It’s the end of summer: The weather is ready to cool off, good beers are almost on tap, and pests are hammering ornamental plants. You’ve probably noticed your azaleas are covered in caterpillars, and almost every plant you own has sad, yellow leaves draped in spider mite webbing. So it goes.
Late summer is a fun time for entomologists for several reasons, and I am particularly interested in the suite of caterpillars that hatch and feed this time of year. Most late-season caterpillars have the ability to eat leaves that are low in nutrients and full of defensive compounds built up over the growing season. Some of them even take up their host plant’s defensive compounds and turn them into defenses of their own against parasitoids and predators.