Solitary Bees

 

Did you know that Britain has more than 250 species of native bee? All of these bees play an essential role in your garden by pollinating flowers. But these bees are becoming scarce, with fewer wild flowers and suitable nest sites and an increase in pesticide use. Now around 25 per cent of our native bees are listed as endangered species.

Out of these 250 species ... over 90% of them are solitary bees. There are too many to name and talk about each one individually ... so I have picked but a few.

 

I will also show how YOU can help ... read to the end

By solitary we mean that a single female, after she emerges from her pupae and is mated by a male, constructs, provisions and lays an egg in each cell in a nest by herself. This in comparison with social (called eusocial) bees like the Bumble Bees, Honey Bees and Stingless Bees, all of whom have a Queen who lays eggs and a number of workers who look after them.

Female solitary bees prepare their own nest in the ground, in cracks or crevices in walls, or in wood. They gather nectar and pollen as food for their own offspring, and provide little or no further care after their eggs are laid.

Solitary bees come in many different sizes, colours and shapes. Common solitary bees are mason bees, miner bees, sweat bees, wool-carding bees and carpenter bees. They vary in colour from basic black to bright metallic green, blue or red. Some solitary bees superficially resemble wasps.

 Leafcutting and mason bees, collectively called megachilids

( pronounced mega kyle' lids )

Leafcutter bees ... nest in soft, rotted wood, thick-stemmed pithy plants such as roses and in similar materials that the bees can easily cut through and excavate. Nest tunnels may extend several inches deep and coarse sawdust is thrown out at the entrance.

leafcutter bee making her nest leaf cutter bee nest
Photo by Alun Thomas, Southampton Jul 08 Photo by Sue Girling, Jul 09

 

Leafcutter bee cells After the nest has been produced, leafcutter bees collect fragments of leaves to construct individual nest cells. The bees cut leaves in a very distinctive manner, making a smooth semicircular cut about 20mm in diameter from the edge of leaves.

 

These are carried back to the nest and used to fashion nest cells within the previously constructed tunnels. Each leaf-lined cell is then provisioned with a mixture of nectar and pollen. An egg is then laid and the cell sealed, producing a finished nest cell that somewhat resembles a cigar butt.

A series of closely packed cells are produced in sequence so that a finished nest tunnel may contain a dozen or more cells forming a tube 10cm to 20cm long. Adult females only live up to about two months and lay between 35 and 40 eggs.

Leaf-cutter bee Megachile sp.

 

Leaf-cutter bee entering its nest with part of a leaf  Once the nest is finished, the female caps the nest with a solid plug made of cemented leaf pieces. Once the female leaf cutter has finished her nest and plugged up the end ... she will desert it and not return, leaving nature to takes it course.

The eggs hatch into larvae, consume the pollen ball and enter hibernation. The following spring, the larvae pupate and turn into adult bees.

Photo by: Terry Stanfield Sutton Coldfield West Midlands Aug 07 Leaf-cutter bees differ from related species in that they collect pollen on their abdomens rather than on their hind legs.

There are some great photos of a leafcutter bee cutting a section of leaf here

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Masonry bees ... much like leafcutter bees, prefer south-facing nest sites, and use naturally-occurring holes in either the bricks themselves or in the mortar joints (especially soft mortar, with a high lime or sand content).

Nests are established in spring or summer and contain six to 12 eggs, each in a cell provisioned with pollen and nectar and sealed, usually with mud. New adults emerge the following year to repeat the cycle.

Red mason bee, Osmia rufa

Nesting burrows are excavated or enlarged by use of the bee's jaws

Click  here to download an information sheet ...

Masonry bees jaws

 

A short Masonary Bee Documentary

 

This busy bee spent over an hour working hard on our bee house. Fabulous close ups, not to be missed.

Video courtesy of Amanda at
Wildlife in the Westcountry

 

The Ivy bee A real autumnal species is the IVY bee which is only active between September and November so its short year begins and ends within the space of a few weeks. As the name suggests its primary food source is the pollen from ivy blossom - the last of the year's flowers.
Male ivy bees emerge first in order to be ready for the first females. Unmated females are pounced on my several males all attempting to be the first to mate with her. Unlike honeybees or bumble bees the ivy bee is solitary - the female prepares a nest-hole on her own in which to lay her eggs which she will provision with ivy pollen. Whilst the ivy bee is solitary they tend to dig their nest holes in large aggregations, sometimes in the thousands, in suitable sloping sandy banks.

 

Wool Carder Bees ... the females use the hairs (or "wool") from plants to line their burrows, using their mandibles to "card" the fibres into cell walls and are quite choosy about the flowers that they will visit for pollen and nectar

The best flowers to plant and attract the wool carder bee is the well known garden plant, 'Lamb's Ear' Stachys lanata. Also foxgloves, Digitalis lutea and Digitalis grandiflora & purple toadflax Linaria purpurea and those from the family Labiatae - woundworts and mints

Click  here to download an information sheet ...

Wool Carder Bee - Anthidium manicatum

 

 Miner bees ... are one of many familiar black and yellow summertime bees often mistaken for bumble bees. As their name suggests, burrow down into the ground and in this country something like 30 to 45 cm, where they make a labyrinth of tunnels in which they lay their eggs. The eggs will hatch out the following spring. Miner bee's burrow

Miner bees are active April/May for about 8 weeks only, individual females live 4-6 weeks while male lifespan is less than half as long. They and do not collect honey nor do they sting, however they could bite if handled roughly.
Miner bee Andrena sp.

They have a docile disposition (they are know to be great around kids and pets) and are very beneficial to gardens and are needed right now given the current devastation of the honey bee population. You can actually enhance miner bee populations by providing dried mud blocks for nesting.

Click  here for more info on the Tawny Mining bee ...
Click  here for more info on the Ashy Mining bee ...

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Large carpenter bee - Xylocopini virginica Carpenter bees ... the most common species are in the genus Xylocopa, which resemble bumble bees, except that these carpenter bees have a relatively smooth abdomen and bumble bees have very hairy abdomens.  Carpenter bees dig holes in dead wood where they lay eggs and provision them with nectar and pollen.  Carpenter bees are sometimes considered pests because they will bore holes in wooden sheds, porches, and other structures, but rarely do any serious damage.
Small carpenter bee - Xylocopa  Ceratina Common carpenter bees are about 25mm long, but some species are smaller and have black or metallic coloration, like the Ceratina sp. pictured left.

Once again like the leaf cutter and mason bee, adults spend the winter in nests constructed the previous year, and become active in April or May. After mating, females construct new nesting tunnels or use pre-existing tunnels. Nesting tunnels are about 12mm wide and start on the end of wooden beams or at right angles to a surface for 10mm to 25mm before turning and following the wood grain. Tunnels are clean cut and may extend 15cm to 20cm. Females collect pollen and nectar to produce a dough-like mass called "bee bread." The eggs hatch into larvae that feed on the bee bread in their cells.

Ever heard of the "The Spring (Hairy-footed) Flower Bee" ... Anthophora plumipes

Click here for more info ...

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Bumblebees ... There are 19 different species of bumblebee found in the UK and three of these species are already extinct with a further nine are on the critically endangered list.

"Bumblebees are disappearing at such an alarming rate in Britain that scientists are warning they could be wiped out within a few years. Their numbers have been falling in recent years, largely due to intensive farming practices. "The last 50 years have seen hedgerows ripped up and most of the flower-rich grasslands once used for grazing have been reseeded with rye grass

http://news.bbc.co.uk/1/hi/sci/tech/1314012.stm
bumble bee - bombus terrestris

Bumblebees are most efficient pollinators.  They grab the anthers of flowers and shake them to free the pollen of some blossoms. Bumblebees will work on cool, overcast days while honeybees remain in their hives.

Quick guide to the BIG SIX species of bumblebee ...

http://www.nhm.ac.uk/research-curation/projects/bombus/bumblebeeid.html

There are also six species of Cuckoo Bumblebees ...Psithyrus spp

Cuckoo bees do not build their own nests. Like the cuckoo birds that get another species to raise their young, these bees lay their eggs in other bees' nests.

Cuckoo bumblebee - Bombus sylvestris
Bombus sylvestris
The females cuckoo bee stalks the nest of other bees and tries to sneak into it during construction of the cell intended for the nest-owner's egg where she will then lay her eggs, the workers then rear these eggs as if they were their own sisters and brothers. Cuckoo bumblebee - Nomada ruficornis
Nomada ruficornis

These bees have no pollen baskets on their back legs, and do not secrete wax for nest construction.

There is no worker caste, and all cuckoo bee eggs hatch as reproductive males or females

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Finding nest sites has become crucially important for our bee population. You can give them a helping hand, improve pollination in your garden and give your family a lot of pleasure.

How to build a Bumble bee nest ... ?

Build a box of solid construction with removable top and two compartments, a vestibule that measures roughly 12.5cm by 15cm and serves as a staging ground where bees can poooh and set up defences from the main nesting compartment located at the back of the house.

The nesting compartment measures 20cm by 15cm and this is where queens will spend their lives.

Drill a peep hole in the back wall, with a flap, so you can sneak a look inside to see what's happening.

Line the floor with cardboard to make once a year cleaning easier.

Use cotton and/or wood shavings as nest material in the rear compartment.

Site the box outside, off the ground on two thin pieces of wood, to avoid damp.

Bumble bee nest box

You can put the box almost anywhere ... in a garden, along a fence row, under hedges, by a flower bed, around mulch piles or anywhere you have seen bumble bees foraging.

 

Other types of homes for solitary bees

Any type of cavity is likely to prove attractive to solitary bees. Try putting up old, dry, hollow stems of plants like bramble. You can use bamboo canes or even drinks straws ... something about 6-10 mm in diameter and 15cm long.
Tie them in a bundle and fasten them (horizontally) to a tree or post about 1.5 meters off the ground and facing south ... or place in a wooden frame as opposite ...

Leafcutter bees occupying home made box
Photo by Sue Girling

 

Bee apartments ... Photos by Chris Cardwell ... more at ... tinyurl.com

 

Download information sheet on "Bee Apartments/Hotels" ... here

 

A log makes an excellent home

Or ... Get a block of untreated soft wood, say 10cm x 10mm by 20cm ... maybe a section of a tree ... drill a series of holes into it, drill LOTS of holes, 15cm deep of varying diameter from 6 to 10 mm
Once again hang as above.

 

You can also use an old fence post ... It does not matter if it's old and battered. In fact this will look more like the natural, weather worn wood that many solitary bees nest in,  just drill a series of holes 6 to 10 cm deep ... do not drill all the way through ... into the top 20cm of the post.

Make sure that holes are drilled slightly upwards into the wood and not to steep, this will prevent rain water from collecting in the tunnels.

Make sure you place your posts in a sunny position, facing the south.

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Can't someone make bee homes for me?

Chapelwood Bee & Ladybird Nesting Box