[Annelida] An answer to an age-old earthworm question
(by romunov from gmail.com)
Wed May 21 23:56:26 EST 2008
We've been told at our U that the rain excursions can also be the result of
overcrowdness. When I was confronted with this question during the course of
lectures, the oxygen hypothesis seemed the most intuitive. I would, of
course, love to read a paper discussing territorial behavior between
On Thu, May 22, 2008 at 6:41 AM, Geoff Read <g.read from niwa.co.nz> wrote:
> "Why do those foolish earthworms venture out of their safe burrows and get
> washed down my garden path overnight," Mr Darwin asked himself. He scratched
> in his beard thoughtfully. "And will they ever adapt to the built
> environment? Well, time will tell I suppose. Best get on with the blasted
> Chuang, Shu-Chun & Chen, Jiun Hong. (2008) Role of diurnal rhythm of oxygen
> consumption in emergence from soil at night after heavy rain by earthworms.
> Invertebrate Biology, 127, 80-86.
> doi:10.1111/j.1744-7410.2007.00117.x Reprint author: chenjh from ntu.edu.tw
> Two species of earthworms were used to unravel why some earthworm species
> crawl out of the soil at night after heavy rain. Specimens of Amynthas
> gracilis, which show this behavior, were found to have poor tolerance to
> water immersion and a diurnal rhythm of oxygen consumption, using more
> oxygen at night than during the day. The other species, Pontoscolex
> corethrurus, survived longer under water and was never observed to crawl out
> of the soil after heavy rain; its oxygen consumption was not only lower than
> that of A. gracilis but also lacked a diurnal rhythm. Accordingly, we
> suggest that earthworms have at least two types of physical strategies to
> deal with water immersion and attendant oxygen depletion of the soil. The
> first is represented by A. gracilis; they crawl out of the waterlogged soil,
> especially at night when their oxygen consumption increases. The other
> strategy, shown by P. corethrurus, allows the earthworms to survive at a
> lower concentration of oxygen due to lo!
> wer consumption; these worms can therefore remain longer in oxygen-poor
> conditions, and never crawl out of the soil after heavy rain.
> Geoff Read <g.read from niwa.co.nz>
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