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Tuesday, March 17, 2015

Hauling in the net


A few years ago, I was excited to write about one of our local tube snails, Petaloconchus montereyensis.  (You can review that post from 11 June 2012).  

I mentioned that Petaloconchus produces mucus nets to capture food particles from the water.  Well, just last month, Eric caught some of their feeding behavior in a short video.

Before watching the video, it will be helpful to remember a few things:

Petaloconchus has two sets of tentacles: the cephalic tentacles are larger, darker, closer to the edge of the shell, and near their base, have a black spot, which is the eye.  The pedal tentacles are smaller, paler, and closer to the operculum (the round "trap-door").  Look for both types of tentacles in the photo below and in the video.  (The pedal tentacles help guide the mucus nets when feeding.)


To feed, Petaloconchus spreads a large mucus net into the water for capturing drifting particles.  Then they use their radula (tongue-like organ lined with rows of shiny teeth) to grasp the mucus net and haul it back into the mouth using a very rhythmic motion.  This is one of the behaviors highlighted in the video.




These tube snails are relatively small the largest tube openings are ~2 mm across  so Eric filmed them under a microscope.  Otherwise, it wouldn't be easy to observe this behavior and to watch these fascinating snails in action.  Thanks, Eric!

1 comment:

Leth Benz said...

In Moorea, the vermetids living in massive coral bommies create humungous mucus nets!

Also - my friends wrote a neat note about their ecology:
http://link.springer.com/article/10.1007/s00338-014-1141-6