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Rusty-patched bumblebees could vanish in the next couple decades

Remember those fuzzy, black and orange bumblebees buzzing around your garden? The ones with the rusty-colored patch on their backs? They’re called rusty-patched bumblebees. Sadly, the bees are now endangered and nearing extinction.

Colorado State University researchers have led a landmark genetic study, casting light on the bee’s drastic decline. The findings mark a critical step towards reviving this endangered pollinator.

Endangered rusty-patched bumblebees

The rusty-patched bumblebee has a sad claim to fame. It was the first bee species to land on the U.S. Endangered Species list way back in 2017. The situation’s gotten worse since then. Scientists estimate a staggering 90% decline in their population compared to just a few decades ago.

“If that trajectory continues, this species could blink out in the next couple of decades,” warns John Mola, an ecologist at Colorado State University who led a major genetic study on these bees.

What’s driving the endangered bumblebee’s decline?

The rusty-patched bumblebee is facing a perfect storm of threats, each contributing to its alarming population decline. These threats include:

Pesticide exposure

Widespread use of neonicotinoid pesticides causes the decline of bumblebee populations. These chemicals can harm bumblebees directly or indirectly by affecting their food sources (plants) or disrupting their navigation abilities.

Pathogen pressure

Bumblebees, like many other animals, can be susceptible to various diseases and parasites. The introduction of new pathogens or the spread of existing ones due to factors like habitat loss can put additional stress on already struggling populations.

Habitat degradation

Habitat loss and fragmentation are major threats to bumblebees. Converting natural landscapes to agriculture or development deprives bumblebees of critical resources like nesting sites and food-providing flowering plants.

Climate change

A changing climate disrupts weather patterns and flowering times of plants. This can make it difficult for bumblebees to find food and complete their lifecycles successfully. The combined effects of these factors are likely synergistic, meaning each threat worsens the impact of the others.

However, to develop the most effective conservation strategies, scientists need a deeper understanding of the situation beyond just the environmental threats. This is where genetics comes in.

Endangered rusty-patched bumblebees genetic history

A team of researchers collected tiny samples of bee DNA from across their entire range. What they found wasn’t pretty. Not only are there fewer bee colonies overall, but some of the remaining ones are showing signs of worryingly high inbreeding. About 15% of the bees studied had genetic glitches that suggest their parents were closely related.

“When that happens, those populations essentially face a death sentence,” explains Mola. Inbreeding makes bees less resilient to threats in the long term.

Adding another layer of complexity to the rusty-patched bumblebee’s decline is a surprising discovery about their genetic makeup. Scientists initially assumed these bees formed a single large population across the United States. However, their research revealed a different story: the rusty-patched bumblebee is actually divided into three distinct genetic groups.

Geographic separation

These groups are geographically isolated, with one population concentrated in the upper Midwest, another in the central Midwest, and a third tucked away in the Appalachian Mountains. This separation likely occurred due to historical habitat fragmentation and changes in climate patterns.

Limited gene pool

Each of these isolated groups has a smaller gene pool compared to a single, larger population. This limited genetic diversity can make them more vulnerable to threats like disease or environmental changes.

Conservation challenges

From a conservation standpoint, this discovery presents a significant challenge. Strategies that might be effective for one bee group may not be suitable for another due to their unique genetic makeup. Additionally, the smaller population size of each group makes them more susceptible to extinction if threats aren’t addressed effectively.

Scientists now face the complex task of tailoring conservation efforts to address the specific needs of each genetically distinct group. This highlights the importance of considering both environmental and genetic factors when developing strategies to save endangered species like the rusty-patched bumblebee.

Importance of the bumblebees

Bumblebees play a vital role as pollinators, responsible for fertilizing both wildflowers and a wide range of crops. Their unique ability to carry large pollen loads and work in various conditions makes them especially valuable.

Without bumblebees, food production would become more difficult and expensive, posing an economic risk in addition to the ecological one.

Sadly, the rusty-patched bumblebee isn’t the only one buzzing into trouble. “Unfortunately, we’re looking at a future scenario where about one in five bumblebee species in the United States could be endangered,” says Mola.

Will the endangered bumblebees go extinct?

So, are we doomed to say goodbye to the rusty-patched bumblebee? Not necessarily. Its endangered status has triggered projects aimed at restoring their favorite habitats and helping them find food.

Here’s what we can do, too:

Planting native plants

Planting a variety of native wildflowers in your yard or garden provides a reliable food source for bumblebees and other pollinators throughout the growing season. Native plants have co-evolved with local pollinators, offering them the specific types of nectar and pollen they need to thrive.

Ditch the pesticides

Avoiding the use of pesticides, particularly harmful insecticides, is crucial. These chemicals can directly harm bumblebees, disrupt their behavior, or damage the very food sources they depend on. If you must treat pests, opt for natural or less harmful alternatives whenever possible.

Spread the word

Encourage your neighbors, friends, and community members to do the same. By creating safe and pollinator-friendly spaces, we can collectively contribute to much-needed habitat restoration, giving bumblebees and other pollinators a fighting chance.

Mola reminds us, “At times, there can be doom and gloom in conservation, but there are good examples of butterfly species that have been recovered through careful conservation planning. The same thing applies with bumblebees.”

Saving endangered rusty-patched bumblebees

The recent genetic study is a huge deal. Understanding the rusty-patched bumblebee’s distinct populations means scientists can tailor recovery plans for each region. They now know they can’t simply scoop up bees from one area and move them to another.

“This research is invaluable—it helps us refine healthy colony targets and shows us the importance of optimizing conservation efforts in genetically distinct areas, like the Appalachians,” says Tamara Smith, a wildlife biologist with the U.S. Fish and Wildlife Service.

The future of the rusty-patched bumblebee is still uncertain, but scientists haven’t given up on them. So, next time you spot one of these little buzzers, take a moment, appreciate their fuzzy cuteness, and wish them luck.

The study is published in the Journal of Insect Science.


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