New York – A team of researchers from SUNY College have conducted a study and came across another harm caused by global warming. The team noted that global warming and evolution is reshaping bodies of some American bumblebees.
As climate change kills off some of their favorite flowers, several bumblebee species in the Rocky Mountains have responded to those losses by evolving shorter tongues. In a new paper published Thursday in the journal Science, researchers found that tongues on two alpine species of bumblebees in the Rocky Mountains have shrunk by nearly 25 percent in approximately 40 years.
There has long been evidence that two long-tongued alpine bumblebee species – which feed upon flowers with deep corolla tubes – were seeing their numbers drop. But with evidence lacking to explain the decline, Nicole Miller-Struthman, of SUNY College at Old Westbury, New York, and her colleagues decided to take a look at the tongues of the two species, Bombus balteatus and B. sylvicola.
To investigate how flowers and bumble bees changed, a team of scientists dug through over 40 years of records. They tracked down thousands of bumble bee specimens collected on mountains in Colorado between 1966 and 1980, and compared them to bumblebees collected in the same areas between 2012 and 2014. Since 1970, the total number of flowers available for bees on the mountain study sites declined by 60 percent overall.
Tongue size is important in bees because it controls which flowers they can visit for nectar. With fewer flowers to choose from overall, it makes less sense to be so specialized, says Nicole Miller-Struttmann, lead author of the new study and an assistant professor of biological sciences at SUNY College at Old Westbury. The Washington Post reported that she and her colleagues believe the bees’ tongues are shrinking to allow them to be more generalized when it comes to the flowers they visit, giving them a wider range of food sources to choose from.
Again in five years
“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.”
More broadly, the authors said these bees could help shed light on how climate change disrupts the mutually beneficial relationship between insects – as well as long-tongued critters like bats and hummingbirds – and their hosts.
“Changes that disrupt such matching can alter plant species recruitment and the trajectory of co-evolution,” they wrote.
As he told to the Washington Post, Cameron believes it would be a good idea to conduct the same study again in five years, just to be sure that the tongue-shrinking is a long-term trend and not just “short-term cycling.” But if the trend holds true, it represents an instance of surprisingly rapid evolution in the bees.
Source: The Washington Post