Our precious bumblebees

No summer’s day in the garden would be complete without the buzz of the busy bees. Bumblebees are the most noticeable species of bees. Their genus name is Bombus, allegedly named for their deep, booming buzz.

Broken-belted bumblebee. © Cherry Alexander
Garden bumblebee. © Cherry Alexander
Tiny worker Early bumblebee on a brassica. © Cherry Alexander

Although there are only 19 species of bumblebees that are found in Scotland, there are altogether 270 species of bees in the UK, but most of these are solitary bees, masonry, mining, cuckoo, leaf cutter, or our domesticated honey bees.

The bumblebees we see and hear in our garden have life cycle of about a year. The new queens emerge from nests in the late summer and autumn and these virgin queens mate with newly hatched male bees. The males will die before the winter and she looks for a sheltered spot to hibernate. When she emerges in the spring she needs to find a nest. Old mouse nests are popular but carder bees often nest in long grass, insulating the nest with moss. Once she has built her own strength up, she will start to forage for nectar and pollen to feed her offspring. She will continue this until the first worker bees, all female, are produced, and from then it becomes their task to forage to feed the colony. It takes about six weeks from egg, through pupa, and larval stages to adult bee. The life of the bumblebee hive is about 10 to 12 weeks, and then the queen stars to lay eggs that will turn into new queens and many male bees. The males develop from unfertilised eggs. And the cycle begins again. If the new queen emerges before midsummer she will start her own colony then, but any later and she will hibernate, ready to start her own nest in the following spring.

The value of bees as pollinators cannot be underestimated. Some crops can only be pollinated by bumblebees and this has led to bees being transported around the world to pollinate crops like indoor tomatoes and red clover.

There are many things we can do to help our bumblebees. Lavender is a good plant to have in your garden for bees, they love simple, open faced flowers, like single roses and daisies where the pollen and nectar are easy to access, also composite flowers like alliums. Sadly the garden favourites, petunias and annual geraniums have little value for bees. Recently the Royal Horticultural Society recommended some plant combinations which they say enable a bee to fly for longer on a feed of nectar. These are, A. lavender, fiddlehead and marjoram, B. Cosmos nasturtium and snapdragons, C. blueberry, strawberry and chives.

Bumblebees love simple, open faced flowers, like single roses and daisies where the pollen and nectar are easy to access, also composite flowers like alliums

The population of bees has been falling as ancient wildflower pastures are built on or ploughed and sprayed. The use of neonicotinoid pest control has a ‘sub-lethal’ effect on bees. The chemicals are systemic and are absorbed by the plants, but they are also present in the pollen and nectar, which is where the bees come into contact with them. This is affecting their central nervous system, causing disruption to foraging behaviour, homing ability, communication and larval development. Neonicotinoids are also present in the products used to protect our pets from ticks and fleas and can be passed into the soil in animal waste.

More and more people are leaving their dandelions in the spring as food for the bees, following publicity that to poison your dandelions will also poison your early bees. In my garden I have another bonus from leaving the dandelions to flower, when they run to seed the siskins and bullfinches come down and gorge on the dandelion clocks. By avoiding the use of toxic spray in our gardens we can encourage the beneficial insects that feed on the ones we don’t want. Untidy corners in a garden offer habitat for hedgehogs, small rodents and bees, both bumblebees and solitary bees.

If a honey bee stings you, it has a barbed sting, which will stay in your skin and pull out the abdomen of the bee, it will die, but it only stings once, Bumblebee stings have no barb so they do not die after stinging anything, but they are gentle creatures and are far less likely to sting, they will wave their legs at you as a warning. The foraging range of a bumblebee on a meal of nectar is about 40 minutes so if you see an exhausted bee on a plant or sitting on a path, mix it a tiny drink of sugar water so it can refuel, or put it on a flower so it can feed and return safely to its nest.

As well as the six most common bumble bees found in Scotland, there are also Cuckoo Bees. One species, the Gypsy Cuckoo Bee (Bombus bohemicus) females parasitise nests of Northern white-tailed bumblebees (Bombus magnus) by entering a nest, killing the queen and laying her eggs in the cells so the workers in the nest rear them as their own. Female Cuckoo bees have no pollen baskets on their hind legs, their plan is that other bees will do their work for them.

Insects are cold blooded, but bumblebees have evolved strategies to help them regulate their temperatures. They can shiver to warm themselves up and their furry coats keep them warm. A bumblebee can be on the wing at 10C which is 4-5C degrees lower than honey bees and solitary bees, enabling them to make the most of early spring flowers.

There is compelling evidence that bees and other pollinators are in decline. If action is not taken there are serious implications for biodiversity and food production. I hate to think of a summer where the buzz of bumblebees is silenced forever. Bumblebee Conservation Trust (bumblebeeconservation.org) publish an excellent guide to UK bumblebees, called Bumblebees, an introduction. The Field Studies Council publish a fold out identification of the UK’s commonest bees (field-studies-council.org)

By Cherry Alexander

Last Updated on 10 June, 2022 by Kyle Chronicle

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