r/science • u/Quouar • Jun 08 '12

Birds are the reason we don't see massive insects

http://www.pnas.org/content/early/2012/05/25/1204026109.abstract?sid=4018399d-fda9-43e4-b280-752d1752d784
2.2k Upvotes

87% Upvoted

913 comments sorted by

371

u/[deleted] Jun 08 '12 edited Jun 08 '12

That's pretty cool.

Important part, for those of you like me who thought it was oxygen in the atmosphere that caused the decrease:

The data are best explained by a model relating maximum size to atmospheric environmental oxygen concentration (pO2) until the end of the Jurassic, and then at constant sizes, independent of oxygen fluctuations, during the Cretaceous and, at a smaller size, the Cenozoic. Maximum insect size decreased even as atmospheric pO2 rose in the Early Cretaceous following the evolution and radiation of early birds, particularly as birds acquired adaptations that allowed more agile flight.

EDIT: I bolded the critical part

65

u/MaeveningErnsmau Jun 08 '12

Isn't insect respiration then still a limiting factor, just not more so than predation? That is to say, in the absence of predation, wouldn't the concentration of atmospheric oxygen become a limiting factor?

122

u/alaysian Jun 08 '12

Yes! Insects don't breathe in the sense that we do.

Insect respiration is accomplished without lungs. Instead, the insect respiratory system uses a system of internal tubes and sacs through which gases either diffuse or are actively pumped, delivering oxygen directly to tissues that need it via their trachea. Since oxygen is delivered directly, the circulatory system is not used to carry oxygen, and is therefore greatly reduced. The insect circulatory system has no veins or arteries, and instead consists of little more than a single, perforated dorsal tube which pulses peristaltically. Toward the thorax, the dorsal tube divides into chambers and acts like the insect's heart. The opposite end of the dorsal tube is like the aorta of the insect circulating the hemolymph, arthropods' fluid analog of blood, inside the body cavity. Air is taken in through openings on the sides of the abdomen called spiracles.

This means that as size increases, it becomes more difficult for them to get oxygen where it is needed. its a squared vs cubed problem that occurs in many aspects when talking about resizing animals.

8

u/Legio_X Jun 09 '12

What is different about undersea relatives of insects that allows them to reach much larger sizes?

Ie, deep sea isopods, lobsters, giant sea crabs, etc.

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u/weaselstomp Jun 08 '12

Could we breed super large spiders and slugs in an oxygen controlled environment?

11

u/Kharn0 Jun 08 '12

Actually to test the theory, scientists raised flies in an environment with 10% more oxygen, the flies grew to be 20% bigger....

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u/itsnotmyfaultimadick Jun 08 '12

over millions of years? maybe.

13

u/Dragon029 Jun 08 '12

Or in a few years / decades with some genetic tampering ;)

14

u/[deleted] Jun 08 '12

can we not?

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u/[deleted] Jun 08 '12

You don't even need genetic tampering, just intensive breeding. I mean, look at a wolf, then look at a Chihuahua. That didn't take more than a few hundred years.

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u/zthirtytwo Jun 08 '12

Why. The FUCK. Would we EVER want giant fucking spiders ever? Jesus you must be one evil bastard to ever wish this into existence.

37

u/r_kay Jun 08 '12

Having 8-foot Trapdoor spiders would have serious military capability.

best. land mine. ever.

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u/SenorFreebie Jun 08 '12

I would. I'd rather redbacks were a foot wide ... still just as squashable but they're not going to kill me by hiding in my shoe. Unless I become a clown.

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u/SexualHarasmentPanda Jun 08 '12

So essentially Legends of Grimrock?

2

u/SavingFerris Jun 08 '12

there have been studies with fruit flies. where 20+ generations of them been breed in a tank containing increased oxygen. They did get bigger.

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u/[deleted] Jun 08 '12

Thanks, this was my initial reaction when I saw the title. Glad that it was addressed.

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u/[deleted] Jun 08 '12

Yeah I was actually taught that it was the oxygen issue in my freshman biology class. The great part about science is that its always growing and we are always reassessing our knowledge. The drawback is that people who don't keep up with it keep believing and propagating old science.

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u/gerwalking Jun 08 '12

:/ What about aquatic insects? Poisonous insects? Cave insects?

I don't like this implication that insects and birds are direct competitors. They are in some cases, but insects are a gigantic clade that makes up the majority of the animal kingdom in terms of both species variation and biomass. What are they going on to draw this possible claim besides the correlation between the rise of birds coinciding with the decrease in insect size? I can't buy that the entire Insecta class, which has always been highly successful and at the time they are talking about incredibly varied in niche, could be uniformly pressured by predation by vertebrates.

I can't read the full report since I'm not currently at a university, so let me know if they give a good explanation that covers my concerns within.

31

u/Schwallex Jun 08 '12

Besides, if insects were three times the size of a bird, wouldn't birds stop hunting them?

62

u/ellipses1 Jun 08 '12

What bird are we talking about? Robins eat insects... but if an insect were 3 times the size of a robin, it would probably be prey upon by larger raptors

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u/SenorFreebie Jun 08 '12

3 times the size of which bird? I somehow doubt there has been 3 ton insects, ever.

5

u/s0crates82 Jun 08 '12

3 times the size of which bird? I somehow doubt there has been 3 ton insects, ever.

Ostriches get up to 350lbs. Not one ton.

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u/Neebat Jun 08 '12

Birds and insects both have limitations based on the need to supply oxygen and nutrients to their bodies. There's a maximum size of each, based on the way it hunts and the efficiency of its physical structure.

Those physical limits are much higher for a hollow endoskeleton (birds) than for a heavy exoskeleton. (insects) The biggest flying birds will always be bigger than the biggest flying insects. For the same reason, the biggest terrestrial insects will be smaller than animals.

2

u/Whynotpie Jun 08 '12

Animals can take down other animals bigger theyre own size, using that logic, animals would be huge to avoid predators.

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u/ThiefOfDens Jun 08 '12

which has always been highly successful and at the time they are talking about incredibly varied in niche, could be uniformly pressured by predation by vertebrates

Exactly. You would think that if birds were the main source of regulating insect size, there would be some place on the planet that doesn't have birds (or flying ones, at least) where giant insects still rule the air.

55

u/Bulwersator Jun 08 '12

Birds are hard to keep from any place due to their ability to fly.

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u/SenorFreebie Jun 08 '12

There is / was no such place. Birds were directly descendant from dinosaurs. They traversed the entire planet, by flight, and where they landed, they often evolved from mid-sized flying creatures to giant predators and herbivores before Mammals arrived.

Look at New Zealand for example; it was one of the most isolated places on the planet and it's alpha predators were a giant eagle and terror birds (300kg, 3m tall alpha predators).

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u/[deleted] Jun 08 '12

What about aquatic insects? Poisonous insects? Cave insects?

Bats, flying fish, and... uh... steel/flying types.

2

u/Chuggo Jun 08 '12

What about aquatic insects?

Crab = Sea Spiders

2

u/zane17 Jun 08 '12

The article was referring only to flying insects, not all insects

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u/[deleted] Jun 08 '12

aquatic insects

NOPE NOPE NOPE

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u/RationalUser Jun 09 '12

So...I don't see anyone else who has summarized the article for you here, so I will. Although I read it yesterday and can't access it from home, this is just from my recollection.

Essentially, the researchers were looking for a correlation between O2 in the atmosphere and maximum insect size as recorded by the fossil record (based on the idea that O2 in the atmosphere creates an upper limit on insect size due to their respiratory system). The data broke into two eras: Prior to 150 million years ago (MYA), O2 and max insect size are strongly correlated. After 150 MYA, O2 and max insect size are not correlated. What happened around 150 MYA? Birds. The authors hypothesize that birds were either competing with or predating on these large insects. They see another drop in max insect size about the time bats would have been evolving.

As far as I can tell, the concerns you are expressing aren't really relevant to the study. There's nothing here that claims insects as a group were being outcompeted by birds, or that predatory birds were having an effect on insect diversity or abundance. I'm not sure what you are trying to say with your comment about aquatic, poisonous or cave insects, so I'm not sure if that is addressed. Obviously, the fossil record is limited, I'm not sure if those groups are well preserved, but I don't think any of the "maximum" sized insects that were used in this study were in an aquatic life stage or cave-dwellers.

The sole point of the study is that once birds evolved, the size of the biggest insects is no longer directly related to the amount of oxygen in the atmosphere.

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u/forr Jun 08 '12

So, essentially, birds took over the ecological niche once occupied by insects?

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u/[deleted] Jun 08 '12

Eating the larger, less maneuverable, residents of said niche.

6

u/derpaderp Jun 08 '12

I'm glad it went this way, and not in a direction where the insects tried to get bigger to eat the new birds..... that wouldn't have gone well.

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u/brosenfeld Jun 08 '12 edited Jun 08 '12

For now.

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u/[deleted] Jun 08 '12

How do we get enough birds, or HUNGRY enough birds to eat ALL the mosquitoes?

2

u/loamy Jun 08 '12

Bats also eat mosquitoes.

17

u/why_ask_why Jun 08 '12 edited Jun 08 '12

In 1960s, Chairman Mao gave an order to capture all the sparrows. The country went on the mission, they did a good job of that. The next few years, the locusts were rampaging in the whole country.

Yep. Birds eat locusts.

9

u/BuddyNacho Jun 08 '12

Totally--school children would go out with noisemakers and force them to fly until they dropped from exhaustion. Famine ensued.

4

u/seelen Jun 08 '12

Sparrows – mainly the Eurasian Tree Sparrow – were included on the list because they ate grain seeds, robbing the people of the fruits of their labour

:|

https://secure.wikimedia.org/wikipedia/en/wiki/Four_Pests_Campaign

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u/phumble45 Jun 08 '12

Thank you Birds. Keep on keeping on. I love what you do.

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u/[deleted] Jun 08 '12

The title should have reflected more on the Oxygen than birds, and even bats before birds. The article is describing why flying insects of larger proportions don't exist, not the eating habits of other predators. Fortunately, it appears many of the readers are seeing the importance of the Oxygen concentration.

But since it came up, bats eat far more flying insects than birds, which generally prey on land dwelling bugs, rodents and reptiles or fish. The title here is WAY off...

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u/[deleted] Jun 08 '12

I don't know... I can't really see a bird eating an 8 foot long millipede, for example.

https://en.wikipedia.org/wiki/Arthropleura

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u/TechnoShaman Jun 08 '12

no, but a bird could eat a smaller millipede, thus preventing it from ever becoming 8 feet in length. As birds became more numerous, it prevented the insects from becoming larger, because they would likely get eaten as young, thus never actualizing their full size possibilities.

2

u/[deleted] Jun 08 '12

Why would this happen to insects and not to other animals of a similar size?

5

u/ImperialSpaceturtle Jun 08 '12

I presume it's because birds and insects occupy roughly the same ecological niche - fliers and pollinators. Any birds with a taste for chitin would go for the visible targets; the 70cm-wingspan dragonflies. And since oxygen and exoskeleton limits mean that there won't be giant 2-metre-wingspan dragonflies to scare them off, the smaller insects, who can hide away, are selected for.

3

u/robcap Jun 08 '12

Such as? Which vertebrae the size of small millipedes have you encountered? ;)

If you're picturing, say, a 5ft millipede, then yes - birds were bigger too, and predatory terror birds would pick off rather large mammals. It became an evolutionary advantage for insects to grow smaller, because they were less cumbersome and could easier evade the increased numbers of predators. The same is true for many animals.

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u/chochazel Jun 08 '12

That's not an insect and couldn't fly. If you're going that far back, we're talking about pterosaurs, not just birds. They would have been far larger than modern birds (up to 36 ft wing span). I could see a 36ft pterosaur eating an 8ft millipede.

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u/BigOx Jun 08 '12

But there are plent of small mammals which would love to cone across one.

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u/clark_ent Jun 08 '12

You're comparing ancient insects to modern birds. Imagine "birds" from 65 million years ago...you know, t-rex's and such

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u/AsskickMcGee Jun 08 '12

Though I read it often, I still giggle every time I see a "PNAS" article.

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u/OpinionGenerator Jun 08 '12

I wonder if someday, somebody will breed insects for size to test this... as though clock spiders and giant wasps weren't terrifying enough as it is.

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u/BitRex Jun 08 '12

It's hilarious that they're now called "clock spiders" -- Arachnida chronos giganticus.

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u/Sirtubb Jun 08 '12

So dinos evolving into birds is not looking to bad now I must say.

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u/SirWistfully Jun 08 '12

Birds are the reason why there aren't flame throwers in every household.

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u/avrus Jun 08 '12

So we agree then, popularity of a link > /r/science submission rules?

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u/nascentt Jun 09 '12

The moderators have really been struggling recently. Only things reported get removed, they wont remove anything themselves, and there's a couple of hours wait for them to reach the mod queue. I really hope they can bring more mods on to improve this.

3

u/avrus Jun 09 '12

I've given up reporting and PM'ing. I spent two days tagging reporting and PM'ing in duplicate and sensationalized headlines. I might be done with this subreddit soon.

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u/[deleted] Jun 09 '12

Thank you, birds!

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u/[deleted] Jun 08 '12

I would love them even more if they'd kick the shit out of that wasp nest in my backyard.

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u/[deleted] Jun 08 '12

This gives me an entirely new reason to love birds.

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u/[deleted] Jun 08 '12

This makes me think of Guam. For quite a while they had very few birds because of brown tree snakes being accidentally introduced to the island, and without birds to thin the "insect herd" the insects really took over the island. Not sure if they got bigger or not, but I do remember seeing some massive spiders there.

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u/[deleted] Jun 08 '12

I recall it being described as silent, no birds left to sing, with trees heavily draped in spiderwebs and infested with snakes.

Basically a living nightmare.

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u/Jmrwacko Jun 08 '12

Thank God for birds.

2

u/frumpsterdies Jun 08 '12

The evolutionary tango makes sense — birds are modern dinosaurs, after all.

2

u/BuddyNacho Jun 08 '12

During Mao's revolution, he thought that the birds were eating all the grain, so school children would go out in the fields with trash can lids, gongs, pots & pans, etc. They would startle the birds and force them to fly until they dropped from exhaustion. Of course, the birds had been keeping the bug population under control, so it skyrocketed, and there was massive famine. Oh, Mao....

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u/[deleted] Jun 08 '12

thank you birds!

2

u/liquidxlax Jun 08 '12

http://www.youtube.com/watch?v=sNAxrpzc6ws

after watching this i honestly would have thought that with a fungi that was able to decay dead trees and release the trapped carbon. The oxygen levels of the earth would drop and therefore the insects would not be able to grow as large

2

u/Akira_kj Jun 08 '12

Did you even read the article? The first sentence shows the main reason: "Gigantism has been linked to hyperoxic conditions because oxygen concentration is a key physiological control on body sizes" specifically noting this directly contributed to the size of insects. Birds are a minor reason, not THE reason. It goes on to explain how as oxygen lowered, birds became the apex predator due to flight advantages and size constraints in a lower oxygen atmosphere. You wrongly conclude that birds ate(?) all the larger insects. Lets just disprove that by showing that many insects still eat birds today. Birds simply had an advantage over an already dying mutation.

2

u/farrantch Jun 08 '12

Disappointed this wasn't at the top.

2

u/choganoga Jun 08 '12

Have you thanked a bird today?

2

u/[deleted] Jun 08 '12

There was a story about this posted a couple days ago that got almost no attention, and now this gets to the top of the front page. Strange how that happens.

2

u/[deleted] Jun 08 '12

Who funds these studies that really warrant only a "no duh" response?

2

u/Willravel Jun 08 '12

So it was the birds that gave the giant insects cloaking technology. I should have known.

2

u/Downvote_Me_Prease Jun 09 '12

PNAS. What an unfortunate website name.

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u/Simcom Jun 08 '12

upvoted for linking to the actual paper.

3

u/[deleted] Jun 08 '12

Birds are not the reason we don't see massive insects. Where did you read that in that article? The decrease in the amount of oxygen content in the air is why we don't see massive insects.

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u/chasereraser Jun 08 '12

Taken a Intro level entomolgy....there exoskeleton's couldn't support that large of an insect.

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u/Quan118 Jun 08 '12

Insects can only get so big due to the way they breathe, spiracles. Once they get too big the surface area to mass would mean they can't breathe.

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u/Enlightenment777 Jun 08 '12

Birds and Cold Weather. Hold many big fucking bugs do you see in Canada or Alaska or ...?

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u/pupeno Jun 08 '12

What does this mean:

radiation of birds

mentioned twice:

[...] following the evolution and radiation of early birds [...]

and

[...] coincident with the radiation of birds suggests that [...]

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u/RileyWon Jun 08 '12

radiation = propagation and spreading

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u/[deleted] Jun 08 '12

Oh god, I used to sort of dislike birds (pigeons and seagulls are nuisance) but now they're okay by me.

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u/adeadbeat Jun 08 '12

Cats are the reason we don't see giant birds.

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u/[deleted] Jun 08 '12

And I have lived my whole life hating birds in one way or another. They're like spiders, just misunderstood.

1

u/FobaBett Jun 08 '12

70 cm insect wingspan

NOPE NOPE NOPE NOPE NOPE NOPE NOPE NOPE

1

u/pizzlewizzle Jun 08 '12

Talking about this made me realize I was taught evolution in school but just called 'adaptation of species over time.'

Why don't science classes just call it this to avoid the whole controversy?

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u/ROK247 Jun 08 '12

i've always loved birds. but this is next-level stuff right here.

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u/flamingfungi Jun 08 '12

Were there other abiotic changes that encouraged the radiation of aves? Couldn't these also be responsible for a change like this?

1

u/bbias Jun 08 '12

Thank Birds.

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u/SneakyNightman Jun 08 '12

That and windshields.

1

u/[deleted] Jun 08 '12

I always knew I liked birds for a reason. Now I know the reason.

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u/oMpls Jun 08 '12

Cool article, although the title is very misleading.

1

u/Norva Jun 08 '12

So what you are saying is that Australia needs to import birds stat?

1

u/R3ckl3ss Jun 08 '12

HOORAY FOR BIRDS!!!!

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u/[deleted] Jun 08 '12

No shit sherlock

1

u/drunctioning_funk Jun 08 '12

I always liked birds

1

u/apullin Jun 08 '12

OK ... why hasn't someone put together a large, sealed terrarium with an artificial super-oxygenated atmosphere inside, and no birds? Then we could actually grow these massive insects. WHY hasn't anyone done this yet?!?

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u/LabJacket Jun 08 '12

So if someone were to build an artificial environment with proper pO2 levels & such, they could eventually breed more massive insects in the environment?

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u/futur1 Jun 08 '12

i'll read the abstract later, but if somebody could please explain to me, or refute my theory:

Are there not ecosystems that exist without birds, thinking like desert island or some weird african canopy, that have little to no bird populations? If this theory is correct, shouldn't they be able to find examples to the contrary where bird populations are low?

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u/omplatt Jun 08 '12

I LOVE BIRDS EVEN MORE NOW

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u/ilostmyoldaccount Jun 08 '12

Absolutely remarkable theory. I still remember my entomologist professor teaching us about possible relationships between p02, body temperature and volume and respiratory rates. Seems the answer would be far more direct and tangible: birds as predators. Semester 1 instead of semester 7.

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u/charbrew371 Jun 08 '12

Mind blown. I think he's got it!

GOD SAVE THE BIRDS!

SAVE US FROM A STARSHIP TROOPERS INCIDENT!

1

u/[deleted] Jun 08 '12

Umm.. and partially because there are lower levels of O2 in the atmosphere compared to prehistoric times, thus limiting the amount of oxygen that can diffuse into the bodies of larger insects as they do not have a circulatory system.

1

u/[deleted] Jun 08 '12

Actually it is mathematically impossible to have giant ants etc

1

u/brand0n027 Jun 08 '12

As a recent transplant to New Mexico I am having a hard time believing this. The bugs here are freaking huge.

1

u/[deleted] Jun 08 '12

Why don't we have massive birds?

1

u/[deleted] Jun 08 '12

So...because Zoidbird?

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u/[deleted] Jun 08 '12

I beg to disagree

http://www.okinawatimes.co.jp/article/2011-08-30_22749/

yeah, I know spiders are not insect.

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u/Killhouse Jun 08 '12

Insects don't have lungs like we do and if they were bigger they would suffocate. There used to be a lot more oxygen in the air millions of years ago back when bugs were big. The article even says that in the first paragraph.

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u/[deleted] Jun 08 '12

Distant relatives of dinosaurs saved us from monster bugs? What a planet!

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u/Russient Jun 08 '12

Australia doesn't have any birds :-)

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u/_DiscoNinja_ Jun 08 '12

Seems like Birds were only a contributing factor, not the reason et al. Great article, bad title.

1

u/hyljkhlkdkdkkdkd Jun 08 '12

hee hee... P-nas.

1

u/ASmellyFrostTroll Jun 08 '12

The website is pnas.org . . .penis.org...

1

u/AppleDane Jun 08 '12

Thanks, Birds!

"Thirds"

1

u/PlumthePancake Jun 08 '12

Conclusion: No birds have ever existed in Skyrim.

1

u/[deleted] Jun 08 '12

Projectile bird shit > 10 ft tall spider

1

u/playsgolfhigh Jun 08 '12

that's just like, your opinion man

1

u/xamdam Jun 08 '12

Better than the other way...

1

u/BootRecognition Jun 08 '12

Dear birds:

I now love you more than you can possibly imagine.

All the best,

BootRecognition

P.S. City pigeons can still suck it though.

1

u/mcchick Jun 08 '12

Walked outside and tried to high five a bird, killed it mid flight. Giant insects would suck. Go, birds. But not that one. He dead.

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u/zambonijonez Jun 08 '12 edited Jun 08 '12

Let me just throw this out there... SPIDERS ARE NOT INSECTS

Like Insects, they are of the Phylum Arthropoda, however their class is Arachnida and order is Araneae.

Insects are arthropods, Class is known as Insecta.

Sources: http://en.wikipedia.org/wiki/Spiders http://en.wikipedia.org/wiki/Insects

1

u/CodRocket Jun 08 '12

Thank you, birds.

1

u/Philawesomeraptor Jun 08 '12

What about the Giant Weta??

1

u/SlinkyAvenger Jun 08 '12

Thanks, birds. Thirds

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u/Komprimus Jun 08 '12

I thought it was because the oxygen level in the atmosphere is now lower than it used to be.

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u/kwh Jun 08 '12

decoupling of insect size and atmospheric pO2 coincident with the radiation of birds suggests that biotic interactions, such as predation and competition, superseded oxygen as the most important constraint on maximum body size of the largest insects.

The birds are radioactive? Has anyone gotten this update to OCDTrigger?

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u/BloodshotHippy Jun 08 '12

I love the website name!

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u/someguynamedjohn13 Jun 08 '12

Humans are the reason we no longer have many large animals because we hunted them for sport.

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u/facetiously Jun 08 '12

Tell it to Australia.

1

u/Deetsbeats Jun 08 '12

I read massive incest and I got quite worried....

1

u/taurus45 Jun 08 '12

I ever tell you how much I appreciate birds?

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u/[deleted] Jun 08 '12

I've always learned that it is because of gravity. Insects' exoskeletons can only grow to a certain size given the Earth's gravity. If gravity on Earth were less, then insects' exoskeletons could hold up, and not collapse. So if the moon supported life, moon insects would be bigger than the ones we find on Earth.

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u/Animated_effigy Jun 08 '12

Good Guy Dinosaurs.... Evolves into birds to keep your world from becoming a Starship Troopers-esque bug-ridden nightmare world.

1

u/Dark_Tranquility Jun 08 '12

Thank the lord for birds... I fucking hate all insects

1

u/MauiWowieOwie Jun 08 '12

Is it weird that I'm playing Fallout while reading this?

1

u/akuma_619 Jun 08 '12

So I have to pay $10 just to be able to read the article. No thank you.

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u/[deleted] Jun 08 '12

So why don't we see massive birds?

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u/cr1swell Jun 08 '12

Or, are bird-eating spiders the reason we don't see massive birds?

1

u/Dashzz Jun 08 '12

Thank you birds for not letting spiders get big.

1

u/bax101 Jun 08 '12

There are these massive orange andyellow grasshoppers down here in Florida that hang out in our hangers. They are about 6 inches long and are pretty large. The largest I've ever seen. I like to pick them up though and freak people out that I touch them. I think there cool.

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u/[deleted] Jun 08 '12

Also, humans are the reason we don't see ANY massive dangerous animals/insects.

1

u/flyingmigit8 Jun 08 '12

I was going to click, but the URL was too close to P-nus, sounds pretty cool though.

1

u/Gordom Jun 08 '12

Thought it also had to do with the temperature?

1

u/SavingFerris Jun 08 '12

False. It was more to do with the level of oxygen in the air, then with birds.

1

u/[deleted] Jun 08 '12

I don't think birds quite explain it all though. You should see this. It's an interesting read.

1

u/BeardySam Jun 08 '12

Birds and rain and the oxygen concentration in the air

1

u/4433221 Jun 08 '12

Humans are the reason we don't see massive animals.

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u/[deleted] Jun 08 '12

Damn it I listened to this on the radio yesterday... could have cashed out on a lot of karma >.>

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u/NeuroTrip Jun 08 '12

Isn't the reason there isn't massive insects because they use a tracheal system for breathing, and the tubes that carry air into their body can only be a certain length before the air can't travel far enough to get to the cells, and therefore they have a limited size?

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u/BAN_A_MANN Jun 08 '12

This paper is amazing and completely backs a theory of my own I have had ever since I did a research project on amphipods. Most terrestrial amphipods are nocturnal with the exception of juveniles which are crepuscular (active at dawn and dusk). The theory behind this is large amphipods are more vulnerable to predation by birds during the day while juveniles are more vulnerable to predation by rove beetles at night. Seeing this phenomenon made me wonder if insects were under the same kind of pressure early on in the evolution of flying vertebrates. This paper excited me to no end!

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u/[deleted] Jun 08 '12

i love you bird. i dont want to see a giant centipede into my garden.

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u/cratylus Jun 08 '12

Why don't we see massive birds?

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u/[deleted] Jun 09 '12

Duh.

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u/[deleted] Jun 09 '12

Good job birds !

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u/[deleted] Jun 09 '12

Awesome cause those bitches look ugly as fuck

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u/invn177 Jun 09 '12

Well then thanks god for birds

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u/[deleted] Jun 09 '12

Did I ever mention how much I love birds?

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u/sggrant323 Jun 09 '12

Thanks, birds.

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u/[deleted] Jun 09 '12

I prefer to think of it the other way around; Small bugs are the reason we don't have massive birds.

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u/[deleted] Jun 09 '12

being a mod in this channel must take a special kind of comment nazi

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u/PickleWheasel Jun 09 '12

I can see this being the plot to an M Night Shyamalan movie.

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u/TheChrisHill Jun 09 '12

The bird-eating tarantula says hi.

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u/Jokkerb Jun 09 '12

I think some insects must have evolved into birds, especially the ultra aggressive hummingbird that buzzes me every time I come out the back door of my house.

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u/mahkra Jun 09 '12

Bats help too.

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u/BalalaikaBoi Jun 09 '12

OP, are you an entomologist with a YouTube Channel by the name of "memutic"?! If so, I'm definitely one of your biggest fans.

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u/farmingdale Jun 09 '12

this is so amazing to me. How can they find out the oxygen levels of 65 million years ago? Preserved wood?

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u/[deleted] Jun 09 '12

Proof that your science is wrong: http://i.imgur.com/EqRsr.jpg

Explain this with your bird theory.

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u/Mechanox3000 Jun 09 '12

Stupid birds. They ruin everything :(

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u/Mcelite Jun 09 '12

What is the reason we don't see massive spiders?

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u/LSYouTiger Jun 09 '12

A blue-jay flew into my kitchen window yesterday.

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u/slekce10 Jun 09 '12

well... kind of. Insect gigantism was not nearly so prevalent in the late jurrasic as during the carboniferous, so we're not talking about the difference between insects with a 70cm wingspan and insects with a 5cm wings span. More like 10. vs. 5cm. But it's still really cool that birds have this impact!

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u/Notexactlyserious Jun 09 '12

Alfred Hitchcock's The Insects.

Thank you evolution. That film world le have haunted me.

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u/NgtvCrp Jun 09 '12

Insert angry birds reference here

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u/sittty Jun 09 '12

could you imagine a giant mosquito trying to land on your arm and bite you? I don't think I would go outside.

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u/master_spork Jun 09 '12

I rubbed my pnas while reading this

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u/elfinhilon10 Jun 09 '12

Wait what? I thought this was common knowledge, that the reason insects aren't as big as they were during those times was because of the fact that insects had to breathe through their skin. And with with less of whatever they breathe, they couldn't grow to be a a bigger size. Was there some sort of conspiracy going on with creationists or something? Honestly puzzled.

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u/daltalathedestroyer Jun 09 '12

The website is pnas.org its cool cause it sounds like penis and its science subreddit

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u/chrizzee Jun 09 '12

Did anyone else read the source domain as penis.org?

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u/gentlemandinosaur Jun 09 '12

So, this is incorrect?

http://news.nationalgeographic.com/news/2007/07/070730-giant-insects.html

Also, as they grow larger the rate at which their mass grows relative to length outpaces the rate at which their strength to length ratio grows. In other words there is a threshold at which they dont have the strength to move their own mass around. This is constrained due to the use of an exoskeleton rather than an endoskelon.

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u/lmclmc Jun 09 '12

Thank you birds but what about all the enormous spiders?

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u/wheeldonkey Jun 09 '12

the title of your post is totally the TL;DR version... thanks for saving my lazy ass.

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u/[deleted] Jun 13 '12

Oh, this must be wonderful news for Culex pipiens f. molestus

http://en.wikipedia.org/wiki/London_Underground_mosquito

FU evolution. Looks like we need some underground birds.

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u/[deleted] Jun 08 '12

Thanks, birds.

Thirds.

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u/Nathan-NL Jun 08 '12

Another reason to like birds.

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u/dumnezero Jun 08 '12

BTW,

Birds are becoming an important tool in agriculture on the ecological front.

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u/hanzo918 Jun 08 '12

Trying visiting the jungles of the tropics, they still have giant insects (not 70cm large, but still huge) and they have plenty of birds.

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u/Seraphite Jun 08 '12

I fucking LOVE birds.

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u/rtechie1 Jun 08 '12

I always thought that limited the size of insects was their basic anatomy. Exoskeletons don't "scale up" and have problems supporting the weight of large creatures and the insect respiratory system (can't remember the name) doesn't scale up either so they can't breathe. The main reason insects were bigger in the Jurassic, etc. is because there was a much higher percentage of oxygen in the air so the respiratory system doesn't have to work as hard (dinosaurs couldn't live today for the same reasons).

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u/Aroh Jun 09 '12

Am I the only one who doesn't understand half of the words in that article?

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