Members of two subfamilies (Mesostoinae and Doryctinae) are known to form galls on plants.

Once on Douglas-fir, the adelgids consume the needles but do not form galls.

They form large galls on the branches of their host plant.

The roots become gnarled or nodulated, forming galls, hence the term "root-knot" nematode.

The aphids form galls and act as colony defenders, at times sacrificing their own lives to do so.

R. salicis and R. heterobia also form galls on willows.

Herbivores also manipulate their microhabitat by forming galls, plant structures made of plant tissue but controlled by the herbivore.

Cryptochiridae is a family of crabs, known as gall crabs, because the females cause corals to form protective galls around themselves.

The females form galls which are often quite ornate.

Like the Mesostoinae (a small subfamily endemic to Australia), some Doryctinae are known to form galls on plants.