A Selection Of Other Papers And Posters

Several discrete sperm characters can be used for cladistic analysis of basal caenogastropods
(John Healy, Queensland).

Some arionid slugs combine selfing and outcrossing, others are strict outbreeders. Arion intermedius is predominantly selfing, but there is some heterozygosity for HBDH, and reports of spermatophores (Heike Reise et al, Naturmuseum Görlitz).

Discoidal/globular pulmonates, like Bradybaena similaris, mate reciprocally while facing each other, so mating between left and right-handed partners is difficult; tall-spired species, such as Partula suturalis, mate non-reciprocally, with the male-acting partner mounting the shell of the female-acting partner, so inter-chiral matings are easily accomplished by moving the head across. Thus chirality evolves more frequently in high-spired species (Takashiro Asami, Tokyo Metropolitan College, and K. Ohbayashi,Tokyo).

Using pigmented and albino Biomphalaria as genetic markers, revealed no preference between the use of partner's sperm and own sperm (Jaqui Trigwell and Georges Dussart, Christ Church College, Canterbury).

Use of shell colour as a genetic marker in the land snail Arianta reveals that sperm of a first partner take precedence over those of a second partner when matings are 70 days apart, but not if the second mating is delayed to the next season. Size of partner does not influence fertilization success. (Bruno Baer, Basel).

Stirpulina ramosa from west Pacific is a living fossil bivalve with primitive clavagellid features. (John Pojeta, Smithsonian).

The enigmatic Xenoturbella bocki, a 3 cm ciliated sac with mouth, statocyst and no anus, has been described as a platyhelminth, enteropneust or holothurian; its embryology clearly indicates its protobranch bivalve relationship (Ollie Israellson, Swedish Museum of Natural History, Stockholm).

When coining common names for molluscs to capture the interest of the young naturalist, lump small or unstable groups - so any hydrobiid becomes a `waterling', give a rare topshell a unique name e.g. `starlet', and avoid transliteration of Latin names (Jo Heller, Hebrew University, Jerusalem).

Medical malacologists can help conserve biodiversity by being aware of the hazards from chemicals or introduced competitor species to control snail hosts of parasitic diseases (Tom Kristensen, Danish Bilharziasis Lab, and David Brown, NHM, London).

A crude methanol extract of tomato leaves is effective against Biomphalaria but not its egg masses (V Leyton, T Hendersonn and T Kawano, Sao Paulo and Illinois); and a crude aqueous extract of Agarve attenuata leaves is as good as Phytolacca against Bulinus. (T Brackenbury and C Appleton, Natal).

Black carp (Myllopharyngodon piceus) can control Physella and Melanoides, aquatic snails which block filters, over several months even if the snails can shelter (Freda Ben Ami, Hebrew University, Jerusalem).

A four hectare site in Jamaica yielded 70 species of land snail and 3 species of slugs, of which 63 were native (58 endemic). Only 21% are less than 5 mm when mature, compared to 86% from a highly diverse New Zealand reserve. (Gary Rosenberg and Igor Muratov, Academy of Natural Sciences of Philadelphia).

Zebra mussels, Dreissena polymorpha, severely lower phytoplankton stocks and increase water clarity. Their invasion of the Hudson River in 1989 led to diatoms replacing blue-greens as the dominant stock. Dreissena select blue-greens and smaller greens, and exclude larger greens and diatoms. (Shirley Baker and Jeffrey Levinton, New York.)

The winkle Littorina littorea shows greater trail following on trails coated with the microalga Amphora coffeaeformis. (Mark Davies (Sunderland) et al.)

The marine chink-shell Lacuna has pointed cusped teeth when feeding on macroalgae and blunt cusped teeth when feeding on microalgal epiphytes on eelgrass; tooth type changes a few weeks after transfer. (Dianna Padilla (New York) and Karen Fear (California, San Diego)).

Recent studies of tropical reefs have brought to light the first documented cases of Batesian and Mullerian mimicry in marine organisms from distinct phyla -nudibranch molluscs and polyclad flatworms. (Terry Gosliner (California Academy of Sciences, San Francisco) and Leslie Newman (NMNH, Washington)).