|LITERATURE||Molecular ecology of slugs;|
|Electronic J Moll Stud from Vol. 1;||Arctica - tree of the sea?;|
|Manchester Museum;||Gonadotrophin releasing hormone in molluscs;|
|Flashing squid;||Endocrine disruptors;|
|Whelks as biodiversity indicator;||Cuttlefish culture;|
|Mussels return to Svalbard;||Antarctic molluscs;|
|Shell making 1 & 2;||Aquaculture for natural non-food products;|
|Abalone gills;||Freshwater gastropods website;|
|Slugs as neuroscience models;|
|MRI scan of oysters;||Scallops website.|
Stud. available on line back to Vol. 1.
Oxford University Press has completed the electronically retrievable archives of Journal of Molluscan Studies (and its predecessor, Proceedings of the Malacological Society of London) back to Volume 1.
megalab for Darwin 200
Central to Darwin's genius was his ability to see evolutionary processes operating within commonplace observations of natural history. A Megalab enables large numbers of people to contribute simple observations in individual locations to a geographical survey to investigate a scientific hypothesis. In 2009, 200 years from Darwin's birth and 150 years from the publication of Origin of Species, the Open University will conduct an Evolution Megalab re-surveying Cepaea polymorphism, with funding from the Royal Society and publicity from the media including a series on BBC2 called Darwin's Garden.
Information from thousands of samples collected over almost a century has shown that most populations of Cepaea nemoralis and C. hortensis display an easily seen polymorphism in shell colour and banding. The genetic basis of that polymorphism is well established and Arthur Cain and others showed that in some places the shell polymorphism was subject to natural selection involving predation by birds and different morphs were adaptively camouflaged against different backgrounds. There are also correlations of behaviour and shell morph with temperature and latitude.
Over the past fifty years, thrush predation has become rarer, and our climate has become warmer. The Evolution Megalab will investigate whether shell polymorphism has evolved in response over the last fifty years, by inviting the public to look for banded snails in gardens and public open spaces across Britain and report the numbers of different morphs found. Laurence Cook, Robert Cameron and Steve Jones will provide the scientific basis and historical context, and the maps produced will be compared with historical data.
Subject to funding, the software created for the UK Megalab will be versioned to provide a Europe-wide Megalab run collaboratively with institutions across Europe.
If you represent an organization that would like to participate in any aspect of Evolution Megalab, please contact Prof. Jonathan Silvertown : j.si...@open.ac.uk
The Manchester Museum
The Manchester Museum contains a significant body of literature relating to molluscs. A list of this material, which includes books, journals and theses, has been prepared by Laurence Cook. The full list can be found on The Society's website, http://www.Malacsoc.org.uk. This material is available for consultation; if you would like access, then contact me on henr...@manchester.ac.uk.
Head of Natural Sciences and Curator of Zoology
Big flashy squid filmed
A new high definition underwater video camera has taken live images of the large (up to 2.3 m) mesopelagic squid Taningia danae at 240 - 940 m off Ogasawara Islands. T. danae attains speeds up to 9 km/h when attacking bait, by flapping its fins, and it can alter direction rapidly by flexing its body. It emits short bright light flashes from large arm-tip photophores. These may blind prey as well as allowing the squid to measure target distance. The squid also emitted long and short glows separated by intervals while investigating the torches around the rig, suggestive of potential courtship behaviours. A BBC NEWS story with video are at
T Kubodera, Y Koyama and K Mori. 2007. Observations of wild hunting behaviour and bioluminescence of a large deep-sea, eight-armed squid, Taningia danae. Proc. Roy. Soc. B doi: 10.1098/rspb.2006.0236.
Using both molecular and fossil data, the Vampyromorpha, Octopoda and most extant decapodiform taxa appear to originate in the Palaeozoic -considerably earlier than palaeontological estimates. The main groups of octopods diverged in the Mesozoic, but decapodiform relationships are obscured by their antiquity.
Strugnell J, Jackson J, Drummond AJ, Cooper A. (2006) Divergence time estimates for major cephalopod groups: evidence from multiple genes. Cladistics 22 (1): 89-96.
Abalones have an unusual gas exchange strategy - while the right gill is perfused at a fairly constant rate, the left gill has almost no haemolymph flow when at rest. During periods of increased demand, however, perfusion of the left gill can increase almost 30 fold.
Ragg NLC, Taylor HH. 2006. Heterogeneous perfusion of the paired gills of the abalone Haliotis iris Martyn 1784: an unusual mechanism for respiratory control. Journal of Experimental Biology 209 (3): 475-483.
Where there's a whelk there's a way
When making conservation surveys, reliable indicator taxa can reduce field sampling time and the need for taxonomic expertise. Macrobenthic prosobranchs like whelks provide the most accurate predictions of species richness in rocky shores.
Smith SDA. 2005. Rapid assessment of invertebrate biodiversity on rocky shores: where there's a whelk there's a way. Biodiversity and Conservation 14 (14): 3565-3576.
Climate change: mussels return to Svalbard
Unusually high sea temperatures in 2002 allowed blue mussel larvae from the Norwegian coast to be carried north and settle at the mouth of the Isfjorden on Svalbard - 900 km from the North Pole - the first time since the Viking era.
Berge J, Johnsen G, Nilsen F, Gulliksen B, Slagstad D. 2005. Ocean temperature oscillations enable reappearance of blue mussels Mytilus edulis in Svalbard after a 1000 year absence. Marine Ecology-Progress Series 303: 167-175.
Making shell 1
The way that molluscs form crystals to build their shells surprises chemists. Molluscs use a hydrophobic silk gel and very acidic proteins. The crystals apparently form from an amorphous precursor phase in a highly structured chitinous framework. Addadi et al ask how these disparate components might work together to produce the highly structured pearly nacre.
Addadi L, Joester D, Nudelman F, Weiner S. 2006 Mollusk shell formation: A source of new concepts for understanding biomineralization processes. Chemistry-a European Journal 12 (4): 981-987
Making shell 2
The mechanical properties of nacre rely on its bricks and mortar construction, with 95% formed from inorganic aragonitic calcium carbonate as the bricks and 5% as a mortar of protein and polysaccharide. Recent work suggests that water present in nacre platelets is a significant contributor, along with aragonite, to the viscoelasticity of nacre.
Mohanty B, Katti KS, Katti DR and Verma D 2006. Dynamic nanomechanical response of nacre. Journal of Materials Research 21 (8): 2045-2051.
Cuttlefishes' thermal tolerance limited by oxygen
There is evidence for an oxygen limitation of thermal tolerance in the cuttlefish Sepia officinalis, as indicated by a progressive transition of routine mantle metabolism to an anaerobic mode of energy production. It is probably mainly the constantly working radial mantle muscles that become progressively devoid of oxygen.
Melzner F, Bock C, Portner HO 2006 Critical temperatures in the cephalopod Sepia officinalis investigated using in vivo P-31 NMR spectroscopy. Journal of Experimental Biology 209 (5): 891-906
Slug models in Neuroscience
Tokyo neuroscientists led by Inoue have developed an in vitro odour-aversion conditioning system involving the 'nose', brain, and parietal nereves of Limax. The parietal nerves are active, causing the mantle to shorten in response to aversively conditioned odours. Before conditioning, no activity occurs in the parietal nerves in response to attractive odours, but after aversive conditioning, discharges occur in response to originally attractive odours to which the slugs are now aversively conditioned. Perhaps the greater interest, in view of work on oscillations in olfactory networks of vertebrates and arthropods, is the change in frequency of oscillations recorded in the procerebrum of the brain.
Goel and Gelperin in USA construct a neuronal network model of associative conditioning shown by Limax, in which 'blocking' to a previously conditioned stimulus in the presence of an unconditioned stimulus emerges as a property of the network.
Inoue T, Murakami M, Watanabe S, Inokuma Y, Kirino Y.. In vitro odor-aversion conditioning in a terrestrial mollusc. Journal of Neurophysiology 95 (6): 3898-3903.
Goel P, Gelperin A. 2006. A neuronal network for the logic of Limax learning. Journal of Computational Neuroscience 21 (3): 259-270.
Pouvreau S, Rambeau M, Cochard JC, Robert R. 2006. Investigation of marine bivalve morphology by in vivo MR imaging: First anatomical results of a promising technique. Aquaculture 259 (1-4): 415-423.
Molecular ecology of slugs
It is a tenet of detective work that a criminal always leaves a trace of their presence at the scene. Similarly, slugs leave a trace of proteins which can be washed from soil with salt and detected by a new slug-specific monoclonal antibody. There is a linear relationship between slug biomass in any given soil and slug proteins detected. The ELISA technique gave comparable results to the most accurate conventional technique of soil flooding, but was faster.
McKemey AR, Glen DM, Wiltshire C W, Symondson WOC. 2006. Molecular quantification of slug density in the soil using monoclonal antibodies. Soil Biology & Biochemistry 38 (9): 2903-2909.
"Obviously, Watson, this is the work of a one-footed slug with a ruddy appearance, whose father travelled from Eastern Europe."
Tree of the sea?
Lack of an absolute timescale for the marine environment has precluded understanding of climate changes in the last glacial period, but annual growth bands from the bivalve Arctica islandica have been crossbanded to provide an initial 267 y series, encouraging hope that this species may provide a method of dating similar to tree growth rings.
Scourse J, Richardson C, Forsythe G, Harris I , Heinemeier J, Fraser N, Briffa K, Jones P. 2006. First cross-matched floating chronology from the marine fossil record: data from growth lines of the long-lived bivalve mollusc Arctica islandica. Holocene 16 (7): 967-974.
Gonadotrophin Releasing Hormone (GnRH) in Molluscs. GnRH occurs not only in all chordates, including tunicates; there is recent evidence for GnRH-like molecules in Octopus, Aplysia and Helisoma, suggesting that GnRH is an ancient peptide present prior to the divergence of protostomes and deuterostomes.
Tsai PS 2006. Gonadotropin-releasing hormone in invertebrates: Structure, function, and evolution General and Comparative Endocrinology 148 (1): 48-53.
Endocrine Disruptors (EDs). This review of EDs in marine organisms focuses on several recent advances in ED effects and mode of action in invertebrates, and on top predators (large pelagic fish and cetaceans). The review covers pathways of steroid synthesis and metabolism in invertebrates, actions of estrogenic compounds in mussel immunocytes, potential use of vitellogenin-like proteins as bio-markers in marine bivalves, and a survey of ED accumulation and effects in marine fish and mammals.
Porte C, Janer G, Lorusso L C, Ortiz-Zarragoitia M, Cajaraville M P, Fossi M C and Canesi L. 2006. Endocrine disruptors in marine organisms: Approaches and perspectives. Comparative Biochemistry and Physiology C-Toxicology & Pharmacology 143 (3): 303-315.
Cuttlefish culture. Sykes AV, Domingues PM, Correia M, Andrade J P. 2006. Cuttlefish culture - State of the art and future trends. Vie et Milieu - Life and Environment 56 (2): 129-137.
Antarctic molluscs. Linse K, Griffiths HJ, Barnes DKA, Clarke A. 2006.and biogeography of Antarctic and sub-Antarctic mollusca. Deep-Sea Research Part II-Topical Studies in Oceanography 53 (8-10): 985-1008.
Pharmaceuticals, cements, antibiofouling compounds. Liebezeit G. 2005. Aquaculture of "non-food organisms" for natural substance production. Marine Biotechnology II Advances in Biochemical Engineering / Biotechnology 97: 1-28.
Freshwater Gastropods of North America
This site now has North and South Carolina gastropods photogallery and dichotomous key together with distribution maps, status, and conservation recommendations. There are also links to essays on shell shape and gigantism from Rob Dillon.