Book of Abstracts (PDF) - International Mycological Association

IMC7 Main Congress Theme IV: POPULATION DYNAMICS AND ECOLOGY Posters
Nitrogen is a major factor of the lichen biodiversity in
maritime Antarctica. At coastal habitats, there is a luxuriant
lichen flora because of nutrition by the sea and animals,
while the lichen flora in inland habitats is rather poor. The
percentage of taxa containing nitrogen-fixing cyanobacteria
either as primary or secondary photobiont is increased in
inland communities. We have investigated the cyanobionts
of lichens occurring at two ice-free locations on Livingston
Island: inland habitats of South Bay and Byers Peninsula.
The cyanobionts of two lichens with primary cyanobiont
(Leptogium puberulum, Massalongia carnosa) and three
species containing Nostoc in cephalodia (Placopsis
contortuplicata, P. parellina, Psoroma cinnamomeum)
were examined using molecular techniques and compared
with free-living Nostoc colonies found in the area.
Nucleotide sequences of the cyanobacterial tRNALeu
intron were employed as genetic markers. Preliminary
results suggest that different species at the same location
share a common cyanobiont.
1060 - Small scale distribution pattern of
ectomycorrhizal types in a red oak stand
J. Wöllecke * , S. Gebhardt & R.F. Hüttl
Brandenburg University of Technology Cottbus, Box
101344; D-03013 Cottbus, Germany. - E-mail:
jenswoellecke@ektomykorrhiza.de
Forest soils, especially the organic layers are very
heterogenious substrates. Parameters like water content, pH
value or the organic content could vary in the range of
millimetres. Fungal mycelia or ectomycorrhizae are
dispersed dependent of the heterogeneity of micro-habitat
conditions. Beyond, the spatial distribution of
ectomycorrhizae is influenced by interspecific interactions.
As a result of all these influences, the ectomycorrhizal
coenosis form a mosaic structure in the soil. At present,
very few data on micro-scaled distribution of
ectomycorrhizal fungi are available. First investigations
started in recent years. To find characteristic structures of
ectomycorrhizal coenosis in different scales, is one of our
goals. Therefor we map the ectomycorrhizae in a coherent
soil volume. This project is established in red oak stands of
former mining sites and compare these afforestations with
stands growing on undisturbed soil. Soil units of 6 cm
width, 100 cm length and 3 cm depth taken from the top
organic soil layer are divided in subunits of two to two cm
and one cm depth. These subunits are solved in water and
the ectomycorrhizae are qualitatively recorded. Maps will
visualize the distribution of the ectomycorrhizae. We know
from investigations in Scots pine stands, that the
assemblage of ectomycorrhizal types can vary between
sides and that nearly the half of all combination of
ectomycorrhizal types never grow together in the same
micro-habitat.
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Book of Abstracts
1061 - The longevity of Cordyceps humberti on Icaria
wasps (Hymenoptera: Vespidae)
A. Wongkaeo 1 , N.L. Hywel-Jones 2* , S. Sirimungkararat 1 &
W. Saksirirat 1
1 Khon Kaen University, Facultu of Agriculture, Khon
Kaen, 40002, Thailand. - 2 BIOTEC-Mycology, National
Center for Genetic Engineering and Biotechnology,
National Science and Technology Development Agency,
113 Pahonyothin RD., Khlong 1, Khlong Luang, Pathum
Thani 12120, Thailand. - E-mail: nigelhj@biotec.or.th
Cordyceps stromas persist for some time but little work has
been done on longevity of individual stromas.
Identification of a Cordyceps humberti epizootic in Nam
Nao National Park, Thailand provided an opportunity to
examine longevity of individual stromas. Cordyceps
humberti and Hirsutella saussurei infected Icaria sp. The
nest (ca. 80 cm long, 50 cm across) was in a tree at ca. 10
m. Infected wasps were found up to 30 m radius from the
nest. Wasps were attached by their mouth-parts to the leaf
margin. Bamboo was a preferred substrate for settling but
dicotyledonous plants were also used. The first wasps were
seen in August (1999). Thirty wasps were tagged and
observations made every 3-4 dy. Five of 27 specimens
were Cordyceps while the rest were the Hirsutella form.
However, after 1 month, of 23 specimens remaining 13
were the Cordyceps form. Of 27 specimens recorded, 17
were lost within 100 dy while 4 survived 100-200 dy and 5
specimens were documented from 200-300 dy. One
specimen was still present at the end of the work (513 dy).
Significantly, of persistent specimens, 2 produced 2 crops
of perithecia. One specimen remained in the Hirsutella
form for 169 dy before synnemata were lost and it entered
a dormant state. After ca. 15 days of dormancy new
synnemata developed and ca. 30-40 dy later the Cordyceps
developed. This work demonstrates that in Cordyceps
humberti perithecia can be produced over an extended
period with hosts providing material over more than one
season.
1062 - The structure of symbiotic communities:
population-level patterns of association between lichen
fungi and their algal photobionts
R. Yahr 1* , P.T. DePriest 2 & R. Vilgalys 1
1 Duke University, Department of Biology, Box 90338,
Durham, NC 27708, U.S.A. - 2 Smithsonian Institution,
National Museum of Natural History, Washington, D.C.
20560, U.S.A. - E-mail: ry2@duke.edu
Morphological and molecular studies have largely rejected
broad coevolutionary patterns between lichen fungi and
their photobionts, but theory predicts that populations of
intimate symbionts become locally coadapted to each other
and to their environment. In the place of broad-scale
phylogenetic congruence, we test this alternative
hypothesis of fungal-algal association on a population-level