Redshouldered Leaf Beetle

These tiny Leaf Beetles completely swarmed this tree (I forget what it was) one night, leaving it pretty much defoliated the next morning. The beetles were about 5mm long, orange with yellow elytra that had a dark band at the 'shoulders' and another one at the tip. Picture #5 was taken some days later, but I'm pretty sure it's the same species. Wonder if anyone has observed anything similar with this species.