Comox Valley Naturalists Society
Knowing Nature . . .
The Buzz about Bees
April 14, 2006
As we head into Easter weekend there are signs of spring everywhere. Flowers and blooming and bees are buzzing. Last week, Black Creek resident Gordon Cyr called to pass on some exciting news; the Blue Orchard Mason Bees have emerged!
Cyr explained that these bees are the best pollinators, since they are faster and more effective than Honeybees and Bumblebees. Human made nesting homes can help Mason Bees flourish, insuring a good crop of fruit from the orchard.
Despite being such great pollinators, most of us are less familiar with Mason Bees than other bees. Mason Bees belong to a family of bees called “solitary bees”, many of which are native to North America. The species that frequents our area is Osmia lignaria. It is known as the Blue Orchard Mason Bee, or Orchard Mason Bee. Honeybees and Bumblebees form colonies, with a hierarchy of a queen, drones and workers. Mason Bees have a more independent and solitary way of life.
Mason Bees and other solitary bees nest in small holes that they find rather than make. Females nest in holes the width of a straw, and about 15 cm deep. In woodlands and forest edges such holes are readily available, created by grubs, beetles and woodpeckers. Small fissures in bark may also be utilized. Mason Bees go about their tasks of gathering nectar and pollen, and each female bee works independently on a single-holed tube. Though these activities are solitary, Mason Bees prefer to nest gregariously, near tubes of other bees.
Blue Orchard Mason Bees are smaller than Honeybees. They look black, but in the light will appear a dark metallic blue. These bees lack the striped abdomen of the honeybee, and may at first be mistaken for a fly. Females are larger than males, but males have longer antennae and a distinctive tuft of light colored hair on the front of the head. Once noticed, these bees are easy to identify.
In the spring, when temperatures reach about 14°C, Mason Bees emerge. Males emerge first, followed by females, and mating ensues. The females then pursue a hectic schedule of nest building. Males do not assist with the nest and sip nectar for their own consumption only, inadvertently pollinating the flowers as they go.
Mason Bees may seek nectar and pollen from several species of trees and shrubs, but they prefer fruit trees such as apples, pears and cherries. Female bees gather pollen from the male parts of flowers (anthers), which is packed into the stiff hairs under the abdomen. While getting the pollen, nectar is simultaneously sucked from the flower.
A female bee lays one to two eggs a day, which takes an average of 25 loads of pollen. According to Cyr it takes about 75 flower visits to make up just one of these loads, which means that the bee visits around 1875 flowers in a single day. It is little wonder that Mason Bees are such great pollinators!
After finding an existing tube to nest in, the deep end of the tube is sealed with mud. Prior to egg laying, the female builds a wad of nectar and pollen. When several loads have been deposited, a last load of nectar only is brought. The bee then lays an egg, and seals the egg cell with a thin mud plug. This process is then repeated until the tube is full. It is then sealed with a thicker mud plug. This mud work “masonry” gives the Mason Bee its name.
Interestingly, female Mason Bees are able to determine the gender of their eggs. Female eggs are laid further back in the cell, because they emerge later than males, which are laid toward the front of the cell. If a predator such as a woodpecker attacks the cell, the male may be sacrificed, but the female will be spared, insuring a future generation of bees. Females typically lay 30-35 eggs in their life span. After a month or so of hard work, the exhausted bees die, but life continues in the next generation.
After a week, the egg hatches, and the developing larva gradually consumes the wad of pollen and nectar. Eventually the larva cocoons, and then pupates in the late summer. It then slowly metamorphoses into an adult bee, which remains dormant until the following spring, thus completing the cycle.
It is important that we become familiar with Mason Bees, and help perpetuate the bees by placing bee homes on our properties. Mason Bees do not sting like other bees, and females will only administer a mild sting (like a mosquito bite) if squeezed between the fingers. Though some Mason Bees take advantage of holes and crevices in buildings, there is little opportunity for them to nest in many urban and suburban areas due to a lack of nesting habitat.
Fruit production depends on adequate bee pollination. In recent years Honeybees have been decimated by two species of blood-sucking mites, which have killed off 50-90% of the population. As a result, Honeybees only account for 15% of the pollinating done by bees. Bumblebees and Mason Bees are therefore the most active pollinators of fruit trees.
Gordon Cyr sells specially designed and easy to clean bee homes. The homes can be bought at the Campbell River Garden Center at 673 Peterson Rd. For more information check Cyr’s web site at www.masonbeehomes.com
If you prefer to construct your own mason bee home, there are several good websites with useful tips. Try a Google search or head to the local library.
Click on a link below to view the CVNS newspaper column.