Caterpillar feeding on White Deadnettle (Lamium album). The flowers of White Deadnettle are important for pollinators; it's a widespread "weed" i.e. wildflower that flowers early and for a long time. Native species like Lamium album are also important as food plants. 

 The point is well made that many non-natives are a valuable source of pollen and nectar but caterpillars feed mainly on native plants.