OAK-APPLE
GALL
Donald
A. Windsor
Oak-Apple
Galls are formed by oak tree leaves under the control of the gall
wasp Amphibolips confluentus, Family Cynipoidea.
These
two specimens were picked up under a Red Oak (Quercus rubra)
in front of 51 Sheldon Street in the City of Norwich. I regret that
I did not record the date, but it was the late spring or early summer
of 2016.
The
female wasp lays an egg on a leaf. The egg hatches into a larva that
then feeds on the leaf, stimulating the leaf tissue to develop into a
gall. The gall acts as a cocoon, protecting the larva as it pupates.
When the pupa reaches adult stage, it breaks its way out of the
gall.
Note
the larval-pupal chamber suspended by fibers in the center of the
opened gall.
Oak-Apple
Galls have been found in several places in Chenango County.
Reference
consulted:
Craighead,
F.C. Leaf galls. In: Insect Enemies of Eastern Forests.
Washington DC: US Department of Agriculture. Miscellaneous
Publication Number 657. 1950. Pages 597-598.
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