The Straight Dope

Go Back   Straight Dope Message Board > Main > General Questions

Reply
 
Thread Tools Display Modes
  #1  
Old 07-17-1999, 01:49 AM
Guest
 
Why don't ants like chalk (calcium carbonate)? If you find an ant on a sidewalk, and draw a circle around it (the ant) with a piece of chalk, the ant will not cross the line (at least not immediately).

O.K.... let's get this out of the way.... Yes, I do have too much time on my hands.
Reply With Quote
Advertisements  
  #2  
Old 07-17-1999, 07:24 AM
Guest
 
How about we draw a circle around Steve-o?
Reply With Quote
  #3  
Old 07-17-1999, 08:42 AM
Guest
 
- - - The book I read this in said that ants don't seem to like crossing white lines and offered the example of chalk - it just happens to be a common way of making a white line somewhere ants are likely to be found. I haven't tried it with anything else. - MC
Reply With Quote
  #4  
Old 07-17-1999, 11:31 AM
Guest
 
Yeah.... but.... if you draw a circle around me.... how am I supposed to go to work? Hmmm.... perhaps I'm starting to like that idea.

As for ants not wanting to cross any white line, I wonder... Surely they cannot actually see that the line is white (or can they). Perhaps it is that the white line's reflection of light makes the line appear bright, and evolution has taught ants not to walk into bright things (such as fire, or concentrated light from magnifying glasses (pop!)). I have quite a few ants around my house, so I think I will do some experimenting.
Reply With Quote
  #5  
Old 07-17-1999, 12:25 PM
Guest
 
Ants find their way by marking their paths with scent trails. Possibly, when you draw a line around the ant, you're disrupting that trail, and the ant has to look harder to find it.
Reply With Quote
  #6  
Old 07-17-1999, 12:43 PM
Guest
 
Lissa -

That had occurred to me during my original experimenting, so I procured an ant trap (piece of paper for it to crawl on), and captured the beast. I then transported it to a remote location (further down the sidewalk), and released the creature into a previously drawn circle of chalk. After about 2 minutes, the ant did cross the line, but up 'till it crossed the line, it turned around each time it came to the line. I thought that what probably happened is that it was marking its trail inside the circle, and finally "realized" (after crossing his own trail several times) that it was trapped. At this point it had no "choice" but to cross the line.

By the way, when that dang ant crossed the line, I had to put my foot down. Bwahhahaha
Reply With Quote
  #7  
Old 07-18-1999, 12:09 AM
Guest
 
Isn't this how Dahmer got started?
Reply With Quote
  #8  
Old 07-18-1999, 01:17 AM
Guest
 
My theory is that the chalk particles are abrasive. I know that you can use diatomaceous earth as a pesticide, and the way it works is that its tiny particle invade the bugs' bodies and abrade them to death. Chalk seems very similar to diatomaceous earth in that it is made up of relatively large particles which could scratch an ant up pretty bad if it got in the wrong place -- kinda like sand in the old swimsuit, if you follow my meaning.

------------------
President of the Vernon Dent fan club.
Reply With Quote
  #9  
Old 07-19-1999, 03:26 PM
Guest
 
Quote:
Isn't this how Dahmer got started?
Nah, Nick. I, too, used to think humans could not get out of a chalk outline. Then I found out that the chalk lines were drawn around those bodies after they were dead. The police do it. Dahmer must have killed them some other way.

------------------
The overwhelming majority of people have more than the average (mean) number of legs. -- E. Grebenik
Reply With Quote
  #10  
Old 07-19-1999, 03:49 PM
Guest
 
Back when I worked at a student store, we always used talcom powder to stop ants in places where we didn't want to use poison. Our working theory was that the powder was like small, loose rocks to the ants, and they had trouble crossing without stumbling. Now that I think of it, that sounds like a pretty stupid theory.
Reply With Quote
  #11  
Old 07-19-1999, 04:14 PM
Guest
 
It's probably a combination of things. Ants can see the lines, but I'd bet they would behave the same even in pitch darkness. Also, there are any number of substances that would cause the same basic response - that is, hesitancy to continue moving in that direction. That sort of hesitation does not *necessarily* mean that they are repelled by chalk, though the idea that chalk works like diatomaceous earth is probably a pretty good theory, since that is pretty much what chalk is, except just the marine equivalent (full of shells of foraminifera, radiolarians, etc.). Gets into the breathing passages and wreaks havoc.
Reply With Quote
  #12  
Old 07-20-1999, 10:47 AM
Guest
 
I think Doug Yanega is on the right track when he suggests that chalk gets into the breathing passages and wreaks havoc.

As I understand it, rather than a thick bark for protection, aspen trees instead developed a coating of fine white powder. The powder protects the tree from invading bugs by clogging the little critters’ air passages, which in many species are located on their undersides. Rather than a tasty aspen treat, the insects get death by asphyxiation.

Perhaps chalk does the same thing.


------------------
~ Complacency is far more dangerous than outrage ~
Reply With Quote
Reply



Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 02:23 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.

Send questions for Cecil Adams to: cecil@chicagoreader.com

Send comments about this website to: webmaster@straightdope.com

Terms of Use / Privacy Policy

Advertise on the Straight Dope!
(Your direct line to thousands of the smartest, hippest people on the planet, plus a few total dipsticks.)

Publishers - interested in subscribing to the Straight Dope?
Write to: sdsubscriptions@chicagoreader.com.

Copyright © 2013 Sun-Times Media, LLC.