Why Aren't There Giant Insects?

Hank and physiologist Jon Harrison discuss the question of insect size and major theories that attempt to explain why there is a limit to how large insects can get with current conditions on Earth.

#SciShow #bugs
References

[RAGEAlanBun]

Could an artificial environment be created to represent the atmosphere and oxygen levels 30 million years ago? I don't know how long it would take but since most insects breed extremely quickly compared to mammals, over a long period of time we might be able to test whether or not this affects insect size.

Not that I'm particularly advocating massive insects or anything, I'd rather not have to question whether or not it's physically possible to ride a cricket through the skies at any point in my life.

[Owelzilla]

nah man, bugs getting smaller woudnt be a good thing, u wont see them comming :O

[dantereal]

i want a giant dragonfly as a pet. one with a body size of about 0.5 meters long that would eat all the annoying spiders around the house. i would name him "flygon"

[jackiez]

All I can hear is that.
WE'RE RUNNING OUT OF AIR

[dierderikd]

no giant insects? have you ever been to Australia?

[MajoraZ]

I remember seeing a program that raised various arthropods in high oxygen conditions, and the resulting individuals ended up being anywhere from 20% to 300% larger then the average individual in normal oxygen levels.

[ManintheArmor]

I prefer bigger insects so they're easier to see. :P

[Bozterror]

The oxygen theory sounds good. I feel like there would be ways to test it tho. For example keeping a insect in a high oxygen environment but pick a insect that has a short life span with fast reproduction cycle. This will simulate multiple generations of said insect in a high oxygen environment which from there can be studied. I only have experience with this in plants and bacterial work that I do but feel it might be harder for the insect experiment due to the complexity of organism compared to plants and bacteria which im used to.

[marquiniopinio]

What if we put bugs in a sealed chamber with 32% oxygen? Wouldn't that be a good test for the oxygen delivery theory? May be expensive but It's not like we are sending bugs to space or something...

[ewan.cartwright]

Really? I would much prefer huge insects you could marvel at and go 'woah, that's really cool' to tiny little ones crawling about everywhere, into your food and various bodily cavities.

[KawaiiKemonomimi]

These ideas have been bounced around a lot on the arachnoboards. I love videos like this!

[mothman]

So if I catch a grasshopper and place it into a sealed glass tank, then pump 100% pure oxagen into the tank while it is still in the growing stages of life, it will become the size of a small dog?  I must try this.

[tegan]

"as Gregor samsa awoke one morning from uneasy dreans he found himself transformed in his bed into a giant insect"

[warywolfen]

Back in the late 90s, I saw, clinging to the side of a tree, a giant moth. It had the brownish-grey coloration of a normal moth, and its wings were folded in a triangular shape, like that of a regular moth. But its wingspan, at its wing tips, was 6--8 inches! It then took to flight, and looked more like a bird in the way it flapped its wings. I later learned that moths like these are native to Southeast Asia. I guess that some hitched a ride on a cargo ship, and made it to the U.S.

[huitzilopochli]

Q:Why aren't there giant bugs
A:NOPE!Dont know don't care

[lenny]

dude I want a dog sized spider to guard my house :3 imagine how fluffy and cute it would be

[crazycatperson]

When I was little I thought the world was encased in a bubble, and giant wasps would get into the bubble and take me away and sting me to death. Still gives me goosebumps.

[valken]

Smaller insects are harder to kill, Hank was not so smart on this one.

[TomyLobo]

Don't say "just a theory", Hank.

[liljozee]

I also heard that one possible explanation to this fact is that if insects were larger, as they don't have a myelin sheath surrounding their nerves (which permits the acceleration of the neural transmission), would need to have enormously large nerves to "keep up" in regards to smaller insects.
Great video BTW!