Friday, September 25, 2015

Climate change is having a surprising effect on bumble bees

[Washington Post] Climate change is making some pretty strange things happen in the world. It’s able to alter the behavior of tiny marine organisms, change the circulation of the oceans and even prompt walruses to huddle en masse on the Alaskan shore. But one of the weirder effects of global warming may be happening inside the mouths of one of our most beloved insects: the bumble bee.
In a new paper published Thursday in the journal Science, researchers suggest that the effects of climate change are causing some bumble bees’ tongues — yes, their tongues — to shrink. In fact, they found that tongues on two alpine species of bumble bees in the Rocky Mountains have shrunk by nearly 25 percent in approximately 40 years. And it might sound bizarre, but this tongue-shrinking could actually have big implications for both the bees and the flowers they pollinate.
Tongue size is important in bees because it controls which flowers they can visit for nectar. Bees with longer tongues are able to collect nectar from flowers with longer corollas (that’s the tube shape a flower’s petals form, protecting the tasty nectar inside).
Bees with more medium-length tongues tend to pollinate many different species of flowers. But bees with long tongues are often considered specialists, meaning they only pollinate flowers with deep corolla tubes — and this can be a beneficial arrangement for both the bee and the plant. The bee gets to collect nectar from flowers that insects with shorter tongues can’t access, meaning it has less competition for food. And the flower is pollinated by bees that are only visiting other flowers of the same type, meaning there’s a better chance its pollen is getting transferred to the correct species.
This tactic works best when food is abundant. But the researchers on this study found that rising temperatures are causing flowers (of all sizes) to decline in the mountains, putting more stress on the bees when it comes to finding food. Read More