dejayM's picture

Dog Whelk (Nucella lapillus) egg capsules.

Observed: 6th April 2013 By: dejayM
Biological Recording In ScotlandHighland Biological Recording GroupOrkney Biodiversity Records Centre
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Maturing
Laying
Mini winkles
Description:

The post is related to http://www.ispot.org.uk/node/320809
These egg cases are quite mature - I'd say between 10 and 14 days (based on observed tide cycles). It seems that the eggs become mini-whelks after a few months.
Picture two shows a mother, which I have lifted to expose the process. I cannot explain the adjecent transluscent structures but they may be related to the process (of laying or protecting). I'd appreciate comments.
For the third picture see Comments.

Identifications
Species interactions

No interactions present.

Comments

dejayM's picture

Periwinkes

Origin 9 April 2013
The third picture appears to show Common Periwinkle (Littorina littorea) eggs. Though you should look here http://www.ispot.org.uk/node/320895 as Gramandy suggests clumps not strings.
In any case one has to wonder WHY there are such a huge structural difference between Winkles' and Whelks' eggs.
ðj
EDIT (revisit)
The eggs in jelly are still a mystery - Littorina littoria casts eggs directly into the sea "....in 1 mm wide, gelatinous, floating egg capsules, each containing usually 2-3 eggs, but sometimes up to 9 eggs."
http://www.exoticsguide.org/littorina_littorea

Littorina obtusata lays eggs in jelly but in rounded clumps not trails.
Now see http://www.ispotnature.org/node/321807

ChrisMcA's picture

In your 2nd photo it does

In your 2nd photo it does look like the dog whelk's laying some sticky stuff, but possibly 'twas another creature? On the common winkle, from my extensive knowledge (actually Collins seashore guide '96) the common & small winkle shed capsules into the sea (about 1mm wide) so it might be feeding. Other winkles shed larvae/juveniles, but these eggs could well be flat periwinkle L. obtusata (oval/kidney shaped jelly encased egg masses).

dejayM's picture

Looks flat

Thanks Chris
The second picture shows the capsules and structures upside-down - I turned the stone over to take picture. 'Stuff' can be seen on the shell too.
As for Flat Periwinkle - well it could be, it's flat enough (common or edible P is quite pointed).
I shall spend time tomorrow.
http://oceana.org/en/eu/home
... "Female common periwinkles release egg capsules, containing two or three eggs, directly into the water during the spring tides."
ðj