Springtime, and the woods is full of fresh green foliage. With such tenderness and delectability in abundance, it's not surprising that very hungry caterpillars and other insects respond by chowing down.
Earlier this spring, the tent caterpillars got busy in the Barden at Herrontown Woods defoliating the black cherry trees.
Last year's chow down was particularly extravagant, resulting in near total defoliation that ultimately extended to the neighboring pin oak. In the process, the caterpillars
built lavish highways of silk, the better to navigate over the cherry's rough "black potato chip" bark. Once the communal caterpillars had had their way with the trees, they individually wandered off to pupate, and the trees grew a second set of leaves. This relationship seems to keep the black cherry trees perpetually stunted, but still healthy enough to grace the Barden grounds.
Another woody plant burdened by the overwrought appetites of native caterpillars is the
Hearts a Bustin (
Euonymus americanus). Because deer browse was preventing this native shrub from growing to maturity in the wild, we transplanted some into cages in the Barden at Herrontown Woods. For years, they thrived, but this year the webworm larvae of the
American ermine moth (Yponomeuta multipunctella) showed up to chow down. As with the black cherry trees, the Hearts a'Bustin' shrubs are having to be way more generous than seems fair.
Interestingly, the Hearts 'a Bustin' we have growing in sunnier locations are thus far sustaining less damage from the insects. Perhaps the extra sunlight improves their defenses.
More modest in their appetites are caterpillars found on ferns. Deer tend to avoid eating ferns, and insects may find them less edible as well.
Early in the process of creating what became the Barden, we discovered a pussy willow growing there. This spring, some of its leaves were getting "windowpaned" by larvae of the imported
willow leaf beetle (Plagiodera versicolora). Like kids that won't eat the crust of bread, the larvae leave the leaf veins uneaten.
Oaks sustain a tremendous variety of insects, among them the wasp
Callirhytis seminator. The wasp lays its egg on the oak, simultaneously injecting a chemical that causes the oak to create a growth called a Strawberry Oak Gall, or
Wooly Sower Gall. The gall conveniently provides food for the wasp larva.
These are but a few examples of the varied ways plants support the local insect population, which in turn provides sustenance for birds.
