Bees Adapt to Climate Change by Growing Shorter Tongues, Report Finds

Bees have been adapting to the climate changes within their environment, a new study found.

According to Nicole Miller-Struthman of SUNY College at Old Westbury in New York and her team, two types of bees living in the Rocky Mountains have developed shorter tongues over time in order to feed from other flowers that do not have deep corolla tubes.

For this study, the researchers focused on the Bombus balteatus and B. sylvicola, two species of bees that were from three mountain peaks in Colorado. They compared the tongue lengths of the bees from two time periods, 1966 to 1980 and 2012 to 2014 and found that "a significant shortening" had happened.

In order to uncover why these bees were evolving, the team analyzed field data on the bees and their host plants. They concluded that smaller body size, competition from invader species and co-evolution with the flowers within the area were not factors. After weeding those variables out, the researchers reported that the climate change was most likely the cause of the bees' tongue length evolution.

"Our analyses suggest that reduced flower density at the landscape scale is driving this shift in tongue length," the researchers wrote.

They explained that the warmer summers have led to a decrease in the number of deep flowers, which are the preferred types of flowers for the bees. This change then forced the bees to forage in flowers with a much more shallow tube. The team noted that this change is somewhat beneficial for the bees.

"Although populations of long-tongued bees are undergoing widespread decline, shifts in foraging strategies may allow alpine bumblebees to cope with environmental change," the authors wrote. "We see broader bumblebee foraging niches, immigration by short-tongued bumblebees, and shorter tongue length within resident bee populations as floral resources have dwindled. In remote mountain habitats - largely isolated from habitat destruction, toxins, and pathogens - evolution is helping wild bees keep pace with climate change."

The study was published in the journal, Science.