We have already discussed pollinators in general in the January newsletter, and honeybees in particular last month. This month we want to tell you about a pollinator that will become active in March – a misunderstood, misidentified, and occasionally maligned species, and yet the hardest working of the native bees of North America.
There are over one hundred types of Mason bees. These are solitary bees – they do not live in hives, nor do they swarm, nor do they depend upon other bees to care for their young. There is not one queen, but every female is a queen: that is, capable of laying eggs. Female Mason bees do have a stinger, but have no venom, and rarely sting unless they are being squeezed. Mason bees are smaller than honeybees, are not territorial and are far more docile as they have no single queen or large brood of eggs and young to defend. The male Mason bee has no stinger and only one purpose: to fertilize the eggs which the female is carrying inside her abdomen. Once that is accomplished, the male dies, and the female is left to build homes for the eggs, which she does using tunnels she finds in hollow stems of dead plants and in holes or tunnels made by other insects or woodpeckers.
As she lays each egg in a tunnel, she deposits a stockpile of pollen, then carefully seals the cell with fresh mud, and immediately starts another cell. Instead of carrying the pollen on her back legs, as does a honeybee, she has a pocket on her belly, called a scopa, that holds less pollen, necessitating more visits between the flowers and the mason bee’s tunnels. When she arrives at a flower, she lands with a bellyflop in the middle of the flower, covering herself and filling her sack with pollen. This is a far more effective pollinating strategy than the honeybee which is quite precise in landing and gathering pollen. Her multiple trips means that she visits more flowers more often in laying aside enough pollen for her young.
You will see Mason bees emerging in March when daytime temperatures reach the mid-fifties, so having plants that are already in bloom is helpful. This demonstrates why having Mason bees near orchards and berry farms is an effective strategy. By June, each female will have filled several tunnels with individual cells with walls of clay, each containing a fertilized egg and a cache of pollen. The first eggs laid, deepest in the cell, will be female. The last two or three cells in a 6-inch-deep tube will have male eggs laid in them. These will hatch first, and the males will hang out around the tubes waiting to fertilize the females as they emerge. And the cycle will begin again.
In coming months, we will be introducing you to leafcutter bees which take up the responsibility of pollination after Mason bees complete their cycle. Leafcutter bees will pollinate your warm season vegetables such as squash, beans, tomatoes, and peppers. This fall we will focus again on Mason bees and how to encourage them in your yard for the betterment of your neighborhood.
