The two-horned oak gall wasp is just one of dozens of species of gall wasps that incubate their eggs in oak leaves.

Learn about the wasps that have a gruesome but fascinating way of surviving.

Q • My oak trees have more large galls than I’ve ever seen on them, and I’m worried about their health. What can I do about ...

Hugo’s father, Andrew Deans, a professor of entomology at Penn State, identified the objects as oak galls – abnormal plant ...

Tallamy describes oak galls being make from a cynipid gall wasp, but not what we typically think of as a wasp, “cynipids are tiny and cannot sting you and most people would dismiss them incorrectly as ...

Adult gall wasps will inject a chemical into the leaf buds as they're forming, and these little green balls form in that spot, providing us with these funky-looking mini-apples.

Eventually, one full-size adult wasp emerges from each horn. Imagine how many wasps come out of a full-size laurel oak covered with galls! The eastern horned gall wasp has been around for a long time.

Will thousands of oak leaf galls produce a mass invasion of wasps? The red cone galls, also known as Hershey kiss galls, are thick on many oak trees throughout the Bay Area this year, but there ...

A: It sounds like you have jumping oak galls. These are tiny, seed-like galls that form on the undersides of valley oak leaves. They are caused by the tiny gall wasp, Neuropterus saltatorius.

The researchers hypothesize the wasp could have developed acidic galls as an alternative strategy to the tannin accumulation observed in most other oak galls.

A more commonly seen gall formed by a different type of wasp is the brown, papery oak apple gall. The size of a ping pong ball, it’s found on oak leaves.