Under the Microscope - MU Study Finds Some Bees Evolve with Climate Change

Oct 22, 2015

Research shows that the Earth’s warming climate can have a massive impact on many parts of the ecosystem, from the ocean down to the tiny bee. Recently, bees have been dying in increasing numbers due to environmental changes.

Some sub-species, however, seem to be putting up a better fight than others.


In 2012, researchers from the University of Missouri went to the central Rocky Mountains to revisit a 1970’s-era study of alpine bumblebees. Specifically, the study measured the length of the bees’ tongues, which help them pollinate wild plants.

The new study examined how changes in the environment had affected bee populations over the past several decades. They found that the bees had adapted by evolving 25% shorter tongues—a big change for only forty years of evolution.

Candace Galen, a professor of biological sciences at MU, was one of the group’s lead researchers. She said the changes could occur over such a short time period because bumblebees are annual species, meaning they only have one generation every year.

“That’s pretty rapid evolution, and to me it speaks to the strength of the pressures that bees must be under to adapt that quickly,” Galen said.

The researchers found that the earth’s warming climate was changing the density and diversity of bees’ main source of food, wildflowers. The region was left with fewer long-stemmed flowers, which caused a problem for the long-tongued bees that specialized in that flora.

“The balance has shifted from sometimes benefiting the generalist and specialist to almost always benefiting the generalist,” said Ricardo Holdo, an assistant professor at MU who created the paper’s theoretical models.

The bumblebees followed suit, evolving shorter tongues that allow them to feed off of a wide variety of flowers.

Galen said that is good news for alpine bees, but that Missouri bumblebees may not have it so easy. If they live near farms that use agricultural chemicals heavily, they might not be able to adapt as quickly.

“In these remote, almost pristine alpine regions, there’s very little other kinds of human pressures that bees have to adjust to,” Galen said.

Going forward, Galen worries what bee adaptations might mean for the wildflowers that depend on them for pollination. She said that future studies should examine the flowers, and other parts of the ecosystem that depend on bees, that might get left behind.