Beiträge der Hymenopterologen-Tagung in Stuttgart (1 ... - DGaaE

Beitr. Hymenopt.-Tagung Stuttgart (2004) 25
weiter nahe, dass Arterkennung eine Rolle bei der Evolution des Duftstoffsammels spielt oder
gespielt hat.
Literatur
BEMBÉ, B. 2004: Functional morphology in male euglossine bees and their ability to spray fragrances (Hymenoptera,
Apidae, Euglossini). — Apidologie 35: 283-291
ELTZ, T., WHITTEN, W.M., ROUBIK, D.W. & LINSENMAIR, K.E. 1999: Fragrance collection, storage, and accumulation
by individual male orchid bees. — Journal of Chemical Ecology 25: 157-176
ELTZ, T., ROUBIK, D.W. & WHITTEN, W.M. 2003: Fragrances, male display and mating behaviour of Euglossa
hemichlora - a flight cage experiment. — Physiological Entomology 28: 251-260
Is there a particular ant fauna
in Araucarian rain forests in South-eastern Brazil?
Manfred VERHAAGH
Staatliches Museum für Naturkunde Karlsruhe
Erbprinzenstr. 13, D-76133 Karlsruhe, manfred.verhaagh@smnk.de
Investigations of the myrmecofauna of the litter stratum in a mountainous Araucaria forest (960
m) and a nearby coastal escarpment forest without this neotropical conifer (670 m) on the Serra
Geral in Rio Grande do Sul, Bazil, showed that the spectrum of the ant communities was very
similar in both forest types. By standardised litter extraction in Winkler bags a few more species
could be recorded in the escarpment than in the Araucaria forest combined with a higher density
of species and individuals and higher values of diversity and evenness indices. The difference
in the indices decreased when they were recalculated with presence-absence instead of absolute
abundance data. The dominance structure in the Araucaria forest was strongly biased towards
one species of Hypoponera which was present in all samples and numbered half of the specimens.
Among the 20 species with significant differences in site frequency only 3 could be found
exclusively in the Araucaria forest and 4 in the escarpment forest. Generally, the litter stratum
of both forest types was dominated by species of Hypoponera, Pheidole and Solenopsis
(Diplorhoptrum). Species richness estimated by different extrapolations resulted in about 100
litter ant species for either forest plot, showing that our samples covered certainly more than
50% of them.
The differences in the structure of the litter ant communities at the two neighbouring forests
presumably reflect the local microclimate conditions. The escarpment forest at a lower altitude
on the steep slopes towards the Atlantic ocean is much more sun-exposed, resulting in higher
ambient temperatures.
In a second study on arboricolous ants a so far unknown high number of ant species associated
with Araucaria trees could be recorded. However, no specialised „araucariocolous“ ants seem
to be among the species found because most of them could also be detected on nearby broadleafed
trees or on the ground. In most taxa of the Araucarian ant fauna the workers are small and
the colonies are not very populous. Only a Crematogaster and a Myrmelachista species were
common and conspicuous on Araucaria trees and may dominate the complete crown of a
particular tree with there often polydomous colonies.