[Annelida] Mole man (& others) test worm grunting harvest method

Geoff Read via annelida%40net.bio.net (by g.read from niwa.co.nz)
Thu Oct 16 01:15:20 EST 2008


Hi all,

Expect to see variations on this story about Diplocardia
mississippiensis, mole predation, and 'worm grunting' in your mainstream
news sources. 

Catania, K.C. (2008). Worm Grunting, Fiddling, and Charming - Humans
Unknowingly Mimic a Predator to Harvest Bait. PLoS ONE 3(10): e3472. 

Open access: http://dx.doi.org/10.1371%2Fjournal.pone.0003472 

pop backgrounder #1:
http://www.vanderbilt.edu/exploration/stories/wormgrunt.html 

pop backgrounder #2:
http://environment.newscientist.com/article/dn14940-how-bad-vibes-can-catch-you-a-worm.html

(There's a nice little Utube video with it - see the worms pop up when
the mole goes in!)


And remarkably there is this forthcoming paper:

Mitra, O.; Callaham, M.A.; Smith, M.L.; Yack, J.E. (2008). Grunting for
worms: seismic vibrations cause Diplocardia earthworms to emerge from
the soil. Biology Letters efirst. 

Subscriber access (not open to me):
http://dx.doi.org/10.1098/rsbl.2008.0456 

Abstract: "Harvesting earthworms by a practice called ‘worm
grunting’ is a widespread and profitable business in the
southeastern USA. Although a variety of techniques are used, most
involve rhythmically scraping a wooden stake driven into the ground,
with a flat metal object. A common assumption is that vibrations cause
the worms to surface, but this phenomenon has not been studied
experimentally. We demonstrate that Diplocardia earthworms emerge from
the soil within minutes following the onset of grunting. Broadband low
frequency (below 500Hz) pulsed vibrations were present in the soil
throughout the area where worms were harvested, and the number of worms
emerging decreased as the seismic signal decayed over distance. The
findings are discussed in relation to two hypotheses: that worms are
escaping vibrations caused by digging foragers and that worms are
surfacing in response to vibrations caused by falling rain.

There's online video for both papers. Both worked in Apalachicola
National Forest.






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