Friday, April 15, 2016

Oligolectic bees

The Edge staff, along with eager students were lucky enough to spend a week with bee expert, Mike Arduser and his wife Jane.  Mike was here to teach a class on bee identification.  What an incredible and patient teacher Mike proved to be as bee's are not an easy subject to identify.  Now that he is gone, we are finding that more than his friendliness will be missed.  We are also missing his knowledge of bees, bee anatomy and the plants they feed upon.

Bombus sp. on Virginia bluebells, Mertensia virginiana  (not an oligolectic species)

Our brains were filled and tested during the week, but one thing I will always remember and share
with you is that some bees are oligolectic.  I know it's a bit of a glossa twister (bees tongues are called glossa), but oligolectic bees are pollinator specialists on specific plants.  Many bees will pollinate a large host of plants, but some only visit one specific plant, and you need to find that plant if you want to find that bee.  In fact, during the class, Mike collected one of the oligolectic bees for us.  White trout lilys, Erythronium albidum, were blooming during the class and it turns out there is a bee called Andrena erythronii that specializes on this plant.

Erythronium albidum, white trout lily
Andrena erythronii, the trout lily andrena
Mike gave us a list of oligolectic bees and the plants they pollinate.  This week we have been going out and watching some of these plants as they slowly start to bloom and await the bees.  Chris Bedel, Preserve Director,  picked up this bee shown below from a spring beauty, Claytonia virginica.  Using the dichotomous keys Mike provided us, I believe it is the spring beauty bee called Andrena erigeniae

Spring beauty, Claytonia virginica (photo by Robyn Wright-Strauss) 

Andrena erigeniae, the spring beauty andrena

Our quest will continue to find bees off plants that we know are oligolectic bee hosts.    One thing to remember is that a bee that is not oligolectic may also visit some of these plants.  But an oligolectic bee will only visit it's host plant.   For example, other bee species might visit a spring beauty, but the spring beauty andrena bee will only visit spring beauties.  So you still may need to research the bee and make sure it looks like the one you are looking for. 

Here are a four common spring flowers to watch for that have oligolectic bee associations:

On Packera sp. (formerly Scenicio) (golden ragworts) watch for Andrena gardineri.
On Cornus sp., dogwoods, look for Andrena fragilis. (photo by Robyn Wright-Strauss)
On Viola sp., violets, watch for Andrena violae.
On Geranium maculatum, wild geranium, watch for Andrena distans.
Most exciting so far was learning there is an oligolectic bee on one of the preserve's rare state listed plants.  Nothoscordum bivalve, false garlic or crow-poison, is threatened in Ohio and only found in small patches in 2, maybe 3 Ohio counties.  Waiting for the flowers to open this week, myself and Robyn Wright-Strauss searched a roadside of false garlic for pollinating bees.  Within minutes of searching,  we caught a couple of these small Andrena bees.  Most certainly the first found and caught in Ohio, these were the oligolectic bees called Andrena nothoscordi.  This find is a range extension northward for this species.  All these years this rare plant has been growing roadside in the southern parts of the preserve, but who knew there was a bee associated with it, which is equally as rare.

On false garlic, Nothoscordum bivalve, watch for Andrena nothoscori
Andrena nothoscordi feeding on Nothoscordum bivalve, false garlic

Close up of Andrena nothoscordi (photo by Robyn Wright-Strauss)
Bees can be challenging to identify, but if you know the plant it is feeding on, it can make the task a little bit easier.  This seems to be another good reason to promote the diversity of native plants in your area.   There just might be a native bee relying on them for survival.

To see a list of more oligolectic bees and their host plants, use this link:

Posted by:  Mark Zloba