Here beginneth my two prong post:

PRONG ONE is in reference to the concept of a larval host for the order Lepidoptera.

Here are my references. I like them because in each case they include host or food plants for the larva to eat. IDK why but this is a concept that escapes many people. If one rescues a caterpillar from pipevine swallowtail and puts it on a milkweed, it will die.

Here is my state's butterfly, the B'more Checkerspot. I have never seen it. It seems the host plant is white turtlehead, no host plant = no butterfly.

One of the favorite places for us to see butterflies/moths is the serpentine barrens. In addition to nectar plants like green-flowered milkweed, dittany and NJ tea we see alot of larval host plants like little blue stem and eastern red cedar. The native lupine is rare (maybe extirpated) for us and therefore no Karner blue butterfly which depends on it. The same principle applies to a mating pair of birds. They must have suitable habitat to make the nest and caterpillars or similar to feed the young. Unsuitable habitat (think concrete jungle) no birds. This leads me to

PRONG TWO - What's up with the fastidious gardener?

This is attributed to the Xerces Society and expresses it much better than I could. Have you ever seen the enchanting Luna Moth? It looks like a Fabergé creation but even more exquisite. It overwinters as a papery cocoon at the base of the host tree. Well-meaning gardeners, the kind that "meatball" their shrubs, kill the cocoons accidently. I have a friend who starts off every day with the leafblower (maybe he is wound up just a little too tight?) Unlike honeybees, mason bees are native polinators. They need the hollowed out stems like the sign says.

These prongs are not nuclear physics. Without suitable host plants and habitat for the larvae, there will be no adults. That sums it up.