"Adult workers chew and condition the meat fed to the larvae. Larvae in return secrete a sugar material relished by the adults; this exchange is a form of trophallaxis
. In late summer, foraging workers change their food preference from meats to ripe, decaying fruits, or scavenge human garbage, sodas, picnics, etc., since larvae in the nest fail to meet requirements as a source of sugar."
(Mostly, I just thought that was interesting; maybe, only maybe, relevant to their potential upcoming behavior and that of boaters seeking relief. I know they were all about meat late July/early Aug.)