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 if you’re a generalist, short-tongued bee, you’re more likely to run into your resource”. And it might sound freakish, but this tongue-shrinking could actually have big implications for both the bees and the flowers they pollinate. Long tongued bees will probably spend more time searching around for deep flowers, while bees with shorter tongues will be less particular about the flowers from which they feed.
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A survey of the region’s flowers did indeed show that the deeper flowers favoured by long-tongued bees had been largely replaced by shallower flowers. The costs of sporting long tongues now seem to outweigh the benefits, so natural selection has favoured bees with shorter tongues. Flowers rely on bees to transfer their pollen and if no bee can reach it, they have no way of reproducing.
This tactic works best when food is abundant. She cites changes in flower species as a reason for the decline in bee tongue length. To better understand why, a team of researchers studied two species of the bees in Colorado. Another species, Bombus sylvicola, saw a drop to just under four millimetres from just over five millimetres. That evolution, it turns out, could be an important aspect of bee survival in the face of changing climates.
A new study has shown that the effects of climate change on floral growth may be leading to shorter tongues in bumblebees. The ruled out decreasing body size, competition from invaders, or co-evolution with flowers in the area before concluding that climate change was to blame.
“They have adapted to diminished resource levels, a major impact of climate change”, writes senior author Candace Galen in an email to the Monitor.
The warmer temperatures also mean that the once-barren summits are now more flower-friendly, but that’s not enough to make up for the losses, say researchers. Climate change is to blame, Miller-Struttmann says. “And it takes less energy to get to them because you don’t have to search them out as much”. There were also indications that in some species, long tongues were shrinking.
In one of these species, the tongue had been half the size of the bee’s body – the equivalent of a human tongue going down to the waist. “It is possible that, at the same time, plant species that depend on these bees are receiving less effective pollination service”, Richardson said.
Armed with field data on the bees and their host plants as well as bee specimens, they went looking for the cause of this change. But for now, it’s still unclear how the flowers will be affected.
More than 85% of flowering plants – including some crops – require pollinators to reproduce.
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And Richardson added that similar studies should be conducted in other locations to see if the trend holds up. But the bees’ successful adaptation may be the silver lining of a very dark cloud.
