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What solitary bees can you see in your garden or allotment at the moment?

May 10, 2013 nadinemitschunas, Urban Pollinators Project No Comments

Spring is a good time to see solitary bees which are often overlooked in favour of the bigger and more obvious bumblebees and honey bees.

There are only around 24 species of bumblebees, 1 species of honey bee but over 200 species of solitary bees in Britain! Solitary bees are also important pollinators and as they often emerge quite early in the year (often as early as late February or early March) they can pollinate early fruit trees and bushes when bumblebees are just starting their colonies and honey bees are still hibernating in their hive.

Solitary bees do not live in large colonies and do not have any worker bees. Each female solitary bee is fertile and inhabits a nest built by herself. There are two different types of nests; ground nests build by sweat bees, (Halictids) and mining bees (Andrenids) and cavity nests build in hollow reeds, twigs or holes in wood by leafcutter bees and orchard bees (e.g. genus Osmia).

The burrow entrance of a mining bee nest

 

Each female constructs a series of cells, each with a food source (pollen and nectar packed into a ball) and a single egg that is laid on top. The nectar and pollen for each cell is gathered in several foraging trips, and this is why solitaries are such useful pollinators. Depending on the species, the cells are lined with various materials, including leaves, petals, mud or body secretion. When the entire nest is complete it is sealed off and the next nest started.

 

Depending on the species, solitary bees have one to several generations a year. In species with just one generation per year, it is usually the pupae or larvae that overwinter in the nest and emerge in spring the next year. The first bees to emerge are normally the males. They will often wait near flowers for the emerging females to mate. The males will then die and the females search for nesting places.

 

Here are some of the more common solitary bees you can see at the moment:

 

Hairy-footed flower bees (Anthophora plumipes), probably one of the fastest bees in the UK, are often seen hovering around Pulmonaria flowers. They will also visit other spring flowers such as comfrey (Symphytum), Flowering current (Ribes sanguineum) and Aubrieta. The bees are the size of a small bumblebee and both sexes look quite different from each other. The males, which normally emerge earlier than the females in late February or early March, have gingery hair with a darker tail whereas the females are black with yellowish hair on the hind legs. The females build their nest in soft mortar in walls or more rarely in the ground.

Female Hairy-footed flower bee

The bees are common and widespread in central and southern areas of the UK and can often be seen in gardens, parks and on allotment sites, especially if there is a patch of Pulmonaria present.

Male Hairy-footed flower bee

 

Mason bees, especially Red mason bee (Osmia bicornis), are also out now. The bees are about the size of a honey bee. The males are smaller than the females and have white hairs on the face. The females are larger, have bright orange hair on the abdomen and black hairs on the face. The females of the Red mason bee have two very distinctive black “horns” on the face which are unique to this species in the UK.

Female Red mason bee: the “horns” are good to see

The bees are cavity nesters and use holes in woods and walls or hollow plant stems to build their nests. If you have a ‘bee hotel’ in your garden or allotment this is the species you will most likely see at this time of year.

A female approaching her nesting hole

Mating Red mason bees, the male is on top, the female below

The nest consists of a series of cells, each with a single egg and a food provision (pollen) separated by a layer of mud. The cells with the female eggs are at the back of the hole, the cells with the male eggs at the front. If you watch closely you can see the females transporting mud pellets to close each single nesting cell. They also collect pollen as food provision for the larvae which they transport underneath their abdomen. Red mason bees are good pollinators of fruit trees and bushes.

A Red mason bee male

A cheeky male tries to follow a female into the nest

You can also see mining bees (Andrena spp.) now.  One of the prettiest mining bee is the Tawny-mining bee (Andrena fulva). The female bee is covered in dense reddish hairs on the top of the thorax and abdomen and black hairs on the head, side of thorax and legs. The male looks less pretty and is a lot smaller with greyish to brownish hairs and white hairs on the face.

A Tawny-mining bee female

The males have white facial hair

Tawny-mining bees are quite wide-spread in England and Wales and like to nest in lawns and short turf. The bees fly between March and June and like to visit a variety of different flowers such as fruit trees and fruit bushes, blackthorn (Prunus spinosa), buttercup (Ranunculus sp.) and daisies (Bellis perennis).

Another pretty mining bee is the Ashy mining bee (Andrena cineraria) with bands of grey hairs on the thorax and abdomen.  The bee likes sunny open areas often on sandy soil. They will visit a variety of flowers such as cabbages, dandelion, roses and brambles (Rubus sp.).

Ashy-mining bee female

 

Other mining bees you can see are for example Andrena nitida, Andrena bicolor and Andrena minutula but as there are many similar looking species it is often difficult to say exactly which bee you have found without consulting a bee expert.

Andrena nitida likes dandelion flowers

A very small Andrena bee, probably Andrena minutula

 

So next time you are out in your garden, allotment or local park have a closer look at the bees you see and you will probably be surprised how many are actually solitary bees and not honey bees or bumblebees. If you want to attract more solitary bees to you garden build a ‘bee hotel’ and plant a variety of different flowers as food plants (look here for some ideas of how to attract pollinators )

 

You can also have a look at our Urban Pollinators Project blog, our Urban Pollinators website  or follow us on twitter 

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