| from the October 18, 2009 Newsletter, from near Natchez,
Mississippi OAK-APPLE GALLS FALLING Oak-apple Galls are found nowadays on the ground beneath several oak species nowadays, as seen below:
These are caused by a wasp in the same Gall Wasp Family, the Cynipidae, as well as the same genus, Amphibolips, as the Acorn Plum Gall wasp. It's AMPHIBOLIPS CONFLUENTA. Compared to solid, heavy, juicy Acorn Plum Galls, the Oak-Apple Galls in the picture are much larger, though much lighter, and rather spongy inside, and occur on oak leaves instead of acorn cups. Otherwise the gall-wasp lifecycle is the same as with the Acorn Plum Gall -- one little larva in the center eating the tissue around it, someday to metamorphose into a quiescent pupa, from which will emerge a tiny adult wasp. You may remember the oak-apple galls we saw on Oregon's Brewer's Oaks this summer, shown at http://www.backyardnature.net/n/w/brewer-o.htm#brewer. They were made by a gall wasp of an entirely different genus, yet still they are "real" oak-apple galls. |
