A Guide to Dawn Muricene Woodlice

The pill bugs of Apterra are arguably its most important large animal group. These hardy crustaceans occupy a decomposer niche, feasting on mold, detritus, and decaying plant matter. They live in the shadows, under rocks and in the soil, and are a vital food source for the rats, kiwis, and geckos of their world. They are immensely widespread, and at this point they are the most diverse animal lineage on the planet. They now fill a variety of roles in their environment, and in some regions up to a dozen incipient species can be found living alongside one another.

One tropical population has a symbiotic relationship with grasses, consuming pathogens and mold growing within their stems, leaves, and roots, receiving in exchange a reward of nectar secreted along the plants’ stalks. A close relative has a far less friendly partnership with the local flora, taking on a parasitic lifestyle. These isopods consume the nectar and the mold like their cousins, then proceed to eat the plant itself. Some species of grasses, in turn, have already begun to evolve mild toxins to avoid this fate. This marks the beginning of an arms race that will take both groups in extreme directions as the Muricene progresses. For now, though, the grazing woodlice dominate many ecosystems, in some regions making up over 75% of isopod biomass.

Another lifestyle has emerged in a clade that dwells on the cold steppes of Loxodia, nestled between a towering mountain range and the expanse of the ten-year desert. In these foothills, little grass grows and little rain falls. Nightly temperatures can drop below freezing even in the summer, and cold, dry winds blow down from the peaks above them. Despite this, one tough branch of the Armadillidium descendants has made its home here, huddling in rare pockets of moisture beneath rocks. By night they remain here, sheltered just above the freezing point until the sun rises again. Each morning they scatter, looking for food across a wide area surrounding their gathering place. The modest warmth of summer allows a few hardy grasses to grow with relative abundance, but winter forces the pill bugs to go without food for up to four months.

Of these mountain isopods, one solves this problem the simple way: it enters diapause through the long cold season, waking only when the sun warms the soil around their winter nests. A close cousin of this variety collects seeds during the autumn months. These are its sole food source during the winter, and it takes care to avoid letting them rot, as a mold outbreak could destroy its entire supply in a matter of days. When spring comes, it shifts its diet back to an assortment of detritus and rotting plants, abandoning whatever seeds are left over from its stockpile. A lucky few of these may sprout soon after, beginning a new generation of flora for the bugs to feed on. In particularly high-elevation regions, this is often the only reliable means for plants to reproduce, as any seed left outside the warmth and shelter of a nest would quickly find itself destroyed by the elements.

On the warm plains of Abeli, local pill bugs have a foe even deadlier than the cold: rats. These opportunists can consume dozens of isopods in a sitting, and there are precious few places to hide on the savanna. The lowland woodlice, though, have devised a few tricks to keep themselves safe. One lives alongside the burrowing kiwis, emerging at night to forage and retreating every morning into the safety of the nest. They face danger here too, as their hosts would be more than happy to snack on them given the chance. However, these isopods' flattened bodies allow them to slip into crevices out of the kiwis' sight. In exchange for a safe place to hide and reproduce, the crustaceans eat any mold growing in the nest, increasing the chick’s odds of survival.

A heavily-armored variety, on the other hand, braves the open grassland all day long, relying on nothing but its exoskeleton to keep from being eaten. Two rows of spikes emerge along its back, piercing the gums of any rat that decides to try its luck. These isopods are also much larger than most of their cousins, reaching lengths in excess of two centimeters. Despite this, they maintain the capacity to roll into a tight ball, covered in sharp spines pointing in all directions. While an especially crafty rodent would likely be able to break through these defenses, the vast majority tend to stick to easier foods, such as the smaller isopods hiding in the soil below.

The armored woodlice, despite their adaptations, do have one enemy. Kiwis, with their long beaks, have no trouble plucking a rolled-up bug from the ground, bashing it against a hard object, and eating the soft meat inside. As a result, the spine-backed Armadillidium keep a wide berth from any Apteryx nests they find, leaving their cryptic cousins to dominate those microhabitats.