Ah, the winter blues.  More accurately, the late winter blues.  Blue Orchard Mason bees, Osmia lignaria, are exiting their year-long incubation chambers and buzzing my garden.

The goal for their short lives is to mate, rummage around flowers and foliage for nesting material, lay eggs, and pack the eggs safely to ensure the next generation of bees who will appear, on cue, next February.

The blue bee bonanza is an annual event in my garden.  These beautiful insects–an eye-popping, rich, iridescent blue–zoom from the native bee houses where they grow up, to the garden and beyond, and then back again, as they mate and then gather pollen and other material for the next generation’s nesting chambers.

These bees are important for commercial orchards, but thrive in welcoming home gardens, too.  In our garden, we’ve placed several boxes with drilled wood and lengths of cut bamboo.  These bee houses are utilized by a variety of native bees throughout the year.  Because the Blue Orchard bee adults emerge in February, they’re the first native bees to pack away their babies in the bee houses.

Packed nursery holes, as well as some where a bee (or bees) have exited, and a new adult.

After mating,

…the females begin their egg-laying process in a hole in wood or masonry which is of a size and length that the adult female finds appealing.  The first eggs laid–those at the back-end of the cylinder–are female, and the eggs at the front–potentially the most exposed–are male. Between each egg laid, mom bee builds a wall of mud and pollen so that each is snuggled into its own room.  The entire nursery, all chambers therein, is then sealed firmly until the next year.

Do the girls get pink rooms and the boys, blue?  Nah, the rooms are gender-neutral, as far as color choice goes.  However, gender differentiation is present: the female eggs-larvae-adults are at the furthest end of the nursery cylinder so that those most responsible for successful procreation are best protected, or so suggest the entomologists who study these bees.  The male eggs-larvae-adults are situated at the front of the nursery cylinders, emerging as adults first, so that they’re ready, eager, and awaiting their potential mates.

The two bees in this photo are males; one is fully emerged, the other peeking out, ready to take on his corner of the world.

Males have a white patch on their faces which is a mustache-like clump of white hairs.

Hairy dudes.

This fella rested on an upturned plastic bin under one of the bee houses.  He posed handsomely for me.  Or was he challenging me to a duel?  Or perhaps wondering what I am?  Who knows what a bee thinks?

The females (with the males, of course) mate, then begin preparations for laying eggs and provisioning for their offspring.  This female wriggled and writhed around the pollen-laden center of a Desert mallow bloom. 

Unlike honeybees, who carry their pollen packs on their legs in what are formally known as corbiculae or pollen baskets; I call them pollen pantaloons, but that’s just me. Blue Orchard bees,  members of the Mason bee family, carry gathered pollen on their tummies.  This is the best shot I  managed of a female heading into a nesting chamber with pollen.  These gals are fast fliers!  I’ve observed creamy white pollen-coated tummies, as well as cheery yellow and orange, color depending upon what bloom, or blooms, the female worked.

The females fly into the holes head-first, making their way to the back of the cylinder, then working their way forward–one egg and egg prep–at a time.  Mom bee rolls the pollen into balls, adding nectar and microorganisms, to make pollen bread. Each egg is laid on its own ball of pollen bread, which will be the food source for the larvae.  A mud wall is built, sealing in the egg and its food source.  Then mama works on the the next egg and chamber, so it goes until she reaches the front of the hole, which she seals thickly with mud and pollen.

The female has chosen this bamboo cylinder for her nursery. To the left, see the two cylinders with holes; adult bees, plopped in last year, have exited their nursery chambers.

I don’t grow any fruit trees, though I have some early spring blooming trees in my garden  There are flowering fruit trees in my neighborhood–peach, apple, and pear–and I expect that the blue bees nesting my garden visit those flowers.

Building native bee houses, or hotels, is easy.  Using untreated wood and providing a variety of different sized holes for different sized bees, you’ll attract a wide array of native bees to your garden.  You can even leave cut logs from downed, or pruned, trees in your garden, and with some aging of that wood, the native (carpenter) bees will find them.  Check out these links for instructions and ideas about attracting these fascinating and beautiful pollinators to your garden.

https://www.nwf.org/en/Garden-for-Wildlife/Young/Build-a-Bee-House

http://www.foxleas.com/make-a-bee-hotel.asp

As much as the appearance of new buds on trees or the thickening of bloom stalks on spring perennials, the arrival of the adult Blue Orchard bees heralds the onset of Spring in my garden.  New life emerging and continuation of the alliances between flowering plants and their pollinators confirms a time-honored environmental zeitgeist of the natural world.

What indicates spring–or autumn–for your garden?  Please share your wildlife garden observations and insights, then leave a link to your post when you comment here–and happy wildlife gardening for March!