Sniffing out one nest at a time How Wisconsin's bumblebee brigade is averting extinction

Sniffing out one nest at a time

- Anne Readel

On a summer day in Somers, Wisconsin, Dave Giordano heard an unexpected buzzing in his backyard. What he found shocked him – a rusty patched bumblebee nest. The discovery was so rare it made the local news.

Once widespread across the Midwest and eastern US, the rusty patched bumblebee has seen its population plunge by nearly 90%, prompting its listing in 2017 as the first federally endangered bumblebee in the US.

Each spring, a solitary rusty patched bumblebee queen emerges from hibernation and starts a colony – often in an abandoned rodent burrow. She raises workers through the summer, then shifts to producing males and new queens, or "gynes." After mating, the gynes burrow into the soil to overwinter, while the rest of the colony dies off.

Since the species was listed, only a dozen nests have been documented – leaving big gaps in understanding, says Jay Watson, a conservation biologist with the Wisconsin Department of Natural Resources. Most bee conservation work has been focused on planting flowers, but nesting habitat is just as important, adds Amy Toth, an entomologist at Iowa State University. "If they don't find a good location to nest, the entire colony can fail."

Finding those nests has proved exceptionally difficult, however. Scientists are spending a significant amount of time searching and not finding any, says Watson. To improve their odds, researchers have turned to conservation detection dogs.