J. Moll.
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.
Cepaea
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.
Henry McGhie,
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
http://news.bbc.co.uk/go/pr/fr/-/1/hi/sci/tech/6357005.stm.
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.
Coleoid divergences
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.
Abalone gills
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.
Anatomical Technique
The rapid and non-invasive technique of MRI has been used for the first
time to depict the anatomy of an oyster. The resolution was good enough
to reveal all the main organs.
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.
REVIEWS
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.
WEBSITES
Freshwater Gastropods of North
America
http://www.cofc.edu/~fwgna/fwgnahome.htm
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.
Scallops
Henk Dijkstra's excellently illustrated website of Pectinidae and Propeamussidae
is at www.scallop.nl
Indrella amputta. © The Natural History Museum, London.
Mariaella dussumieri. © The Natural History Museum, London.
Beddomea trifasciatus (lowland form). © The Natural History Museum, London.