Earthworm group

Earthworm group

Earthworm Group (Elphinstone College)

So Ritik and me are working on the simple model organism, Earthworms (species: Eisenia fetida)

Long term objective:

To study nerve cord regeneration in earthworms. So we do this particular assay called Rapid Escape Response (RER). So in this assay, we take an earthworm and two Testubes one contains distilled water and the other one contains 200mM solution of NaCl and we put a timer for 2 minutes. And we introduce the earthworm first in distilled water testtube.
And then if the earthworm does not come out in 2min. Then we introduce it in the salt solution.

So our expectations are that the earthworm will not come out of the distilled water TT (testube). And it will come out of the NaCl soln TT.


Since distilled water does not have any ions it does not irritate the earthworm but since NaCl soln has has Sodium and chloride ions it irritates the earthworm hence the earthworm
comes out under 2 mins. So we have done many rounds of RER It mainly helps us to check whether the earthworm’s nerve cord is intact or not for further experiments

So after the RER we gave lesion on 17th of April

  1. 4 earthworms for dorsal cut
  2. 4 earthworms for ventral cut (control setup)
  3. 4 earthworms for normal earthworms (control setup)

On giving lesion we see that the ventral cut earthworms are not able to climb out of the NaCl TT. But after 48hrs the earthworms regenerate.



Why the design has distilled water and why only 200 mM NaCl solution…

What makes it part of the experimental design …

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@Vaibhavib99 Good to see post on experimentation …

I also request Cubists to discuss about your experimentation …

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Since distilled water is deficient of any ions it is used as a control set up to compare with the NaCl testube and we tried with 1M Nacl but some earthworms died so we tried with a weaker concentration which will be enough to get a response from the earthworms


Reading all the cubist’s posts is so interesting.


@Vaibhavib99 can you explain what do you mean by regeneration? How your Rapid escape response assay is helpful to study regeneration?

What is the response of control setup without lesion? Have you standardized it?

Please post some photos/videos as evidence…

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So… why do you say distilled water acts as control… N the control is against what… first of all why should there be a control in an experiment…

Even if I accept that distilled water is control then what is NaCl solution acting as …

Also you have to convince me how you arrived at 200mM concentration right after 1M concentration… Why not 800mM , or 500 mM or even 100nM…

To the group members: please think what is NaCl used for or used as in the experiment…

If it’s an experiment, what parameters it should have…

An interesting article to read.

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