With no idea what on earth could have caused this phenomenon, my hand reached out to swipe them away from the shelves when...the moved. I don't mean they drifted along; no, they scurried here and there and everywhere causing me to leap, jump, holler and swat. They weren't little black spots; they were little baby spiders!
After some seriously embarrassing moves (thankfully no teens were on hand to use this against me in the future), a damp cloth and a big broom...the pantry is clear again; safe to enter..at least for now.
So, when in the pantry..be careful what you reach for!!