Hv1a/GNA affects an underexplored insecticidal target, calcium channels. These are more diverse than commonly-targeted insecticide receptors, such as sodium channels, and therefore offer the potential for more species-specific pesticides.
"Calcium channels are linked to learning and memory in bees so it's vital that any pesticide targeting them does not interfere with this process," said Nakasu.
"Although Hv1a/GNA was carried to the brain of the honeybee, it had no effect on the insect which suggests the highly selective spider-venom toxin does not interact with the calcium channels in the bee.
"The larvae were also unaffected by the Hv1a/GNA, which they were able to break it down in their gut," Nakasu said.
