Flies

Remove all ads!

Do flies breathe? How? Erm, what do they use to breathe with?

 

Skin, most insects use there skin as a way to asimilate "air"

 

If you define "breathe" as "taking up oxygen", then yes, they do. If you define breathing as having a specialised organ for gas exchange (such as lungs for us, gills for fish, and so on), then no, they don't "breathe" per se.

Insects in general don't have "blood". Their equivalent of it, called hemolymph, flows through the entire body, rather than being confined into "vessels", which is the reason the whole system is called an "open circulatory system" (humans and all other vertebrates have a "closed circulatory system" because blood is confined to vessels). This allows the hemolymph to permeate nearly everything in their body. Insects also have little (well, microscopic really) pockets on their skin surface, through which air can go in and oxygen dissolves into the hemolymph.

Therefore you could say flies have respiration (exchange of gas between the body and the outside), but not breathing (no specialised organs, no inhale/exhale, and so on).

 

*blink* Ziad, you need to get out more. And thanks for answering a question that plagued my childhood.

I didn't think insects had lungs, but for the life of me, I couldn't figure out how they could drown!

 

Another somewhat related question:

Why aren't insects any bigger than they are? I know of some moths which grows to be as big as bats, but are anyone bigger than that?

 

The largest moth and butterfly have a wing span of 30cm, but a big insect has trouble breathing and keeping cool.

 

I was always told that insects weren't any bigger for exactly the reason that Ziad laid out. Namely, that if you breath through your skin, you need a fairly low surface area to volume ratio (otherwise you wouldn't have enough skin to provide oxygen to your whole body). As any object gets bigger, its surface area is squared, but its volume is cubed, so that ratio gets unsustainably high very quickly. Even a mouse sized insect would have a hard time getting enough oxygen. You need lungs to be able to grow any bigger (because lungs have a huge surface area with their little pockets).

 

That's really interresting! I never knew any of this!

 

Ooh... smart asking this here - I actually wondered the same thing before. Funny, how something as fundamental to our physiology can be completely different in something that lives in the same biological environment...

 

You can find the answer to almost any question at SP! I should know, because it's usually me doing the asking.

 

@Mollusken

Actually the biggest insect in record is a Walking Stick, is found in south Asia and is about 21.8 inches long (55.5 cm).

 

big? there is a point or reason of getting big. For insects, small is better that big.

Advantages of being small
1 - fast grow rate => fast reproduction rate. Insect reproduction is quantity over quality.
2 - Don't need to eat or drink as much.
3 - easy to hide and escape.


if i might add,
hemocoel ~= blood vessel
hemolymph ~= blood
BUT, hemolymph has nothing to do with oxygen exchange. Insects have a whole seperated "organ" for oxygen exchange - trachea.

Trachea is a network of tube across everywhere of insects. Everywhere that need oxygen that is. So, we have lung that exchange oxgen and CO2 and we use blood to send oxgen to body and CO2 to lung. Insects, with trachea, exchange gas directly. One end of this tube connects to the cells, the other end, opens directly to outside. You can see these openings with magnifying glass at the abdomen of your average grasshopper. As you can see, this direct exchange is not really efficient for large body organism.

As for gas exchange. Laws of Thermodynamics dictate that "stuff" in a concentrated area will move to less concentrated area, i.e. diffusing. When a cell undergoes metabolism, it uses oxygen, and produces carbon dioxide. Oxygen concentration goes down, carbon dioxide concentration goes up. So, in a concentrated environment, carbon dioxide will try to move out of that cell. And the vessel outside with highier concentration of oxgen will move in. All these happens "naturally", without the need to use energy.

i can keep on and on and on. i study biology, in general. interested in entomology, semi-spefically.

 

So, is it very cruel of me to drop live insects in the toilet and put a sheet of toilet paper over them? I like to give free shrouds with every burial at sea.

 

What? You smash them against a wall or window, either with your bare hand or with a paper covering it. Then you take a/the paper, scrap the remains up and either throw them out the window or in the toilet. The trick is to smash the bug so that it dies, but doesn't create a mess on the object you smashed it.

I feel it is our duty to annihilate them before they solve their oxygen uptake problems and grow stronger...

 

Of course the Jews were eeeky too. That's why we sent them to a place to work together. Or just simply killed them before they ate our food.

 

@teekc - WTF?

Sometimes, the bug lives even after a good squishing. I will feel guilt for shrouding them. Again, thanks for the info about how flies breathe.

 

ahhhh well, the whole story, and you and anyone for that matter have to forgive my sexist, size-ist comment,

let's imagine on a beach, good view, great girls with bikini, then suddenly a reeeeally fat girl with bikini, naturally i would be disgusted by the "view". Why, i don't know. Then i thought of the nazism in ww2. isn't that the same thing?

Oh, on the usefulness of insects,

Australia, the semi-new world, you know how imported cattle is to the austrlians. The problem was, these cattle produced enormous amount of dung that disrupt the growth of grass. No grass to feed cattle = no cattle. To slove the problem, one has to slove the origin of the problem, i.e. the cow dung. Then they imported dung beetle. dude, those dung rolling bugs roll dung. Because the dung bettles were able to roll dung, they effectively processed the dung and slove the "dung problem" in Australia. The moral of the story, only 1% of all insects are considered pests, either transmitting disease or competing food or fiber with human.

by the way kuemper you live in iowa city yes?
i study entomology in ISU. There is a whole entomology department in isu.

[ May 09, 2006, 22:48: Message edited by: teekc ]

 

Removed by me

[ May 09, 2006, 21:17: Message edited by: DarkStrider ]

 

Um, this will (probably) make me look dumb, but do flies grow hugely in size? I'm talking about 3-4 inches long. I've seen horseflies, which are flies on steroids. I remember from my swimming pool days about 20 years ago seeing this huge fly in the pool. Was it a fly or another bug?

I'm asking because I just saw a CSI episode where they showed a grown cicada and it looked like the giant fly from my kidhood.