#holometabolism

[ronimiez]

explaining the differences between the 3 different types of metamorphosis

there are 3 different growth cycles/metamorphosis that insects go through:

ametabolism

hemimetabolism

holometabolism

i want to try and explain this because it turns out theres a lot of people who dont know that butterflies arent the only insects that go through metamorphosis!

1. ametabolism

this growth cycle is by far the rarest and can only be found in the 2 most primitive insect orders: zygentoma (silverfish and firebrats) and archaeognatha (jumping bristletails).

the reason its called ametabolism is that because it describes the absence of a metamorphosis cycle. instead, they just gradually increase in size with no other morphological differences between juvenile and adult.

fun fact: you can tell how primitive an insect order is based on how many "insecty" aspects it has! for example, you can tell that blattodeans (cockroaches and termites) are primitiver than lepidopterans (butterflies and moths), as blattodeans undergo partial metamorphosis and not full metamorphosis.

2. hemimetabolism

this growth cycle is the second-most prominent growth cycle in insects and can be found in 11 orders.

it describes the partial metamorphosis that these insects go through. this means that they lack the pupal stage that holometabolistic (full metamorphosis) insects have, but they still undergo significant changes while growing up.

for example: grasshoppers, katydids, and crickets are born without wings, but after the final moult they will have fully developed wings that they can use.

3. holometabolism

this growth cycle is by far the most prominent in insects. it can be found in 11 orders just like hemimetabolism, but these 11 holometabolistic orders are the most diverse in the insect kingdom. these orders include coleoptera (beetles), lepidoptera (butterflies and moths), diptera (flies), and hymenoptera (bees, ants, wasps, and sawflies).

it describes the complete metamorphosis that these insects go through. all of them have a larval stage, a pupal stage, and an adult/reproductive stage. the appearance of the adult stage is always very different than that of the larval stage.

take the butterfly, the most popular example of holometabolism used.

i hope you found this explanation useful! if you have any questions, feel free to send them my way :]

[ipsen]

Holometabolism is now complete to read on AO3

[ravingrovebeetle]

What's your favorite bug fact?? 🎷🐛

omg i actually have no idea when this came in because i learned how to check my asks like five seconds ago but!! i shall answer it anyway!! my favorite bug fact is how metamorphosis works---look up imaginal discs, they are super cool!! essentially they are undifferentiated cells (basically cells that seem to be regular ol' guys, nothing special about them yet) that during metamorphosis, causes the larval cells to undergo apoptosis (see also: self-destruction) and then they turn into the individual cells that you would see in the adult insect

[horrendousmustard]

AWWWWWWW KANEKIS SLEEPING BESIDEHER FKDKFJGDJKFJSKFBGKDBFJGBBFJDHFBFJDJJFGHJFGJFF

[ipsen]

”For those of you who don’t know me, my name is Hideyoshi Nagachika. I am single. I am an ambassador for the TSC’s peace efforts here in Tokyo. In my spare time, I volunteer at the 24th ward. For those of you who do know me, please keep your mouths shut about me.

“They say you should never meet your heroes. Ken Kaneki met me when I pissed all over the local school bully’s desk.”

Hide's speech at Kaneki's wedding

[crevicedwelling]

as much as I grumble about holometabolous insects hogging all the research and popularity I can’t deny that ants are pretty damn amazing in about every way it is possible for a bug to be amazing

[konjaku]

七節擬[Nanafushimodoki] Ramulus irregulariterdentatus

七[Nana] : Seven

節[Fushi] : Joint

擬[Modoki] : Pseudo-, -like

It is very commonly called Nanafushi and is also written as 竹節虫, which is an ateji and means Bamboo joints insect.

The length of the body is about from six to ten centimeters. Not uncommon, but hard to spot due to its mimicry of plant branches. This time this one was on the leaves of 躑躅[Tsutsuji](Azalea) and I noticed it right away. The way it moves slowly on its long legs looks like that of a sloth, and its humorous face reminds me of "What do we want meme".

The metamorphosis, or the process by which an organism changes its form as it grows, is called 変態[Hentai]. Take insects, for example, one that goes through the processes of egg, larva, and pupa to become an adult is called 完全変態[Kanzen hentai](Holometabolism; 完全 means perfect), one that does not go through the process of pupa is called 不完全変態[Fukanzen hentai](Hemimetabolism; 不完全 means inperfect), and Nanafushi is the latter. By the way, there is a certain word that has the same reading, the same kanji, but a different meaning, I will not mention here, though.

[uncharismatic-fauna]

Horsing Around with Horse Flies

Though horse flies are regarded worldwide as pests, members of the family Tabanidae are an important part of their natural environments. Adults feed on nectar, and some are specialized pollinators that have evolved to only collect from a few select flowers. Just like mosquitoes, only female horse flies feed on blood. Reproduction requires moisture; typically clean, stagnant or slow-moving water. Because of this, some species of horse fly are excellent indicators of an ecosystem’s health. Their role as disease carriers is also a valuable part of any functioning ecosystem; diseases can keep animal populations in check, and sick animals are often easier targets for predators. Horse flies themselves are also a juicy treat for amphibians, reptiles, and birds, as well as insects like wasps and spiders.

There are about 4,455 species of Tabanidae flies, the majority of which reside in the genus Tabanus. Most species share the same general body shape: a large head, a fat body supported by six legs, and one pair of wings. However, there are many variations on this pattern in terms of size, color, and specialized appendages. The smallest horse flies are only 5 mm (0.19 in) long, while the largest is over 30 mm (1.18 in). Like other flies, horse flies have a set of compound eyes made up of thousands of ommatidia: specialised units which allow them to combine input from multiple angles. The resulting image has a poor resolution, but it’s useful for detecting rapid movement-- an important tool when trying to avoid predators. The eyes of male horse flies are holoptic, meaning they meet in the middle to give the appearence of one continuous eye.

Horse flies go through a complete metamorphosis, also known as holometabolism, over the course of their lives. Eggs are laid of clusters of anywhere from 100 to 1000, typically on plants near a source of fresh water. After about six days, the larvae hatch and drop down into the water or burrow into the moist ground, and use a respiratory siphon to pull air from the surface. In temperate regions the grubs enter a stage of dormancy, while tropical horse flies develop year-round. While in this stage individuals consume a number of other insect larvae, worms, and aquatic insects. Once fully developed the horse fly larva pupates for one to three weeks, after which it emerges as a fully-grown adult. Mating can occur as soon as the wings have fully expanded, although female horse flies need to feed on large quantities of blood before depositing the egg mass, in order to provide her young with the nutrients they need to develop.

Conservation status: No horse fly species has been evaluated by the IUCN, and due to their large numbers  populations are considered stable. However, some species only live in certain habitats, particularly wetlands, which are threatened by pollution or destruction.

If you like what I do, consider leaving a tip or buying me a ko-fi!

Photos

Large marsh horse fly (Tabanus autumnalis) by AJ Cann

Greenhead horse fly (Tabanus nigrovittatus) by Claudia Husseneder

American horse fly (Tabanus americanus) by Sturgis McKeever

[dingodad]

i spent so many years arguing against grubscars by being like guys that's not how REAL insects work .. trolls don't moult they're holometabolous read the comic closely.. which was such a waste of my time because you don't even need to bring entomology into the conversation. this is the textual metaphor for troll pupation

yeah i'm sure this is just a gradual process of moulting layer by layer. i'm sure vriska only had a couple of scars on her ribs after this happened to her

[ipsen]

Holometabolism has reached 100 kudos!

thanks so much for your support for the Sincerely, Sen series!

[jimkinnz]

homunculus facts¡

homunculi are typically hemimetabolous' lacking any sort of pupal stage•

some homunculi recovered in amber deposits from the latest cretaceous seem to have done a process similar to pupation' however•

in my experience' some homunculi are perhaps voluntarily holometabolous•

by cuddling down in a sleeping bag or duvet•

pictured below; the author pupating but not metamorphosing•

[bowelfly]

What are imaginal discs? That’s something I see mentioned about insect larvae, but I’m unclear what they are exactly?

okay so. to begin with, you have holometabolous insects, that is to say ones with grub-like immature stages rather than ones whose immatures are basically smaller versions of the adults, so things like flies and beetles and moths as opposed to grasshoppers and true bugs which are hemimetabolous insects. the advantage of the holometabolous lifestyle is that the larvae exploit entirely different ecological niches from the adults and thus don't compete with them for space and resources. like a maggot and an adult fly live in different places, eat different things, and so on. additionally, when your body is basically a big flexible sac with a mouth, you can eat a lot more and grow a lot faster, while immature hemimetabolous insects have to go through the whole molting rigamarole every time they outgrow their chitin.

the problem of the holometabolous lifestyle is how the hell do you transform from a grub or a maggot or a caterpillar to an adult insect? they're entirely different body types built for different things; again a simple sac with a mouth vs a complicated adult with wings and legs and genitals and all that fancy stuff. when a larva pupates, it doesn't just completely liquify and regrow all those parts from nothing, that would be ridiculous. so instead what happens is that the larva has these imaginal discs, which are clumps of special cells throughout its body that, as insect grows and nears pupation time, develop into the precursors to all the adult limbs and organs. imagine them as sort of deflated versions of the adult organs, tightly packed into little disc-shaped bundles that, when the larva pupates, evert and inflate, while all the other non-imaginal cells liquefy.

[sonohban]

Oh this is something I'm awfully excited to ask you but I keep on forgetting!! But anyway, if you'll create an alien race based on bugs in dragon ball how would you go about it? Like what would be the most important detail do you think they should have? (I want to ask you about specifics of that race too but I don't want to pressure you on answering since I'm sure that would be long. Just an idea of what an alien bug race can be would be awesome!)

THIS IS SUCH A GREAT QUESTION..... because it makes me think so hard i can't think of anything conclusively :') first up is- would this insect race be one species? one family? one order? or just a mix of all different kinds? there's literally around a million insect species and almost 30 orders that are INCREDIBLY diverse in form. i don't want to paste every single example here but here's just the silhouettes to give you an idea!!

(deep longing sigh, a graphic from one of my favorite papers by misof et al. 2014)

but also i could just. make up a new bug entirely?? 😳 like just smash together my favorite characteristics from across the insect world... what sounds good to me atm is cool wings (i like plain membranous more than the scaly wings of butterflies/moths, you can get cool patterns with them too), the general horse shape of a mantis/snakefly and sound producing organs (insects make noises in different ways! crickets stridulate by rubbing their wings together, cicadas expand/contract their tymbals, hissing roaches compress air through their spiracles). i like the idea of insects singing to communicate, it's pretty much only to attract mates or scare predators but i think it's a generally romantic idea :'3 i also think it's cool to consider aspects of physiology, like insects have an open circulatory system (their organs are bathed in hemolymph instead of supplied by vessels), they have a more decentralized nervous system (can still get around despite lots of their body missing), they can overwinter, among other things. oh i think i'd also like them to be holometabolous (larva>pupa>adult rather than a nymph that gradually sheds into its adult form) because i want to see proud parents holding their cute little worm babies :3c

in terms of dragon ball i can say what i won't do- toriyama i'm making a callout post on tumblr dot com- there are insects other than cicadas (although i LOVE cicadas) but i am tired of these things

it is a real structure found among the true bugs (order hemiptera, includes aphids, leafhoppers, cicadas, etc.) called a cibarium which basically houses the big muscles the herbivorous members use to suck up plant juices. SUCK, you say?? yeah these things don't have chewing mouthparts so shut your weird beak mouth, cell. you're supposed to be sucking up people with that instead. their mouths have been modified into straw things called a rostrum which you can barely see under the cibarium of that cicada. if i had to make an alien race based off these kinds of bugs, their mouths would remain rostra and i'd definitely have them communicate through sound production only. that would be hella cool.

(also while we're on the cell callout train, cell's wings are based off the shell of a beetle which are technically called elytra but THERE'S ALSO SUPPOSED TO BE MEMBRANOUS NORMAL WINGS UNDERNEATH! insects typically have two pairs of wings and the shell of a beetle is just the hardened first pair.)

hehe sorry that went on for a bit. take some bonus doodles that this inspired although i wouldn't consider these examples of a sentient alien race. i really like snakeflies and think they're adorable OTL

[horrendousmustard]

MY SWEET APATHETIC SOUL RETURNS!?!?!?

[bugginzoey]

Pokémon like butterfree and heracross are holometabolous. This means means that they undergo complete metamorphosisis

Pokémon like scyther, and durant are hemimetabolous. This means that they undergo incomplete metamorphosis. The nymphal stages will look more or less like the adult but their will be differences

Now yanma is hemimetabolous but it’s goofy and silly cuz there is quite a bit of physiological variation between their nymph (driad) stages and their adult stages (not as much as butterflies and beetles but still holy Mary mother of mackerel)

[crevicedwelling]

Might be a silly question, but do all arthropods have a larval stage?

no, arthropods like spiders and centipedes don’t have larvae and hatch directly into juveniles; and while the bulk of insect diversity is made of species that do have larvae, a lot of insects, like mantises, roaches, and grasshoppers, also have no larval stage.

the insects do that have the larva-pupa-adult lifestyle form a monophyletic group, the Endopterygota, which means larval juveniles only evolved once in insects.

(from Wikipedia)

ancestrally, insects hatched out of the egg looking like a tiny adult, and kept on molting even after becoming adults (today, bristletails and silverfish are the only ones that still develop like this). at some point, the adult stage of some insects evolved wings, which is where molting stops for an individual (pretty much all of the insects you’re familiar with). these insects still had juveniles that resemble adults, like how cockroach nymphs look and live similarly to adults. eventually, the ancestors of the Endopterygota evolved juveniles that didn’t look or act like adults, which allowed the larvae and adults to efficiently make use of different food sources and habitats.

larval instars, or molting stages, are the same instars that non-holometabolous insects go through, but to support the complex development of a very different body plan, the second-to last doesn’t do much moving—it’s a pupa. a hypothetical exopterygote (no larva) might develop like this: egg, i1 (nymph), i2, i3, i4, i5, i6, i7 (adult). meanwhile, a hypothetical endopterygote with the same number of instars would develop like this: egg, i1 (larva), i2, i3, i4, i5, i6 (pupa), i7 (adult). essentially, larvae and pupae are just highly modified nymphal stages!

however, “larva” is a general term for a juvenile stage that’s very different from the adult. many marine arthropods have tiny juveniles that drift as plankton before growing large enough to live on solid ground. many crustaceans, like crabs and shrimp, do this, but chelicerates like sea spiders and horseshoe crabs, and the extinct trilobites, also have or had tiny planktonic larvae. these larvae don’t share a an evolutionary origin with insect larvae though.