DEVORE, MELANIE L.1*, KATHLEEN B. PIGG2, AMANDA M. WESTBROOK1, and EVERETTE BARMAN1. 1Department of Biological & Environmental Sciences, Georgia College & State University, Milledgeville, GA, 31062-0001 USA; 2Department of Plant Biology, Arizona State University, Box 871601, Tempe, AZ, 85287-1601 USA. - Galling cynipids, larval traces, and fungal infestations from the Miocene of Washington.
The middle Miocene Yakima Canyon Flora of central Washington State is
rich in anatomically preserved plant remains including well preserved
acorns of the white oak Quercus hiholensis. While completing
anatomical and developmental studies of the acorns (Borgardt and Pigg,
1999), unusual damage patterns were noted on some specimens. This
provided an excellent opportunity to document both herbivore-plant and
parasitic relationships of Quercus hiholensis. One set of
damage patterns consists of burrows ranging in length from 1.23-3.25
mm and 0.60-2.17 mm in width. Currently, we are unable to document
whether two organisms are responsible for these patterns. Also present
are well preserved galls clearly assignable to cynipid gall wasps.
Galls range in size from 1.23-3.20 mm in diameter. Associated with
these galls are fungal hyphae located at the interface between the
gall wall and surrounding plant tissue. Although galls have been
documented in acorns recovered from the Quaternary La Brea tar pits,
the permineralized acorns examined in this study may document the
first host-gall-fungal association in the fossil record and suggest
that hyperparasitism may have been established by the Miocene.
Key words: cynipid, gall fungi, gall-wasp, Miocene, plant/animal interactions, Quercus