Invertebrates eat a great variety of plant and animal matter; some invertebrates eat fungi, carrion or other detritus. Some invertebrates don't feed at all as adults but live only to reproduce.
Among the invertebrates that don't feed are some species of butterflies and moths, including the luna moth. However, its caterpillar eats the leaves of trees such as sweet gum, persimmon, walnut and birch.
Carrion beetles, as their name states, live in and eat the bodies of dead animals, but are especially partial to maggots, who also eat and live in carrion. Carrion beetles also lay their eggs on carcasses so that their larvae have a good food source when they hatch.
The sea cucumber is basically a digestive tube. These invertebrates, which can grow from 3/4 of an inch to 6 1/2 feet long, live at the bottom of the ocean and feed on debris, tiny animals and algae.
Leaf cutter ants not only eat fungi, but grow their own fungus farms. They do so by bringing bits of leaves to the colony and allowing them to decay, eating the fungi that result.
Spiders are notorious carnivores. They eat insects and some even eat other spiders. Some are so large they can take small fish, frogs and lizards.