All sources say heliotrope, commonly known as "Cherry Pie Plant" has few pests that like it, i.e., spider mites, mealy bugs, or aphids. The pest that is bothering my plants doesn't show any signs of the aforementioned. The leaves are being chewed as if by a caterpillar or worm but nothing is visible. Seems to happen at night and small, round pellets are left on the ground when I go out on my open air porch in the am to check my plants. They are growing in containers...Appreciate any help anyone has to offer! Thank you!!!