A parasite has made its home within this tree branch. Boring a tiny hole, it crawled inside and excreted a chemical that induced an abnormal, bulging
growth ― a Gall. Enlarging and multiplying the plant’s arterial tissue (phloem) not only provides a torrent of nourishing sap for this tiny orgo-chemico-structural-engineer, it turns the branch into a fortress against predators and the elements.
Gall: Ugly, crinkled deformity. Terrifying work of an invader.
But I have ascribed good and evil value judgments where they shouldn’t belong. What gives a host (the tree) priority over its invader (the insect) in the struggle for existence? The forest is a universe of countless life-giving and life-taking inter-dependencies, where destruction leads to creation and creation leads to destruction and so on, and so on. This parasite may exit as a nymph and become food for a Blue Jay, who may in turn become food for a hawk.
Attributing priority seems to result from imposing my intuitions about human affairs onto the non-human world (it seems bad if a parasite were to attack me or if one human being attacks another).
And so I set such value judgement aside. The gall is the work of an awe-inspiring, evolutionary adaptation; a marvelous feat of blind, biochemical engineering.