Gypsy moth caterpillars will defoliate just about any plant once the supply of their preferred food is exhausted. I wouldn't worry too much about them unless your neighborhood trees are completely stripped of leaves already.
The European gypsy moth has taken more than 130 years (since 1869) to spread throughout the Northeast. They were being evaluated for silk production, and were blown from a window sill in Medford, Massachusetts.
The Asian gypsy moth was first identified in North America late in 1991 near the Port of Vancouver in British Columbia, Canada and have spread at a much quicker rate as the Asian females can fly up to 20 miles, whereas the European females are totally flightless.
The European gypsy moth has more than 250 known host plants but prefers oak. The Asian gypsy moth has a much broader host range, over 500 known host plants including larch, oak, poplar, alder, willow, and some evergreens.
When I was a child, I remember a spring and summer where the infestation was so bad that there were no leaves left on any trees here in Massachusetts. They eventually attacked the evergreens until there was nothing left for them to eat, literally.
It was eerie to walk outdoors; you could actually hear them chewing the leaves by the millions...and their little black droppings fell like rain from the trees.