World Congress of Malacology Antwerp ... - Unitas Malacologica

Sexual conflict and conflict resolution in hermaphroditic gastropods
Michiels, Nico K.
Faculty of Biology, Univ. Tuebingen, Morgenstelle 28, 72076 Tuebingen, Germany,
Email: nico.michiels@uni-tuebingen.de
Sexual selection results from competition within and between sexes over reproductive success.
Although Darwin coined the term, and assumed that it would be limited to species with separate
sexes (gonochorists), consequences of sexual selection have now been shown for many
hermaphroditic taxa. A majority of these studies have focused on pulmonate gastropods and
opisthobranch sea slugs. This talk gives an overview of some of the most spectacular examples of
excessive and complicated traits that have evolved in the context of sexual conflict and conflict
resolution found thus far in these groups. The sheer diversity and nature of these traits is
overwhelming. This is particularly obvious when compared to prosobranchs, where such diversity
seems to be absent. I shall offer some explanations, which are sometimes non-intuitive and based on
theoretical models. No explanation seems to be sufficient to explain all the known systems,
suggesting high evolutionary dynamics. At the end, I shall speculate on whether hermaphroditic
groups like these should be considered derived or ancestral, and whether they may lead into
evolutionary dead-ends.
Bivalves of the Florida Keys – The monograph
Mikkelsen, Paula M. 1 ; Bieler, Rüdiger 2
1. Paleontological Research Institution, 1259 Trumansburg Road, Ithaca, New York 14850 USA,
Email: pmm37@cornell.edu
2. Department of Zoology (Invertebrates), Field Museum of Natural History, 1400 S. Lake Shore
Drive, Chicago, Illinois 60605-2496 USA,
Email: rbieler@fieldmuseum.org
Molluscan diversity in the Florida Keys, a relatively well-known and oft-sampled area (10,000 km 2 )
by professional and amateur collectors and now Florida Keys National Marine Sanctuary, has
surpassed all previously published estimates and checklists. A combination of region-wide qualitative
sampling, thorough and rapid collecting techniques, "data mining" of museum collections and
literature, and a large-scale transect project have nearly tripled the number of known marine mollusks
to about 1,700 species, and provided insight into their distribution and ecology. Dated records were
used to investigate species occurrences over the past 100+ years and indicate recent introductions and
losses in this region. After more than 12 years of intensive study, a first phase focusing on bivalves is
being completed, resulting in faunal analyses and critical catalogues including photographic
documentation of the nearly 400 species. Although the molluscan community is relatively uniform
throughout the Keys, results indicate (1) nearly half of the species can be characterized as rare, (2) no
losses were recorded, and gains can be attributed to introduced exotic species, increased freshwater
input (from The Everglades), and new sampling technologies, (3) a distinct northeast-to-southwest
gradient in community structure was evident only in the shallow-water bayside of the island chain
(absent on the oceanside at all depths), and (4) the overall community showed greatest similarity with
those of the Gulf of Mexico and Cuba. The considerable clade richness (representing half of the
world’s bivalve families) prompted a comparative survey of bivalve morphology, the focus of a
forthcoming book-length monograph. Text and images combine to present the full range of species-
to family-level characteristics exemplified by the Florida Keys fauna. Illustrations include 1,500
color images of shells, underwater habitats, bivalves in situ, original anatomical and hinge drawings,
scanning electron micrographs, and unique “transparent clam” anatomical drawings. [Supported in
part by NSF PEET DEB-9978119].
145