Big Bugs of the Hothouse Age

290 Million Years Post-Establishment

The dense jungles surrounding the Serinan south pole remains perpetual sweltering and muggy year-round, from the sunlit summers to the darkness of winter. Even during the height of mid-summer, when twenty-four hours of sunlight beats down for months on end, the dense tree-cover obscures the beaming rays from the forest floor far below. This crowded twilight realm teems with invertebrate life of spectacular diversity and immense proportions, well-suited to a life of warmth, humidity, and darkness, and a cacophonous din echoes with the screams of countless billions of insects and other arthropods day and night. It would be almost as if one stepped back more than three-hundred million years back in time on Earth, were it not for the birds and three-legged land fish of many sizes and shapes that inhabit the region.

One group of insects that flourishes in this region are the trundlebeetles, a group of large, mostly flightless beetles (descended long ago from burying beetles), that include among their ranks the most massive insects to have ever lived. In the absence of the rodent-like poppits and seed-snatchers on the southern continent has in part prompted the evolution of these rodent-like insects. Many species of this group feed predominately on the bamboo-like polepoas and tree sap, but an equal number are opportunistic foragers of the leaf litter. Trundlebeetles are extremely numerous and form a significant basis in the food web of the longdark swamp and surrounding habitats as major prey species for native mesopredators, their numbers kept from scouring the region's vegetation by heavy predation. All but the smallest and most primitive members of this group have given up flight, due to being so large and heavily built, merely taking off would be an arduous struggle. Instead, they have doubled down on defence, fusing their elytra into a single solid carapace, like a turtle's shell, a protective structure often further augmented with vesicant secretions, urticating hairs, or bristling chitinous spines. This has culminated in the group's very largest representative, the behemoth trundlebeetle, the insect equivalent of a tank, slow and ground-bound, but with a shell harder than a coconut rind and capable of ferocious counterattack if pushed. Adults of this species can approach three kilograms in weight and over a foot long, dwarfing the largest beetles on Earth some thirty times over.

So heavy this species grows that it is unable to climb trees or the tall shoots of polepoas to feed from the trunks, and it falls into the other category of being a foraging opportunist, feeding primarily on whatever organic detritus it can uncover on the forest floor. Fallen fruit, fungi, seeds, and carrion are preferred, but it is also capable of hunting smaller, slower, primarily soft-bodied invertebrates like worms, snails, and grubs of other beetle species. Such pickings can be found year-round, and even in the winter, when much life in the region flees or goes dormant, the beetles continue to actively forage. This species is quite social, living in family groups that can number up to three-dozen adults in number (although around one-dozen is much more common), holding territories which they defend viciously from outsiders. Fights between trundlebeetles are quite fascinating, as they smash and swing at each other with their abdomens, the back ends of which are studded with long spikes for this very purpose. Their back ends are brightly marked compared to the dark, dull-coloured rest of the body, keeping the attention away from their more vulnerable heads. Due to their thickened exoskeletons, injuries are extremely uncommon, but fights are prolonged, ending only when one hits exhaustion or is toppled by their foe. Territory locations are primarily coveted for suitable nesting sites, abandoned animal burrows, shaded crevices, or hollow logs, where the beetles can sleep communally and deposit large clutches of eggs. While the adults were well-defended, the eggs and grubs are extremely vulnerable.

During the first few weeks of hatching, the young are soft and feeble, living in their nesting chamber and fed a nutritious liquid regurgitate by the adults. Growing rapidly, they increase in mass some five-hundred times over in the first month of life. At around seven to nine weeks old, they begin to grow independent and start foraging outside the nest alongside the adults. The full-grown behemoth trundlebeetles are not only defended by their physical resilience, rows of urticating spines along their underside, and a powerful bite, but they can spray a blistering fluid from their rear end from a distance of up to twelve feet away. Larvae have few physical defences (outside of simply hiding out of sight), but possess a bioluminescent rear end, which allows the adults to easily keep track of their young and defend them, even in pitch blackness. Due the massive size of the beetles, they have an exceptionally lengthy life cycle for insects; it may take over a year before the grubs reach close to the size of the adults, and they begin to disperse to new territories. Adults will begin breeding again before previous clutches are independent, so multiple generations and numerous sizes of grubs will regularly coexist. Although adult beetles are hostile to adult strangers on sight, they are tolerant of larvae (likely an evolutionary extension of their communal parental care), which intermingle and continue to grow, gradually gaining a familiar scent to a new colony, allowing them to maintain genetic diversity when the larvae pupate and metamorphose into new adults. When a behemoth trundlebeetle grub is preparing to pupate at nearly three years old, it can exceed an adult in weight, reaching nearly 5 kilograms. While this is truly colossal for an insect, in the longdark swamp, this species still coexists with terrestrial invertebrates of far greater sizes.

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Big, unusual insects, of course, are not exclusive only to the longdark swamp; similar giants can be found around the world. A most unique group of insects to have evolved on Serina and can now be found worldwide are the vermites, the equivalent of termites on this world, but evolved from a group of crickets. Specifically, these are the last living descendants of a once diverse group of pollinating crickets that flourished during the early periods of Serina's history, the florgusts. However, the vermites now bear little to no resemblance to the florgusts, due to more than a hundred million years of neotenous degradation, becoming flightless and vermiform, analogously caterpillar-like in appearance, including the development of stumpy pro-legs at the end of the abdomen. These were originally solitary omnivores living in the undergrowth, filling niches similar to Earth's myriapods, but one lineage evolved back into specialized grazers. From this, a species evolved a great degree of sociality, eventually elevating to eusociality, allowing the worm-like insects far greater defences against predators and allowing them to feed far more efficiently in complex cooperations in great numbers.

Most vermites are mound-builders, creating huge and sophisticated constructions that house their colonies, although some species live inside trees and others are completely subterranean. Their nests are complex, with outer walls comprised of a concrete-like composite of hardened mud and cellulose pulp and inner walls held up by paper-like walls of regurgitated wood pulp enforced with thick weaves of overlapping silk strands. Such reinforcement is necessary for withstanding powerful insectivorous predators, the trampling of huge megafauna, and the fury of the hostile elements. Most vermites feed on grass, although others also feed on wood and other plant matter, and others still specialize in fungi or lichen, and can plague the surrounding lands feeding on vegetation like a flightless swarm of locusts in optimal conditions. The colony sizes are primarily limited by two factors; the presence of incredibly destructive megafauna like giant skuorcs and monstrocorns, that can demolish entire mounds with great ease, and competition. with and predation by, ants. Ants are the predominant limiter in terms of vermite range and numbers; despite being on average much smaller in terms of physical size than vermite workers and soldiers, their colonies are capable of razing vermite nests. The vast and towering forests of cementrees that consolidate over the landscape into mountainous sky islands, stretching kilometres high, dwarfing the largest vermite mounds many times over.

However, this is true primarily on the northern supercontinent of Serinarcta. On the southern continent of Serinaustra, cementrees are scarce, and sky islands even scarcer, while thorngrazers and giant skuorcs do not exist. Vermites arrived on the once-barren continent by chance, several million years into the hothouse era, as drifting reproductive nymphs, blown across the sea by their silken parachutes by powerful storm winds. Those that survived the trip discovered an environment free of their primary limiting factors and abundant in natural food sources, primarily in the form of the dancing tree forests that carpeted the landscape. They quickly spread across Serinaustra and diversified, becoming a major herbivorous force in the continent's ecology. Where on the northern landmass, the largest vermite hives reach a few metres tall and may very rarely last for several decades, on the opposite landmass these can tower into the sky and last for millennia, housing many billions of individual insects over their existence.

The most impressive of these mounds are the ones constructed by the obelisk vermite, a large species widespread over the clearview mountains, some more northern portions of the longdark swamp, and the surrounding regions. Their hives can reach over eleven storeys high, dwarfing even the tallest contemporary giraffowls, these frequently contain several million individuals at any one time, mowing through surrounding vegetation as efficiently as any herd of lumpelopes. At such sizes, they become practically permanent landmarks, their surroundings becoming open grasslands over decades as they devour entire trees over decades, leaving only fast, low-growing vegetation in their wake. And running beneath and out of these colossal mounds are kilometres worth of tunnels beneath the earth that maximize foraging efficiency around the central hive. Although they do consume such plant matter as a source of sustenance, the size of their mounds and their collection of vegetation functions primarily as a food source for their main source of sustenance, a type of symbiotic fungus which they cultivate and nourish in vast quantities within their hives. Huge, vertical chambers within the mounds, sometimes several metres long and wide, function like fungal greenhouses, which the vermites constantly fertilize with fresh semi-digested regurgitated plant matter, mixed with microbial secretions of cellulose-digesting gut flora.

Workers make up the vast majority of vermites within the colony, being the primary foragers, farmers, builders, and caretakers within the hive. Enlarged and robust tarsal forelimbs assist them in tunnelling through earth and cleaving new tunnels through their mounds. Soldier castes are separated into two subcastes, the mandibular soldiers and projectile soldiers, which are differentiated by their method of attack. Mandibular soldiers possess massively enlarged mandibles mounted on a large head, allowing them to deliver powerful bites, and their abdomens are covered in rows of urticating hairs that dislodge easily. Projectile soldiers possess large glands next to the mandibles able to spray powerful acidic secretions, as well as a secondary pair of nozzles at their rear end able to spray a vesicant agent from a few meters away. The term "soldier" in this case is a little misleading; although both do play the primary role in defending the hive from raiders and other potential threats, they also play a significant role in other manual labours. The huge jaws of the mandibular soldiers allow them to excavate and move away more soil more quickly than a worker, while the acidic secretions of the projectile soldiers initially evolved to help bore through rock and harder earth, and predigest wood (and are possessed also by workers to a less degree for this purpose), and are continued to be used in this function (the ejective glands at the rear end are purely defensive however). And, although not particularly specialized for the task, workers will also take part in defending the colony.

Vermites communicate primarily through vibrations and pheromones, and generally have very poor eyesight (the projectile soldiers being the main exception, as they have large eyes that help them to aim their shots). Alert pheromones have a rapid cascading effect over the colony, allowing them to very quickly mount a defence towards the perceived threat. Soldiers flush obvious visual signals to ward away dangers, the mandibular soldiers undulating their bodies to show off their toxic spines and projectile soldiers raising the back portion of their flattened abdomen like a cobra flaring out its hood. Retaliation to damage of the hive is swift and in great numbers, as thousands upon thousands of enraged insects pour forth from any breach in their mound walls. Even the largest megafauna of Serinaustra keep a respectful berth from the colossal hives of the vermites for fear of attack.

Workers and soldiers both start off as identical nymphs, and only gradually transform into their roles over multiple instars over the course of a couple of months. Workers and soldiers are both sexless; they do not reproduce and in fact do not possess sex organs at all. As with all eusocial animals, this function falls to the specialized reproductive castes of the colony, in the vermites these are the kings and queens. These dwell within a centralized reproductive chamber deep within the heart of the mound. A hive is initially born when a male and female reproductive nymph encounter one another and mate, which triggers a change in behaviour, from wandering drones to sedentary builders, and begins their metamorphosis into maturity. Before workers are born, the king will initially take on the tasks of building the initial foundations of the nest and defending the queen (and so mostly resembles a larger and more robust worker vermite). The queen develops a massively engorged abdomen that functions as a baby factory, sometimes reaching nearly ten inches in length. Although initially spewing out a mere hundred eggs per day, at full maturity this increases to well over twenty-thousand eggs a day. In larger obelisk vermite colonies, even this is not sufficient to keep up the numbers of the nest's population, and in such situations, the queen may produce eggs through thelytokous parthenogenesis, creating offspring that are genetically identical and metamorphose into neotenous "secondary queens" that pump out eggs at a reduced rate. In the very largest colonies, there can be over forty of these secondary queens present at once.

Both kings and queens can live for decades, sometimes producing millions of children in their lifetimes. Should the primary queen die, one of her neotenous secondary queen offspring may fully metamorphose into a replacement queen, or, if none are present, a nymph may metamorphose into a queen (these are known as "tertiary queens" and their egg output is much less than a primary or even secondary queen, although the name is a bit misleading since they generally only exist when neither secondary or primary queens are present). Should a king die, the workers will release a pheromone scent which attracts roaming male drones, advertising a vacancy in the sperm giving role of the colony, to function as a new replacement king. Vermites are completely flightless at all stages of life. To disperse from a colony in a nuptial flight, the reproductive drones create silken parachutes to balloon great distances from the main mound, avoiding potential inbreeding or competition when searching for mates or building their own nests too close to their original hive. These can travel for tens of miles on optimally windy days, and once the drone touches down, it can travel much more quickly over great distances on the ground than mature vermites due to its, somewhat ironically, atavistic state. Unlike the vermiform adults, the reproductive drones much more closely resemble their original cricket ancestors, lacking the elongated abdomen and prolegs, and retaining the powerful jumping hind legs, helping them to find mates, feed themselves, and avoid predators during the period when they only have themselves to depend on. Very, very few ever survive to successfully create and maintain a thriving mound, but those that do can potential create insect superstructures that can reshape the surrounding landscape for miles around over centuries.

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During the summer months in the longdark swamp, many subtropical forest plants bloom in vast numbers and awe-inspiring splendor to take advantage of the perpetual sunlight and great numbers of pollinating animals. One of the most widespread and numerous of such flower-hunting groups are a subgroup of tickflies which have been drawn away from a diet of blood to one of pollen, plant juices, and nectar known as the mothmites, taking a similar niche to the now long-extinct pollinating florgusts and Earth's lepidopterans. Here, they grow larger than anywhere else on Serina, for this humid, warm forest undergrowth is the perfect habitat for the evolution of gargantuan invertebrates. Hundreds of species adapted to feeding from so many different flowers from many different microbiomes and layers of the forest, as well as other food sources such as the fluids of soft fruits and polepoa sap, ranging in size from fluttering little things less than an inch in wingspan to aerial goliaths stretching nearly fifty centimetres across. On the latter end of this scale is the stupendous mothmite, one of the largest flying arachnids to ever live.

Similar to many tickflies, in mothmites, the females grow heavier than males to facilitate larger egg clutch sizes; in this species, the size difference is not particularly extreme, but males can nonetheless be easily distinguished from females by the vibrant colours and patterns that adorn their wings, which allow females to assess their physical health and identify them from other mothmite species. In the larger and more advanced tickfly species such as these, they have evolved a "tail" of flattened and overlapping hairs on the end of their abdomen that increases their lifting area, allowing them to remain aloft and balanced in the air with less effort. The ability to pivot the abdomen has also allowed this tail to function like a rudder, similar to the tail feathers of birds or the hindleg of tribbats; this is an important attribute for such a large flying arthropod to swoop deftly through the tangled understoreys of the swamp forests, while also avoiding other flying hunters in flight. The stupendous mothmite's size puts it out of the typical diet range of most flying insectivores, but it can still defend itself if necessary with a pair of sharpened pedipalps. These are normally used to help cling to tree trunks at rest, but can be brought out as defensive weapons as a last resort. The stupendous mothmite feeds on large, orchid-like ephiphytes that grow on the branches of large trees, with a long, retractable pair of fang-like chelicerae that draws up the nectar through capillary action.

The imago stage typically lives through from late spring and into early or mid-fall, living around six months at most, at which point the arachnids die as the sunlight hours of the day begin to dwindle. Their adult lives are spent feeding and reproducing almost nonstop, and a typical female will deposit countless hundreds of eggs in the soil over this period. Males compete to mate with as many females as possible, while females attempt to mate with as many males as possible (leading to egg clutches which have multiple different sires). As males tend to be proactive in their efforts to search out females, devoting much more time to searching than eating compared to females, and frequently come into conflict with rival males in the process, they tend to start dropping dead a while before the females do, out of exhaustion or starvation. Young hatch resembling typical mites, feeding on organic matter and smaller invertebrates. Like many insects, the nymph stage of a typical tickfly's life cycle is much lengthier than their adult lifespan. This is more true than ever for the stupendous mothmite due to its tremendous size, which takes considerable time and effort to reach; a hatchling emerges as less than a centimetre in length, but must gradually take in enough nutrients to metamorphose into an adult nearly a foot in length. This process takes upwards of a decade, with the nymph repeatedly moulting and going through radial changes in morphology as it increases in size. From a dirt-forager, it grows into a fearsome, tarantula-like ambush predator weighing some two-hundred grams; large enough to kill and consume prey with endoskeletons, like lumpuses and gups. The spike-like pedipalps function as killing tools in this life stage, only to be repurposed as climbing and defensive tools when it swaps diet from meat to pollen and nectar. Unlike true spiders, it lacks venom, but its size allows it to subdue prey easily enough without it. The lifestyle of the nymph stage varies widely between mothmite species; while the stupendous mothmite becomes an active predator, many smaller species remain detritivores, consume leaves, or subsist on plant sap. Some are tick-like parasitic species with a more rapid life cycle, while others still are maggot-like scavengers.

Unlike insects, which only receive wings during the final moult, certain larger tickflies develop wing buds during earlier moults leading up to the completion of their incomplete metamorphosis, allowing them to more gradually grow in exceptional large wings that would be difficult to develop in a single moulting cycle. This is seen in the stupendous mothmite, which begins development of bulbous nubs that are the precursors to the huge and beautiful filamentous wings of the adults. The nymphs attempt to time their final moult to within a week or two of the mass flowering of spring; if they are ready too early, they will burrow into the soil and enter a dormant state to await this period. Their activities also vary from the sunlit season to the nighttime season; during the summer, the adolescent mothmites enter a hibernation state deep underground, which both helps keep them from accidentally preying on adults of their own species when they descend to the ground to lay eggs, and avoiding larger predators that become far more abundant in the environment during this time. As the night hours grow, the mothmites emerge to prowl the blackened undergrowth, now with far fewer threats to worry about in the dead of winter. From this life stage to adulthood, they possess huge compound eyes: in the adolescent stage these allow the mites to pick up the slightest bit of light and tiniest movement in the leaf-litter, while in adults it is useful for quickly identifying specific flower types and differentiating one another from other mothmite species.

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One of the most fearsome predators to roam Serinaustra is a species of arthropod, small in individual size, but insurmountable in numbers: the terrifying shoggoths. Ants are already among the most feared of all hunting insects, but shoggoths honed their carnivorous efficiency far beyond this over millions of years, evolving into gigantic gestalt superorganisms with a collective intelligence, sometimes several metres in width, capable of bringing down large megafauna with ease and stripping them to the bone within minutes. Such a beast is an undisputed apex predator, threatened only by other large shoggoths, but it is still far from infallible, and has enemies that can penetrate its defences. A myriad of tiny creatures that understand how superbly well-defended and effective a hunter a large shoggoth is, and, against what may seem like common sense, make it their business to be as close as they can get to one as long as possible. Just as a normal animal can succumb to sickness, a shoggoth battles its own microcosm of specialized parasites and freeloaders.

Among arthropods, by far the most common of those to invest the living hives of shoggoths are mites, but one of the most unique is a species of air-breathing crustacean, a decapod which has evolved to live undetected alongside those that would otherwise tear it apart in an instant. The shoggoth crabs (technically, Serina has no true crabs; these, like all Serinan "crabs", are ancestrally hermit crabs) have modified every aspect of themselves to blend into the formic masses. They appear to have three body segments, they walk with an insect-like six-legged skittering, they've mastered the art of communication through antennae-touching, and they extrude the same pheromonal scent that marks them as friend instead of foe. This is all by absolute necessity, for the rewards may be high, but failure is death. The abdomen has become narrow and cone-like and the body itself has elongated to resemble its host species. What may seem like an ant-like head is actually a pair of interlocking and grossly enlarged secondary antennae (similar to the grossly enlarged secondary antennae of slipper lobsters), with the pincers underneath disguised as mandibles. The fourth pair of decapod legs has become extremely reduced and fold underneath the body (as hermit crabs, they were already greatly reduced long before their evolution into insect mimics), although they have a limited function in helping to spread pheromonal secretions over the underside. On side-by-side inspection, it may be easy for human eyes to pick out the crab from the ant, ants are not visual animals, relying on scent, sound, and touch far more greatly, so this is more than able to fool them.

Shoggoth crabs likely evolved around the time sea shoggoths began travelling inland at the end of the. Before becoming inquilines, the earliest species likely evolved from amphibious, air-breathing hermit crabs to resemble shoggoth ants simply as an anti-predator defence while foraging in their wake, snatching up tiny invertebrates flushed out by the colonies' movements, and their disguises got so superb as to fool even the shoggoths themselves. The process of newly joining a shoggoth colony is extremely risky, for the crab must study and imitate the workers' movements, signals, and chemical scent, for it differs just ever slightly between colonies, but once accepted it gains unlimited access to food and shelter for the rest of its life and potentially even beyond, as the crabs will even breed within, depositing their own eggs amongst those of the queens in the incubation chambers, where they develop in complete safety. Due to their elongated, ant-like shape, shoggoth crabs have tiny clutch sizes compared to most crabs, rarely more than a dozen or so, which they compensate for with enormous eggs relative to their size. The offspring skip the larval stage of most other crustaceans, hatching into the intermediate glaucothoe stage, which is already ant-like from the moment of birth.

Numerous castes of varying size and shape make up the superstructure of the shoggoth, and even within each caste the individuals can have a wide size range, and numerous shoggoth crab species have evolved to mimic most of these castes, often within a single species. In the tenebrous shoggoth crab, the male and female sexes mimic differing worker castes. The larger female, which can be more than thrice as massive as the male (sometimes reachinging over four centimetres in total body length), mimics the supermajor workers, the frontrunner soldiers with huge jaws for tearing apart prey, while the smaller and more slenderly built male mimics the major worker, a much more generalist caste which is quite literally the main building block of the colony, operating as both soldiers and linking their bodies together to knit the superorganism together. Such a position gives them easy access to first pickings, as they are among the first upon newly captured prey, racing ahead on a tide of attacking soldier ants. The small, pale megalopses mimic the nursemaid caste, and nestle deep within the safety of the central mass, feeding and growing quickly on regurgitated slurry from replete ants, which they can effortlessly steal right from under the ants' antennae, and sometimes even consuming ant eggs.

To keep from being too suspicious, shoggoth crabs will occasionally assisting in the colony's activities. Female crabs can use their pincers to cut apart food items and attack prey animals, and male crabs will help relay messages and intertwine their bodies with the ants when needed. This is also for the secondary reason of helping keep their host healthy, which is ultimately beneficial to them as well. In a large shoggoth, there may be up to a hundred adult crabs infiltrating them at any one time, although lower numbers are far more common. When a colony fragment splits off to form a new shoggoth, a number of crabs will usually go with it, although if the population rises too high at other points, the excess crabs may leave the colony and attempt to join a new shoggoth, which also helps decrease inbreeding stress. Such extreme behavioural and physiological complexities are necessary for the success of this most unusual of myrmecophiles, inhabiting colonies constructed by the most unusual of ants.