World Congress of Malacology Antwerp ... - Unitas Malacologica

closely matched in size. Male-female interactions involved fewer and less-physical acts than malemale
interactions. Aggression did not appear to correlate with mate-rejection, reproductive strategy,
or size, and thus did not appear to be an aspect of direct mate choice by females (although possibly
by males). Although aggression was most common between males, males and females had similar
degrees of arm injury, indicating that many injuries sustained at these sites might not result from
aggression.
Assessment of Dosidicus gigas sperm longevity using fluorescence microscopy
Huffard, Christine L.; Buck, Kurt; Robison, Bruce
Monterey Bay Aquarium Research Institute, 7700 Sandholdt Road, Moss Landing, CA, 95039
Email: chuffard@mbari.org; buku@mbari.org; robr@mbari.org
Cephalopod sperm demonstrate among the most prolonged longevity of any animals. During mating,
many male squids deposit sperm in packets (‘spermatangia’) externally to the female’s buccal area
where it is then stored for an unknown time before fertilization at spawning. An understanding of
sperm longevity is integral to our understanding of reproductive activity in cephalopods. So that we
may measure sperm longevity of species that must be examined at sea, we employed an alternative to
traditional motility assays, thereby avoiding the complications of shipboard vibration and the
occasional need to conduct analyses well after samples have been taken. Spermatangia of Dosidicus
gigas were stored in 1 ML filtered seawater at 12°C for seven days, and sperm suspensions fixed in
3% formaldehyde every six hours. Samples were then refrigerated and protected from light until
examined at a later date using fluorescent microscopy. Taking advantage of the autoflourescence of
fixed squid sperm, we counterstained sperm suspensions with the cell-impermeable dye Propidium
Iodide, which only enters dead cells. Ratios of live to dead sperm at time of fixing were calculated to
create a mortality curve for this species.
Synanthropic terrestrial mollusc faunas of Colorado and Utah
Hutchinson, John M. C. 1,2 ; Reise, Heike 1
1. State Museum of Natural History Görlitz, PF 300 154, 02806 Görlitz, Germany,
Email: majmch@googlemail.com; Heike.Reise@smng.smwk.sachsen.de
2. Max Planck Institute for Human Development, Berlin, Germany
Our aim was to establish semi-quantitatively which are the important synanthropic species in big
conurbations such as Denver and Salt Lake City positioned either side of the Rocky Mountains, but
both with a similar continental climate, and both only 150 years old. The synanthropic sites surveyed
were mostly garden centres, flower beds and bushes around town centres, public gardens, parks and
cemeteries. We sampled 31 sites in Colorado, from Fort Collins to Colorado Springs, and 28 sites in
Utah, from Provo to Logan. At most cultivated sites the generous and regular watering, usually
automated, sustained a mollusc fauna, sometimes to the extent that gardeners felt the need to apply
molluscicides. Wood-chip mulch was extensively used to conserve moisture, and was particularly
favourable for Vallonia and other species, especially underneath spreading perennials. However,
some sparsely watered allotments seemed devoid of molluscs and most uncultivated rough ground
also dried out too much. European and Holarctic species predominated. The introduced Deroceras
reticulatum, Oxychilus draparnaudi and Arion fasciatus were particularly widespread, extending also
into some less disturbed sites along rivers and in the mountains. Several other introduced pest species
(e.g. Deroceras panormitanum) were more widespread than published records suggest, and by
dissecting material (where necessary after rearing to adulthood) we recognised species that are
mostly not distinguished in the North American literature. The garden centres were especially rich in
molluscs, and extensively supplied with material from out of state, thus providing a ready means for
the spread of exotics despite the difficulty of unassisted dispersal in the dry climate. This would
explain the similarity in faunas within and between states. More introduced species were established
102