Solitary Bees: What they are and how to help them
Did you know the majority of the world’s bees are solitary and do not live in hives? These are solitary bees. They make up 90 per cent of bee species globally and are extremely important pollinators. Like many insects, habitat destruction has led to a reduction in their numbers and they now need our help.
Below is an extract from my 2021 book Patch the Solitary Bee, a children’s book aimed at engaging young people in the lives of solitary bees. The book follows the life of Patch, a solitary bee who does not know she is a solitary bee, as she seeks to find out what sort of insect she is.
The back of the book contains a bit of information on these bees and what you can do to help them out.
Learn more about solitary bees
When we think about bees we often think of honeybees and bumblebees but as Anna says in the story, around 90 per cent of all bee species are solitary bees.
Some people mistake solitary bees for their hive-dwelling cousins, or for hoverflies and wasps.
Next time you are out in your garden, take a closer look at what you might think is a bee, wasp, or a fly…you may be looking at your very own solitary bee. Find yourself a handy guidebook to your local bees — the differences between bees can be hard to spot and even the experts need a good bee book.
Types of solitary bee
The term “solitary bee” is given to a very large and diverse group of bees that don’t form hives. They come in many shapes, sizes and colours but all of them nest as individuals.
Digger (Mining) Bees
Female digger bees are particularly fluffy, which means they can carry a lot of pollen. Also referred to as mining bees, this group compromises over 700 different species.
Their name comes from their habit of digging nest sites in the ground. These typically consist of one central tunnel a few inches deep, with several chambers branching off where the young bees are left to develop.
In Europe, a species known as the tawny mining bee is known for creating volcano-like mounds in the earth where they make their nests. The bee lives down the central hole while the dust forming the “volcano” is the earth the bee has extracted from digging.
They won’t nest in your bee hotel. Instead, think about leaving an area of earth left uncovered for them.
Leafcutter bees
In the story, Patch is a leafcutter bee. In common with many other solitary bees, the leafcutters are also named after their nesting habits. The female bees cut holes in leaves and use the circular cuttings to protect and secure their young in their nests. As is the case with other solitary bees, male bees are the first to emerge from nests and quickly go in search of females to mate with.
The patchwork leafcutter bee is one of the most common of the solitary bees. Patch and her fellow leafcutters can be found throughout Europe and much of North America. There is no chance of a leafcutter getting confused and thinking it might be a honeybee, but they do look very similar.
Look out for strange semi-circular holes appearing in your garden plants. This may be female leafcutters taking bits of leaf to use as building material for their nests.
Carpenter bees
These bees are found all over the world, including the Galapagos Islands, where the Galapagos carpenter bee (Xylocopa darwini) is the only bee to live on the islands. These bees nest in dead wood, which has led scientists to believe that the first of the Galapagos bees probably reached the islands by floating there as young bees inside driftwood.
Living in wood also means they sometimes become food for woodpeckers and have a reputation as pests in some parts of the world, where they build their nests in the sides of people’s homes.
Mason bees
Around 300 bee species can be described as mason (or masonry/mortar) bees. They are common occupants of bee hotels, like the one Patch has built for her, where they seal up the tunnel entrances with wet mud. It is their habit of nesting around the brickwork of buildings that gives them the name “mason bee”.
The world’s biggest bee
The world’s biggest bee is a solitary bee. It is known as Megachile pluto or Wallace’s giant bee. This bee has a wingspan of 2.5 inches (over 6cm) and lives in the forests of Indonesia where it is called raja ofu. Most of us are very unlikely to find a bee of this size (no one reported a Megachile pluto for around 100 years!) and it certainly wouldn’t fit in your garden bee hotel.
With its large pointy jaws, it is hard to believe this giant belongs to the same family as Patch! In the UK and the US, the biggest bees you are likely to see are the queen bumblebees, which appear in springtime, while much of North America has larger species of carpenter bee.
The world’s smallest bee
At least two bees are potentially the world’s smallest and both are species of solitary bee. At just 2mm long, North America’s Perdita minima is a strong contender for the title of world’s smallest bee. A more recent discovery, Quasihesma clypearis, is found in Australia where it visits eucalyptus trees for food and bores small holes in wood for nests. The male bees can be just 1.8mm long, barely the size of the eye from Australia’s largest bee species, the great carpenter bee.
Help the bees and they will help you
Solitary bees feed on both nectar and pollen and they are extremely good at pollinating plants.
Many solitary bees get their hairy bodies completely covered in pollen, meaning they pollinate 95 out of every 100 flowers they visit. By comparison, honeybees only manage around 9 flowers.
Pollinators are essential for our food production and the welfare of much of the natural world but unfortunately many bee populations are in decline, with human activity largely to blame. Habitat loss, pesticides and climate change are all contributing to the reduction in bee numbers.
Build a bee hotel!
Solitary bees are hardworking and resourceful but like many insects they could do with a helping hand from us. In the book, Anna builds a bee hotel by herself but in order to make your hotel as safe and as homely as possible, you should ask help from an adult.
Solitary bees are largely non-aggressive and are very unlikely to sting. However, picking up a bee like Anna does in the book is not going to be good for you or the bee. The bees will find their home by themselves.
Find a ready-made bee hotel
Look for bee hotels that have been recommended by wildlife charities where you live. You can now find “interactive bee hotels” which allow you to life up the roof of the hotel and see whether you have young bees developing inside. Bee “bricks” provide similar nest sites contained within a brick which can be inserted into a wall.
Placing your bee hotel
Find a location that is south-facing so your bees get the most sun during the day. It is important that your bee hotel is sheltered. Adverse weather conditions such as strong winds and rain can ruin the bee’s nests. Try to place your bee hotel at least one metre above the ground.
Although the safety of your bees is important, also think about placing the hotel somewhere in your garden where you are likely to see them regularly. You will want to keep track of their progress and make sure nothing has happened to their home.
Maintaining your bee hotel
Bee hotels can’t be left on a wall and ignored. A bit like bird feeders, they need to be looked after.
Unborn solitary bees are at risk from parasites and damp conditions. These cannot always be avoided but you can take steps to reduce the chances of any harm coming to your bees.
Some people like to bring their bee hotels indoors over the winter in order to prevent the bee’s nests from getting damp. It also makes sense to replace some of the tubes you are using every year.
Plant for bees
The most help you can give bees is having a bee-friendly garden. You can do this by planting “pollinator friendly” plants which provide bees and other pollinating insects with nectar. These plants will vary depending on where you live.
The majority of solitary bees will remain close to their nest, usually venturing to flowers within a 90 metre (300 feet radius). Your plants — and your neighbour’s plants! — will be very important to them. Some “pollinator friendly” plants sold by garden nurseries and supermarkets actually use chemicals that harm bees so be careful when choosing your plants.
