Tag Archives: Bumblebees

Solar parks could act as life rafts for bumblebees and other pollinators

Bees around the world are struggling under habitat loss; solar parks could provide a safe haven, according to new research.

Image credits Josef Pichler.

Researchers at Lancaster University have used computer modeling to investigate how different management scenarios of solar parks could help provide a home for ground-nesting bumblebees. The results are quite encouraging, the team explains, showcasing that solar parks can help maintain significant populations of bumblebees both inside their bounds and in their surroundings.

Although the research focused on bumblebees, the authors are confident that the findings translate over to other pollinators as well.

Solar neighborhoods

“Renewable energy development is projected to grow and solar is predicted to lead the way. Solar parks have a high land take per unit of energy produced and this will lead to significant land use change in the future,” says Hollie Blaydes, PhD student and Associate Lecturer at the Lancaster Environment Centre, lead author of the paper, in an email for ZME Science.

“Understanding of the environmental impacts of this land use change is only just emerging, but there is scope to incorporate environmental benefits into the energy transition. One potential benefit is the creation of pollinator habitat within solar parks.”

For the study, the team used computer models that simulated bumblebee foraging behavior across the UK’s solar parks. From there, they examined how different management strategies (each offering varying degrees of resources for the insects) would influence their numbers and activity. They then used statistical analyses to investigate differences in bumblebee density and nest density across the different solar parks in the model.

Managing solar parks as meadows, they explain, would make the most resources available to bumblebees, and could support populations four times as large as solar parks as solar parks with only grassland and no flowers. The changes required to transition solar parks from grass to meadows are quite simple and could provide significant benefits for pollinators across the country — in addition to generating clean energy.

Larger, more elongated, and more resource-rich solar parks (i.e. with more flowers) could help increase bumblebee density up to 1 km outside of their bounds, the team found. This means that well-managed solar parks could act as hotspots, delivering pollinator services to crops in nearby agricultural lands.

“Pollinator habitat has already been established within some solar parks, but there is little evidence of how effective this is and how pollinators respond,” Blaydes added for ZME Science. “This knowledge gap inspired us to perform this research and by doing so we have provided some of the first evidence to suggest that creating suitable habitat on solar parks could be an effective way to support bumblebee populations.”

Solar parks in the UK are often located within areas where intensive agriculture is practiced. This makes them ideally suited as bumblebee refuges, the team explains. Further increasing their potential in this regard is that the total land area used as solar parks in the UK is increasing steadily as more and more of the country’s energy demands are covered by solar panels.

The UK currently has around 14,000 hectares, which is projected to increase to 90,300 hectares as part of the UK’s plan to meet net zero-emission targets. All that space can be put to good use in the service of pollinators.

However, the path forward is not really clear-cut. Solar park management is often outsourced on contracts that typically last around two years at a time. This can make it hard to plan management strategies for the long term, as each new company will need to adapt to and maintain the habits they inherit.

“The creation of floral-rich habitat on solar parks is likely to benefit a wide range of pollinators. In this study, we focused only on ground-nesting bumblebees given they are a key pollinator of agricultural crops in the UK. Other pollinator groups rely on similar resources to ground-nesting bumblebees, but differences in flight ranges and foraging patterns means that a slightly different modelling approach would be needed to test solar park management and design options for these groups,” Blaydes adds for ZME Science.

Besides offering huge economic benefits for farmers and society as a whole by harboring bumblebees which would handle the pollination of crops. Pollinators the world over are struggling, and spaces such as solar parks could provide veritable lifeboats for these species, who are under pressure from habitat destruction, pesticides, pollution, and dwindling food supplies.

“Solar parks could act as safe havens for bumblebees and other pollinators if managed appropriately. Our study found that solar parks providing the most foraging and nesting resources were most effective at boosting bumblebee numbers both inside the solar park and in the surroundings,” Blaydes adds for ZME Science. “This suggests that resource-rich solar parks could be used as a conservation tool to help address drivers of bumblebee decline and that there could be implications for pollination to crops and wild plants in the surrounding land.”

Hollie Blaydes will present the work at Ecology Across Borders’ Annual Meeting, 2021. This study is unpublished and is currently under review. Original story here.

Warmer climate is making bumblebees’ tongues shorter

A new paper published Thursday in Science looks at how climate change is (out of all things) making the tongue of some bumble bees shrink. Two species of alpine bumbles in the Rocky Mountains already show a decrease in tongue volume of nearly 25 percent in the last 40 years; and smaller tongues could spell big trouble for the flowers that rely on bumble bees for pollination.

They'll have a hard time raspberrying from now on. Image via wikipedia

No pollen and a raspberry for you. Take that, flower!
Image via wikipedia

Uhh…Tongues?

Well you see, if you’re a bumble bee, size matters — more to the point, tongue size matters because it dictates which flowers the insects can harvest for nectar. This sweet liquid pools in the corolla, the long tube-y shape petals form at the base of the flower, and the taller the corolla, the longer the tongue needed to scoop out the tasty treat.

While bees with medium-length tongues tend to pollinate many different species of flowers, the ones boasting a longer tongue tend to feed off of only a few species, specializing in flowers with deep corolla tubes. This benefits the plants and the bees themselves, as the hungry insects get exclusive access to the nectar and the flower enjoys selective pollination — visiting only flowers with long corollas, the bees carry only a few types of pollen, increasing the chance that it will be transferred to the right species.

This tactic works really well when food is abundant, but the researchers on this study found that rising temperatures are causing flowers (of all sizes) to decline in mountainous regions, putting more stress on the bees when it comes to finding food.

When there are fewer flowers to choose from, specialization becomes a curse rather than a blessing, says Nicole Miller-Struttmann, lead author of the new study and an assistant professor of biological sciences at SUNY College at Old Westbury. They believe that shrinking tongues can be explained by an evolutionary attempt to make the species more generalized, giving them a wider range of food sources to visit.

“[The study is] a beautiful piece of work that shows the first incidence of climate affecting an important functional trait in the bees,” said Sydney Cameron, a professor of entomology at the University of Illinois at Urbana-Champaign, who was not involved with the study.

Shorter and more versatile

The study involved measuring Bombus balteatus and Bombus sylvicola (two species of bumble bees) tongues from two different spans of time: samples collected between 1966-1980 taken from a museum collection were compared to more recent ones, from 2012-2014. Balteatus and sylvicola were chosen as they are the most commonly encountered species at high elevations in the Rocky Mountains, and the results were quite shocking: tongue length of both species has declined by 24.4 percent overall, for an average of 0.61 percent each year.

Cameron believes it would be a good idea to conduct the same study again in five years, just to be sure that the tongue-shrinking is a long-term trend and not just “short-term cycling.” But if the trend holds true, it represents an instance of surprisingly rapid evolution in the bees.

“It’s a very short period of time to have seen such a strong shift,” said Leif Richardson, a postdoctoral research fellow at the University of Vermont’s Gund Institute for Ecological Economics, who was not involved with the study.

“It suggests that these bees may have an especially low effective population size and that they could have been through an evolutionary bottleneck, allowing very rapid change in these traits,” he added.

Climate change was not the first cause of this shortening the team thought of — they investigated whether a reduction in overall body size (which would mean the muscle shortened, but remained proportional with the bumble bee) occurred, if there was an increase in short-tubed flowers that would allow the species to harvest more food sporting shorter tongues, they even looked for an increase in food competition from other organisms might have caused the bees to evolve. Their theories didn’t pan out,  and the team was puzzled.

Then they looked at the effects of climate change on floral resources in the area. According to the researchers, minimum summer temperatures in the mountains they sampled have increased by about 2 degrees Celsius since 1960. That means it’s become more common for temperatures to get warm enough to cause flowers — of all sizes — to decline. And, in fact, the researchers found that total food resources for bumble bees in the region have fallen by about 60 percent since the 1970s. It fit, and it explained the shortening — it was an evolutionary response, allowing the bees to make the most out of dwindling food supplies.

So the tongue-shrinking seems to be an adaptation that allows the bees to better cope with dwindling food supplies.

“When resources are low, it’s more advantageous to go to lots of different flowers because there’s more resources that way,” Miller-Struttmann said. “And it takes less energy to get to them because you don’t have to search them out as much.”

But versatility is the death of specialization

“We’re gonna need some straws now, kids.” – Mr. Bumblebee.
Image via wikipedia

Great for the bees, but terrible news if you’re a flower — the shrinking could have catastrophic effects on the long-tubed flowers that the bumbles used to pollinate.

“It is possible that, at the same time, plant species that depend on these bees are receiving less effective pollination service,” Richardson said.

It’s possible that the plants could also adapt to the bees’ new behavior, perhaps by evolving shorter corollas, said Miller-Struttmann. But for now, it’s still unclear how the flowers will be affected.

“It will be really interesting to use some models to see how sensitive some of these species we see are to changes in bumble bee behavior,” she said.

Richardson said that similar studies should be conducted in other locations to see if the trend holds up. The areas they sampled are fairly isolated and thus show a strong reaction to environmental pressure, but the trend should be visible to one degree or another in other areas affected by climate change.

“Bumble bee species that live in lower mountainside habitats and have larger populations might be buffered from these very strong selective pressures,” he said.

So, while the researchers have uncovered an intriguing trend in one instance, work remains to be done.

“We documented something that has happened, but we’re not exactly sure what’s going to happen going forward,” Miller Struttmann said. “That’s true from both the plants’ and the bees’ perspective.”

Bumblebees in Europe and North America bumble away from the equator as habitats shrink due to climate change

In the most comprehensive study ever conducted of the impacts of climate change on critical pollinators, scientists have discovered that global warming is rapidly shrinking the area where these bees are found in both North America and Europe.

Researchers examined more than 420,000 historical and current records of many species of bumblebees and confirm that they are in steep decline at a continental scale because of climate change. The new research is reported in the journal Science.

Bumble, bumble, toil and trouble. Image via: pixgood.com

The reduction in the habitable areas of these tiny fuzzy insects would make being a bumblebee really cramped and uncomfortable (we sympathize with the plight of our bumblebee readers), but more importantly, it would affect entire ecosystems that rely on them for food:

“Bumblebees pollinate many plants that provide food for humans and wildlife,” says Leif Richardson, a scientist at the University of Vermont who helped lead the new research. “If we don’t stop the decline in the abundance of bumblebees, we may well face higher food prices, diminished varieties, and other troubles.”

And we, as a species, rely on them, their honeybee brethren and other pollinators heavily in agriculture; farmers worldwide depend on them to pollinate crops, from onions to celery to tomatoes and sunflowers effectively, and free of charge. The buzz is a bonus.

“Pollinators are vital for food security and our economy, and widespread losses of pollinators due to climate change will diminish both,” stated leader of the study Jeremy Kerr, a biologist from the University of Ottawa. “We need to figure out how we can improve the outlook for pollinators at continental scales, but the most important thing we can do is begin to take serious action to reduce the rate of climate change.”

If only this poor farmer fought climate change so he would have a few bumblebees.
Image via: garden.lovetoknow.com

Many species of animals and insects have been observed to expand their territories northwards, towards the North Pole, as previously frigid lands become more hospitable due to climate change. Bumblebees however are a special and worrying case, as they do not seem to move north at all, and even worse, the southern boundary of their territory is starting to creep away from the equator.

“This was a surprise,” said Richardson, a bee expert at UVM’s Gund Institute for Ecological Economics. “The bees are losing range on their southern margin and failing to pick up territory at the northern margin–so their habitat range is shrinking.”

The new study shows that the culprit is not pesticides and it’s not land use changes–two other major threats to bumblebee populations and health. Instead, the research shows clearly that this “range compression,” as the scientists call it, tracks with warming temperatures.

The team also found that bumblebees are starting to move to higher elevations, up hill and mountain sides, searching for cooler, more comfortable temperatures.

“Moving upslope doesn’t necessarily mean they’ve lost area there yet,” said UVM’s Richardson, “but, eventually, they may simply run out of hill.”

To conduct their study, the scientist used geo-referenced databases from museum collections on both continents. In Vermont, Leif Richardson examined bee specimens at UVM’s Zadock Thompson Zoological Collections.

Over the 110 years of records that the team examined, bumblebees have lost about 185 miles (300 km) from the southern edge of their range in Europe and North America, the scientists estimate.

“The scale and pace of these losses are unprecedented,” said Ottawa’s Jeremy Kerr.

They speculate that the explanation lies in the bee’s origins: many other species of insects originated and diversified in tropical climates, so the higher temperatures bode them well, as they can better adapt to them. Bumblebees however have “unusual evolutionary origins in the cool Palearctic,” the scientists write, which may help explain their rapid losses of terrain from the south and lagging expansion in the warming north.

To respond to this problem, the research team suggests that a dramatic solution be considered: moving bee populations into new areas where they might persist. This “assisted migration” idea has been considered–and controversial–in conservation biology circles for more than a decade, but is gaining support as warming continues.

“We need new strategies to help these species cope with the effects of human-caused climate change, perhaps assisting them to shift into northern areas,” said Kerr. But the most important message of this study is “the need to halt or reverse climate warming,” says Leif Richardson, a USDA National Institute of Food and Agriculture postdoctoral research fellow at UVM.

“These findings could spell trouble for many plants–including some crops, like blueberries–that depend on bumblebees for pollination,” he said. “Bumblebees are crucial to our natural ecosystems.”