UC Berkeley California Native Bee Garden

So I also went to the CA native Bee Garden at UC Berkeley as part of the Bringing Back the Natives Tour (see my previous post).  I had been two years ago, and probably wouldn't have gone again if my cousin, Marissa, wasn't working there.  I ran into Marissa on the tour there 2 years ago, not knowing she was helping her professor do native bee research.  And now that she's graduated she has a job doing research.

Not sure which species this is.  They were sleeping on a cosmos bloom last year. It might be Melissodes robustior (males).

I'm glad I did go this year.  The garden is looking much nicer and Marissa gave me a little private tour of the garden, interrupted frequently by other people who were curious to know about the bees or the plants.  So here are some of the more interesting things I learned while there.  (And for more info visit the garden's website.)

None of our native bees live in hives.  The bees you see this year actually emerge from nests that were laid last year by solitary females.  The male bees tend to hatch a few days earlier than the females and then stake out some flowers and patrol them, either to protect a nectar/pollen source for females of their own species, or more importantly to mate with a female who will (hopefully) visit those flowers looking for pollen or nectar.  If you see a bee zooming around and around a particular patch of flowers, you're looking at a male.  Females will come to gather pollen and go back to their nest.  The guys want to cruise and the ladies are all business.  And only the females can sting.  Stingers are modified ovipositors, which males don't have.

Most native bees dig holes into the ground to make their nests, so don't mulch your whole yard.  Leave some areas unmulched to provide nesting habitats for the bees. Some will dig a vertical shaft down and then dig out horizontally in a spoke-like pattern to create individual cells for each egg.  Each cell is lined with a waterproof coating and each egg is laid with with a bit of bee bread, a mix of pollen, nectar and bee saliva.  They then hatch, eat, grow, and then go dormant to stay underground until  the following year.

Many of our species of native bees only come out into the open for a few weeks.  They mate, the females build their nests and then die.  Their emergence from underground is often timed to match the blooms of favorite species.

There are approximately 1600 species of bees (mostly native) in California.  This is an amazing number considering the US has about 4000 species total and there are an estimated 25,000 in the world.  And our adult bees vary in color and in size from the size of a grain of rice to big furry ones the size of bumblebees (very different) or bigger.  We have leafcutter bees (Megachilidae family, which I've seen in my own garden), headbonker bees (Anthidium sp.), carpenter bees and green sweat bees.  The leafcutters cut pieces off of leaves to help build their nests.  Headbonkers are called that because the males pick a plant and guard it.  They will actually bonk bees off the flowers to protect the nectar and pollen for themselves or their females. 

The blue orchard bee (Osmia sp.) and some other species live in tunnels found in old wood (preferably oaks).  So at the garden the researchers drill holes into blocks of wood of varying widths to attract bees to nest in them.  Since the young bees stay in the nest until the following year, the blocks can be transported to a new area.  Because of this and of CCD (Colony Collapse Disorder) affecting honeybees, these bees are being used more frequently for agriculture.

And most importantly native CA bees prefer native CA plants.  They will also gather pollen and nectar from some non-natives, and the bee garden is doing research to see what plants are useful resources for bees, but in general they prefer the plants they have co-evolved with.  Go figure.

For more info and pics on individual species at the garden check out this article at baynature.org.  And also here is the list of plants from the garden with details about which bees they attract and some planting advice.