Thanks again, any comments on the fluid?

Did you see it come out of the proboscis, or did you just notice it there? My suspicion is that it was excess water expelled from the anus. Many liquid-feeding insects do this, especially if they are drinking watery nectar.

For several years in the 1970’s I was privileged to have my desk adjacent to two large plate glass windows on the first floor of the lab in which I worked. The building was away from the city on a partly wooded lot with considerable wildlife so I kept my binoculars at the ready. Outside the windows was a wide (8-10 feet) sidewalk with a matching overhang. The underside of the overhang had been painted white, probably a few years earlier. This resulted in old weathered drops of white paint scattered on the sidewalk. On numerous occasions a Silver-spotted Skipper (Epargyreus clarus) would land on the sidewalk, walk up to one of the paint spots and check it out with its proboscis. It would then walk forward, deposit a drop of liquid on the white spot from the tail, and then move slightly back and sample the liquid with the proboscis. Usually the spot was abandoned within a minute or so. Often the skipper then departed, but sometimes sought out another white spot and repeated the procedure. All three of the skippers that I caught and examined were females.

My theory: The white spots were mistaken for bird droppings which if fresh would provide needed nutrients. A dry dropping would not be usable, so the drop of liquid was used in an attempt to bring the nutrients into solution, after which the drop could be recovered by the proboscis.

This activity was observed dozens of times during the several years that I was there.

This photo of a Lerema accius re-imbibing the drop of liquid previously deposited from the tail looks very familiar except for the absence of a drop of white paint.

Gayle

Now THAT is an ingenious behavior. So maybe this butterfly is using the droplet to get salt from the granite it is resting on?

The proboscis was already out. It may have been an anal secretion.