To Bee Or Not To Bee, A Home For The Red Mason Bee

Late March to early April, when the dandelions flower en masse, is also the time for Red Mason Bees to appear. They will feed on many of the spring and summers flowers for the next 12 weeks, including orchard trees, which they successfully pollinate, but dandelions are a favourite.

It is a small bee, smaller than a honeybee with a black head and an abdomen covered in distinctive fox-red hairs. Nectar is sipped for an energy food and pollen is eaten for the protein to lay eggs. Surplus pollen is also collected by the female and carried back to her nest attached to rows of hairs on the underside of the abdomen. This mixed with a little nectar will be used as a paste to be eaten by her young. The Red Mason Bee is a species of solitary bee that can be helped and encouraged to live in the garden by providing it with an artificial bee nest, commonly seen in shops that stock items for wildlife. In the wild, it uses hollow plant stems or holes previously bored in wood by beetles for its nest, but it will readily accept suitable artificial substitutes. Although classed as a solitary bee because each female chooses and provisions its own nest, if good nest sites are found together, then females will nest alongside each other. Mason bees use clay to line their nest tubes, and their close relatives, the leaf cutter bees use pieces of leaf. An existing tube is used and so they are not to be confused with mining bees which dig their own holes in bare soil or cliffs.

Chris`O Toole a researcher at Oxford University studied the Red Mason Bee in detail and developed a system of managing it as a pollinator. He founded the Oxford Bee Company, a spin out company of Oxford University to provide nest kits for use in gardens, allotments and orchards. Sadly, it has now gone out of business. Information detailing his work was published in 2000 in his booklet “The Red Mason Bee : Taking the sting out of Bee-keeping”. It provided all the details for the success needed to use the nest kits. Many other providers copied his system but unfortunately have produced nest kits which are poor and ineffective substitutes.

The nest kit needs to be sited at least three quarters of a metre above ground but preferably higher and also on a solid foundation, not on a moving branch. A suitable place would be under the eaves of a shed or summer house. Another site would be on a fence but the nest is not likely to be used if it is placed on an isolated post or holes drilled in to a stake. If part of a larger bug hotel e.g. made from old pallets or as part of a log pile then they should be at the top. The nest kit should never be put in the shade or shadowed by overhanging branches, and always in a sunny position facing south east or south west. Many bug hotels are tucked away and are good for hibernating insects and other species of breeding insects that prefer to be nearer the ground, but not for the Red Mason Bee. One of the most overlooked considerations is the depth of the burrows in the nest kit. These need to be 15 cm or 6 inches deep, not easy to achieve if the holes are being drilled in to wood. The reason for this is that any less will produce an imbalance of too many male bees. When the female mother bee finds a nest burrow or tube, she first blocks the end with clay and then lines the rest of the burrow with clay. Eight eggs are laid, each on a bed of pollen softened with nectar and each separated from the next by a clay partition. The first four at the back will become males and the other four nearest the entrance will be females. It might be assumed that a shorter nest with less than eight offspring would still have equal numbers of each sex. Unfortunately, this is not what happens, if tempted to use the burrow then the shorter burrow will have mostly males. If only half the correct depth, then there will be four males, not good for the long-term survival of the species.

Another important consideration is the width of the burrow, which should be 8mm, if a little larger the female will narrow it down with clay. If smaller, then it will be no use for the Red Mason but there are two other related species that may use it.

The easiest way to make a nest kit is to use a piece of plastic pipe cut to 16cm or a wooden box of the same depth. Then close one end with a plastic cap or a piece of wood. The individual tubes can be made from lengths of hollowed garden cane or plant stems from last year, such as teasel or agapanthus. Cardboard tubes can be obtained from arkwildlife.co.uk. After a few years of use the tubes should be replaced to prevent disease. The whole kit can be moved indoors after September in to a shed as protection from the weather and then brought out again in mid-March. The males always emerge first, chewing through the first partition and then deliberately nipping their brother on the bum and this continues down the tube until the last female leaves the entrance. Hopefully this happens on a nice warm day for them all to get over the shock!

Mick Street

To discover more about bee hotels and nesting boxes follow this link Rethinking Bee Hotels