Our initial protocol for painting bees called for painting bees as they were collecting pollen on the flower heads using a small paintbrush. Before starting painting, we had created "paint bandoliers" that consisted of microfuge tubes filled with different colors of paint and then taped in a line with duct tape to keep them together. We ordered the colors according to the rainbow to make it easier to keep track of the colors. Each color was given a three letter abbreviation. Painting the bees with paint brushes was fairly easy, but the shape and thickness of the dot had the possibility of being very variable. After researching bee painting, in particular queen honeybee marking, it appeared that the ideal dot that would last the longest amount of time is circular and uniformly thin. To obtain this ideal dot, it was suggested that a piece of wire whose diameter was the size of the desired dot be used.
We made new painting implements based on this information. We cut the wire on flags into about 15 cm sections, sanded one end flat, and then made handles for them from sticks and tape. We bent the sanded end about 45 degrees roughly 2.5 cm from the end so that we would be able to more easily paint the bees. At this point we were only marking Agapostemon virescens. It proved to be harder to paint them with the new tools as they were collecting pollen from the flowers. We had problems both getting a good dot on their thorax and also avoiding painting any other part of the bees, which would then decrease their survivability. We eventually planned on painting Melissodes. If we started painting them as well as A. virescens, we anticipated more problems with painting them on the flower heads because it appeared that they spent less time on the flower heads and moved faster and more jerkily while on the heads than A. virescens.
After a few poor painting jobs, we decided to chill the bees. The new protocol which proved effective was to catch 2-3 bees as we walked the random rows and then place them in labeled vials. These vials were placed in small lunchbox coolers that had ice packs in them. At first we used both glass and plastic vials, but we found that the glass vials worked better because the glass got cold while the plastic did not. We initially had 1 ice pack in each cooler and this worked fine for a little while, but once the ice pack was no longer very cold, we had problems with bees simply flying away before they could be painted or moving around too much for an easy paint job. To remedy this problem we started using two ice packs per cooler, which helped.
I found that the best way to continue to keep the bees cold was to paint the bees while they were still sitting on the ice pack. I left the ice pack in the cooler and placed a plastic bag on top of it. I did this so that the bee would not get wet from the condensation on the ice. This method worked rather well and the bees were usually very sedated and easy to paint. Working with the bees in the cooler also shielded them from the sun, keeping them cooler. One difficulty was making sure that the bees did not simply roll over on their backs in their stupor and smear the paint spot. Painting the bee on ice worked very well, but it also caused the ice packs to not last quite as long. It would be a good idea to have several other ice packs on hand in a larger cooler for when the first ones lost their coldness.
After painting a bee, we gently removed it from the cooler while it was on the plastic bag and allowed it to warm up in the sun, at which point it flew away. We released all of the bees within a few meters of where they were captured.
Pictures of equipment and painting will be posted once Andes has internet