next message in archive
no next message in thread
previous message in archive
Index of Subjects
Hi Steve & All, Nov 19, 2009
Being not nearly as tidy as an earwig I still have that earwig ramp
gathering dust in the basement.
It consisted of two thin brassl plates; upper 10 mm wide & lower 13 mm
wide, transverse to a rigid, overhead, transparent plastic observation
housing/earwig passageway and spaced 1.5 mm apart on a lucite slab.
With the slab slightly inclined, when an earwig was placed into the
lower end of the passageway it would walk up the slope and have 4-5 feet on
the lower plate before the first foot contacted the upper plate to close the
circuit.
Being free to move forward, I think they just kept walking because the
4-5 hurting feet in back out-voted the one hurting foot in front. I don't
recall the details now but I likely turned the power off when they stopped
moving in an organized way and/or flopped over. They sure looked stunned to
me, as opposed to taking time out the think things over and learn something.
I remember that animal behavior fad well underway in the 50's within
which scientists tabulated all responses by experimental animals as some
mechanical response to some stimulus and, while keeping a straight face,
concluded that all animal behavior consists of mechanical responses to
stimuli.
Yt, Dave
----- Original Message -----
From: "Stephen Shaw" <srshaw@DAL.CA>
To: <naturens@chebucto.ns.ca>
Sent: Thursday, November 19, 2009 11:59 AM
Subject: Re: [NatureNS] shocking earwigs
> Hi Dave, Angus & all,
> Hello Dave -- they were probably not stunned and you almost managed to
> re-discover the `headless learning` insect preparation first uncovered by
> my
> old boss, back in St. Andrews, Scotland in the 60s (though he used
> cockroaches).
> This caused a stir at the time because very little was then known about
> the
> neural mechanisms behind any kind of learning, of great interest then as
> now:
> the search was on for a so-called `simple` system in which to elucidate
> these
> mechanisms at the level of single nerve cells, and this insect system
> looked
> promising to some at the time.
> To shock such an insect you need 2 electrodes connected through a switch
> to
> opposite terminals of a voltage or current source, as Dave says. If
> you tether
> the insect (to stop it running away) so that its front legs rest on one
> electrode and the body or the other legs touch the other electrode, then
> close
> the switch, a roach will immediately raise its front legs, so breaking the
> circuit and terminating the shock. The elevation lasts for a few seconds
> then
> the legs come down. After a few more such shocks, the roach keeps its
> legs up
> for longer periods (it has learned by association). This happens even with
> the
> head removed, showing that the changes reside in the thoracic nervous
> system,
> not the main brain. The ingenious part of this was the `yoked control` --
> the
> same current was sent also through a hapless second roach, which got the
> same
> number of zaps as the first, but these were now not related to its
> forelegs`
> position and so it failed to learn the `legs-up` trick.
> This fizzled out after a few years because no-one got very far with the
> single neuron approach in the thorax and much better preparations were
> discovered where this approach did work. Eric Kandel, who appears
> fairly often
> in science segments on Charlie Rose's midnight TV show on PBS, got the
> Nobel
> Prize a few years back for his work on learning in this area, but on
> different
> neural systems.
> So Dave, perhaps you might have got there first.
> Steve
>
>
> Quoting Angus MacLean <angusmcl@ns.sympatico.ca>:
>> Hi David:
>> Wow, David, quite the experiment. Now that I know how fastidious they
>> are about their appearance, I find myself changing my mind about
>> them! My wife thinks I would do well, in her eyes perhaps, to follow
>> their example more.
>> Thanks,
>> Angus
>>
>> At 10:27 AM 18/11/2009, you wrote:
>>> Hi Angus, Steve & al, Nov18, 2009
>>> The earwig thread prompted me to dig out an old e-mail to another
>>> site; pasted below.
>>>
>>> Abundant or sparse they must feed something else. No longer abundant
>>> here.
>>> DW
>>>
>>> START OF PASTE\\\\\\\\\\\\\\\\\
>>> Mar 9, 2003
>>> On a related note--
>>> Shortly after earwigs appeared in Kentville, and started taking over
>>> lawns & gardens, I wondered about the feasibility of an active earwig
>>> trap, i.e. using electric shock to herd them into traps, so I borrowed
>>> some scrap electronic components that when assembled formed a variable
>>> voltage and harmless low current power supply. To observe behavior when
>>> they were exposed to shocks, I made a small chute of lucite with thin
>>> brass strips spaced such that when an earwig walked along the chute it
>>> closed the circuit. I don't recall the voltages now but, at low voltage
>>> there was no response, at higher voltage they stepped lively and at even
>>> higher voltages tiny sparks from foot hairs could be seen in dim light,
>>> there was sometimes an odor of burning protein and/or earwigs were
>>> stunned and remained immobile for ~5-30 seconds. Their behavior after
>>> being shocked and especially after being stunned, convinced me 1) that
>>> earwigs were just small people with slightly different body parts and 2)
>>> that one should not herd earwigs by electric shocks even if a trap of
>>> this kind could be made to work.
>>> After they came to, they sat back so fore legs were free to move and
>>> laboriously groomed head, antennae and front leg joints (I can't recall
>>> with certainly that mid and hind legs were groomed) apparently using
>>> fluids from the mouth. After this bath, presumably to remove materials
>>> that are released from between joints when under stress, they would
>>> resume normal posture and walk off.
>>>
>>>
>>> Yours truly, Dave Webster, Kentville
>>> END OF PASTE\\\\\\\\\\\\\\\
>
>
>
>
>
--------------------------------------------------------------------------------
No virus found in this incoming message.
Checked by AVG - www.avg.com
Version: 8.5.421 / Virus Database: 270.14.69/2508 - Release Date: 11/17/09
07:40:00
next message in archive
no next message in thread
previous message in archive
Index of Subjects