Upon closer inspection, their unexpected beauty becomes apparent. Clusters of these eggs are evidence of the perfect geometry in nature.
I felt a combination of amazement and dread at first, as do many gardeners. “Will they have a positive or negative impact?” It occurred to me. I am relieved to report excellent news!
Ally or Enemy? Why Mourning Cloak Butterflies Are Beneficial

If you’re a gardener, you probably wouldn’t mind if the Nymphalis Antiopa caterpillars munched on willows, elms, and poplars instead of leaves. So, you may relax if your garden is overflowing with blooms and veggies. Because they eat on rotting fruit, these butterflies really help the decomposition process along, so they’re not all bad.