The Malacologist | The Malacological Society of London The Malacological Society of London The Malacologist

Volume 51

News & Correspondence

Member's access rights at UCL Library

The Radley book collection bequeathed to The Society in 1929 is housed in the library of University College London. By an agreement currently being negotiated between the library and The Society, members of the Malacological Society of London will be able to borrow five books at any one time, visit Special Collections (by appointment) and use 'Walk-In' access machines for on-site access to much of the library's e-resources. The library will hold a list of members' names (title, given and family names). This list will be forwarded to the library unless objections are received by the membership secretary, Dr Richard Cook, in which case that member's name will be withheld. No access will be possible for that member.

Information on the Radley collection is on The Society's website - click on library.

Freshwater gastropod diversity review

The 4000 or so described freshwater gastropods comprise about 5% of gastropods, but 20% of known gastropod extinctions. Ancient oligotrophic lakes like Baikal, Ohrid and Tangganyika are key biodiversity hotspots but lower river valleys like the Mekong, Congo and Mobile Bay are also noteworthy. The most speciose assemblages of freshwater gastropods are in small strams, springs and groundwaters, where they are under thresat from unsustainable abstraction, landscape modification and damage by livestock.

Strong, Ellen et al. 2008 Hydrobiologia 595: 149-166.

 

Abstracts of 1998 World Congress of Malacology

The complete abstracts are available on the Unitas website. See http://www.ucd.ie/cobid/congress.html

Education Awards - spread the word!

Annually, The Society awards three prizes of 200 each to schools which have undertaken a project on molluscs. Council would like to encourage readers of The Malacologist to spread the word about these to teachers, parents and pupils of both primary and secondary schools in the UK. The next round of awards will be made in Spring 2009. Further information about the awards can be obtained from the back page and page 27 of this issue or from The Society's website: http://www.Malacsoc.org.uk

 

A stem group chiton from early Cambrian?

Microscopic teeth isolated from the early Cambrian Mahto Formation, Alberta, Canada, arecomponents of a radula, the oldest on record. Associated pock-marked cuticular fragments are interpreted as having supported multiple biomineralized sclerites/spines in the manner of a modern chiton girdle. If the cuticle and radula derive from the same species, there is a strong case for identifying this fossil as an aculiferan (aplacophoran + polyplacophora) mollusc, possibly a stem-group chiton.

Butterfield N.J., 2008. Journal of Paleontology 82(3): 543-554

 

Cone snail genome project for health

This project is an 8m EU-fuded project involving 13 countries to study cone snails, isolate their toxins and exploit them to make drugs for treating stroke victims, painkillers, controlling the effects of diabetes, and new anti-microbial agents. The project is co-ordinated by Dr RetoStocklin at the Atheris Labs in Geneva.Ziconotide, developed at the University of Utah, is a synthetic form of the venom of Conus magus. It is 1000 times more potent than morphine but is not addictive, and blocks calcium channels on nerves that transmit pain signals.

www.guardian.co.uk/science/2008/apr/27/genetics/

 

Male reproductive success in Crepidula

In species where polyandry occurs, reproductive success can be quantified only by determining paternity of offspring. Microsatellite loci were employed to establish paternity for 12 families of Crepidula fornicata where a family is defined as a single female, her brood, and the males stacked on top of her. Genetic data were analyzed and paternity was assigned to a single potential father for more than 83% of the offspring tested. One male within the family fathered the majority of offspring and he was usually the largest male and the one closest to the brooding female. The dominant male's success tended to decrease as the number of mature males within the family increased.

Proestou D.A. et al., 2008: Biol Bull 214(2): 192-200.

 

Prior selfing in an hermaphrodite snail

Inbreeding hermaphrodites practising copulation show few copulations, no waiting time (the time that an isolated individual waits for a partner before initiating reproduction compared with paired individuals) and limited inbreeding (self-fertilization) depression. An experiment conducted under laboratory conditions over two generations (G(1) and G(2)) used 100 freshwater snails, Biomphalaria pfeifferi, from each of two populations. G(1) individuals were either isolated or paired once a week (potentially allowing for crosses), and monitored during 29 weeks for growth, fecundity and survival. On the whole, the self-fertilization depression was extremely low in both populations. Paired G(1) individuals began laying (selfed) eggs several weeks prior to initiating copulation: this is the first characterization of prior selfing (selfing initiated prior to any outcrossing) in a hermaphroditic animal.

Tian-Bi Y.N.T., et al., 2008: Genetical Research 90(1): 61-72.

 

Ibuprofen affects growth of ram's horn snails

Ibuprofen is a widely used non-prescription non-steroidal anti-inflammatory drug used to treat rheumatic disorders, pain and fever.Up to 80% is excreted. Regulatory base studies of aquatic contaminants concentrate on algae, cladocerans and fish, but freshwater molluscs show high extinction rates and are known to be sensitive to pharmaceuticals such as steroidal oestrogens and antidepressants. The keeled ram's horn snail Planorbus carinatus is well suited to ecotoxicological studies.The most sensitive effect was on growth rate with a 21d LOEC of 2.43 mg/L.

Pounds N et al. 2008. Ecotoxicol & Environ. Safety 70: 47-52.

Estrogenic effluent affects dogwhelk estrogen receptors

Estrogen receptors, previously known in vertebrates have recently been found in molluscs. The ER of the dogwhelk Nucella lapillus was cloned for a study of the effects of estrogenic chemicals in sewage effluent. An increase in mature females was found in dogwhelks exposed to effluent, and ER expression in overies was also increased.

Castro LFC et al. 2007. Aquatic Toxicol. 84: 465-468.

 

TBT-induced imposex linked to retinoid X receptor

Retinol (vitamin A) is required for spermatogenesis in mammals, and retinoid signalling is implicated in the regulation of male reproductive differentiation and development. Tri-Butyl Tin has recently been shown to have a high affinity for the human retinoid X receptor (RXR), suggesting that TBT might act through a molluscan RXR homologue to induce imposex. RXR mRNA levels increase at the same time as the recrudescence of the reproductive tract in both sexes of the mudsnail Ilyanassa.

Sternberg RM et al. 2008. Environ. Sci. Technol. 42: 1345-51.

 

Kleptoplasty increases sacoglossan survival

Kleptoplasts (chloroplasts incorporated into digestive cells by phagocytosis) provide Elysia with extra energy to compensate for a shortage of food. After 28 d, specimens kept in the dark showed greater size decrease and lower survival than those kept in the light.

Canalduero FG & Muriain C. 2008. J exp mar Biol Ecol. 357: 181-7.

3 Feet Under: Digging deep for the Geoduck

This is a DVD about digging for the large burrowing clam Panopea abrupta in Puget Sound. An entertaining and enlightening film about the US Pacific Northwest and the iconi Geoduck, explored through the eyes of a family and their annual clamming ritual, and a perfect balance between recreational clamming, commercial harvesting, hatchery rearing and government management. The film is featured at http://www.imdb.com/title/tt0389720 , and can be purchased from www.cybique.com/Duckumentary/DVDs.htm

 

Re-seeding giant clams in Philippines

Once common thtoughout Philippine reefs, giant clams, Tridacna gigas, had become depleted by hunting for the food, aquarium and curio trade by the mid-80s, and were classified as 'vulnerable'. An attempt to re-populate reefs by Dr Mingoa-Licuanan of the University of the Philippines Marine Science Institute and WWF-Philippines has re-seeded 50 reefs.

www.panda.org/news_facts/newsroom/news/index.cfm?uNewsID=139941

 

Modelling productivity of mussel farms

Mariculture of filter-feeding bivalves is an important source of food, but there is concern about decreasing growth rates and mass mortalities in bivalve cultures due to overstocking. Models (based on water renewal rate, phytoplankton production and bivalve clearance rate) suggest that current mussel culture practices in Galician rias are close to the carrying capacity at the raft scale, and increasing rope density by 1.5x may lead to a decline in adult production. Better yields per unit area may be achieved by reducing raft size, and effects at the scale of the raft park and the ecosystem should be used.

Duarte P et al. 2008. Aquaculture 274: 300-312.

 

Growth of triploid scallops in food-rich environment

Triploidy in mariculture organisms has been promoted because triploids show better growth. This is supposedly due to their partial or total sterility, since no resources have to be channelled to sustain gametogenesis. However in a food rich environment, this is not a problem, and assimilation efficiency in such conditions may well be reduced. In support of this, adductor muscle growth in lion-claw scallops, Nodipecten subnodosus, is no different in triploids and diploids in food-rich conditions.

Racotta I et al. 2008. Mar Biol. 153: 1245-56.

 

Probiotics in Aquaculture

Aquaculture production of molluscs is worth $11 billion per year, 65% of world mollusc production. This review looks at the use of probiotics to manage disease in aquaculture.

Kesarcodi-Watson A et al. 2008. Aquaculture 274: 1-14.

Street Scene for Snails

In June, masses of snails crossing a busy dual carriageway in Stuttgart caused a six-car pile-up, and closed the road for hours until slime and snails were removed.

In London, an artist named Slinkachu released brightly painted snails as a street art project.

Around Trafford in Greater Manchester, snails on traffic signs warn motorists to slow down in suburban streets.