Understanding the needs of bees is an important first step in being able to make better provision for them, such as when establishing new margins under the Countryside Stewardship scheme.
In the first of this two part series on helping farmland bees, Crops looks at current bee knowledge with the help of an expert team.
Just like all wildlife, bees have three basic requirements – a home, a supply of food and a mate. Where all of these exist, bees will thrive and can recover quickly from low levels.
Not surprisingly, the farm environment can be perfect for fulfilling the first two of these essential needs, says Marek Nowakowski of The Wildlife Farming Company.
“If they don’t already exist, it’s about developing appropriate habitats and managing them correctly. Then things should fall into place – both for bees and other insects.”
He has been working with a team of experts, including independent bee specialist Mike Edwards, Richard Pywell and his team at the Centre for Ecology and Hydrology and Mike Green of Natural England, for the last 20 years.
Together, they have developed the science, practical understanding and political will to help farmers give bee populations a boost, without the need to restrict farming activities or take large areas of farmland out of production.
“Well managed habitats need only take up a small percentage of farmland,” says Mr Nowakowski. “They aren’t a threat to food production or farm profits – in fact, the opposite is true.”
All agree that the current level of interest and focus on pollinators is a positive development, stressing that differentiating between the three different types of bee is the first step, so that their varying requirements for food and nesting sites can be met.
Three bee types
“There are three different types of bee in the UK, all of which become active in mid-March,” reveals Mr Nowakowski.
“The first type is the honeybee, of which there is only one species. The second is the bumblebee, of which there are seven common species out of a total of 26 known species, and the third is solitary bees, which have more than 250 species, including mining, mason and leafcutter bees.”
The honeybee is the only one that makes honey, he notes. “It can be farmed and has been for thousands of years. It responds well to man-made hives.”
The bumblebee can also be farmed as a pollinator, with the buff tailed bumblebee (Bombus terrestris) being most commonly used for this purpose. Bumblebees will either nest above ground or below, depending on the species.
“Like honeybees, bumblebees are social. They live in a community dominated by a queen,” he says.
In both cases, the queen bee lays fertilised eggs which hatch to become female worker bees. These live for just 6-8 weeks, either performing nest duties or foraging for food.
“Food for bees is pollen and nectar. Nectar is sugar and known as flying fuel for bees – it provides the energy they need. Pollen is the protein, and is used to feed the queen and the young.”
Mr Nowakowski points out that honeybees have their supplies of honey to keep them going over the winter, so their communities tend to keep going from season to season in hives.
“With bumblebees, it is different. The queen moves out of hibernation in the spring, having been hidden underground over the winter. She carries all that’s needed to produce the next generation.
“She then builds up her energy for a short time, before nesting underground or in a hollow – often a disused vole’s nest. She lays her eggs and sits on them, until the female workers hatch.”
Bumblebees live in smaller communities, of 50-150. Later in the year, the queen lays unfertilised eggs, which hatch into males. These mate with the new queens, before they go into hibernation, ready to start the next generation in the following spring.
The old queen, as well as all the males and workers, then die.
Work done by the Centre for Ecology and Hydrology shows that more bumblebee queens are produced where there is an abundance of food for the developing larvae. “This is really important, as it’s only the new queens that go into hibernation,” he stresses.
Solitary bees are different. Although they can live in groups of 20-30, they live separate lives, and with one exception, can’t be farmed.
“These bees, which include mining and mason bees, as well as leafcutters, aren’t dominated by a queen,” explains Mr Nowakowski. “The males come out first and wait for the females to emerge. Once they’ve mated, the female has just six weeks to make a nest.”
She lays each egg individually, putting pollen next to it, before building a “wall” and then laying the next egg. In this way, she creates a tube of eggs, which she places in a chamber that she has dug.
“Some solitaries will double brood, in spring and summer, but not all.”
Bare ground is an important habitat for solitary mining bees, he reveals. “It had been overlooked before, but it’s a habitat that is readily used and occupied by mining bees. So it can really make a difference.”
Of course, bare ground in the wrong place won’t make much of a difference to mining bee numbers, he adds. “It needs to be in a warm, sunny location – preferably south facing. And if it’s next to wildflower strips, the bees will also have a food source.”
Wet or dry pollen?
Pollination occurs when pollen is moved from flower to flower.
However, flower visitation by bees doesn’t mean that pollination has taken place, points out Marek Nowakowski. “The bee may just have landed on the flower and taken a drink of nectar. Pollination requires the transfer of pollen from anther to stigma.”
Both honeybees and bumblebees collect pollen and mix it with saliva, forming a ball of pollen which is then stuck to their back legs. This wet pollen is only of limited use in pollination, as it is less viable than dry pollen.
“Honeybees are neat and clean, not woolly, so they will only carry a small amount of dry pollen on them as they move around,” he explains. “Of course, the massive numbers of them mean that they will do something for pollination.”
Bumblebees, being woolly, offer a greater chance of effective pollination, as some dry pollen can be transferred on their bodies, he acknowledges.
“Solitaries actually move dry pollen,” he reports. “These could well be the unsung heroes of pollination. Some are very small, so they can get to the anthers very easily, where they either jam the pollen in to a brush on their backside or stick it on to their legs.”
Of course, solitaries can’t be farmed, so they are very dependent on the right habitat, he adds.
“There is some work being done on their private lives, to see whether by specific habitat creation we can increase their numbers.”