Antidote to deadly pesticides boosts bee survival

In the first study of its kind, scientists have discovered that feeding bees absorbent bits of hydrogel boosts their chances of surviving exposure to toxic pesticides.

As key pollinators, bees provide essential services to both wild plants and human-grown crops. But the pollen they ingest is often contaminated with chemicals that can have devastating biological effects on the bees, such as spurring colony collapse or causing near-instant death.

Earlier studies found that particles of hydrogel – a soft, non-toxic material that is highly absorbent – mixed into soil can bind to and trap neonicotinoids, a class of pesticides widely banned in Europe, but still used in the US. That led Julia Caserto and her colleagues to investigate if small pieces of hydrogel could neutralise pesticides inside the bodies of common eastern bumblebees (Bombus impatiens).

“No one – to my knowledge – had done this,” says Caserto, who did the work while at Cornell University in New York.

The researchers began by mixing microscopic hydrogel particles – small enough to pass through the bee’s digestive tract, but not to travel elsewhere in its body – into sugar water. After the bees slurped the solution, researchers gave them a high dose of pesticides. Bees that received the hydrogel treatment had a 30 per cent higher survival rate compared with those that didn’t.

When the researchers gave bees doses of pesticides that would scramble their nervous systems, but not kill them, hydrogels reduced the insects’ symptoms. Bees that got the gel were better able to feed and walk than those that went without, and they beat their wings at a faster, healthier rate.

Because the bees eventually excrete the hydrogel particles, they would have to be continually re-dosed with the antidote. While this makes the treatment improbable for wild bees, it is still a promising option for human-managed bees, like those used for honey production and crop pollination.

“These particles could be incorporated into pollen patties or sucrose feeds that are already used for managed bee colonies,” says Caserto. “And hopefully, when bees go out in the field and get exposed [to pesticides], they will be less susceptible.”