Border Wars: Of the Bamboo and the Ant

Five million years is not a long time on a geologic time scale - it is, however, enough to have brought some significant innovations to Serina's ecology. Within this span have occurred numerous large evolutionary innovations not quite reached just five million years ago. Entire new forests now grow across Anciska and the north of Striata - no longer unnatural monocroppings, the sunflower barrens, these have instead given way to diverse forests of false trees composed in fact of large, perennial sunflowers which have since traded their annual growth habit to stand the year round on insulated above-ground trunks, providing a source of food and shelter to many animals the year round.

Grasses begin to diversify noticeably in the Tempuscene as initial explosions of adaptable primitive plants die back and are replaced by, or themselves adapt into, forms adapted specifically to the conditions on Serina. Bamboo, pushed to rarer wet environments by a drying climate, still absolutely monopolize anywhere wet enough to support them, from pole to equator, thanks in part to an increasingly mutualistic relationship many species have begun to develop with a number of species of small leafcutter ants which evolve to live almost their entire lives based within the warmth and safety of their hollow stalks. Aided by the shelter that nests within the bamboo provided from cold, rain, and predators, the insects have begun in the Tempuscene to spread back northwards and south. Protected by nests inside these hard woody stalks, they can hibernate long winters away without much worry of being eaten by hungry birds. Initially existing as a parasite to the bamboo trees, they live within them as long as they can before they've eaten away too much of a cane's foliage for it to survive, and the cane dies - and takes with it the colony. By now however, some species have ceased to feed upon their own host plants or host species, allowing it to grow for longer and prolonging their own lifespans. In return, some bamboo begin now to evolve specially-designed hollow knots at their joints to accommodate the insects, which now serve to guard them from the onslaught of other ant colonies which try to feed on them. It becomes advantageous for bamboo clumps to attract and hold onto their own resident ant populations, for if claimed by one as home, it will not be eaten by another as supper. Many leaf-cutter ants evolve new warrior casts similar to those normally only seen in predatory ants, which serve only to guard host trees from the hungers of neighboring ant colonies while foragers, similar to the ancestral ants, go out to feed on their neighbor's home groves and braving their own warriors, unaware of the irony in the whole situation. It is the bamboo which are the true winners no matter what, however - all guarded by their own armies, they are individually all eaten considerably less frequently and in lesser quantity than otherwise they would be without the ant's border wars. Though the ants must consume the same amount of food no matter what, they no longer decimate single groves to death, instead taking only small and sustainable quantities from each plant.