Scientists at the SUNY College at Old Westbury found a surprising new change global warming has brought to some bumblebee populations living in the Rocky Mountains – their notoriously long tongues shrank by one-third in less than a century.
The Central Rockies are a welcoming home to many types of bees including the long-tongued ones. These animals have disproportionately long tongues as compared with their body size because of the flowers they used to feed on.
Those flowers have long tubes, so only long-tongue species can have access to their nectar i.e. the long-tongued bumblebees. The insects provide exclusive pollination services in return.
But researchers noted that the bees are very rare now in the Rockies. They also nearly went extinct in many parts of the world. Additionally, species from lower elevations are now invading their territory, and scientists have a main suspect – climate change.
The team first measured the tongues of two bee species in three locations in Colorado mountains. Next they compared the data with measurements made in the 1970s and the early 1980s.
Study authors found that the bee’s tongues shrank at a 0.6 inch pace on a yearly basis. Currently, they lost one third of their length and the situation may get worse. Researchers were stunned by the findings. They did suspect the phenomenon to occur but not to such a large extent in just 40 to 50 years.
Critics of the study said that maybe the bumblebees became shorter and their tongues really didn’t shrink. But the team replied that there were no changes in body size; additionally, the bees couldn’t have adapted to a change in mountain flora because shorter tube flowers didn’t invade the mountainsides. And competition didn’t chased long-tongued species from their favorite flower either.
The only explanation scientists could find was global rising temperatures that now affect the Rocky Mountains, as well. Jennifer Geib, one of the researchers involved in the study, explained that the bees’ habitat is usually dry due to the high altitude. But in recent decades they became even drier, while summers became 2 degrees C hotter.
As a result, the soil lost a lot of moisture, while mountain snowcap can no longer provide local floors with the necessary meltwater in spring. So, many wildflowers that were already affected by prolonged droughts vanished. And the bees lost 60 percent of their food stock.
Long-tubed species were also reduced so the bees had to go for other flowers in order not to starve. In consequence, they no longer required long tongues so they quickly adapted to the new diet.
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