The parasite in question is called Nosema ceranae and was first identified in Beijing in the 1990s. By 2007, a team of scientists including Robert Paxton, confirmed that Nosema ceranae had gone global.
“We predict that, as the world warms, beekeepers in cooler regions will suffer increasing problems.”
This dramatic spread is alarming, believes Paxton, because the parasite Nosema ceranae is more virulent than Nosema apis, its native sister variety. N. ceranae weakens bees, sometimes leading to total colony loss. What is more, his laboratory experiments showed that the invasive virus can displace its native sister species.
This suggests that even though, for now, the non-native parasite remains a rarity in northern Europe and North America, it won’t stay this way for long. Using a simple mathematical model to analyse the dynamics between the two species of parasite, Robert Paxton’s research team found that N. ceranae’s competitive advantage increases the warmer the weather gets, perhaps a legacy of its origins in the warmer east Asian climate: “We predict that, as the world warms, beekeepers in cooler regions will suffer increasing problems,” he says.
And it may not only be our honey bees which suffer: Earlier this year he also showed that the foreign parasite – unlike the native – is also widespread in bumble bees, so it may cause knock-on problems for our wild pollinators too.
Author Robert Paxton is Professor of General Zoology at Queen’s University, Belfast.