Bumble Bees at Risk, While Others Thrive
“Bees are going extinct, you know,” announces my third grader to his younger brother, usually while we are in the car. This favorite recurring assertion of his always prompts me to remind him that it’s not exactly true, because there is more than one kind of bee and pollinator in the world. Then, for lack of any more information to share about bees, we get sidetracked into explaining to the kindergartener just what the word “extinction” means.
So today I’m very pleased to learn that there is a new and rather remarkably long-term study about how bees are doing, at least in the northeastern US. The study, led by Rutgers University researchers and based on 140 years of historical specimens from the American Museum of Natural History (AMNH) and nine other bee collections, shows that some species of bees — particularly bumble bees — are declining while introduced species of bees are hanging in there. The study was published this week in the Proceedings of the National Academy of Sciences.
Here are some of the key findings:
From the years 1872 to 2011, the researchers see slight declines in the overall number of bee species in the northeastern United States.
Three species — all bumble bees — showed signs of rapid and recent population collapse. Other species showed more gradual declines
More than half of all bee species changed in proportion over time. Twenty-nine percent of the species decreased and 27 percent increased.
Bees that showed the greatest increase are mostly species introduced to North America by Europeans that were scarce in the earliest historical samples but made up an ever-increasing proportion of more recent samples.
The declining bee species tend to have larger body sizes, restricted diets, and shorter flight seasons.
“Southern” bees are getting more abundant as the climate warms.
Besides the fact that generations of field biologists contributed to this work, I find the study remarkable in another way: It’s one of those works that shows the power of web-based science. In this study the researchers used new web-based software to sift through 30,000 museum specimen records of 438 bee species.
“A novel aspect of this study was the use of collaborative online tools that allowed data to be captured quickly and accurately across 10 institutions, many of which lacked pre-existing capabilities in this area,” said AMNH’s John Ascher in a press release. He’s an author on the paper and the leader of the data-collection effort.
Now all I have to do is find a way to explain all this to an 8 and 5-year-old before the next drive. There’s no way I’ll try it while operating a vehicle.
Image: The cleptoparasitic bee Coelioxys sayi is widely distributed in North America and parasitizes Megachile leaf-cutter bees. This photo was taken in Prospect Park in Brooklyn, New York (image courtesy of AMNH/J. S. Ascher)