Wednesday 3rd November 2005. The annual forum for young researchers at the Natural History Museum in London attracted 31 presentations from 13 countries. Abstracts are given in alphabetical order below.

More scenes from the meeting

Giant's Tale: How the NHM acquired, preserved and plans to display a rare, live caught specimen of Architeuthis dux

Jonathan Ablett

Curator of Non-Marine Mollusca, Division of Invertebrates, Zoology Department, Natural History Museum, London SW7 5BD. (jonaa2@nhm.ac.uk)

Architeuthis dux (Steenstrup, 1857) is the scientific name for the Giant Squid, the largest living invertebrate, that has long been a mystery to scientists. Early sightings of mythical sea dwelling beasts dating to as far back as 1555, have since been postured to have actually been sightings of Architeuthis. But, what do we actually know about this rarely seen creature? The answer is very little, although a great deal of new research is adding to our body of knowledge every year. Most of what we know is about the physical structure and physiology of the Giant Squid and comes mainly from the remains of dead or dying specimens, many from the stomachs of Sperm Whales. Because of this little is known about the diet, behavior, locomotion, reproduc­tion, or habitat of the Giant Squid.

The NHM recently acquired a live caught specimen of Architeuthis dux which was caught by the Falkland registered trawler ‘John Cheek’, on 15 March 2004 at a depth of 220m (it was caught as part of a bottom trawl) 15.6 km (9.7 miles) NW of Port Stephens Settlement, about 2km offshore. The Captain of the ship gave it to the research station on the Falkland Islands, and the Falkland Islands Government donated it to the museum on the provision that it was put on public display. The specimen was 8.62m in length with a mantle diameter of approximately 0.60m.

When the squid arrived samples were taken for DNA analysis, the specimen was measured and then the specimen was fixed in 10% formol-saline. This process took many months and required a great deal of preparation to ensure that such a large and important specimen was correctly preserved. Although it is not the largest specimen ever caught (18.5m in 1880, Island Bay, New Zealand) the fact that it was caught live and is therefore virtually complete makes the specimen in the NHM a very important specimen for future research. [Poster]

The detection and impact of microsporidian and schistosome parasites on the freshwater snail species, Bulinus globosus and Bulinus nasutus, from Zanzibar

Fiona Allan^1,2, Judith E. Smith¹, David Rollinson² & Alison Dunn¹

¹ Department of Biological Sciences, University of Leeds, Clarendon Way, Leeds, LS2 9JT, UK;

² Department of Zoology, The Natural History Museum, Cromwell Road, London, SW7 5BD, UK (bgyfea@leeds.ac.uk)

The freshwater snail Bulinus globosus acts as the intermediate host for Schistosoma haematobium on Zanzibar Island, Tanzania. Microsporidian parasites have also been found to infect this species. Eleven populations of Bulinus globosus from Zanzibar have been screened using microsporidia SSU rDNA specific primers. A PCR assay has been optimised to detect a repeated sequence of S. haematobium DNA, the Dra I sequence. The sensitivity of this technique was tested using prepatent S. haematobium infections in B. globosus from day one post-miracidial exposure. Bulinus nasutus and Bulinus natalensis were also exposed to S. haematobium miracidia to observe how long the parasite DNA would remain in a non-susceptible snail. The detection of patent S. haematobium in field caught snails using the Dra I primers agreed with observed cercarial shedding. This method could be used for monitoring transmission and infection in this intermediate host. The result from the microsporidian screen of 337 snails was that all samples were negative; this suggested that the parasite was not present at any of the sites or has low prevalence. [Poster]

The population dynamics of zebra mussels on different substrata in Lake Balaton (Hungary)

Csilla Balogh^1,2 & I. B. Musko²

¹ University of Veszprem, Veszprem, Hungary;

² Balaton Limnological Research Institute of the Hungarian Academy of Sciences, Tihany, Hungary

The Ponto-Caspian invasive exotic species, the zebra mussel, appeared and mass-spread in Lake Balaton in the 1930s. Since then it has become dominant invertebrate on different substrata.

We made yearly studies of the population dynamics of the mussels in Tihany on the stony littoral zone (2003-2004), on submerged macrophytes (2000-2002) and on different natural substrata (stones, wood pieces) exposed in Lake Balaton at three different water depths, 100m from the shore and near the shoreline (1999). We compared the data in July and September.

The population dynamics of zebra mussels showed horizontal and vertical differences and depended on the material and the position of the substrata. The mussel grew most intensively on submerged macrophytes and on exposed substrata 100 m from the shore. Vertical stratification occurred in stony littoral, where the growth rate on the bottom was very low but the average length was the largest there. [Poster]

Rewiring reproduction- the case of the netted dog whelk (Hinia reticulata (L.))

Maria Campbell

Marine Biological Association of the UK, Plymouth

Tributyl tin (TBT), formerly used as a biocide in marine antifouling paints, persists in marine sediments. In neogastropods, TBT causes ‘imposex’ in which male characteristics, including a penis, are imposed on female sex organs at concentrations of 1 ng TBT l^-1 or lower. Anthropogenic release of oestrogens and xeno-oestrogens induces ‘superfeminization’ in the freshwater snail Marisa, and these alterations have also been observed in Hinia.

Samples of Hinia from three sites in Plymouth Sound all show >75% incidence of imposex, determined by VDS and RPS indices^1,2. Although TBT concentration in water and sediments are declining, levels in sediment from Drake’s Island (7.3 ng Sn g^-1 ) suggest that hotspots remain.

Hinia from Cawsand Bay in the Sound are being subjected in the laboratory to low concentrations of the natural steroid 17b-oestradiol and the synthetic hormone 17a-ethinyloestradiol, together with the oestrogen mimics octyl-phenol and nonyl-phenol. Preliminary results show a significant increase in number of egg capsules and larvae released if exposed to these xenoestrogens, compared with controls. [Poster]

¹ Stroben E et al. 1992. Mar. Biol. 113, 625-636.

² Gibbs PE et al. 1987. J. Mar. Biol. Ass. U.K. 67, 507-523.

Nicole Černohorská

Department of Zoology and Ecology, Faculty of Science, Masaryk University, Kotlář ská 2, CZ-61137 Brno, Czech Republic. (nicolehana@mail.muni.cz)

There have been few studies of the relationships between the number of mollusc species and area in terrestrial habitats. Published studies have investigated the species/area relationship at a large scale (e.g. regions), but no work has dealt with relationships on a small scale within individual sites. In 2005 we studied these relationships in the Western Carpathian spring fens. Altogether, 10 sites differing in their mineral richness were chosen, three of which were extremely mineral rich with strong tufa precipitation, four were mineral rich but without tufa precipitation (including the cases with individual tufa grain occurrence), and three were mineral-poor Rich Sphagnum fens. We sampled with a set of three quadrats (25², 50², and 75² cm²), using the nested sampling design in each site. To obtain data about the site's heterogeneity we collected a 12 litre sample in an area of 16 m² around the quadrats. The number of individuals of land snails from each sampling plot was analyzed. Live individuals and empty shells were counted separately. Considering only live specimens we found 2-10, 5-14, and 7-16 species in the quadrates 25², 50², and 75² cm², respectively. When considering both live individuals and empty shells the number of species increases significantly (2-17, 8-19, and 9-23 species in the 25², 50², and 75² cm² quadrats, respectively), especially in the case of the 25² cm² quadrat. On average, 87 % of all species found in the 12 litre sample were recorded in 75² cm² quadrats. This shows that the sampling of a 75² cm² plot can represent a site's heterogeneity reflected by the mollusc assemblage very well. [Poster]

Role of silicon in the amelioration of aluminium toxicity to the freshwater pond snail, Lymnaea stagnalis, at neutral pH

Abraham Ejim

Faculty of Life Sciences, The University of Manchester, Oxford Rd, Manchester M13 9PT, U.K.

(Abraham.i.ejim@stud.man.ac.uk) 

Previous studies have shown that Al toxicity to L. stagnalis is ameliorated intracellularly by Si as a result of the formation of a hydroxyaluminosilicate complex in the digestive gland. Characterization of the Al and Si entity will ascertain whether the association is the hydroxyaluminosilicate, imogolite, found naturally in soils. To do this, nuclear magnetic resonance spectroscopy was performed on whole digestive glands of snails exposed to Al and Si for 20 days. Past work has centred on the amelioration of Al toxicity by exogenous Si but few have investigated the role of endogenous Si. Experiments are currently being carried out to investigate the role of endogenous vs exogenous Si in ameliorating Al toxicity to L. stagnalis by presenting Si at different time points to the pond snail. [Poster]

Martin J. Genner^1,2, Ellinor Mickel³, Dirk Erpenbeck¹, Jonathan Todd⁴, Frans Witte⁵, Andrzej Piechocki⁶ & Jean-Pierre Pointier⁷

¹ Inst. Biodiversity & Ecosystem Dynamics, Univ. Amsterdam, PO Box 94766, 1090 GT Amsterdam. Netherlands (mjgenner@hotmail.com);

² Dept. of Biol. Sciences, Univ. of Hull, Hull, HU6 7RX, UK;

³ Dept. of Zoology, Natural History Museum, London SW7 5BD, UK (e.michel@nhm.ac.uk)

⁴ Dept. of Palaeontology, Natural History Museum, London SW7 5BD, UK;

⁵ Inst. Evol. & Ecol. Sci., Leiden Univ., PO Box 9516, 2300 RA Leiden Netherlands;

⁶ Dept. Invertebrate Zoology and Hydrobiology, Univ. of Lodz, Banacha Street 12/16, 90-.237 Lodz, Poland;

⁷ Centre de Biologie et Ecologie Tropicale et Mediterraneene, EPHE, UMR 5555 CNRS, Avenue de Villeneuve, 66860 Perpignan cedex, France

Lake Malawi contains an endemic radiation of soft sediment-living gastropods belonging to a single highly polymorphic group referred to as the Melanoides polymorpha ‘complex’. The origins and systematic status of the members of this complex have, until now, been unclear. Here we show using mitochondrial DNA sequences that this group shares comparatively recent common ancestry with M. anomola a species from the Congo, and Tarebia granifera, a species native to Asia. Both mitochondrial DNA sequences and markers and nuclear AFLP revealed sympatric morphs of this complex to be genetically differentiated. Males were absent from our samples, indicating that reproduction in these lineages is now predominantly parthenogenetic. Genetic diversity is likely to have arisen pri­marily through within-lineage mutational processes, but multiple mtDNA haplotypes shared among morphs indicates infrequent introgression has taken place. On the basis of these results, we propose that the extensive morphological diversity in the M. polymorpha complex has been promoted through the generation and persistence of primarily clonal lineages in a deep lacustrine environment that has been stable over evolutionary timescales, in comparison to the more ephemeral adjacent water bodies. [Poster]

Toxicodynamic and long term toxicity of soil Cd for the snail Helix aspersa

Gimbert F, DeVaufleury A, Douay F, Coeurdassier M, Scheifler R, & Badot P.M.

University of Franche-Comte, Department of Environmental Biology, UsC INRA EA 3184, F-25030 Besançon Cedex (frederic.gimbert@univ-fcomte.fr)

Among soil fauna, molluscs can be used to assess the transfer and effects of pollutants. Ecotoxicological works on the snail Helix aspersa, led to the standardisation of sub-chronic toxicity tests (4 weeks). We aimed to complete this basic device by a partial life-cycle toxicity test lasting 6 months, to assess the effects of long term soil cadmium (Cd) exposure on the survival, growth and reproduction of H. aspersa. Growth modelling highlighted physiological responses to low and environmentally realistic metal concentrations dependent on exposure duration, Cd concentration and soil characteristics. Growth inhibition appeared after 91 and 70 days of exposure to soil spiked with 20 and 100 μgCd.g^-1 respectively. Delayed effects occurred also on reproduction demonstrating the necessity of long term experiments to evaluate and predict the toxic effects of pollutants. The proposed models allowed a toxicodynamic approach of subacute effects which cannot be expressed by classical EC50 calculation.

Figure 1:

Delay of egglaying in Helix aspersa resulting from the exposure to soils contaminated with 20 and 100 μgCd.g^-1

Florian Hispard¹, A. De Vauflery¹, R. P. Cosson³, S. Devaux², R. Scheifler¹, M. Coeurdassier¹, H. Martin ², L. Richert², A. Berthelot² & P.-M. Badot¹

¹ EA 3184 USC INRA, Depart, of Environmental Biology, University of Franche-Comte, France (florian.hispard@univ-fcomte.fr);

² A 3921 OMC, Faculty of Medicine/Pharmacy, Besancon, France;

³ ISOMer-UPRES-EA 2663, Department of Marine Biology, University of Nantes, France.

Transfer and toxic effects of Cadmium (Cd) were studied in an experimental food chain involving the snail Helix aspersa (a macroconcentrator of Cd) as prey and the Wistar rat as predator. Cd was added to rat food under two different forms: a chemical form (CdCl₂ at 0, 2.5 or 100 ng Cd.g^-1) and a biological form i.e. Cd linked to metallothioneins (MTs) in the digestive gland of snail (Cd-MT at 0 or 2.5 ng Cd.g^-1). Both forms of Cd were bioavailable for rats with a transfer of 1% for all the contaminated groups but with differences of Cd tissues distribution. Regarding physiological (food consumption, growth) and biochemical responses (synthesis of detoxification proteins i.e. MTs), the biological form appears to be less toxic for rats than the chemical form. Therefore this study of poisoning risk from snail to mammal allows integrated risk assessment of chemicals.

Historical development of the White Carpathian spring fens based on palaeomalacological evidence

Michal Horsák

Department of Zoology and Ecology, Faculty of Science, Masaryk University,Kotlář ská 2, CZ-61137 Brno, Czech Republic. (horsak@sci.muni.cz)

Calcareous spring fens are unusually frequent habitats in the White Carpathian landscape (SE Czech Republic and SW Slovakia). These habitats host rich mollusc communities and they are also very favourable for shell fossilization due to precipitating tufa. Many endangered plant and snail species inhabit the White Carpathian spring fens, which are of prime importance from nature conservation point of view. Before the research, we addressed two questions: (1) how old is the present . treeless state of these sites and (2) when did Vertigo moulinsiana appear for the first time in this region? We dug out four profiles. A one litre sample was taken from each visible layer (determined according to the structure and colour of sediments). The age of some particular layers was determined by ¹⁴C dating. The oldest profile (called Tlstá hora hill) was sampled at a dug out exposure 290 cm deep and its base was approx. 4 000 years old. We confirmed that the treeless state of all studied sites is quite recent, the result of human deforestation ca 650 years ago (during the main Walachian colonisation, in progress 700-600 years ago). Vertigo moulinsiana, a threatened relic from the Late Holocene in the Central European landscape, penetrated the area in the same period (ca 650 years ago) from lowland refugia situated southward. The discovery of the young age of these habitats and communities has clear implications for their nature conservation. If we want to maintain the present state of these sites and their threatened communities, we have to provide regular site management by grazing or mowing. [Poster]

Stephanie Huff

Department of Organismic and Evolutionary Biology and Museum of Comparative Zoology, Harvard University, Biolabs Rm 1119, Cambridge, MA, 02138, USA (shufflgoeb.harvard.edu)

The internal relationships of members of the molluscan class Gastropoda vary significantly across analyses based on morphological and molecular data sets, a phenomenon possibly caused by deep divergences within Gastropoda. These relationships are tested in the first combined phylogenetic analysis for Gastropoda using morphological characters and up to 3.5 Kb of molecular evidence from five loci. Data are obtained from 36 gastropod specimens representing 30 families and 13 outgroup taxa.  Phylogenetic analysis via direct optimization using parsimony as optimality criterion is executed for different combinations of parameter sets in a sensitivity analysis framework. The stability and support of the recovered clades is explored and the results of this analysis are compared to those from other molecular and morphological data sets. Although well-supported and stable clades such as Patellogastropoda, Vetigastropoda, Neritopsina, 'Hot Vent Taxa', Apogastropoda, Heterobranchia and Caenogastropoda are recovered, their relationships to each other remain poorly supported and unstable.

Biodiversity and Habitat Complexity: Niche differentiation in an African Rift Lake

Brittany Huntington¹, Ellinor Michel², Peter McIntyre³, Yvonne Vadeboncouer⁴, Justin Meyer³ & Trisha Thoms

¹ San Francisco State University;

² The Natural History Museum, London;

³ Cornell University;

⁴ Wright State University

Lake Tanganyika, in central east Africa, is a highly diverse ecosystem, possessing a structurally complex littoral environment and supporting numerous endemic species. The patchy distribution and diversity patterns of these littoral species remain poor understood. As such, this lake is an ideal system to test the theory that complex habitats support greater biodiversity. Niche differentiation was examined as a potential cause for high observed diversity of endemic gastropods in the rocky littoral zone. Correlates were explored between factors of habitat complexity and snail diversity and distribution. I hypothesized that sites with high benthic primary productivity (snail food supply), high substrate heterogeneity and high rugosity (thus high niche complementarity) will support increased diversities and abundances of gastropods.

Preliminary results suggest that habitat complexity and productivity correlated strongly to gastropod diversity and may play an important role in supporting littoral biodiversity. Contrary to the hypothesis, increased benthic primary productivity correlated to decreased species richness and diversity. GPP in relation to species richness exhibited a unimodal productivity pattern, often seen across a comprehensive productivity gradient and at local scales. Declining gastropod diversity at high levels of productivity may be attributed to competitive exclusion. Structural complexity of the benthic habitat correlated positively with diversity, with evenness accounting for this correlation. These strong associations support habitat complexity as a factor controlling biodiversity and need further study to deter­mine a causal relationship. [Poster]

Lucie Juricková and Tomás Kucera

Department of Zoology, Charles University, Vinicna 7,CZ-128 44 Praha 2, Czech Republic (lucie.jurickova@seznam.cz)

Highways are an increasingly frequently discussed landscape feature, especially in Middle Europe. We established three transects along the three main highways heading east, southwest and north from Prague.  These transects cover major environmental gradients of geographical position, altitude, succession and vegetation cover. Altogether 44 mollusc species (more then 18% of the Czech Republic mollusc fauna) were found in 45 localities along 225 km of highway verges. A surprising 21% of the species are in the Red List of Czech Republic molluscs, including a very abundant population of the endangered species Daudebardia brevipes. We expected that highways, as man-made linear structures, would be important for the spread of invasive species, but only a single one has been found - Monacha cartusiana inhabiting the localities in the initial stages of succession. Hypothesised monotonous communities of invasive or synanthropic species were not found. The most important environmental factors are: particular geographical positions, altitude, vegetation cover (especially shrubs) and succession stage explained by the age of highway construction. We distinguish three main groups of molluscs: open stand species, natural woodland species, and semi-natural woodland species. The number of natural habitat sensitive species increases in highway verges regrown by vegetation in opposition to plantations.

Impact of light on behaviour of the zebra mussel (Dreissena polymorpha)

Jaroslaw Kobak¹ & Przemyslaw Nowacki²

¹ Nicolaus Copernicus University, Institute of General and Molecular Biology, Department of Invertebrate Zoology, Gagarina 9, 87-100 Torun, Poland (jkob@biol.uni.torun.pl):

² Nicolaus Copernicus University, Institute of Ecology and Environmental Protection, Laboratory of Applied Hydrobiology, Gagarina 9, 87-100 Torun, Poland (pn@stud.uni.torun.pl)

Light can provide mussels with important information on their environment. Shaded sites are usually better protected from predators and more distant from the water surface (where the risk of desiccation is higher). Therefore, it is likely that mussels modify their behaviour in response to illumination. We studied the impact of light on site selection, locomotion, attachment strength and valve opening of zebra mussels. Both large (>10 mm) and small (<10 mm) individuals preferred shaded sites, with the former being more sensitive to low light intensities (<1 lx). They responded similarly to various parts of the light spectrum (400 – 700 nm). Locomotion intensity (distance moved) was independent of light conditions, but illumination reduced upward movement of small individuals. Initial attachment strength (after 2 days of exposure) was higher in darkness, but this difference disappeared after longer exposure. The period of valve opening (i.e. active filtration) was longer in darkness.

Karyotypes of land operculate snails of the genus Cyclophorus (Prosobranchia: Cyclophoridae) in Thailand

Bangon Kongim¹, Somsak Panha¹ & Fred Naggs²

¹ Animal Systematic Research Unit, Department of Biology, Faculty of Science, Chulalongkorn University, Phyathai Road, Bangkok 10330, Thailand;

² Department of Zoology, Natural History Museum, London SW7 5BD, United Kingdom

With its earliest known records from the European Mesozoic, Cyclophorus is a genus of dioecious terrestrial prosobranchs that currently ranges from South Asia to the Western Pacific region. Karyotypes of ten species of Cyclophorus have been examined from Thailand. Highly distinct intrageneric similarities in both haploid and diploid chromosome numbers (n = 14, 2n = 28, FN = 56) were exhibited but the karyotypes varied with all 14 metacentric chromosomes in C. volvulus, while the remainder contain both metacentric (m) and submetacentric (sm) types. The two larger species C. aurantiacus and C. malayanus exhibit the same karyotypes of 7m + 7sm. Cyclophorus fulguratus showed karyotype variation in the central region (12m + 2sm) and northeastern region (13m + 1sm) of Thailand. Northern species possess a high metacentric number relative to southern species. The ZZ-ZW sex determining chromosomes were observed in C. fulguratus from Phu Wiang Khonkaen, C. malayanus from Sramorakot, Krabi and C. volvulus from Wang Kan Lueang Waterfall, Lopburi, Krabi. Taxonomic and evolutionary implications of the present findings are discussed. [Poster]

Sphaerium nucleus vs. Sphaerium corneum – sibling species or not?

Tereza Korínková

Department of Zoology, Charles University, Vinicna 7, CZ-128 44 Praha 2. Czech Republic

(korinko l@natur.cuni.cz)

Sphaerium nucleus (Studer 1820) has long been regarded as a subspecies or form of S. corneum. It was first Korniushin who gave convincing proofs (based on not only conchological, but also anatomical and ecological characters) of its distinctness.

In recent years, a few localities where S. nucleus occurs have been found in the Czech Republic. Material of both S. corneum and S. nucleus was examinated anatomically and histologically, the study being focused mainly on the shell pore density, shell shape, nephridium, and other details of internal anatomy (e.g. the so-called “caecal cells” of the mantle epithelium, which were found to be more numerous in S. nucleus). In my material, the main characters originally proposed by Korniushin as stable throughout the Palaearctic region, were sufficient to distinguish individuals of S. nucleus from those of S. corneum. However, in some populations more or less frequent exceptions and irregularities (namely in the arrangement of nephridium and scars of siphonal retractors) were also observed. Which of the characters are good enough to give taxa the range of a species is a point for discussion.

Comparative population genetics of sympatric sister species with contrasting life histories among endemic gastropods from Lake Tanganyika, East Africa

Joan Kuh, Ellinor Michel & Katie Wagner

Dept. of Zoology, The Natural History Museum, London SW7 5BD, UK

(mid_pac@yahoo.com), (E.Michel@nhm.ac.uk)

Lavigeria gastropods are the most common invertebrate grazers in the rocky benthos of Lake Tanganyika, forming a species flock of approximately 40 species with sympatry of up to 6 species at a site. Here we present results of population genetic studies of several of the ovoviviparous Lavigeria species that contrast in life history strategy. Species with small broods of large juveniles are predicted to have low dispersal abilities, leading to low gene flow between populations and localized gene pools. Conversely, greater dispersal and higher gene flow between populations are expected for species that produce large broods of small juveniles. Our mt and nuclear DNA sequence results on among- and within-population genetic variation do not support these standard predictions. L. coronata is a species of special conservation concern, as we have found that the two relict populations are not in genetic contact and likely experienced past bottlenecks. [Poster]

Audrey H. Lacchini, Angela J. Davies, David Mackintosh & Anthony J. Walker

School of Life Sciences, Kingston University, Kingston-upon Thames, Surrey, KT12EE, UK

(K0332092@Kingston.ac.uk)

Although molluscan biology has been studied for many years, little is currently known about the molecular mechanisms that regulate the immune system in molluscs thus preventing infection. This is particularly surprising given that molluscs serve as intermediate hosts to a range of trematode parasites including species of Schistosoma and Fasciola that cause the diseases schistosomiasis and fascioliasis.

In mammals, the protein kinase C (PKC) family consists of 11 isoforms. Some of them play a key role in a range of biological innate immune responses including phagocytosis, the production of reactive oxygen intermediates, and the release of nitric oxide.

The overall goal of my study is to elucidate the role of the protein kinase C (PKC) signalling pathway in haemocytes, macrophage-like defence cells of the freshwater snail Lymncea stagnalis, which is host to the avian schistosome Trichobilharzia ocellata. The study will provide a better understanding of PKC modulation following haemocyte challenge and will also bring new insights into PKC isoform-dependent immune responses in L. stagnalis.

In vitro culture of glochidia from the freshwater bivalve Anodonta cygnea (Linneus, 1758)

Ana Paula Lima¹, Uthaiwan Kovitvadhi², Satit Kovivadhi³ & Jorge Machado⁴

¹ ICBAS - Institute de Ciencias Biomedicas de Abel Salazar, Departamento de Producao Aquatica, Univ. do Porto, 4099 - 003, Portugal;

² Department of Zoology, Faculty of Science, Kasetsart University, Bangkok 10900, Thailand;

³ Department of Agriculture, Faculty of Science and Technology, Rajabhat Bansomdejchaopraya University, Bangkok 10600, Thailand;

⁴CIIMAR - Centre Interdisciplinar de Investigacao Maritima e Ambiental, Univ. Porto, 4099 - 003, Portugal.

Corresponding author: Jorge Machado, Lab. Fisiologia Aplicada, Instituto de Ciencias Biomedicas de Abel Salazar, Lg. Prof. Abel Salazar, n° 2, 4099-003 Porto, Portugal (jmachado@icbas.up.pt)

Freshwater pearl mussels, Anodonta cygnea were cultured in artificial media at 23 ± 2°C. Successful transformations to juveniles were achieved for the first time. Artificial medium contained a mixture of M199, fish plasma and antibiotics/antimycotics. Glochidia transformed into the juvenile stage within 10-11 days of in vitro culture. After 15 days of controlled feeding with phytoplankton, the juveniles showed an elongated shell with several growth lines. Glochidial survival during in vitro culture was 34.3 ± 9.3, with 60.8 ± 4.2 transforming from glochidia to juvenile stage. The ultrastructure of early stages of the mussel, A. cygnea was observed by scanning electron microscopy from the glochidial period until the onset of the juvenile stage 11 days later. Further observations were performed for an additional 15 days to assess juvenile development.

The Systematics and Evolution of the genus Bulla (Gastropoda: Opisthobranchia)

Manuel Antonio E. Malaquias^1,2, Robert Hughes² & David G. Reid¹

¹ Department of Zoology, Natural History Museum, London SW7 5BD (manm@nhm.ac.uk);

² School of Biological Sciences, Queen Mary College, University of London

Bubble shells (Bulla) are a small, worldwide genus of gastropods with predominantly tropical distribution, but with a few species also present in temperate waters. These attributes make this group an excellent case study to evaluate patterns of biogeography and evolution on a global scale. Nevertheless, the use of Bulla as a model requires first a comprehensive systematic revision of the group, since the taxonomy is extremely confused with over 100 available species names.

This project is the first attempt to incorporate data on shells, anatomy and molecular sequences of all available living species of Bulla in a phylogenetic and biogeographic analysis. The main objectives are to produce a species-level phylogeny as a basis for hypotheses of evolutionary radiation, adaptation and biogeography, and to review and clarify the taxonomy of the group.

Morphological characters are both variable within species and similar among them, and none of them alone proved to be good enough for species diagnosis. Shells and reproductive structures are the most informative, but different sources of information must be combined in order to delimit species. Overall, 17 species of Bulla are recognized: 4 in the Atlantic and Mediterranean, 11 in the Indo-West Pacific, and 2 in the East Pacific. A peak of diversity occurs in the Indo-Malayan area where the distributions of 5 species overlap. The preliminary molecular trees are consistent with the monophyly of the genus, and with the presence of an Indo-West Pacific clade. This pattern suggests isolation between the Atlantic and the Indo-Pacific after the closure of the Tethys Sea during the early Miocene, followed by species radiation. Allopatric speciation seems to be the rule, with sister species occurring in distinct geographical areas. [Poster]

Conservation and management of Mytilus edulis seed resources within Northern Ireland

Carrie McMinn

Queen's University Belfast (c.mcminn@virgin.net)

The major constraints on the development of bottom cultivation of mussels in Northern Ireland are (1) carrying capacity limits at licensed sites, and (2) seed procurement. By examining the latter, this project aims to help develop environmentally acceptable strategies of seed mussel collection for the mussel industry in Northern Ireland. This aim will be reached by looking at four different areas related to the mussel industry:

1    The impact of mussel seed dredging on mussel recruitment and seed bed biodiversity;

2    Re-laying of mussel seed and how to ensure the most efficient return of mussel by weight;

3    The impact of predation at re-laying sites;

4    The development of more environmentally acceptable alternatives to the seed dredging process.

This poster will look at these four points separately, giving an insight into the problems in each of these areas of the bottom mussel industry and how my research aims to reduce such problems. [Poster]

Searching for substitute diets for a laboratory culture of zebra mussel (Dreissena polymorpha)

Przemyslaw Nowacki¹ & Jaroslaw Kobak²

¹ Nicolaus Copernicus University, Institute of Ecology and Environmental Protection, Laboratory of Applied Hydrobiology, Gagarina 9, 87-100 Torun, Poland (pn@stud.uni.torun.pl);

² Nicolaus Copernicus University, Institute of General and Molecular Biology, Department of Invertebrate Zoology, Gagarina 9, 87-100 Torun, Poland (jkob@biol.uni.torun.pl)

One of the problems faced by researchers conducting laboratory experiments on Dreissena polymorpha is a diet which could be used to keep mussels in stable physiological condition, as it is not always possible to provide them with their natural food, fresh phytoplankton. Our aim was to find a cheap, easy to handle and efficient food substitute. We examined the influence of five potential diets: powdered milk, yeast, dried lettuce, dried Daphnia sp. and granulated trout food. We measured the attachment strength of mussels fed on these diets or starving for 2 - 6 weeks.

The highest attachment strength was observed in the mussels fed on yeast. Thus, we assume that it seems to be a good choice as a low-cost and low-effort diet, which can be used for short-time culture of zebra mussels. We are also planning further experiments to find the optimum yeast concentration and application procedure.

Figure. Red bars indicate no significant loss of the attachment strength in subsequent trials, when compared to that in initial trials

Biochemical adaptation for overwintering in the snail Helix pomatia (L.)

Anna Nowakowska, M. Caputa & J. Rogalska

Department of Animal Physiology, N. Copernicus University, Gagarina 9, 87- 100 Torun, Poland (noann@biol.uni.torun.pl)

Ectothermic animals, including snails, accumulate glucose and / or glycerol to endure cold stress. The purpose of this study was to check whether the concentration of these substances is triggered by environmental cues or is controlled endogenously. Therefore, Helix pomatia snails collected in their natural habitat were acclimated to cold at short- or long-day photoperiod during summer and to heat at short-day photoperiod during autumn. Moreover, we checked if snails were able to survive the sudden drop of the ambient temperature in summer. In all experimental groups the levels of cryoprotectant substances were measured. Concentrations of the cryoprotectants were higher in winter than in other seasons. The cold exposure during summer did not influence synthesis of the cryoprotectants. Elevated glucose and glycerol concentrations in winter are likely to be controlled endogenously. However, it is likely that glycerol plays a crucial role in overwintering of snails and its synthesis is connected with initiation of winter torpor.

Land-snail community composition of lowland rainforest and village home gardens in southwestern Sri Lanka

Dinarzade Raheem^1,3, Fred Naggs¹, Paul Eggleton² & Richard Preece³

¹ Department of Zoology, The Natural History Museum, London SW7 5BD, UK (dinr@nhm.ac.uk);

² Department of Entomology, The Natural History Museum, London SW7 5BD, UK:

³ Department of Zoology, University of Cambridge, Downing Street, Cambridge, CB2 3EJ

Relatively little is known of the capacity of rainforest species to persist in modified habitats. An investigation of the land-snail community composition of twenty one lowland rainforest fragments and twelve village home gardens in Southwestern Sri Lanka was carried out. Village home gardens represent a characteristic modified habitat in Sri Lanka. Sampling of land snails in leaf litter and in vegetation was carried out from 2000 to 2002 using a standardised transect protocol. Analysis of species and environmental data, using multivariate and other techniques, showed that the land-snail community structure of forest and home gardens was strikingly different. The rainforest fauna was dominated by endemic taxa; 70% of species and 16 of 28 native or endemic genera were found only in rainforest. Home gardens contain a mixture of exotic and native species associated with modified habitats and native and endemic primarily rainforest species. Home gardens are highly threatened by conversion to more intensive land-use forms, but still remain an important land use on rainforest margins. Long-term survival of Sri Lankan endemic snails depends on the conservation of forest habitats, but home gardens are likely to be of considerable value in the development of corridors connecting currently isolated forest fragments. [Poster]

Patterns of distribution of land snails in the Knuckles region of Sri Lanka

K.B. Ranawana¹, Fred Naggs² & Peter Mordan²

¹ Department of Zoology, Faculty of Science, University of Peradeniya, Sri Lanka;

² Department of Zoology, Natural History Museum, London

The Knuckles Range is located in the Kandy and Matale Districts of Central Sri Lanka. It is the northern extension of the Central Highlands of Sri Lanka and lies between 7° 18' - 7° 34' N and 80° 41' - 80° 55' E. Land snails were sampled from 116 transects (2m x 100m) representing six different habitat types, namely montane, submontane and intermediate zone forests, cardamom plantations in the montane and submontane zones, grasslands in the submontane zone and traditional home gardens in the intermediate zone. The three-year survey (from March 2000 to March 2003) has resulted in collecting 5830 snail specimens comprising 5264 (90.1%) shells and 566 (9.8%) live specimens. The, greatest number of species was recorded from the montane forests (35 sp), while the submontane and intermediate zone forests were similar with 34 species each. Among the man-influenced habitats, sub-montane cardamom plantations harboured 28 species while montane cardamom harboured 25 species. Comparatively lower numbers of species were recorded from the sub-montane grasslands (20 species) and the intermediate-zone home gardens (19 species). Species richness in each habitat type related strongly to the number of specimens collected (Pearson r = 0.84 P< 0.05). [Poster]

A survey of genital anatomy in the Streptaxidae (Pulmonata)

Ben Rowson

Dept. Biodiversity & Systematic Biology, National Museums & Galleries of Wales, Cathays Park, Cardiff, UK CF10 3NP (ben.rowson@nmgw.ac.uk)

Conchiolinous hooks or spines on the penis are a putative synapomorphy of the near-circumtropical land-snail family Streptaxidae. To date, great variation in form, number, and arrangement of hooks has been found in the species that have been examined. The taxonomic usefulness of these structures is being explored, although their biological significance remains poorly understood.

Applying Geometric Morphometrics to Distinguish Sibling Species of Polystira (Gastropoda: Turridae)

URSULA SMITH¹, JONATHAN TODD²& NORMAN MACLEOD²

¹Earth and Atmospheric Sciences, Cornell Univ, Snee Hall, Cornell University, Ithaca, NY 14853-1504 (ues4@cornell.edu);
²Dept. of Palaeontology, The Natural History Museum, London, SW7 5BD, United Kingdom

Molecular work carried out on numerous recent marine invertebrate groups suggests that many traditional “species” actually consist of several to many semi-cryptic species. Though these are genetically distinct, these morphologically tightly structured, newly discovered species together encompass what has previously been interpreted as intraspecific variation within a single species. This obviously has implications for recent and past biodiversity estimates, as well as evolutionary studies. If these semi-cryptic species can only be identified using genetic methods, then it will be extremely difficult to understand “real” species diversity in the fossil record.
Morphometric methods have been developed to examine shape in a replicable mathematical manner, and are ideally suited for applying to the problem of distinguishing sibling species. Here, they were applied to Polystira, a hyper-diverse clade (genus) of gastropods endemic to the tropical and subtropical Americas which molecular work has shown to contain sibling species. As Polystira has a character-rich shell with a wide range of ornamentation, which can be homologised, it is ideal for carrying out morphological studies in conjunction with genetic data.
Two methods, relative warp analysis and extended eigenshape analysis, were applied to a traditional “species” in an attempt to distinguish and delimit its sibling members. The methods were able to distinguish three sibling species and produce easily interpretable and biologically meaningful results. Specimens representing “unknowns” could then be compared to the known species to aid identification. We conclude that geometric morphometric methods when combined with other data sources may permit detailed analysis of palaeodiversity patterns at the species level. [POSTER]

First record of arenophilic mantle glands in the family Laternulidae (Anomalodesmata: Bivalvia)

Andre F. Sartori¹, F. D. Passos² & O. Domaneschi²

¹ Department of Earth Sciences, Downing Street, Cambridge, CB2 3EQ, U.K.  (andrefsartori@yahoo.com.br);

² Departamento de Zoologia, Institute de Biociencias, Universidade de Sao Paulo, Cx. Postal 11461, CEP 05422-970 Sao Paulo, SP, Brasil (flaviodp@ib.usp.br); (domanesc@ib.usp.br)

The mantle margins of several anomalodesmatans bear multicellular arenophilic glands whose mucoid secretion attaches sand grains and other foreign particles to the outer surface of the periostracum. These glands have been recorded in many of the anomalodesmatan families (Lyonsiellidae, Verticordiidae, Clavagellidae, Parilimyidae, Periplomatidae and Lyonsiidae), and therefore used as a key morphological character in all recent attempts to unravel the evolutionary relationships within the Anomalodesmata. An ongoing investigation on the functional morphology of Laternula elliptica (King & Broderip, 1831), the only Antarctic representative of the family Laternulidae, revealed that the glands occur in large numbers on the siphons, discharging near to the distal tips. This is the first record of arenophilic mantle glands in a member of the Laternulidae, a finding that not only broadens our current knowledge of the family's morphology, but also provides new clues to the reconstruction of anomalodesmatan evolutionary history.

Kathryn Tanner

Darwin College, Silver Street, Cambridge CB3 9EU (kct21@cam.ac.uk)

In what ways are molluscs traded internationally for the political and economic advantage of individuals or communities? What implications and global dimensions does this trade incur? While baseline studies have been conducted about seashells in Tanzania (Marshall 2001, Richmond 1997, Spry 1961), this paper focuses on the socio-economic and global dimensions of this trade issue. Through an examination of networks and economic exchange, the seashell trade is followed from the coral reef systems of Tanzania to the markets of India. Historically, coastal Tanzania has been linked to South Asia through the trade of goods over the sea, and recent research shows that these trade relationships are still in use. From data collected over the last 6 years, 75% of the seashells exported from Tanzania are destined for India, comprising nearly a million kilograms of molluscs in one year. What drives this demand, and how sustainable is it?

Marshall, N. 2001. Stormy Seas for Marine Invertebrates: Trade in Sea Cucumbers, Seashells, and Lobsters in Kenya, Tanzania, and Mozambique. TRAFFIC East/Southern Africa, Nairobi, Kenya.

Richmond, M.D. 1997. A Guide to the Seashores of Eastern Africa. SIDA. Dar es Salaam, Tanzania.

Spry, J. F. 1961. The Seashells of Dar es Salaam: Part 1 -Gastropods. Tanganyika Notes and Records. 56:1-33.

Illustrations

Molluscs as food

Molluscs in commerce

Some conchological landmarks: the history of the NHM Mollusca Section

Kathie Way & Amelia MacLellan

Division of Higher Invertebrates, Natural History Museum, Cromwell Road, London SW7 5BD, UK (k.way@nhm.ac.uk)

The Natural History Museum's mollusc collection had its beginnings in Sir Hans Sloane's donation of his private museum to form the foundation of the British Museum, Bloomsbury in 1753. In 1836 an estimate of the size of the holdings made by the then Keeper of Zoology, John Edward Gray, gives a figure of c. 15,000 specimens and in 1904, following the 1882 relocation of the collections to the new British Museum (Natural History) in South Kensington, the total was 450,000. A recent estimate suggests that there are now over 9,000,000 specimens in the collection and this poster highlights some of the important landmarks in the history of the NHM Mollusca Section. [Poster]

Elzbieta Zbikowska

Department of Invertebrate Zoology, Institute of General and Molecular Biology, Nicholas Copernicus University

The shells of Lymnaea stagnalis show great variability. It has been described as an effect of environment influence. The main object of the present study was a comparison of some biometric data of shell in naturally infected and uninfected snails from different lakes in the north part of Poland. The height of shell, the height of spiral, the width of shell and the internal volume of shell were measured.

Some interpopulation and intrapopulation differences among individuals were found. Greater variability of shell shape was observed among snails parasitized with digenean larvae than in non-parasitized ones. Snails infected with digenean larvae most differed in shell parameters from uninfected individuals (Fig. 1). The shells of snails in which the commensal oligochaete Chaetogaster limnei was found did not differ from uninfected individuals. The results of the present study give some grounds for the assumption that the deformation of shells of the snails under study was correlated with the intensity of interaction between them and the invader. Parasites appear to be one of more important factors modifying the shell structure.