Plenumeiosis

Public biology record
Property of the Royal Atheneum of Hövnís, Eörpe

Contains mention of parasitism and disease.

Origin: Mersanida Type: Biological Process

Plenumeiosis is a group of biological processes unique to the mersanida sphere of life, and is used to make alien, carbon-based biomatter compatible with their biochemistry. Converting biomatter is necessary for extracting sustenance, sustaining a parasitic life cycle, or providing genetic material.
In nearly all cases, an organism will require one or more donor organisms of a mass that's at minimum equal to their own in order to complete plenumeiosis. Most mersanida tend to not grow very large for this reason, with species within the skethelis order being a notable exception. Also species within the mercurin order had a potential to grow to colossal size, but it'd likely take several centuries even with a steady food supply.

Etymology & Definition

The name is a composite of the words 'plenum' and 'meiosis', and was coined back when it was believed the process was only used as a means for species of the skethelis order to overtake and bioengineer biospheres into new habitats.

Vectors

In order to successfully complete plenumeiosis the foreign biomatter component must be made susceptible to the process, which is typically done by infection via different pathogens. Either the species itself is able to act as a pathogen, or it deploys specialized symbiotes for this purpose.
More information on the pathogens, their symptoms and effects, can be found in the article on ablateocosis.

Function

The exact process and function differ between species, and is highly dependent on their needs. Species may utilize plenumeiosis to fulfill a single function, or several. Known functions include:
◈ An effective and adaptive digestive process.
◈ Asexual reproduction that circumvent creation of clonal offspring.
◈ Refreshing or replacing degrading parts of or the whole self.
◈ Supporting a parasitoid life cycle.

Plenumeiosis have some similarities to morphogenesis, but includes the breakdown of cells and modification of genes in the donor organism. These steps ensure that foreign biomatter can be absorbed and used for nutrition and energy, fusion, or grafts without fear of being rejected by the recipient organism's immune system.

Known Plenumeiosic Processes

This section will go into detail about the different functions plenumeiosis found in different mersanida species.

Pathogenic Digestion

Ranomaru, samleon, and uyetsoub hunt prey of roughly their own size every one or two months, and likely spend a significant amount of the time in between digesting and metabolizing.
Captured prey is kept alive if possible and stored in a secure location, injected with their symbiotic plenumeirons, and then left for at least a day. The chosen location was rarely their own nest. Plenumeiosis triggered by the pathogen breaks down their cellular structure into something that's digestible – more or less liquefying everything beneath the epidermis layer. Once the process is completed, they return to devour their prey. Inedible parts, such as the epidermis, clothes, and any carried personal effects, is left behind.
Parasitoidism
The larva of ahn kereu, lus selec, and samleon use limited pathogenic digestion in order to feed off their hosts – locally converting enough biomatter to sustain themselves in order to preserve the life of their host for as long as possible. I ranomaru, the hatching of the larva will trigger the parent to undergo plenumeiosis with the host. This kills them in the process but means the growing larva will have more than enough food from both their and their victim's combined body mass.

Morphogenesic Fusion

The innuampa and sejotai act as pathogens themselves, and will break down the cellular structure of caught prey before converting what they can into absorbable nutrients. This plenumitosis triggers reflexively upon coming in contact with a food source and the time it takes to digest is relative to its size compared to the size of its prey. Indigestible matter is simply exuded and left behind.

Endocrine Reprogramming

During the later stages of parasitic infection, the larva of the samleon is able to modify their host's endocrine system to increase their survival chances. This will cause the victim to become sensitive to darkness and cold, make them seek sunlit areas, and heighten their tolerance to pain.

Replication

The use of plenumeiosis to perpetuate the self was a possibly unique feature for the uyetsoub, and it's unknown whether they also do non-clonal reproduction similar to other mersanida. The entire process would typically take around two months, during which the uyetsoub and a donor organism would slowly fuse together, liquify, mix, and then re-solidify as a new iteration of the uyetsoub.
Donor Organism
As a suitable donor organism was important for successful replication, uyetsoub were very picky and could spend a long time stalking potential targets. Aside fulfilling the mass requirements, a donor organism had to have finished developmental growth, be in good health, and not passed far beyond their middle-age. With age other qualities could be sought after in donor organisms to determine suitability, but these were results of developing personal preferences and desires.
Once a suitable donor organism was found it'd be captured alive and carried back to the nest. After stripping away anything they may have worn, the uyetsoub would proceed to engulf them. They'd enclose as much of their target as possible in their true maw – usually by lowering down over it as it faces upward, in order to prevent any vocalization from potentially drawing attention.
Morphogenesic Assimilation Stage
Heterotypic cell fusion typically took two to three weeks, beginning with infection of the donor organism with plenumeirons. These virion-like agents would rapidly break down its immune system before proceeding to invade individual cells and release nucleic acids. The nucleic acids either reprogrammed the cells to facilitate the upcoming fusion, or broke them apart into their base components to be fed to the plenumeirons or expelled as waste material. Externally this would be a horrific visual of the two bodies slowly melting together into a mass of flesh, skin, and hairs with just a vague outline of former extremities. This pile exuded an overpowering stench of rot and ammonia.
Expelled waste products and water got excreted as a sticky substance and eventually dried and hardened into a cocoon. The completion of the cocoon triggered the next phase where the encapsulated mass was liquified and mixed together through repeated cycles of cell fusion and division. This could take upward to six weeks.
In the next and final phase, the slurry of protoplasm underwent morphogenesis and cells began to bind together. The bindings continued and increased in complexity until achieving a pre-programmed result: the new iteration of the uyetsoub. Within a day or two after the final phase finishes, the new iteration would gain consciousness. It'd feed on the leftover protoplasm slush before breaking out of the cocoon, ready to resume its life cycle.

Endoparasitic Fusion

21-32 days after the ahn kereu larva has hatched, it'll be ready to begin fusion through plenumeiosis, which serves to bridge the biological gap between itself and its host.
By subtly reprogramming both a part of its own and the host's cell structure until their immune systems recognize each other as compatible, it can graft itself onto the host and seize control of their body. During this time the remainder of the host's brain will be used as fuel for the process, leaving the parasite as its full replacement upon completion.
It appears that the mental capacity of the host has some influence on the development of the larva, but it's not fully understood how. But it explains why the ahn kereu will favor hosts that are sapient above all else.

Klepto-assimilation

In the skethelis order, the agglamus act as the primary vector through which the rest can gain a foothold in alien biospheres. Once it's converted all matter it can, other skethelis species move in and propagate through more conventional reproduction mechanisms.
There appear to be some level of sampling and transfer of genetic code from species that are consumed and assimilated. Subsumed worlds would be expected to turn out mostly uniform, but that's proven to be far from the case. There's entire genomes of new skethelis life forming on these worlds that mimic some or all biological traits of species previously existing there, even when there's not enough external pressure to justify adaptation-driven evolution.

Plenumitosis

The innuampa and sejotai appear to have a strong instinct to devour others of their own species, while otherwise being repelled by the presence of other mersanida. When two individuals meet it's usually the larger and older one that end up consuming the other. The resulting mass of the winning side is directly proportional to the mass they consumed.
In innuampa it's been observed that the losing individual may attempt to split up and flee, to later reconvene in a safe environment, thus managing to preserve at least a portion of itself. The full consequences of any lost mass is unknown.
It's not fully understood what criteria need to be met to trigger their morphogenesic reproduction, but it's thought to have to do with having absorbed enough mass from other individuals of their kind, having a sufficient energy storage, and a favorable environments. Most times it's been observed in wet environments – either open water or wetlands.
Innuampa and sejotai reproduce by splitting their entire aggregated mass into numerous new separate units. Nothing of the original individual is left behind except for some byproducts. The offspring uses genetic material from its sacrificial parent as well as all individuals they consumed. These quickly slither off in different directions, attempting to gain as much distance as possible from one another before their instincts kick in. Even so, it's estimated only 20% of a clutch survives while the rest end up as food for their siblings.