The oak leaf galls of the wasp Amphibolips
quercusracemaria occur on Quercus myrtifolia at Archbold
Biological Station and the adult wasps emerge in April and May; photo
by Warren Abrahamson.
- Published 6 papers and
one book (Princeton Univ. Press Monograph); 5 of these papers reported Archbold- based
research in peer- reviewed journals including Ecology, American Journal of Botany,
and Proceedings of the Entomological Society of Washington.
- Received 2 National Science Foundation grants totaling
$280,000; one of these funded our oak- cynipid host-association and taxonomic studies. A
travel grant from the American Museum of Natural History facilitated travel by Dr. Melika
to the USA during 1998 to work on AMNH cynipid collections.
- Presented 13 talks at universities and at national and
international meetings, 4 of these talks reported Archbold-based research. George Melika
presented 3 talks at international meetings on Archbold- related research.
- Collaborated with James Layne on the analysis of 27 years of
acorn mast data for 5 oak species (Quercus chapmanii, geminata, inopina, laevis,
myrtifolia) from 4 Station habitats.
The oak stem galls induced by the wasp Callirhytis difficilis
occur on Quercus inopina, Q. laevis, and Q. myrtifolia
at Archbold Biological Station and the adult wasps emerge during late
summer and into autumn; photo by Warren Abrahamson.
Plant-Animal Interactions and Fire Ecology
Project Director: Warren G. Abrahamson, Bucknell
Project Assistants: Chris Abrahamson, Jill Abrahamson, Rob Scrafford
Outside Collaborators: George Melika, Systematic Parasitoid Laboratory,
Koszeg, Hungary; György Csóka, Hungarian Forest Research Institute, Mátrafüred,
Hungary; Jonathan M. Brown, Grinnell College
| Biennial 95-96]
Oak-Gall Inducer Studies.
Gall-inducing insects gain nutrition and shelter from their host plants by altering the
development of their host to form a gall. The Cynipidae (wasps) are among the most
speciose families of gall inducers and almost exclusively infest oaks (Quercus).
Ongoing studies are examining cynipid taxonomic and ecological relationships with their
host plants. With Hungarian entomologist, George Melika, we are revising the
taxonomy of this family and its genera and are describing a number of new cynipid species. Jonathan Brown
(Grinnell Coll.) produced and published a preliminary generic-level phylogeny of cynipids
based on mtDNA data from representative species of many genera. The strong host
specificity of cynipid gallers enabled our analysis of putative phylogenetic relationships
among 34 species of eastern USA oaks by comparing the cynipid communities of oak species.
Funding has come from National Science Foundation, Bucknell Universitys Burpee
Endowment, and American Museum of Natural History.
Demography Studies. Understanding the role of fire in altering the growth and
reproductive patterns of the plant species composing fire-adapted ecosystems is critical
to natural areas management and to the preservation of biodiversity. The results of our
long-term studies exploring the role of fire in the reproduction of the palmettos, Serenoa
repens and Sabal etonia, will be published in Ecology (1999).
[ Abrahamson, W.G. 1999. Episodic reproduction in two fire-prone palms, Serenoa
repens and Sabal etonia (Palmae). Ecology 80:100-115. ] The
frequency of flowering in palmettos increased dramatically following fire but the strength
of the flowering response was strongly dependent on palmetto size and light availability.
Additional work will determine the longevity and turnover rates of palmetto leaves. This
work has been supported by Bucknell Universitys Burpee Endowment and Archbold
Study (with J.N. Layne). The number of fruits
produced by a population of woody plants can vary markedly from year-to-year.
Unfortunately, knowledge of the patterns and causes of crop-size variation is limited and
most studies examine only single species in single mesic associations. Annual counts of
acorns were conducted at Archbold by James Layne for 27 years (19691996,
except 1991) on two white oak species (Q. chapmanii and Q. geminata) and
three red oak species (Q. inopina, Q. laevis, and Q. myrtifolia) across
xeric sandhill, sand pine scrub, and scrubby flatwoods. White oak species exhibited more
frequent peaks in acorn production than red oaks, however, there was no correlation of
production levels for species with temperature and few weak correlations with
precipitation parameters. Acorns were produced with reasonable abundance every year by at
least one species. Oaks in sand pine scrub with a well-developed pine canopy produced
fewer acorns than similar-sized oaks of the same species in the more open sandhill and
scrubby flatwoods. Following a prescribed sandhill burn, re-sprouted white oaks produced
acorns more quickly than red oaks. White oaks produced acorns during the first year
following fire whereas red oaks required 3 or 4 years. to produce acorns depending on the
species. The percentage of bearing individuals and the mean number of acorns/bearing
individual increased with increasing plant size for all species across associations.
However, in some species in some or all associations, acorn production declined in the
largest size class suggesting senescence.
Biennial Contents | Top
© Archbold Biological Station, 5 April 2000,
with minor revision from the paper edition.
Webmaster: Fred E.
Station, P.O. Box 2057, Lake Placid, Florida 33862 USA
Phone: 863-465-2571, FAX: 863-699-1927, email