Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Unravelling The Ecology Of Snail Shell Coiling


Ecologists are taking to the trees in a bid to unravel the ecology of shell coiling in snails. Speaking at the British Ecological Society’s Annual Meeting, being held at Manchester Metropolitan University on 9-11 September 2003, Dr Paul Craze of the University of Plymouth will explain how examining the proportion of right- and left-coiling individuals in a species of Bornean tree snail could help ecologists understand how new species arise.

The vast majority of snail species are almost exclusively dextral, or right-coilers, with just the occasional sinistral, or left-coiling, individual. However, in a small number of snail species there appears to be a stable balance between the number of right- and left-coilers. Coil direction in snails is inherited from the mother and is controlled by a single genetic locus or region, and coil direction is important because it is difficult for right-coiling snails to mate with left-coiling snails.

The fact that left- and right-coiling snails cannot align themselves properly during mating is, however, more than an irritation to the snails and an interesting puzzle for ecologists. Understanding how new species arise is a fundamental biological problem, and in the case of snails, some ecologists believe that the existence of left- and right-coiling individuals could be one mechanism for sympatric speciation (the development of new species by isolating them other than geographically). Since left-coiling and right-coiling snails find it hard to mate with each other they may, over time, develop into separate species.

Dr Craze and Dr Menno Schilthuizen of the Universiti Malaysia Sabah studied shell coiling in Amphidromus martensii, a snail that lives in the rainforests of Borneo, and one of the few species that is composed of roughly 50% right- and 50% left-coiling individuals, to find out what factors are responsible for maintaining this 50:50 split, and whether or not the right- and left-coilers show evidence of diverging towards becoming different species.

“There has been virtually no ecological study of shell-coiling polymorphism, so the first thing we were interested in was whether the 50:50 ratio that we know exists at the medium scale (ie between sites separated by tens of kilometres) also exists at a smaller scale (ie between sites separated by tens of metres), or whether the right coilers occupied different habitats from the left coilers,” Dr Craze says.

Because A. martensii lives in the forest canopy, Dr Craze chose to collect shells of dead snails from the ground. “We found equal numbers of left and right coilers no matter what scale we chose, which suggests that we are dealing with a truly balanced polymorphism and that these snails are not at the early stages of speciation. If that turns out to be the case, we need to identify what factors are responsible for keeping the polymorphism so balanced,” Dr Craze explains.

However, to make sure that the results they have found are not only confined to snail shells found on the ground, Dr Craze will be repeating the experiment by hanging from a rope in the rainforest looking at live snails in the forest canopy. “We also plan to use small snail-sized radio transmitters to track movements of snails to see how many snails of each coil-type an individual is likely to encounter and so work out the potential for gene flow between areas,” he says.

According to Dr Craze: “Our work may have some interesting implications. Studies of the ecological factors responsible for maintaining balanced polymorphism are still quite rare. On the other hand, if some degree of divergence between the coil-types is discovered, we have a model system for studying what may be an interesting mechanism of sympatric speciation.”

Dr Craze will present his full findings at 15:00 on Tuesday 9 September 2003.

Becky Allen | alfa
Further information:

More articles from Life Sciences:

nachricht Biologists unravel another mystery of what makes DNA go 'loopy'
16.03.2018 | Emory Health Sciences

nachricht Scientists map the portal to the cell's nucleus
16.03.2018 | Rockefeller University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Locomotion control with photopigments

Researchers from Göttingen University discover additional function of opsins

Animal photoreceptors capture light with photopigments. Researchers from the University of Göttingen have now discovered that these photopigments fulfill an...

Im Focus: Surveying the Arctic: Tracking down carbon particles

Researchers embark on aerial campaign over Northeast Greenland

On 15 March, the AWI research aeroplane Polar 5 will depart for Greenland. Concentrating on the furthest northeast region of the island, an international team...

Im Focus: Unique Insights into the Antarctic Ice Shelf System

Data collected on ocean-ice interactions in the little-researched regions of the far south

The world’s second-largest ice shelf was the destination for a Polarstern expedition that ended in Punta Arenas, Chile on 14th March 2018. Oceanographers from...

Im Focus: ILA 2018: Laser alternative to hexavalent chromium coating

At the 2018 ILA Berlin Air Show from April 25–29, the Fraunhofer Institute for Laser Technology ILT is showcasing extreme high-speed Laser Material Deposition (EHLA): A video documents how for metal components that are highly loaded, EHLA has already proved itself as an alternative to hard chrome plating, which is now allowed only under special conditions.

When the EU restricted the use of hexavalent chromium compounds to special applications requiring authorization, the move prompted a rethink in the surface...

Im Focus: Radar for navigation support from autonomous flying drones

At the ILA Berlin, hall 4, booth 202, Fraunhofer FHR will present two radar sensors for navigation support of drones. The sensors are valuable components in the implementation of autonomous flying drones: they function as obstacle detectors to prevent collisions. Radar sensors also operate reliably in restricted visibility, e.g. in foggy or dusty conditions. Due to their ability to measure distances with high precision, the radar sensors can also be used as altimeters when other sources of information such as barometers or GPS are not available or cannot operate optimally.

Drones play an increasingly important role in the area of logistics and services. Well-known logistic companies place great hope in these compact, aerial...

All Focus news of the innovation-report >>>



Industry & Economy
Event News

Ultrafast Wireless and Chip Design at the DATE Conference in Dresden

16.03.2018 | Event News

International Tinnitus Conference of the Tinnitus Research Initiative in Regensburg

13.03.2018 | Event News

International Virtual Reality Conference “IEEE VR 2018” comes to Reutlingen, Germany

08.03.2018 | Event News

Latest News

Wandering greenhouse gas

16.03.2018 | Earth Sciences

'Frequency combs' ID chemicals within the mid-infrared spectral region

16.03.2018 | Physics and Astronomy

Biologists unravel another mystery of what makes DNA go 'loopy'

16.03.2018 | Life Sciences

Science & Research
Overview of more VideoLinks >>>