• TONMOCON VII Announced | MBL at Woods Hole | Apr 6-8, 2018
  • Thanks for visiting! TONMO is the world's greatest online cephalopod enthusiast community, with interactive content going back to May of 2000, and a biennial conference. If you'd like to join in on the fun, become a TONMO member -- it's easy and free. You can follow us on Facebook and Twitter for more cephy goodness.


chirality of snail shells and survival

monty

TONMO Supporter
Staff member
Supporter
Joined
Mar 8, 2004
Messages
4,887
#1
This BBC article (and probably the underlying paper, which I haven't dug up yet) are probably of interest to some of you, even though it's not directly ceph-related... wasn't sure if here or "fossils and history" is the best place for it, since non-planar shells aren't found on any living cephs (maybe argonauta?)...

http://news.bbc.co.uk/2/hi/science/nature/4831218.stm
 

Euprymna

O. vulgaris
Registered
Joined
Jul 13, 2004
Messages
97
#2
Yeah, very interesting indeed!
My initial thoughts when reading was obviously that if these left handed shells were immune to crab predation, the whelk population would slowly shift towards all left handed whelks but no!! why would left handed shells be less successful in finding a mate, aren't they broadcast spawners anyway? mmmm...have to dig that paper to (monty any success?)

eups
 

main_board

Vampyroteuthis
Supporter
Joined
Feb 5, 2003
Messages
373
#3
I know of some snails that have to, um, 'mount' each other (for lack of a better word, not sure what to call it with gastropods) in order to fertilize the eggs. Perhaps this is more challenging if your holes aren't on the same side of the shell. Seems to make sense. I mean snail aren't the most flexible of creatures. Very interesting article and discovery.

Cheers!
 

Euprymna

O. vulgaris
Registered
Joined
Jul 13, 2004
Messages
97
#4
Yeah right, it makes sense.
However, I would still guess that IF these crabs were the only predators, in the long they would be removing the right handed individuals out of the population, hence the probability that two left handed ones meet and mate would increases and eventually lead to a population dominated by the left handed freaks.
I should read the original paper but from this article it seems that they assume the crab predation to be the only parameter putting pressure on the whelk population. Surely, there are other predators that have no problem in consuming left-handed whelks (such as shell drilling octopuses maybe?? :twisted:) and these would also affects the dynamic of the whelk population...
just a thought!

eups
 

Fujisawas Sake

Larger Pacific Striped Octopus
Supporter
Joined
Dec 24, 2002
Messages
1,169
#5
Aye, dude, you beat me to the punch about the sinistral snails! ;)

Wow! That's actually quite interesting. It makes for an interesting case for predator-prey interactions. Now for a satisfactory explanation on torsion....

John
 

um...

Architeuthis
Supporter
Joined
Sep 5, 2003
Messages
1,968
#6
What's the story from a developmental point of view, I wonder? How does the sinistrality arise? Does the required aberrance in development have side effects that are selected against, either internally or externally?
 

Fujisawas Sake

Larger Pacific Striped Octopus
Supporter
Joined
Dec 24, 2002
Messages
1,169
#7
I think it has something to do with the chemistry of shell formation, and how the respective genes are expressed in said formation. I think the "handedness" of the shell could also be affected by the "handedness" of the populations of snail predators as well.

just my :twocents:

John
 

cuttlegirl

Colossal Squid
Registered
Joined
Sep 16, 2005
Messages
4,930
Location
Pittsburgh, PA
#8

Jean

Colossal Squid
Supporter
Joined
Nov 19, 2002
Messages
4,218
Location
Dunedin, New Zealand
#9
Fujisawas Sake said:
I think it has something to do with the chemistry of shell formation, and how the respective genes are expressed in said formation. I think the "handedness" of the shell could also be affected by the "handedness" of the populations of snail predators as well.

just my :twocents:

John
Although some won't care! We have a number of shell boring whelks that will bore through the shell whereever on another gastropod (they're more discriminating on bivalves and bore at the adductor muscle!) and our wrasses eat the gastros shell and all!!!

J
 

Members online

No members online now.