And the last part of this headcanon series of the typical changeling! I’m planning on making one for Chrysalis and Thorax’s hive specifically too, but that might be a while as I think I’ll take a break from changelings for a bit ^^
 
 
Oh, and once again, please be careful reading this if anything to with reproduction or biology in general is gross to you. I don’t really describe stuff in depth, but I do mention things you might not want to look up on google image search later. Then again, considering the title in the image, I’m not sure what you were thinking you’d read about here. =P
 
Reproduction  
Asexual Reproduction:  
All adults which can lay eggs are able to reproduce asexually, though the eggs they lay will contain clones of themselves. But having a hive full of completely identical individuals isn’t a very good thing -any illness would race though the hive like wildfire. So this method is only ever used if the hive is in desparate need of more grubs.
 
 
Sexual Reproduction:  
Adults which have a functional spermatheca (practically only Queens, barring any unforseen mutations), are able to mate with a drone and will lay eggs which contain grubs made from both their DNA. A clutch of eggs layed by a queen can have several different sires.
 
Queens which are strong enough can use magic to influence to some extent how much the grubs inherit from their sire, which is another reason why having your hive appearing as a specific thing is so desirable -it shows off the Queen ‘s magic ability. So technically are all changelings genetically modified to some degree.
 
 
“Live birth”, Delaying and Implanting:  
A changeling can technically opt to not lay the egg and just wait. They will then give pseudo-live birth to the grub when it hatches and their body will absorb the egg-shell. This isn’t done often, because why would they want to? Carrying around an egg inside you isn’t very comfortable, when you can just pop it out and stick it to the nursery floor with some goop.
 
They can also delay the hatching of an egg by supplying it with love and the right nutients, which are absorbed through the soft egg-shell. This causes the hatching to be delayed and makes the egg, and the grub inside it, larger. This can only be done up to a certain point though, once they reach the size of about a pony newborn they can’t grow any more unless they hatch. A grub that had been delayed like this is obviously much larger than those who weren’t -but it still takes as much time for them to grow up as their counterparts, they just need less food in the beginning.
 
The reason for the existance of the pseudo live birth and delaying, is so that an infiltrator can trick their prey into thinking they’re having a child together. Live birth for obvious reasons; no matter how skilled a changeling is at tricking their prey, it’s very difficult to convince someone an egg is a newborn. The delay is both so that the “pregnancy” lasts the right amount of time, and so that the grub being born is large enough that covering them in an illusion of a newborn foal is easier. A baby the size of a chicken egg would be very… peculiar.
 
They can carry the “pregnancy” themselves, in which case they supply the egg with love and nutirents from their blood, until they “give birth” to a grub already wrapped in an illusion.
 
This takes a lot of energy though. The more effective alternative is to choose a prey capable of being pregnant and implanting and egg inside them. The changeling remains close and supplies the egg with love, while the egg itself tricks the body into thinking it’s actually pregnant and absorbs nutrients from the placenta the body makes. Once again, the grub that’s born is already covered in an illusion so the mother thinks its a foal. The changeling parent remains with the grub at least until it metamorphises into it’s next form, and they’re then free to leave to find another prey if they wish.
 
(Both of these versions of the grub is taken care of by a prey thinking it’s theirs, shall henceforth be known as “surrogacy”, and the eggs being rasied in the hive shall be called …“being raised in the hive”.)
 
 
History of reproductive strategy:  
A few thousand years ago, the surrogacy method (most often implanting) used to be very common, with the majority of hives using it for some if not all of their reproduction. It was a cheap way of raising grubs, as their protection and all their nutritional needs were taken care of by a third party.
 
But, they got a bit too cocky in their belief they were mighty changelings, easily tricking the feeble-minded ponies (Alright, so I’m using “ponies” here as a catch-all term, but technically changelings fed on all equines, not just ponies). Sure, ponies knew that changelings existed, but the changelings didn’t much care; what does it matter that the ponies know about them, if they still can’t tell who is and isn’t one?
 
But the ponies were not happy. Not only were their spouses being kidnapped, but so were their children (obviously assuming that their foals had been replaced, rather than that they never were foals in the first place). And they were pissed. So they tried different methods of revealing the illusions of a changelings, all of which failed, reinforcing the changelings’ belief in their own superiority. Until the ponies eventually found a very interesting type of fungus. It didn’t affect ponies, but insects? Didn’t fare too well. It took over their body and impared their cognitive abilites until they died.
 
Changeling’s are technically insects, but they aren’t exactly normal. The magic and immune system of adult changelings were more than enough for their bodies to fight of the spores. So they thought they’d won again…
 
…Except they were reminded of that the grubs and juvenile changelings don’t have a very strong immune system nor magic.
 
Many hives lost all of their next generation paractically overnight, with some unable to recover and completely fading away. The surrogacy strategy was immedietly abandoned, as all hives kept their eggs and grubs safely inside away from any spores. Changelings were given a kick by reality, and learned the valuable lesson of remaining hidden. Making sure to pass onto their descendants how important it was to never ever let their prey know of their existance.
 
Since then Equestria was founded, Discord returned for a while, the Sisters took over… changeling’s were mostly forgotten except in old mare’s tales. The changelings themselves forgot much of their past over the eons, except for the knowledge that changelings must remain hidden at all cost. Surrogacy is almost never used, and most hives don’t even know that “implanting” it is a thing they can do.
 
It can, however, still be found in pony legends about foals being replaced with monsters who look just like them, draining the parents of their energy until they’re discovered dead with the “foal” nowhere to be found. Or even in the ponies’ scientific name for them (decided after the Canterlot attack and the realization they weren’t just legends): Entomocuculi, the insect cuckoo -an insect named after a bird who lays their eggs inside other birds’ nests, replacing the parent birds’ real offspring with their own.
 
Life Cycle  
Egg  
As mentioned, modern Changeling almost exclusively use eggs. They are soft and sticky and about the size of a chicken egg. As also mentioend they can be larger by delaying the hatching, but that is almost never used in modern times. With surrogacy being largely a thing of the past, they don’t really have much need for big grubs. After hatching they still take as much time to raise as normal sized grubs, and they take more time and energy before hatching. So there’s no point.
 
Workers and soldiers lay one to two eggs at a time, while queens can lay up to twenty in one clutch.
 
 
Grub  
Normal, non-delayed, grubs are tiny. They remain as grubs for about a year, during which time they’ll need to eat a lot of actual food. After a year they’ll have grown to about the size of a pony toddler, at which point they’re physically ready to undergo metamorphosis. Grubs spend their life inside pods on a wall, either eating or sleeping, with adults feeding them and removing their waste.
 
Grubs are connected to the hivemind from hatching, though they don’t contribute much aside from sending distress signals when something is wrong. They might also chirp to indicate that they’re hungry if they see an adult. They have magic, but they can’t really use it by themselves. Adults can put an illusion of them and via the hivemind make them keep it up with their own magic, but they can’t make their own illusions.
 
Initially, grubs can’t share love (well, they can love normally, or as much as babies are capable of it, but they can’t share love they’ve absorbed from others). They gain that ability once they’re about one year old. They also need to actually perform this ability, sharing love, in order to trigger a proper metamorphosis.
 
One theory as to why why the metamorphosis is only triggered by this is because it’s better for the hive in the long run. Those hives where the grubs became adults without having to share love, ran the risk of getting workers who were unable or unwilling to perform this necessary part of the hive’s function. (As mentioned in the previous part, sharing love between changelings is necessary to break it down into a from they can absorb more easily. “Raw” love is tough anf gives less energy) Those hives who had the genetic quirk of needing to share to trigger becoming an adult, guaranteed that all their workers could and would share love. It favoured team players’ survival.
 
Another theory is that some part of a changeling’s magic needs to be “activated” somehow, and sharing love is one way of doing it. Changelings aren’t very open to being studied, and most don’t care enough about the reason to study it themselves, so guesswork is the best most ponies have.
 
 
Pupa  
The pod the grub loved in encases them completely and they turn themselves into liquid. After about a week, they break out as proper changelings.
 
 
Forced Pupa  
If a changeling doesn’t share love they can’t undergo proper natural metamorphosis. Buuut, they can be forced to undergo something similar. The queen can use the hivemind to manually trigger a metamorphosis. The forced pupation takes shorter time than a proper one.
 
 
Pseudo-Adult  
Otherwise known as a Corrupted changeling, results from a forced pupation.
 
The problem is that, due to the pupation being forced, the grub won’t be completely and properly transformed. They’ll retain their grub coloration, and their extemeties will be covered in holes as the exoskeleton is unable to form properly. Their wings and shell will be malformed and the latter often missing completely. Their connection to the hivemind is stenuous at best, and even when they grow old enough, their genitalia hasn’t formed properly.
 
They are very rare, as most grubs do undergo metamorphosis by themselves. If a grub isn’t able to, this Corrupted version isn’t always what happens either. Depending on the hive, they might just be outright culled instead. But many hives do opt for this version instead. A changeling hive’s workers and soldiers are in many cases very tight knit, and will care for one another. Not all hives, but many. I guess I’m trying to say, hives are as varied as people are in how they think, act and what their morals and beliefs are. So anyway, a grub that can’t become a pupa by itself might be forced by the queen, and given some simpler tasks to do while still being fed and cared for. Or they’re culled. It varies a lot.
 
 
Juvenile  
Successful metamorphosis! In normal insects, they would probably be complete adults in this form. For changelings however, they are still unable to lay/fertalize eggs and are much smaller than true adults. They’re kids, still juveniles. They shed their exoskeleton several times over during this time, in order to allow their body to grow. Juveniles follow an adult of their type around and help/learn their duties, until they reach about ten years old.
 
 
Adult  
They are then full adults, and take up all the duties that entails. Yeah, they grow up pretty fast. That’s why Thorax was a teen when he first met Spike, but an adult a bit over one year later - he went from nine years old to ten, or the pony equivalent of a 15 years old, to an 18 years old. Ocellus is eight when she starts going to Twilight’s school.
 
What type they become depends mostly on their own personality -any grub can theoreticallt become anytype fo changeling. If a grub is adventurous or feel like they want to leave the hive, they become a drone. If they feel like they are in danger, or if they’re very protective of their fellow grubs they become a soldier. Pretty much anything else and they’ll be workers. However, in situation such as if the hive is in danger, they might become soldiers despite not feeling suited for that role, because the feeling of being in danger is so strong through the hivemind.
 
A queen can also try to use the hivemind in this way to force changelings to become the type they want them to be. By permeating the hivemind with the feeling of being adventurous to try and make the grubs become drones and so on.
 
The changelings which result from these scenarios, when it’s not just their personalities making the choice, might end up as mixes. A worker/soldeir with a spiked hornm short tail and thick shell. Or a soldier/drone with a small horn, spiked shell and large wings. Soldier/Worker mixes can lay clone eggs like full soldiers and workers, but any drone-mix is usually infertile. Mixes (or those that aren’t any of the three in any way) can also just occur naturally every now and again, if a grub feels like both or neither or anything which isn’t clearly worker, soldier or drone.
 
Ocellus is actually a worker/soldier -she has slight spikes on her horn and no crystals, but a thin smooth shell and long tail. Chrysalis really wanted more soldiers; if she hadn’t pushed grub-Ocellus towards it, she’d probably be a full worker. Thorax’s hive doesn’t really think in those terms though, they’ve modelled themselves entirely after ponies. If you asked Ocellus about this she’d be confused about what you wanted and say that she is female.
 
Old changelings look the same as young ones, but they are physically weaker and are assigned easy jobs if they can still work. If they can’t
 
Workers, Soldiers and Drones usually only live for about 40 years. They’re a species that live fast and die young, much to their non-changeling friends’ sorrow.
 
Reformed Adult  
If a Corrupted adult later gains the ability to share love (or if they always had it and just never used it before), they can often trigger a second metamorphosis which makes them full adults. This one is purely magic-based, so they don’t actually pupae. They usually don’t end up completely unscathed though; depending on how long they were corrupted they might still have holes in their wings, incomplete shells, and almost always discolored spots on their exoskeleton where it used to be broken. But, aside from their outside appearence, they are able to do almost anything any other changeling adult can do.
 
Thorax was barely an adult when he reformed, so he only has a few faint spots on his hooves (in my nextgen vere), while some of the older changelings in his hive look like they have been splattered in ink. Ocellus has a few discolorations on her shell!
 
 
Queen  
If a new queen is needed, the “strongest” (smartest/most confident/best decision maker etc) worker or soldier is picked subconsciously by the entire hive via the hivemind. They are filled with magic from their fellow hivemates, and then metamorphose into a queen. A changeling can theoretically turn themself into a queen by filling themself up with changeling magic somehow.
 
There are many reasons a new queen is chosen. The hive has expanded and a new sub-queen is needed. The old queen has died and they need a replacement. An old queen turned out to be bad, so the hive pushed them out of the hivemind. Or a new territory has been found and they want to claim it -a new queen is quickly made, and the old one sets out with some workers and soldiers to start a new daughter hive. (Has it’s own hivemind, but works very close together to its parent hive, sharing resources and trade workers as needed)
 
Queens live for about 300 years; Thorax is very glad his brother also became one, or he’d have to watch everyone he grew up with die.