Horned Oak Gall

July 13, 2016

Horned oak gall_50 (4)

Photographer: Tom Wildoner
Summary Author: Tom Wildoner

Featured above is one of the most unusual things discovered on a hiking trail inside Presque Isle State Park in Northwestern Pennsylvania. The spiky growths attached to the branches of this oak (possibly a black oak or pin oak) is known as horned oak gall. They're created by the wasp Callirhytis comigera. The horns are used as escape tunnels for the emerging wasps, chewing out an exit on the horn ends. These galls are almost three years old and ready to bring forth new wasps. Photo taken on May 29, 2016.

Photo Details: Camera Model: Canon EOS 6D; Lens: EF100mm f/2.8L Macro IS USM; Focal Length: 100.0mm; Aperture: ƒ/18.0; Exposure Time: 0.017 s (1/60); ISO equiv: 640; Software: PaintShop Pro 15.00.