The Bumble Bee Life Cycle

Updated: 27th April 2021


The bumble bee life cycle starts with an impregnated queen, when she emerges from her nest from her winter snooze. 


In order to prepare herself for leaving her cosy hibernation hole, the young queen bumble bee has to first do a little ’warm up’ – just as you or I may do our own little ‘warm up’ routine before going for a winter jog.  To do this, she vibrates her flight muscles very fast to generate heat, and when ready, she’ll then take off to look for pollen and nectar.


The bumble bee life cycle starts with the queen


Depending on the species, some of these queen bumble bees will appear in the spring the following year, from March onwards. However, some species may appear as early as February. 

For the queen bumble bee, this is a very vulnerable time. Pollen and nectar sources are scarce, and she’ll need to find both very quickly in order to sustain her during these crucial days. The nectar gives her energy whilst the pollen helps her to replace vital body fats. It also provides protein to help her ovaries mature, and is needed later to feed her brood.


White tailed bumble bee foraging on knapweed flowerBombus lucorum - white-tailed bumble bee queen on knapweed.

During this time winter flowering shrubs and plants,  such as mahonia, pussy willow, crocuses, rosemary, winter heathers, blackthorn, berberis and daffodils provide a vital life line for bumble bees.

Once the queen bumble bee has recovered, her next task is to find a suitable place to nest.

An abandoned rodent hole, tussocky grass, or even a bird nest box can provide a suitable home, depending on the species.

Below is a lovely short video following a queen bumble bee as she establishes a colony, in a building:


Below is an entrance to an underground bumble bee nest.

Bumble bee nest entrance in the ground.Site of a bumble bee nest - highlighted by the pink circle, a bumble bee entering the nest.


Again, depending on the species, there are slight differences in the way broods are reared, however, a general description is as follows:

Once the nest site has been located, the queen bumble bee will build a little wax cup inside it, which she will fill with nectar to sustain her whilst she incubates her eggs. She’ll also create a further wax cell, in which she will deposit a mound of pollen, and then lay her eggs on top of it. She incubates the eggs by lying on top of them, and again, by vibrating her flight muscles to generate heat up 30 °C!

The larvae


After about 4 days, the eggs hatch into larvae (these look a little like maggots).

The larvae continue to feed and develop, and will go through a number of stages in development (shedding their skin 3 times) until after about 14 days, they produce silken cocoons and pupate. Within the pupae, the larvae shed their skin once more, and undergo metamorphosis. After about 14 days, the little grub-like larvae are transformed into a young bumble bees, which bite their way out of their cocoons.

Worker bumble bees


The first bees to emerge from these cocoons are young female worker bees.

Meanwhile, the queen has already laid more eggs that are also in development.

The newly emerged workers will be a great help to the queen in rearing the rest of the brood.

Within a day or two, these workers will set about helping the queen, initially with nest duties, but some will then go out to forage for pollen and nectar for rearing the next brood (usually more workers). A colony of bumble bees could have between 50 – 500 workers, but will commonly consist of around 120 to 200. 

Emergence of males and young queens

Red tailed bumble bee male on pink knapweed flowerA Bombus lapidarius - red-tailed bumble bee male


At some point, the queen will stop producing workers, and will switch to rearing males and young queens.

Once the males have emerged, they will soon leave the nest in search of mating opportunities.

The young queens may remain in the nest for a while, laying down fat reserves in preparation for the winter hibernation.

All being well, a honey bee colony should survive the winter. 

In the case of bumble bees, the whole colony will die, apart from the new queens.  The new queens leave the nest, mate, then hibernate, and re-emerge the following year to establish new colonies of their own. And so the next generation of bumble bees begins.


Bombus lapidarius red-tailed bumble bee queen on aster - Stokesia.A Bombus lapidarius red-tailed bumble bee queen on aster - Stokesia.


Providing Habitat For Bumble Bees

It is a good idea to provide plenty of foraging opportunities, with an abundance of flowers over a long season.

Take a look at my lists of plants for bees.


You may wish to consider providing artificial nest sites for bumble bees. You can do this by purchasing one, however, success is far from guaranteed, and indeed, you may have more success with a previously used bird box, or an upturned plant pot under the garden shed.  Some bumble bees like to make their nests in compost bins.


My personal recommendation is don't try to force a bumble bee to nest in a 'bee house' you have purchased, instead, allow nature to take its natural course.  If you have purchased a bee house, it may or may not be suitable or in the ideal location, and there are other factors to be considered, such as abundance of the correct flower types, nest conditions.


 

Ever wondered......
Do bumble bees make honey?

bumble bee foraging on hemp agrimony links to page called Do bumble bees make honey?






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