 Brown-belted bumble bee (Bombus griseocollis) on butterflyweed. Photo by Mike Halverson |
The Minnesota Biological Survey (MBS) conducts surveys for invertebrate pollinators such as bees, butterflies, and moths. Field surveys start in April when flowers begin to bloom and end in October after the first hard frost. Survey techniques include the following:
Pan traps are often used for collecting native bees. These small plastic bowls are painted with yellow, blue, or white fluorescent paint. These colors are especially attractive to bees, and the fluorescence of the paints in UV-rich sunlight makes them more vivid. The bowls are filled with soapy water, which traps bees trying to land there. Field biologists then collect specimens using a strainer and store them for identification in the laboratory.
 A blue vane trap, used for monitoring day-flying pollinators |  A light trap, used for monitoring night-flying pollinators |
Blue vane traps collect bee species that might get missed by pan traps, such as bumblebees. The colorful top half of the trap is visually attractive to bees, which fly into the plastic divider and get stunned. They fall into the bottom of the trap and are unable to escape until a field biologist removes the lid.
Sweep collections are the iconic activity of entomologists! By sweeping a net through the air or near vegetation, many insects can be collected and examined.
Other observations such as nests, host plants, caterpillars, and cocoons are recorded when encountered.
Light traps are used to collect moths at night.
Find out more about pollinators and pollination at the Minnesota Pollinators page.