The Chernobyl Exclusion Zone (CEZ) is the area around the Ukrainian city of Pripyat where the Chernobyl Nuclear Power Plant went into meltdown in 1986. The area is devoid of humans so despite the higher-than-average level of radiation, it is full of wildlife, from wolves and bears to insects like the humble bumblebee.
Researchers are curious about how this low-but-constant amount of radiation affects animals, so a team from the University of Sterling looked to bumblebees to find out. In preliminary studies, they found that when these insects were exposed to a similar level of radiation to that found in the CEZ, they began consuming more nectar. The findings were presented yesterday at the British Ecological Society Annual Meeting in Belfast.
"An increase in nectar consumption for an individual bee could have important ecological consequences, as bees may need to spend more time foraging to collect nectar for their individual needs," Jessica Burrows, who presented the work, said in a statement. "As a result, the growth of bumblebee colonies may be impaired if fewer resources are available for the developing brood; this might reduce the number of bees in the ecosystem."
Pollinators are crucial to the environment and their disappearance can have wide-ranging and long-lasting effects. Pollinating insects are currently quite abundant in the Exclusion Zone but it is unclear whether their numbers will be maintained.
“Further work is needed within the Chernobyl Exclusion Zone to understand the impacts of chronic low-dose exposure on the wider ecosystem," added Burrows. "There has been little work conducted on the effects of radiation on flowering plant species.”
While laboratory settings gave the team greater control of how much radiation the bees were exposed to (simulated with a cesium source), it was not a perfect reproduction of what these insects might experience in nature. The bumblebees in the experiment were given plenty of nectar and didn’t have to forage. The need to fly for long distances in the wild could also negatively affect bees in the CEZ.
The current level of radiation in the Exclusion Zone and in Pripyat, in particular, varies significantly. In some places, it is only marginally higher than the natural background radiation level, while in others it would be concerning if people stayed there for a prolonged time. The team exposed the bees to radiation levels between 300 and almost 5,000 times (200 to 13μGy/hr) higher than what the average person experiences every day, finding that around the 1,000 times mark, the bees started to consume more nectar.
The team hopes to investigate this further, for example by determining how flowering plants might be affected by this change.