When you think of animals preparing for hibernation, bumblebees may not be the first creature that comes to mind. (If you are like me, it would be bears.) And yet inquisitive minds may be asking: where do bumblebees go in the winter?
It seems like spring magic when suddenly you see a bee pollinating those first spring blooms, as if they popped out of the ground the same way the flowers did. Surprisingly, that description is not too far off.
Preparing for hibernation
Over the summer, bumblebees busily work gathering nectar and pollen to feed their young and grow the colony. In the late summer, things start to switch up. Instead of rearing more worker bees, the hive begins to rear male bumblebees and new queens. The original queen and her workers will die after successfully producing new queens and males (drones). Eventually, these new queens and drones leave the nest to find others and mate. Once mated, the drones die and the new queens begin to prepare for a long winter nap.
Just like any other hibernating creature, queen bumblebees need to eat plenty of food to build up their energy stores for hibernation. Once the queen has a very full belly, the search for a hibernation site begins.
Bumblebees below ground
The hibernation habits of bumblebees are difficult to fully understand. Imagine being a scientist and trying to find a tiny bumblebee sleeping during the winter months. It’s not an easy task.
Despite this, we do know a few things. Namely, that bumblebees typically nest underground or bury themselves under leaves. We also know that they need to be in this state of hibernation in order to survive the winter months. The queen’s energy stores won’t keep her alive until spring if she is awake. If she wakes up and can’t go back into a state of hibernation, she will likely die.
A difficult time for survival
Hibernation, technically called diapause in the case of bees, and the subsequent spring emergence, is a particularly difficult stage of life for bumblebees. Queen bumblebees die when they can’t build up large enough energy stores and find suitable habitat.
Unfortunately, bumblebee populations are declining across America. In 2017, the rusty-patched bumblebee was the first bee to be listed as a federal endangered species, with the number of observed colonies falling by 87 percent since the late 1990s. The American bumblebee has seen nearly a 90% drop in numbers and has gone missing across eight states. The Western bumblebee has seen a 72% drop in its Colorado population alone.
These declines are not associated solely with hibernation, but making that stage of life a little easier is important, and it relates to habitat.
Helping hibernating bumblebees: a basic guide
While increasing pollinator habitat during the summer months through the planting of native pollinator-friendly plants is very important to support bumblebees, so is increasing the availability of hibernation habitat.
What to do in the fall
The easiest thing you can do is ditch the rakes in the fall. While bumblebees typically hibernate underground, they stay quite close to the surface. Sometimes they simply crawl under a pile of leaves or other natural vegetation to sleep through the winter. Leaving fallen foliage undisturbed in your backyard, sometimes called “leave the leaves,” is a great way to give bumblebees more hibernation habitat. It does not have to be your entire yard; even just a small section can make a difference if a bumblebee finds its way to your home. Other ways to increase habitat include making undisturbed log or rock piles.
Hibernation habitat is only one piece of the puzzle to help bumblebees survive the winter. Bumblebees need to fatten up for the winter just like any other hibernating animal. Finding flowers from which to collect nectar and pollen becomes harder and harder as fall comes to a close. If you already have a pollinator garden, or are thinking about starting one, make sure you have some plants that bloom in the late fall. Not only will this increase your chances of spotting a bumblebee queen getting ready to hibernate, it will also greatly help the queens survive.
What to do in the spring
Bumblebee energy stores are used up throughout the winter, leaving the waking queens very hungry. In those early spring months after waking, they work hard to build a new colony from the ground up. In order to do that, they need plenty of nourishment. So, just as it is important to have late blooming flowers in your garden, it is equally as important to have early blooming ones. By providing plenty of flowers for bumblebees to forage from both before and after hibernation, you are helping them survive.
A final tip: Choose native flowers
Finding flowers that bloom early, late and in the middle of summer is important. Choosing native flowers is also important. Why? Native plants are suited for the climate and the species in the area. The flowers evolved over the eons alongside native bees and other pollinators. The nectar and even the design of the flowers are well-suited for your local buzzing and flittering friends.
Searching for a hibernating bumblebee
Finding a hibernating bumblebee is hard. Even if you provide flowers for them during the entire growing season and plenty of hibernation habitat in the fall, you may never actually see a sleeping bee. Don’t let that discourage you! Instead, keep a lookout for bumblebees in the early spring and keep making your yard more pollinator-friendly. If you start to notice more spring-time bumblebees, you’re doing something (or lots of somethings) right.
Authors
Aria leads Environment America’s efforts to protect pollinators across the country. She grew up in the woods of New Hampshire, which was what first made her fall in love with the outdoors.
