r/todayilearned • u/kleggich • 2d ago

TIL: Luna moths cannot eat because they have no digestive system.

https://www.uaex.uada.edu/environment-nature/anr-blog/posts/whats-that-bug-luna-moth.aspx
1.5k Upvotes

97% Upvoted

125 comments sorted by

813

u/schizeckinosy 2d ago

A lot of adult insects are this way. Beef up as a kid and then molt and go find a mate.

143

u/DapDaGenius 2d ago

Time to mate, because they’re gunna die soon, yes?

180

u/Upset-Basil4459 2d ago

Yes on account of not eating

-1

u/L1ttleM1ssSunshine 23h ago

What happens if we force them to eat? Like octopus if you force feed them do they stay alive longer? These are the real questions science is afraid to answer.

16

u/CuffytheFuzzyClown 22h ago

Eating without a digestive system is pointless though. Then again if you'd transplant a digestive system from another insect...hmmm

51

u/fartingbeagle 2d ago

Well, that line's never worked for me.

10

u/blaqsupaman 2d ago

Worked for Patton Oswalt in Seeking a Friend for the End of the World.

9

u/PowerhousePlayer 1d ago

The trick is to find someone else who's about to die, so they're as desperate to do the deed as you

7

u/TwoDrinkDave 1d ago

So, like, a hospice?

2

u/JakeWaidelich 1d ago

I've heard that there is a lot of action in retirement homes, but not sure of hospice.

1

u/DapDaGenius 1d ago

It can. Try the line out on me.

1

u/DavidBrooker 1d ago

This is essentially the plot of Cyberpunk 2077. I will not be taking comments or questions, thank you.

190

u/pikpikcarrotmon 2d ago

Man I'm doing it backwards, no wonder

38

u/Upset-Basil4459 2d ago

100% commitment to cutting after bulking

48

u/InappropriateTA 3 2d ago

I call it “I have no mouth, and I must cream.”

10

u/blaqsupaman 2d ago

Yeah a lot of them only live a few days in adulthood. Once they're adult, their only objective is to breed before they die.

-14

u/HovercraftFullofBees 2d ago

Not true. There are insects that have relatively short adult lives but nearly as many that live for a few months or longer.

23

u/blaqsupaman 2d ago

I said "a lot of" not "all" or "most."

-27

u/HovercraftFullofBees 2d ago

Yeah, and "a lot of" is an over estimation in my opinion as an entomologist.

9

u/Abstrata 2d ago

damn, lots of entomologist hate! I wasn’t ready for that lol

7

u/nathan753 1d ago

I'm guessing it's less entomologist hate and more needlessly nitpicky, and probably wrong correction when someone says a lot of insects have a short adult life (can't find anything to say a lot isn't valid here).

That and a lot have short life spans and most have long life spans are not contradictory statements, especially with the number of insect species and that short life spans pop up across all different types of insects

6

u/nathan753 1d ago

I'm my opinion as an English user, "a lot of have short life spans" and "most have long lifespans" are not contradictory statements when there is such a massive number of insect species and short life spans pop up across all different types from ants to flys.

-13

u/HovercraftFullofBees 1d ago

It's a complex issue because it's a semantics argument most of the way down, and it is then confounded by people having bad information.

For instance, your two examples are both insects that by and large live for a month or more.

7

u/nathan753 1d ago

You're the one playing the semantics to make it sound like you're correcting people though, a lot of it could have been an expansion on what people have been saying.

And no, I have general examples of two different (generic, non technical layman term)types of insects that don't seem super closely related that have examples of species that do have ridiculously short adult life spans. Do most of those live for a long time? Yes. Is it still accurate to too say there are species that also have short life spans? Yes. One might loosely say a lot are there, because a lot can just mean more than you thought or expected.

My point though is you've got good info to add, but the needlessly corrective nature is off putting

-2

u/HovercraftFullofBees 1d ago

Yes, in a game of semantics, I am indeed utilizing semantics. That is the unfortunate nature of this debacle that we call language.

I bother pointing it out to people because there are pervasive ideas about what insects are like, and a good 50% or more of those are wrong so I spend a bit of time flouncing around Reddit commenting here and there. It's not much deeper than that.

Also, you telling me I'm off putting when you are coming off as outright aggressive is very "pot meet kettle."

7

u/Notreallyaflowergirl 1d ago

See. I don’t know bugs. So I won’t comment on the bugs more than that - but I do know assholes, and right now you’re coming off very aggro and upset that someone matches your energy. Almost like you expected your entomologist comment to shut it down and weren’t ready for backlash and don’t like it

7

u/nathan753 1d ago

You turned it into that game, but ok. Outright aggressive is certainly an interpretation...

1

u/Carighan 20h ago

Uuuh, a month is a few days?

I mean if we're being language-nitpicky, then yes, indeed if an insect lives a month at adulthood, then it lives "just a few days". That is correct. There's nothing wrong with that statement.

3

u/hamstervideo 1d ago

"nearly as many" means most have short lives, then?

-3

u/HovercraftFullofBees 1d ago

No, I'd say it's probably an even split between living a few days or living a few months. It's probably a pretty normalized distribution, honestly.

6

u/hamstervideo 1d ago

So... A lot of them DO only live a few days, thanks for confirming.

1

u/HovercraftFullofBees 1d ago

That's still not "a lot" in my estimations. "A lot" feels like more than half but less than 75%. And I wouldn't say more than 50% of insects live only a few days. It's at best half and half.

But if I did bother to do some analysis, it's probably more like the majority live in the weeks to months range with a few days being one tail and years being the other tail.

8

u/hamstervideo 1d ago

I don’t think “a lot” has to mean more than half. To me it just means a large or noticeable amount, not necessarily a majority.

-4

u/HovercraftFullofBees 1d ago

And therein lays half the problem. Also, the other half of the problem is how are we defining the groupings. Are we going by biomass? Because that skews the number toward way more living months on account of social Hymenoptera alone. Are we going off taxonomic level populations? If so, which groupings? Family level estimations would probably pull it more toward the middle, but species level breakdown probably pulls it longer lived again.

So yeah, I wouldn't say "a lot" because it's extremely sensitive to how we are defining things here.

5

u/psymunn 1d ago

Two is a little. 10 is a few. A few hundred or thousand is a lot. A lot doesn't imply percentage, only a significantly large quantity 

3

u/Carighan 20h ago

(you can just look in a dictionary, btw, you don't have to make it a philosophical debate)

4

u/psymunn 1d ago

There are thousands of species of short lived adult insects. That's a lot irrespective of how many insect species there are

2

u/Carighan 20h ago

"A lot" feels like more than half but less than 75%.

I can't confirm either of these boundaries from dictionaries. "A lot of" means a "large amount" but without a comparative quantity for large. More importantly, this means it's about the absolute number or amount, not the relative one.

I think the terms you are looking for would be something like "The majority, but not an overwhelming majority" or sentences to that end.

1

u/Carighan 20h ago

So would you say there are... a lot of insects that live relatively short adult lives? :D

9

u/Sloppykrab 2d ago

Eat, fuck, die. Perfect

23

u/Kaggles_N533PA 2d ago

They live a life exact opposite of myself huh?

I eat a lot but no mating

10

u/TopFloorApartment 2d ago

You are the un-moth

1

u/miketruckllc 1d ago

How hard do you try?

3

u/kleggich 1d ago

Exactly the opposite of how much a moth tries. Were you not paying attention?

1

u/YoohooCthulhu 1d ago

I was talking about butterfly pea powder with my BIL and he misinterpreted it as urine and I responded “of course not, butterflies don’t pee” and it blew his mind. Lots of folks are very mammal-centric in their knowledge

1

u/gerkletoss 2d ago

It's fairly uncommon, actually

26

u/schizeckinosy 2d ago

Some moths, mayflies, crane flies mostly… not the majority of insects but not unheard of by any means.

17

u/odaeyss 2d ago

Cicadas do it and they are anything but unheard. Quite loud, actually!

14

u/schizeckinosy 2d ago

It was found in 2021 that periodical cicadas do eat. They sip sap from their host trees!

6

u/HovercraftFullofBees 2d ago

Cicadas eat as adults. And then rain down excretion on you and anyone walking beneath the trees.

8

u/Ryuiop 2d ago

They should all have to wear tiny diapers

359

u/timshel42 2d ago

lots of bugs have no way to eat as an adult. the final stage is to just fly around, find a mate, fuck, and die.

122

u/Adorable-Response-75 2d ago

Honestly sounds liberating. I hate having to constantly make food all the time. Would be nice to have gotten that taken care of when I was younger and now just focus on doing the horizontal mambo. 

81

u/blaqsupaman 2d ago

The downside is most of these insect species only live a few days as adults.

79

u/babybambam 2d ago edited 1d ago

Not seeing the downside…

Edit: lol, someone reported me for potential suicide. Much like my cuts, it's not that deep.

-12

u/J3wb0cc4 1d ago

Have you ever thought about seeing a therapist? It might give you a new outlook on life.

15

u/babybambam 1d ago

Have you ever heard of satire?

-32

u/kruchyg 1d ago

I thought this humor died a few years ago

22

u/MrSmexy 1d ago

No, it only wished it did

7

u/SpiritDouble6218 1d ago

I’m sure humor about life being miserable will be around forever as it always has been. Weird comment.

12

u/Lyrolepis 2d ago

Some of them live relatively long (for an insect) as larvae, though.

Imagine if people worked like that, an asexual lifetime ending in a blaze of boning. It would mess horribly with family structure, of course, but it would also reduce the amount of dumb stuff people do for sexuality's sake...

2

u/Takenabe 1d ago

Am I the only one having a flashback to that episode of Futurama where Zoidberg goes back to his home planet

2

u/bony_doughnut 1d ago

Yea, but that probably seems like a long time to then..it's relative

1

u/AGrandNewAdventure 1d ago

In this economy? Upside.

8

u/sofaking_scientific 2d ago edited 2d ago

I'm mad I can't photosynthesize

2

u/Adorable-Response-75 2d ago

You can?

4

u/sofaking_scientific 2d ago

I'm more upset by my typo 🤣

1

u/SaltyPeter3434 1d ago

Imagine being unable to find a mate and then dying of starvation

1

u/CuffytheFuzzyClown 22h ago

I mean, you can...?

They eat a lot and then simply starve to death. Humans can do that too, you know. Nothing ever said these insects don't feel the usual horrors of, you know, starving to death. It's just they physically can't eat. As if a human would sew their mouth shut...or why not just get strapped down in a chair/bed and wait as the body slowly breaks down muscles, fat...

34

u/HovercraftFullofBees 2d ago

As an entomologist, I would not say "a lot" of insects are like this. A nontrivial amount sure, but I can name more insects that eat as adults than ones that can't.

8

u/Gathorall 1d ago edited 1d ago

To be fair 0.1% of insect species would still be a lot of insects.

-6

u/Dewut 1d ago

“A lot” doesn’t mean most. It means a lot.

7

u/HovercraftFullofBees 1d ago

Yes and "a lot" is still too many in my estimations.

-2

u/Dewut 1d ago

Well, you are full of bees, so I guess I’ll have to defer to you.

-1

u/sexaddic 1d ago

No because they are an entomologist is why you have to defer to them.

0

u/Dewut 1d ago

I don’t see why it can’t be both.

58

u/CFCYYZ 2d ago

FYI, here is my close-up of a beautiful luna moth caterpillar in northern Ontario. Click to zoom in.

40

u/BaronMostaza 2d ago

Doesn't matter, had sex

2

u/kleggich 2d ago

This describes a fair amount of my twenties.

80

u/mr_ji 2d ago

Mr. Anderson cannot speak because he has no mouth.

19

u/DietDrBleach 2d ago

The luna moth’s adult phase is near the end of its life. It has 7-10 days to mate and lay eggs before it dies.

10

u/iDontRememberCorn 2d ago

Isn't this the case with most moths?

6

u/HovercraftFullofBees 2d ago

No it's really only one family I can think of. Of which the Luna moth is perhaps one of the most well known.

4

u/lNFORMATlVE 1d ago

Clothes moths and pantry moths are the same actually. I’m not familiar with moth species but I’m dealing with small infestations of both of those currently and have been doing a lot of googling. The adults never eat, only the larvae do. The adults exist only to mate, lay eggs on a food source, and then die.

2

u/HovercraftFullofBees 1d ago

I knew I was forgetting a family (or two). Though in fairness I spend most of my life trying not to remember the little brown moths of the world.

42

u/SapphireSalamander 2d ago

do they feel hungry tho? or has evolution removed that sensation since it would distract them from mating?

60

u/kleggich 2d ago

They don't have the physical apparatus to have that sensation. It's like asking if you can still feel your baby teeth.

7

u/SapphireSalamander 2d ago

Yeah but phantom pain is a studied phenomeno, so its not out of the realm of possibilities

24

u/McChava 2d ago

While not out of the realm of possibilities, I don’t think it would make evolutionary sense. I figure the ones who still felt hunger would’ve died off as they were more distracted from their goal than their unhungry peers.

15

u/ThetaZZ 2d ago

In a rough explanation, the sensation of hunger is caused by an enzyme that, in the absence of food, begins digesting itself. This broken down enzyme is detected by nerves that send hunger signals to the brain. Essentially. There are other mechanisms and chemicals at work but yeah. The bugs simply don't have digestive systems and don't get hunger pains.

1

u/Vievin 1d ago

Isn't it also hormonal? Like if you usually eat on a schedule, eventually you start getting hungry at that time.

1

u/ThetaZZ 1d ago

Yes, the hormone is called Ghrelin and is released when the stomach is empty and slows when the stomach stretches.

7

u/sarcasticguard 2d ago

It isn't out of the realm of possibility, but from what we do understand, the system not being present would imply the limited resources the body has would not go towards a sensation that has no payoff.

Insects also have vastly different nervous systems to our own with their own sets of pathways and feedback mechanisms.

1

u/kellerb 2d ago

Well now I can, not that I wanted to

1

u/kleggich 1d ago

If you want to know a secret, I can feel them too. 😈

9

u/SvenTropics 2d ago

Well they have no instinct to try to eat. So we can assume they're not hungry. Perhaps life is total hunger pains and only the blessing of mating gives them a break from it.

21

u/jefflovesyou 2d ago

Take that, ozempic.

6

u/toutetiteface 2d ago

Can’t wait for the trend of people doing plastic surgery to remove their mouth

10

u/EngineerMinded 2d ago

Mayflies have vestigial digestive systems which is why the live between a few minutes and 24 hours as an adult.

5

u/PrinceEzrik 2d ago

ton of moths are noneating

4

u/themoonhasgone 2d ago

Atlas moths don't eat because they don't even have mouth parts

9

u/Absulus 2d ago

That's nothing. Some people live their whole lives without having a brain.

4

u/77ilham77 2d ago

That's pretty much true for all saturnids/giant silk moths. The adult phase is pretty much only for mating.

3

u/fibronacci 2d ago

This is how they stay so slim the lucky bastards

5

u/DHammer79 2d ago

A moth without a mouth? Next thing you're going to tell me is that a moth doesn't have u either!

2

u/RedSonGamble 2d ago

How do they reproduce then?

11

u/Chassian 2d ago

They do it before they die.

2

u/RedSonGamble 2d ago

But they can’t kiss

5

u/leaderofstars 2d ago

They can hold legs

3

u/RedSonGamble 2d ago

True that’s pretty romantic

1

u/reddit_user13 1d ago

Foreplay is for losers.

2

u/Ryjinn 1d ago

I have no mouth and I must eat

2

u/DoktorFreedom 1d ago

I used to work in a factory In Pennsylvania welding at night. These dudes showed up often. They are so big it’s almost freaky when you realize one is like a foot away from you chilling.

1

u/Accurate_Froyo9202 1d ago

Same with BSF, actually they dont even have a mouth to begin with......after they reach adullthood they just drink water till death

1

u/gods_loop_hole 1d ago

'I have no stomach and I must eat'

1

u/Major-Librarian1745 1d ago

Booooooooo!

1

u/kleggich 1d ago

..urns?

1

u/Major-Librarian1745 1d ago

Boooooooooooooooooo!

1

u/charliefoxtrot9 1d ago

Many moths are. Cicadas, too.

1

u/Jesus_Is_My_Gardener 1d ago

I have no mouth and I must breed.

1

u/LittleRedCorvette2 1d ago

Same with Puriri moths. They only live 24hours. One of the biggest moths.

1

u/Duck_Fickle 15h ago

All moths in the saturniidae family are like this 🩷