There are more than 260 different types of bee in the United Kingdom, and many thousands worldwide. The vast majority of these are solitary bees that live in the same way as other insects with males and females who produce young for the next generation. The remainder are social bees that live in communities with one reproductive female, called a queen, many, many sterile workers who are also female and are the queen’s daughters, and comparatively few males called drones. Of these social bees, about 24 species are bumblebees, those familiar furry bees that everyone loves and which are so obvious during the Summer, and 1 species is the honey bee which is a wild bee, but has been used by man for thousands of years and usually now resides in hives of various kinds. They are often referred to as ‘domesticated’, but they are always wild and we beekeepers merely provide them with a convenient home to replace the hollow trees, which tend to be in short supply in many landscapes.
All of these bees have two features in common: they all live entirely at all stages of their lives on the products of flowers, i.e. nectar and pollen, and they have branched hairs all over their bodies. These two facts make them very important as pollinators of plants.
Solitary bees vary widely in their appearance, some resembling bumblebees or honey bees, others much smaller and with various colour markings which, at first glance, render them difficult to identify as bees. Many are very small. Irrespective of size or appearance they all need somewhere to build their nests. This will vary depending on the species, many nest in the ground, others use rotten wood or holes in buildings and other places, but their lives are all similar: the females and males emerge and mate, then each female excavates a nest, or takes over an old abandoned tunnel made by other insects such as wood boring beetles or finds a dried hollow plant stem. She collects pollen, moistens it with a little nectar, puts it into her nest and lays an egg on it. She then shuts that cell off and makes another one until the nest is full. Some bees use pieces of leaf to separate their cells and provide a front door, others use mud and others use alternative materials found in the wild or produced by the bee, it all depends on the species. Once the female has filled the nest, she makes another, and carries on until she dies. The larvae feed on the pollen once they hatch from their eggs and the adult bees usually emerge the following year. Most species are active in the Spring but some can be seen later eg. The Ivy Bee feeds almost exclusively on the flowers of ivy in Autumn. Although each female bee works entirely on its own, they are often found in large numbers in a particular place, where they have found a suitable nesting site. Such an area can give the appearance of a swarm of bees, whereas it is simply a large collection of gregarious insects, each working completely independently.
Bumblebees are social, but only primitively so as all the inmates of the nest die in late Summer, or sometimes even earlier, and only the queens, which have previously mated, hibernate through the Winter. Their’s is a precarious existence as they have to found a new nest in the Spring and for the first few weeks, they build the nest, forage for food, lay eggs, keep them warm until they hatch and then feed the larvae. Once these larvae become adults, called workers, they take over all the work, leaving the queen free to concentrate on laying eggs. Most of the 24 species nest in the ground, often taking over old mouse nests, but one species, which has only arrived in this country comparatively recently, nests in holes in trees and also favours bird nesting boxes. This is called the Tree Bumblebee.
Bumblebee nests never get very big and the most successful may contain 300 – 400 individuals. Most of these will be sterile workers, all female, but as the nest reaches its full size males and females are produced and these leave the nest. The females mate, usually with males from other nests, and then go into hibernation ready to start the cycle again the following year.
It is clear from the foregoing, that both solitary bees and bumblebees need somewhere to nest and this is often in the base of hedgerows or on areas of uncultivated land. Both of these habitats have been much reduced in the last 50 years as land is tidied up, brought into cultivation, and hedges are removed to make way for bigger machines. Many agricultural landscapes are now much denuded of all insect life, including bees and the insects have had to switch to gardens and other similar areas to find the nesting sites they need.
When we turn our attention to food for bees, there is a similar story. In rural landscapes, there are a few crops, particularly Oilseed Rape, Field Beans and Borage that provide enormous amounts of nectar and pollen, but these are not in flower for very long so the bees need other sources of food. Farmers can do a great deal by leaving field margins to grow wild flowering plants and provide safe havens for insects, by planting hedges where possible and leaving odd areas on the farm to grow such plants as brambles, which are a very important food source, but gardens, are again, indispensable and, with proper planning, can provide a range of plants that will flower throughout the year from early Spring, with crocuses and snowdrops, right through to the early frosts with some of the later herbaceous plants such as Asters. Simple flowers, that can be accessed by the fairly short tongues of most bees, are best and flowering trees, such as single cherries and crab apples can be very valuable. In the urban and suburban environment, bees are totally dependent on the plants growing in gardens, parks and other open spaces. Street trees can be very important, particularly in cities, but it is gardens where most opportunity lies. Individual gardens are, usually, small, but put together they cover a vast area and if everyone planted at least some plants that bees can use, that is going to make a tremendous difference. Lobbying local councils to allow grass verges to become wild flower areas can make a big difference too, both to the bees and to the cost of maintaining the verges, but this is sometimes opposed by local people on the grounds that it is ‘untidy’. Such views need to be challenged.
You will notice that there has been no mention of honey bees so far. They, too, are wild bees but we give them hives to live in so they no longer have to search for nest sites. However, they still need the nectar and pollen from numerous flowers to survive and flourish so, in that sense, they are just the same as all the other bees. Their requirement for food is greater than the other species as, not only may there by 40.000 or more individuals in a single nest at the height of Summer, they also have to collect sufficient nectar to produce enough honey to give them a food store for the Winter when there may still be 20.000 bees in the nest. They are the only species in the UK to have perennial nests that survive as colonies from one year to the next. This, coupled with their large numbers makes them particularly good pollinators.
In summary, wild bees need places to nest and a huge number of flowers throughout the year to enable them to survive and reproduce and, even in this somewhat overcrowded island, individual efforts can make a real difference: plant bee-friendly flowers, plant a hedge, even if it is only short, leave small areas untended, reduce the amount of mowed lawn in the garden, and you will be rewarded by an increase in these fascinating and useful creatures who will pollinate the fruit trees, and other plants for you, in the perpetual, symbiotic relationship between plants and bees, which is essential for the maintenance of so many ecosystems.
Celia F Davis B Sc NDB