Panning for Bees

Yesterday (Saturday, August 8) I was invited to participate in a mini survey of local bees on the grounds of the Mount Grace Land Conservation Trust in Athol, Massachusetts. It was a unique event that revolved around the use of “pan traps” for bees and other insects that had been set out the day before.

We were fortunate to be under the guidance of Joan Milam, a largely self-taught bee expert from nearby Montague. She explained how pan traps are normally deployed. Pans (disposable plastic bowls were used in this case) of different colors are filled with water to which a single drop of detergent is added to break the surface tension. Bowls that are white, yellow, or blue seem to be most attractive to the wide variety of bees found here. They are often arranged in arrays, the distance between bowls carefully measured. Each separate trap can be addressed as its own sample, or the entire array can be the collective sample.

We collected the bowls, pouring the contents into a mason jar and then filtering the water and soap out with a piece of windowscreen fitted under the screw-on rim. Back inside the offices of the land trust we set about the task of rinsing and drying the catch. Turns out that bees and many other insects can take a surprising amount of abuse in the rinse and “tumble dry” cycles without undo damage. The biggest challenge is not melting the chitin in the exoskeleton.

Meanwhile, a few of us took our time in the field looking at what was currently on the goldenrod and other flowers, that might have escaped the pan traps. One such pollinator was this female leafcutter bee in the genus Megachile. Another was this flower longhorn beetle, Judolia cordifera, brought back to the makeshift lab where I took its picture before releasing it.

Several folks brought microscopes and we set about sorting the bees from look-alike wasps, flies, and other insects, then pinning them and further identifying them to family, genus, and species where possible.

This “crash course” in bee morphology was well worth it. We even got lunch provided, and took home a handy hand-out for our own use later. Special thanks to Sarah Mildren, Learning Services Coordinator, and Sean Pollock, Director of Finance and Operations, both of the Mount Grace Land Conservation Trust, who facilitated and hosted the event, and to Joan who was so patient with us novice bee people.