Bumblebees are the stuff of nature in the UK at its finest, moving from flower to flower in slow motion. But honeybees get all the press. There’s the very obvious reason that they are used commercially to produce honey and to pollinate flowers. In the US, hives are transported hundreds of miles to pollinate almond and cherry trees and others. And why are they transported? It’s because the trees are imports, or the great, great, great, grandchildren of imports from Europe. That being so, there are no natural pollinators – at least not in sufficient quantity – so European honey bees are raised to fill the need.
Honey bees are social, and that is the secret to their success. Until a better hive was invented, it was also a problem. Each year the honey bees would fill a hive with honey, and each year the beekeepers would pull apart the hive to get at the honey.
Here’s a drawing by Pieter Breugel the Elder from about 1568 showing beekeepers with skeps – hives of twined rope – with one of them beginning to pull apart a skep to get at the honey.
As a side note, the man up the tree is taking eggs from birds nests.
All in all it is a scene of death and destruction, plundering and robbery. The people in this drawing thought that nature was inexhaustible. Modern man no longer believes that..
They say that there are none so wise as the experienced, so perhaps it is good that we have seen how we can break the world.
Back to Bees
The revolution in beekeeping came in the 1850s, when the Reverend L. L. Langstroth in Massachusetts noticed that bees will not bring the surfaces of two combs closer together than a ‘bee space’ – about the width of a finger. That was the beginning of the development of the slat arrangement of modern hives. It enables beekeepers to take out the honey without destroying the hives, and lets the bees get on with their lives, storing up food for the winter.
One very basic fact we can infer from honeybee hives is that honeybees live over winter.
Hold that thought, because it contrasts with bumblebees. They generally do not live that long. The queen might live over the winter with a brood, but many bumblebees live just a few weeks.
Bumblebees Pollinate – But How Much?
The Bumblebee Conservation Trust is a UK charity dedicated to saving, studying, and educating people about bumblebees. I asked them whether in terms of overall pollination – not just food crops, but all kinds of flowers – anyone has any idea of how many flower heads bumblebees pollinate compared to honeybees?
The Trust’s Reply
Annie, the Information Officer at the Trust replied, saying –
It’s not the most straightforward thing to study as there is more to it than just the number of visits each type of bee makes to a flower. Bumblebees are much more effective and efficient pollinators compared to honeybees for a variety of reasons. Their hairy bodies attract and collect more pollen than honeybees, (which are much less hairy) therefore increasing the chance of pollination. As a group, bumblebees also visit a much wider variety of flowers – the 24 different species of bumblebee have different lengths of tongue and different feeding preferences, whereas the single species of honeybee in the UK has a very short tongue and so they only visit certain types of flower.
Bumblebees are well adapted to cooler climates and therefore, are active earlier and later in the day than other types of bee. They forage even in poor weather when honeybees won’t leave their hive. Bumblebees also forage over greater distances, at colder temperatures and for longer hours during the day. Some research shows that bumblebees also forage over greater distances than other bees, and move between flowers more frequently. Bumblebees may also selectively forage on flowers that have a higher pollen content, as discussed in this 1994 study by Wilmer et. al. In this study, looking specifically at raspberry crops, the authors estimated that bumblebees were responsible for 60% of flower visits, and honeybees for most of the remainder.
As well as this, bumblebees are also the only insects in the UK that can pollinate certain types of flower, producing tomatoes and other fruits in the nightshade family, through a behaviour called ‘buzz pollination’, which honeybees are unable to do.
Around three quarters (estimates range from 67% to 96%) of plants across the world are pollinated by animals (this includes insects, bats, birds and other pollinators). The remainder are likely to be wind-pollinated (as with many grasses and cereal plants). As you rightly suggest, this varies by country. A study by Professor Jeff Ollerton found that an average of 78% of plants are pollinated by animals in temperate regions (where it’s likely that insects are doing most of this work), and 94% of tropical plants are pollinated by animals. In tropical regions, you are more likely to find non-insect pollinators such as fruit bats or hummingbirds.
Of course, this doesn’t help with the breakdown of bumblebees vs. honeybees, but I hope that this helps answer some of your questions.
Here’s a link to the bee identification page on the Bumblebee Conservation Trust website.