At 01:05 PM 3/27/99 -0500, you wrote:
>Andrew Vik
>Tampa, FL., USA.
>liavik@earthlink,net
>
>Harry:
>
>I had heard from Phil Poland that you are interested in sinistrals.
 
Accurate; perhaps understated.
 
 
Has anyone
>tried dissecting a live egg case and raising the few sinistrals in an aquarium?
 
Not that I know of.  This is not far-fetched; its doable!
 
 
>Why aren't sinistrals more common?
 
Let me consider your question to relate to mutant reversals rather than
"sinistrals."  The answer is may be something akin to: "If it ain't broke,
don't fix it."
 
 
Are they physically incompatible with the
>dextrals when attempting copulation?  I have seen certain pulmonate species
which
>have 50% dextral, 50% sinistral populations. Is this because they are
>hermaphroditic, and thus better able to pass on their sinistral genes?
 
This incompatability is real (and observable).  The hermaphroditic pulmonate
taxa with amphidromine (mixed dextral-sinistral) populations are, for the
most part, obligate cross-fertilizers and are effectively unable to
self-fertilize or efficiently mate with oppositely-coiled partners.  So the
situation is a bit more complex than we would like it.
 
>Andrew
>
>
>Harry G. Lee, MD wrote:
>
>> Dear Questionman,
>>
>> Two interesting observations come to mind:
>>
>> Firstly on the subject of shell aberrations being associated with a
>> selective disadvantage for mollusk within:  I once "dissected" a stranded
>> egg-case of Busycotypus canaliculatus (Linnaeus, 1758) and counted about 800
>> (dead, dried) embryos.  Three had sinistral shells.  The late Bob Wagner had
>> a similar experience in an (unpublished) experiment with the same species.
>> The frequency of reversed B. canaliculatus adults is much, much lower, I
>> only know of two shells (among perhaps hundreds of thousands) - both
>> accounted for by Paul Monfils.  I think it is safe to conclude that the
>> sinistral condition Bob and I observed was mighty sublethal.
>>
>> As regards shell-less mollusks:  There are a few reports of sinistral (soft
>> parts anatomically reversed) adult pulmonate slugs - just like their
>> healthy-appearing testaceous relatives.
>>
>> Harry
Harry G. Lee
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Suite 500, 1801 Barrs Street
Jacksonville, FL  32204
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Visit the Jacksonville Shell Club Home Page at:
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