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 get mega excited about 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.
Scale insects attack plants we care about and poop sticky sugar water on our windshields, and I don’t appreciate either of these very much. But, like most living things, the effects of scale insects on other creatures are complicated, and scale insects also do a lot of things we consider good up in the canopy. I’d argue that scale insects are keystone species, whose poop and leftover carcasses are food and homes, respectively, for many animals and fungi. Here are thrips and mites using scale insect covers and carcasses for homes over the winter.