World Congress of Malacology Antwerp ... - Unitas Malacologica

Interstate Park and Franconia, MN, USA. At each location we sampled 3 1-m 2 quadrats quantifying
mussels, and collected sediment samples from 1 quadrat. Depth and velocity were measured with an
acoustic Doppler current profiler under different discharge levels allowing us to measure the range of
hydraulic stresses experienced by the river bottom. Complex hydraulic parameters (Froude number,
boundary Reynolds number, shear velocity, etc.) were calculated. Analyses of covariance using the
hydraulic parameters as a covariate and location (Franconia or Interstate) showed that there was a
significant interaction between location and the hydraulic parameters Froude number, shear velocity
and shear stress. The Froude number, shear velocity and shear stress are all higher at Interstate which
harbors a greater density of mussels than Franconia. Mussel density was significantly correlated with
these parameters (except Reynolds number), with large numbers of mussels corresponding to high
Froude number, shear stress, turbulent flow, and thin laminar flow layers. These hydraulic parameters
suggest that Franconia is a more depositional riverbed environment, which may account for the
overall lower mussel density there. These data suggest that reach-scale hydraulic measurements may
be helpful in determining habitat suitability for mussels.
Taxonomy of the genus Trochulus (Gastropoda: Hygromiidae) in the Czech Republic
Hrabakova, Magda 1 ; Jurickova, Lucie 1 ; Petrusek, Adam 2
1. Department of Zoology, Faculty of Science, Charles University, Vinicna 7, 128 44 Praha 2, Czech
Republic,
Email: magda.hrabakova@seznam.cz
2. Department of Ecology, Faculty of Science, Charles University, Vinicna 7, 128 44 Praha 2, Czech
Republic
Genus Trochulus (formerly Trichia) was always considered to be taxonomically problematic. The
previous research revealed substantial cryptic diversity in the surroundings of the Alps, however,
little was known about situation in other Central European regions. Our study focuses on the question
whether the observed morphological and ecological differences of populations in the Czech Republic
can be explained by the presence of cryptic species, or by intraspecific variation.
We analysed 35 populations of two species of the genus – Trochulus plebeius and T. hispidus from
Central Europe. Karyotype analysis revealed that all studied populations have identical number of
chromosomes (n = 23) of similar morphology. Sequence analysis of 16S rDNA and COI showed two
main divergent groups of T. hispidus populations. The molecular difference between these two
groups is similar to the difference between the species T. hispidus and T. plebeius. Revealed lineages
differ in geographic distribution (north-western versus eastern). The pattern given by analysis of shell
morphology of studied populations does not correspond with lineages created by molecular analysis.
To clarify the status of the two clades, we are conducting breeding experiments to test for the
potential reproductive isolation.
Male-male and male-female agonistic behavior of Abdopus aculeatus
Huffard, Christine L. 1 ; Caldwell, Roy L. 2 ; Boneka, Farnis 3
1. Monterey Bay Aquarium Research Institute, 7700 Sandholdt Road, Moss Landing, CA, 95039,
Email: chuffard@mbari.org
2. Department of Integrative Biology, University of California, Berkeley, CA, USA,
Email: rlcaldwell@berkeley.edu
3. Facultas Perikanan, Universitas Sam Ratulangi, Manado, SULUT, Indonesia,
Email: Farnisb@gmail.com
Male-male and male-female agonistic behavior by Abdopus aculeatus was studied in situ in Sulawesi,
Indonesia and a summary of interactions is provided. Smaller octopuses consistently fled from larger
octopuses. Most male-male aggression occurred in defense of a female. ‘Grappling’ was most
common between males that did not occupy a den within arm’s reach of a female and between males
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