Recently I came across a video about earthworms which had some great information about how the earthworm gets around in his environment.
What I found most interesting was the comment towards the end about the earthworms ability to regenerate. Now my understanding of this was yes earthworms can regenerate their bodies but only their tail section and only if the cut was far enough back. So to be sure of my information I did some investigation and this is was I found out.
Biology Junction Had this to say:
Q. Can earthworms regenerate themselves
A. Yes, but only the front or head end of the earthworm will survive and the amputated tail portion will die. This remaining front portion must also be long enough to contain the clitellum and at least 10 segments behind the clitellum. This makes up about half the length of the worm. The new posterior segments grown will be slightly smaller in diameter than the original segments and sometimes a bit lighter in color.
Now Wikipedia had a bit more to say on the subject, and apparently the powers of regeneration can vary quite a lot from species to species:
A. Earthworms have the ability to regenerate lost segments, but this ability varies between species and depends on the extent of the damage. Stephenson (1930) devoted a chapter of his monograph to this topic, while G.E. Gates spent 20 years studying regeneration in a variety of species, but “because little interest was shown”, Gates (1972) only published a few of his findings that, nevertheless, show it is theoretically possible to grow two whole worms from a bisected specimen in certain species. Despite denial of this phenomenon by some current experts, Gates’s reports included:
- Eisenia fetida (Savigny, 1826) with head regeneration, in an anterior direction, possible at each intersegmental level back to and including 23/24, while tails were regenerated at any levels behind 20/21, i.e., two worms may grow from one.
- Lumbricus terrestris Linnaeus, 1758 replacing anterior segments from as far back as 13/14 and 16/17 but tail regeneration was never found.
- Perionyx excavatus Perrier, 1872 readily regenerated lost parts of the body, in an anterior direction from as far back as 17/18, and in a posterior direction as far forward as 20/21.
- Lampito mauritii Kinberg, 1867 with regeneration in anterior direction at all levels back to 25/26 and tail regeneration from 30/31; head regeneration was sometimes believed to be caused by internal amputation resulting from Sarcophaga sp. larval infestation.
- Criodrilus lacuum Hoffmeister, 1845 also has prodigious regenerative capacity with ‘head’ regeneration from as far back as 40/41.
So it is apparent that the earthworms ability to regenerate will vary depending on the species. An interesting article written by The Telegraph, back in April 2010, shows how scientists are now beginning to understand the earthworms ability to regenerate.
The research into how Planarian worms can regrow body parts – including a whole head and brain – could one day make it possible to regenerate old or damaged human organs and tissues, the University of Nottingham said.
The research, led by Dr Aziz Aboobaker, a Research Councils UK Fellow in the university’s School of Biology, shows a gene called ”Smed-prep” is essential for correctly regenerating a head and brain in Planarian worms.
The worms have the unusual ability to regenerate body parts, including a head and brain, following amputation.They contain adult stem cells that are constantly dividing and can become all of the missing cell types….read the full article here.
To finish i was going to show you the video that first sparked my interest in earthworm regeneration but for some reason it has been removed for infringement of copyright notice so that will not be happening, but instead I would like to leave you with an excerpt from the the ever popular BBC series Life On Earth presented by David Attenborough. What this shows you is the extreme end of earthworms….The Giant Earthworm.