I'd cut up some old cherries and put them in a shallow bowl for butterfly bait. A downpour made them into a deadly cherry soup. Overcast skies. No polarizer, obviously. Very little PP.
I should add that for me - only one butterfly, a mourning cloak, was attracted with this fruitbait method. For attracting yellowjackets though, it was excellent :0
such in interesting looking image .. all murky and indistinct .. then i see the poor dead insect caught in the liquid ..
its a great shot .. !!
interesting about attracting insects .. i wonder if i can attract some around here .. !!