World Congress of Malacology Antwerp ... - Unitas Malacologica

of Omalogyridae either as an separate clade of early heterobranchs or as a progenetic part of a
superclade Architectonicoidea.
Does lead poison snails?
Beeby, Alan
London South Bank University, London SE1 0AA, UK,
Email: beebya@lsbu.ac.uk
Lead rarely occurs at levels that significantly impair the growth and reproduction of molluscs and
invertebrate studies suggest it is the least toxic of the common metallic pollutants. It is readily
accumulated by groups with a high calcium demand, but nearly all invertebrates respond to other
toxic metals at much lower concentrations than those of Pb.
Lead may follow pathways of Ca uptake and loss and can substitute for it in some enzymes requiring
Ca for their activation. However, Pb is excluded from some Ca-rich tissues in gastropods, suggesting
some protective or other mechanism. Additionally, some snail populations may have a Ca
metabolism adapted to a high Pb environment. If these are responses to some impairment of function
they have resulted from a selective pressure at concentrations beneath those commonly used to define
a toxic response. Simple toxicological studies – much of the existing literature – may not fully
represent the significance of Pb. Determining the significance of environmental Pb may require a
different perspective, with greater attention to its sub-lethal and biochemical effects.
Perhaps lead is relatively benign at most environmental concentrations, when it represents a small
fraction of a snail’s Ca uptake. If Ca is abundant, low Pb concentrations may have little effect.
However, we can detect effects when available Ca is low and demand is high: juveniles across
several populations of Cantareus favour soft tissue rather than shell growth on a high Pb diet. Those
from Ca-rich habitats appear to have different growth strategies to snails from Ca-poor habitats,
which may result in different susceptibilities to a Pb burden. Rather like the close associations
between Cd and Zn, or Hg and Cu, we may only understand the environmental significance of Pb by
reference to an essential metal analogue such as Ca.
Sperm storage organ evolution in the carrefour of stylommatophoran gastropods
Beese, Kathleen 1 ; Armbruster, Georg F. J. 2 ; Beier, Konstantin 3 ; Baur, Bruno 4
1. Department of Environmental Sciences, Section of Conservation Biology, University of Basel, St.
Johanns-Vorstadt 10, CH-4056 Basel, Switzerland,
Email: kathleen.beese@unibas.ch
2. Department of Environmental Sciences, Section of Plant Ecology, University of Basel,
Schönbeinstrasse 6, CH-4056 Basel, Switzerland,
Email: g.armbruster@unibas.ch
3. Anatomical Institute, University of Basel, Pestalozzistrasse 20, CH-4056 Basel, Switzerland,
Email: konstantin.beier@unibas.ch
4. Department of Environmental Sciences, Section of Conservation Biology, University of Basel, St.
Johanns-Vorstadt 10, CH-4056 Basel, Switzerland,
Email: bruno.baur@unibas.ch
An important factor of postcopulatory sexual selection in internally fertilizing species is the presence
of specialized female sperm storage organs. In our study, we morphologically examined the presence
and complexity of spermathecae in the carrefour region of 47 stylommatophoran gastropod species.
Partial 28S rDNA sequences were used to construct a molecular phylogeny, and maximum likelihood
and Bayesian methods were applied to investigate the history of sperm storage organ diversification.
The phylogenetic analyses revealed several independent gains and losses of sperm, indicating rapid
evolutionary changes. The presence of a complex spermatheca was associated with the occurrence of
love darts or any kind of auxiliary copulatory organs, the presence of a long flagellum and cross-
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