How to get rid of ticks and knats

[Salivanto]

Oh, and Martha, this is interesting too...insects breath or absorb oxygen though their skin.

I was going to reply to Martha too... and while we're correcting people's spelling, I figure I'l try to clarify a few things even though it has nothing to do with camping and will probably cost me any friends I've made here.

While some animals can breathe through their skin (frogs, for example), I don't believe that ticks do. Insects have a hard skin which is not suitable as a breathing membrane. They have a series of air holes in their abdomen and a network of tubes through their bodies.

Millions of years ago when the oxygen levels were much, much higher on the planet. Insects where GIGANTIC!! Yup, There used to be dragonflies with wingspans of 3 Feet. Wow, huh?

It is true that there were large insects, but I'm not ready to accept that it's oxygen levels which determines insect size. I haven't looked it up, but my understanding is that oxygen levels are still increasing, as more carbon sinks to the bottom of the ocean and becomes coal.

and in anothr message you wrote:

Know that Knat is on my Knee" Why the G in this case???

Actually, there are a number of words which start with KN or GN. The difference usually has to do with how the words were pronounced hundreds of years ago.

To bring the topic back around, I recall that when my friend got married (in the woods of New Hampshire) I noticed what I thought was a spider on my leg. With great joy I declared "oh look, an arachnid has come to visit." I then recognized that it was an arachnid, but not a spider. It was a tick. I was not at all delighted any more and flicked that dang thing away.

[asianflava]

Millions of years ago when the oxygen levels were much, much higher on the planet. Insects where GIGANTIC!! Yup, There used to be dragonflies with wingspans of 3 Feet. Wow, huh?

It is true that there were large insects, but I'm not ready to accept that it's oxygen levels which determines insect size. I haven't looked it up, but my understanding is that oxygen levels are still increasing, as more carbon sinks to the bottom of the ocean and becomes coal.

I've heard or read somewhere (I don't remember) that an insect's size is limited due to it's exoskeleton. It's weight would grow exponentially in relation to it's size. Or something like that.

[mfkaplan]

This is a bit of insect trivia. I looked for a link that explained this in simple terms but they were all pretty technical. Historically oxygen levels on earth have gone up and down. During the time of the giant insects the oxygen level was 35%, during the time of the dinosaurs, it dropped to 15%. Today's level is about 20%. Insects breathe through a network of little air tubes that run through their bodies including down their legs. That little line of what looks like holes down the sides of their bodies is where the air goes in. They really don't circulate oxygen through their blood like we do. Lower oxygen levels means bigger tubes are needed to get enough oxygen to the cells. Bigger tubes mean no room for other needed body parts like muscles, etc. Yes, insects have muscles. High oxygen levels mean the tubes can remain small and the insect has lots of room for other needed inside body parts. It also means it can get bigger and still get enough oxygen.

[Salivanto]

If there's interest in giant insects, we can start a thread in the off-topic section. This is just to say thanks for the informative replies. I just found an article from MSNBC which discusses the problem somewhat.

http://www.msnbc.msn.com/id/15223856/

I guess I stand corrected, or at least partially so.

BTW, the exoskeleton explanation is a common one, but since great thinkers like Richard Dawkins have questions about it, I will withhold judgement. The oxygen explanation has a lot to go for it.

Now I've got to find out why the oxygen levels change. See you in the off topic section.