I like bees, but I love bumblebees more. The sight of their comedically cumbersome bodies ambling across an umbel, or alighting delicately on a gossamer-thin petal never fails to amuse me. Bumblebees are amiable little creatures, disinclined to harass or sting humans, unlike some of their close relatives. They live in small colonies and tend not to swarm or make a general make a nuisance of themselves. And they are useful to boot, pollinating flowers that even the bravest honeybee cannot tackle.
According to the Bumblebee Conservation Trust, the population of bumblebees in Britain has plummeted over the last eighty years. Two species have become extinct nationally and several others have declined dramatically. The blame for this collapse is mainly laid at the farmer’s door. Changing agricultural practices after WWII, especially the introduction of pesticides and the removal of flower-rich hedgerows, started the decline, but nurserymen and gardeners have also played a part. Over-hybridised flowers with complex double flowers or sterile blooms deprive bees of access to the pollen that they crave. Enlightened gardeners are waking up to the notion that single, uncomplicated flowers are not only more natural to look at, but also much more welcoming to pollinators.
Bumblebees are brilliantly adapted to pollination, a function which if not fulfilled would bring the natural world to a grinding halt. First of all, their disproportionately large bodies are covered in dense hairs which are forked at the tip. These help bumblebees to gather and transport pollen between flowers, pollinating as they go. Different species are equipped with different tongue lengths which are adapted to feed from different types of flower. Short tongues probe flowers with short corollas (the tube that leads to the nectar), leaving species with longer appendages to forage from more complex flowers with long corollas. This is why encouraging lots of biodiversity to your garden is so important. Finally, bumblebees are uniquely able to ‘buzz pollinate’. This involves them contracting their flight muscles to create strong, rapid vibrations which literally shake the pollen from a flower’s anthers, even if the flower is unwilling to give it up. If you listen carefully to a bumblebee ensconced in a particularly pollen-rich flower you will often hear this happening and see the bee dusted with its plunder. Crops such as tomatoes rely on this type of pollination to produce a good crop of fruit.
Bumblebees are social insects, living in nests of up to 400 individuals. A nest is led by a queen and exists for just one year. In contrast, honeybee hives may remain active for several years. In early spring the queen emerges from hibernation to start a new nest. Her first task is to build up her energy reserves so it’s really important that she can find plenty of pollen and nectar-rich flowers. This explains why the first bumblebees you will see in your garden on a warm February day tend to be super-sized – you are enjoying a right royal visit! Once the queen has found a suitable nest site she will rear her first batch of eggs. These will hatch to produce a group of female workers whose job it is to feed and nurture the colony. This process is repeated throughout the summer with the queen rarely leaving the nest. Towards the end of the summer the queen produces male offspring, along with new queens. After mating the males, which have lead in their pencil but no sting in their tail, die off, as do the old queens and workers. Only new, fertilised queens survive to hibernate through the winter and establish their own nests the following year.
If you want to attract more bumblebees to your garden there are a few simple things you can do. Firstly plan a succession of flowers starting from spring, right through to the end of summer. Bumblebee queens emerge very early in spring so greet them with some bright crocuses or forsythia which are easy to spot and packed with pollen. During summer, foxgloves, single roses, lavender, veronicastrums, teasels and a host of other flowers will sustain the burgeoning bumblebee population. In autumn, sedums, golden rod (solidago), cosmos, zinnias, Michaelmas daisies and nerines will help to fatten up the new queens for winter. Avoid double flowers where the anthers are hidden or even absent, and any varieties which are sterile (i.e. Don’t produce seeds). Pansies, begonias and double dahlias are especially unhelpful when it comes to attracting useful insects to the garden. Single flowers with large central bosses, such as daisies, and those with a profusion of flowers, such as the umbels, are perfect food factories for bees of all kinds.
Bumblebees tend to be ground or wall dwelling and, whilst nesting boxes can be provided in both situations, bees will be perfectly happy to find their own quarters provided you leave an undisturbed space in a dry shady corner of the garden. Insecticides should be employed minimally or not at all and should never be applied during the day when bees are actively foraging.
My observation in my own garden is that bumblebees and hoverflies now greatly outnumber honeybees. This seems to be borne out in other gardens I visit too. It’s tragic that any of these precious insects should be in decline as they provide gardeners and humankind in general with a service that would be impossible to replicate otherwise. Furthermore, what joy could there be in a garden without the comforting hum of bees going diligently about their work? We all have our part to play in reversing the plight of the bumblebee, so start now by planting a bag of crocus corms or an early flowering fruit tree to get them off to a happy, healthy start in 2017.
All videos made this weekend at The Salutation, Sandwich, Kent.