We have five species of bumblebees (Bombus) and two species of solitary mining bees (Colletes) in the Outer Hebrides, some of which are rarely found on the mainland; including the lovely Great Yellow Bumblebee (Bombus distinguendus) which I rely on to pollinate my broad beans. In the absence of honey bees, our bumbles, aided and abetted by the hoverflies, other pollinating flies and beetles, are kept busy during the summer.
Crofting is low intensity agriculture which uses no agricultural chemical, only small amounts of artificial fertilisers and a system of growing cereals involving a two year cycle of fallow and cultivation. This system of land management has helped to create the perfect environment for bees and other insects, but we have to be vigilant if we wish to ensure that our precious bees remain safe. It is possible to keep honey bees (Apis mellifera) here but the flowering season is very short and it is difficult to keep the hives going through the long winter period. The absence of commercially introduced bees may also have helped keep our local populations safe. Bumblebees do not carry the varroa mite but they are susceptible to deformed wing virus and a fungal parasite called Nosema ceranae which are carried by honey bees.
Bumblebees are used to pollinate horticultural crops in the UK and it is estimated some 60,000 nests are imported annually, 45,000 of which are for glasshouse crops (e.g. tomatoes or cucumbers) and 15,000 for soft fruit. Since 1988 commercially reared bumblebees (mainly Bombus terrestris dalmatius and Bombus terrestris terrestris) have been shipped around the world. Despite reassurance by producers, research has shown that commercially produced bumblebee colonies may carry multiple parasites that are viable and can infect other species of bumblebees and bees.
It has been possible for gardeners to buy Bombus terrestris (Buff-tailed Bumblebee) in the UK for sometime. This is a native species, but there is no guarantee that they are of British origin, or free from disease or parasites. With respect to claims that they will “reward you with increased pollination of fruits, flowers and vegetables” this at best doubtful. If you have pollination problems it is probably due to the absence of the right kind of flowers in your garden rather than a lack of pollinators, so releasing a few bees won’t really help. It would be better to spend the money on buying some bee-friendly plants.
Several species of our native bumblebees are declining, but Bombus terrestris is one of the most common species and is not threatened. Therefore, the release of commercially reared bees in gardens may do more harm than good. Bombus terrestris is scarce in the Scottish Highlands and only occur in any numbers around the Moray Firth. It is not native to the Outer Hebrides and an introduction could have serious consequences for our local bees. Island ecosystems are particularly vulnerable to introduced species, even when they are native on the mainland. Even a well intention introduction can have disastrous consequences as we have experienced following the release of hedgehogs on the South Uist in 1983.
So if you would really like to help our wild populations of bees and other pollinators it would be better to plant more insect friendly plants and send a donation to Bumblebee Conservation Trust.
How wonderful to have such a variety of bees. We have a few down here but am not good at identifying them! So looking forward to the pollinators returning! Hope it’s not too cold up there just now.. 😀
I love watching the bumbles and I know that summer is on the way when they emerge. Unfortunately sometimes they get it wrong and have to be rescued from the cold and wet and put in the polytunnel to await a warm day. Most of the bumblebees are not too difficult to identify, just a case of remembering the sequence of stripes. The other species are more difficult.
This might help get you started: http://bumblebeeconservation.org/about-bees/identification/common-bumblebees. So as not to confuse you, Heath Bumblebees in the Outer Hebrides have buff tails not white.
Yea I keep down loading the ID charts and there are so many different hover flies too. Did see a bumble bee on the last warm day we had! I get “buglife” alerts too….🐝
Hoverflies are much more difficult to identify, especially as there are some species which are bee mimics and look just like minature bumblebees!
This is interesting Christine, on the mainland Bees are treated as expendable when intensively farmed and imported, which does not encourage a fair assessment either on the effects of neonectinoids. I have heard that bees imported for glass house crops are destroyed after they have done their job, which just typifies the complete disregard man shows to other species.
Unfortunately the bees used as pollinators are expendable, all part of the agri-industrial process. In our industrialised system of food production animals are usually treated as commodities. It is interesting to noted that neonectinoids are about to be banned in the USA where they have very serious problems with their bees.
I had no idea that bees were imported commercially specifically for pollination – and even if I did I would not have imagined they would be destroyed afterwards. Surely that’s very short sighted – wouldn’t it be better for fields of bee friendly flowers to be planted in conjunction with commercial crops? Definitely better to bolster native bees too of course. The buff tailed bee seems to be the most common in our garden – and if the Golfer did not have a phobia about bees I would love to be able to lend a spot in the garden to a beekeeper for a hive. Lovely photos – and that Great-Yellow-Bumblebee is indeed a handsome fellow 🙂
Well I suppose that it is only the young queens who survive the winter and in something like a tomato crop the workers have a fairly long season. Unfortunately in the cold commercial world the idea of planting companion crops is seen as a negative on the balance sheet and it is cheaper to buy new bees each year than waste time and money breeding your own. Not attitudes I condone but unfortunately the world is run by the “bean counters”.
Hello Christine,
Well done for raising this subject.
I phoned one of the companies supplying bumblebee colonies to Uk gardeners a couple of years ago, since I felt that their advertising was extremely dubious ( promoting the benefits of a native bumblebee), but as I suspected all the colonies were imported from Holland which was where such activities took off first. Tomato flowers don’t produce nectar apparently, so the boxed colonies are sent out with sugar solution to keep them going – they are indeed viewed as a disposable item, and in addition rely on harvested pollen from honeybee hives across Europe (contaminated with goodness knows what!) to get them started, so all in all their marketing to UK gardeners is a con and a potential disaster for our native bumbles..
Interestingly too, Australia, which doesn’t have any native bumble bees has banned their import to avoid any disease introduction problems. Tomato growers there presumably do what everyone used to, and I now do to aid fruit set and yield in glasshouse tomatoes – use a vibrator every 2 or 3 days around midday. ( on the flower trusses, of course….).
As you rightly say I think the best thing any gardener can do for pollinators is to grow more insect friendly flowers – and anyone interested might like to look at my diary folders of what seems to work in our own garden throughout the year.
Great post again!
BW
Julian
Thanks Julian. I don’t have a problem with tomato pollination, but then I don’t grow them by the hectare and most of the time the polytunnel is ventilated so there are always plenty of insects in the tunnel. A few tagetes in the tunnel never go amiss either.