Climate Change Causes Bumblebee Queens To Perform Their First Wing Beat of Spring Early

According to new research from Lund University in Sweden, Bumblebee queens are flying earlier in the year as a result of a warmer climate and a changing agricultural landscape.

Reduced biodiversity with modern agriculture

(Photo : Christopher Furlong/Getty Images)

"We risk losing more bumblebee species and having less pollination of crops and wild plants," says Lund University researcher Maria Blasi Romero, as per ScienceDaily.

Bumblebee queens emerge from hibernation when spring arrives and the ground warms. Queens, unlike workers and males, are the only bumblebees that survive the winter, and they spend several weeks looking for a place to nest, where they can lay eggs and start a colony.

Rising temperatures, on the other hand, cause them to awaken earlier in the year. According to the new study, the first flight in Sweden occurs on average five days earlier than it did twenty years ago.

The loss of grassland habitats, such as meadows and permanently grazed pastures, has been the most significant change in the landscapes studied over the last century.

Today, large agricultural fields predominate, with only a few crops often grown. As a result, farmland biodiversity has declined overall.

Bumblebee queens emerging from hibernation much earlier nowadays are most likely due to a warmer climate, a lack of food during the flight period, and more varying microclimatic conditions in today's agricultural landscape compared to older, more diverse landscapes.

The researchers studied ten bumblebee species and discovered that those that flew earlier in the season have become even earlier flyers, while those that fly later in the season have not changed their flight season.

There is a risk that this will result in a mismatch between the activity periods of flowering plants and bumblebees, resulting in bumblebees not getting enough food.

"We see a clear risk that more bumblebee species are at risk of extinction locally, particularly those that emerge later in the summer; this could also lead to a decline in the number of bumblebees overall, which would have consequences for crop pollination and ecosystem functioning; bumblebees are important pollinators, particularly in northern latitudes such as Scandinavia," says researcher Anna S Persson.

Also Read: Climate Change is Killing Bumblebees as Early Spring Forces Shortened Hibernation

Why are bumble bees such great pollinators?

This feature gets its name from the charming buzzing sound made by bumble bees on flowers, as per Bumble Bees of Wisconsin

Bumble bees have the ability to vibrate (by shivering their flight muscles) at specific frequencies while on a flower to help dislodge pollen from the anthers of flowers.

This behavior is required for pollinating fruits such as tomatoes, where the pollen is tightly held on the anthers.

The hairs that cover bumble bees aren't just for show; they're also completely functional.

Individual hairs (called "setae") are branched, which increases surface area and makes them "stickier" to pollen grains.

Furthermore, the hairs protect bumble bees from the cold, allowing them to retain heat and forage even when conditions aren't ideal.

Bumble bees, like all insects, have a cold-blooded nature. This means they are unable to control their internal body temperatures.

Bumble bees, on the other hand, have evolved a mechanism to avoid the limitations of only using external conditions to regulate their body temperature by shivering.

Bumble bees, on the other hand, choose when to shiver, raising their body temperature to the 30C threshold required for flight (86F).

This "facultative endothermy," combined with their insulating hairs, allows them to forage in cold conditions when other bees cannot.

As you might expect, bumble bees are excellent pollinators of spring/early summer crops such as apple and cranberry.

Related article: Urbanization Causing Negative Impact on Ground-Nesting Bumblebees: Study