Microscavengers of Northlox

The Middle Arthrocene has seen both the rise of several new clades of scavengers and new adaptations within older ones. While large-bodied scavenging animals can't afford to be picky, smaller ones with lower metabolic demands can become very specialized. The six little animals discussed here can all be found sympatrically in the forests of northern Loxodia, where their particular preferences allow them to coexist and, in many cases, feed side by side without competing.

1 - Lurching Squashtoad

Squashtoads (Arthrobufo) are a genus of large non-dodecipede squashroaches that occupy a variety of niches in the soil and undergrowth of Panapterran forests and grasslands. While they normally get around in the typical manner for their family (by moving their legs in undulating waves), they can employ a very different gait when they need to flee quickly. When a squashtoad is startled, it launches itself with all fourteen legs, shooting forward up to half a meter in a bound. 

The typical sqaushtoad diet has not changed much from that of the first squashroaches, nor indeed from the preferences of the first isopods brought to this planet. Most species primarily eat rotting plant matter, along with any accompanying fungal or bacterial growths, and occasionally take a bite or two from a living grass. The Lurching Squashtoad (A. atrox) has shifted to a more protein-rich diet, split evenly three ways between carrion, live-caught prey, and high-quality green undergrowth. It is the most massive member of its genus, measuring about 10cm from mouthparts to uropods, and is thus able to easily bully its many smaller competitors and claim the best bits of meat for itself - at least, until truly large-bodied scavengers arrive.

2 - Pseudelytrius

This is a diverse genus of solitary woodlice in the family Dermestemimidae. Like its ancient Armadillidium dermestimimus ancestor, Pseudelytrius feeds on the carcasses of many different animal species. It is a cryptic generalist, always trying to remain unnoticed as it feeds cautiously on the margins. It has a powerful gut that can neutralize pathogens, get nutrition from tough-to-digest organic matter, and even filter out toxins from the flesh of poisonous animals, so it is perfectly happy to settle for scraps of flesh that other scavengers find unappetizing.

The Pseudelytrius exoskeleton represents a compromise between effective body armor and a flat profile that can squeeze into tight spaces. Each segment projects back over the next one, forming an overlapping shell that turns into a prickly ball when the isopod rolls up. When the woodlouse unrolls, these plates of armor lie flat, letting their owner slip into narrow crevices in a corpse or, if it feels threatened, into a hiding place nearby.

3 - Gleanerfly

Gleanerflies (Scabomaxilla) are a branch of the locust reaper family closely related to Foliopteryx, but which is adapted for life at ground level rather than up in the canopy. They scavenge only opportunistically, as their mouthparts are capable of eating a wide range of foods. Unlike the original locust reapers, whose rasping, sclerotized projections of each maxillary segment pointed inward, gleanerflies have cutting surfaces that angle in and downward at a 45-degree angle, allowing them to "cookie-cut" chunks of food out of larger objects, usually either a tree trunk or the body of a large, living animal. However, when given the chance, gleanerflies won't shy away from the easy meal provided by carrion at any stage of decomposition. They land on the most appealing parts, cut a chunk out in a matter of seconds, then fly away with their prize before larger scavengers can retaliate. 

4: Blood-Lapping Dustfly

The Blood-Lapping Dustfly (Corvoculex) is a member of the family Polliniculicidae, whose typical form is that of a brightly-colored, slow-flying, nectar-drinking, pollen-distributing fly with four wings. In physical appearance, this genus is not strange for its clade; it has bright orange forewings with yellow veins, while its enlarged halteres have a dark margin, yellow interior, and a black stripe in the middle, mimicking the eye of a mid-sized carnivorous rat. Its hematophagous diet is not actually much of a departure from the feeding strategy of other dustflies. Unlike its relatives, it enjoys the benefits of a protein-rich diet: it only needs to spend an hour or two finding food per day, while other dustflies must constantly sip nectar to get the same level of nutrition. 

While their fellow blood-drinkers the drillbirds prefer to eat from fresh, mostly undamaged bodies with most of their bodily fluids still inside, this one has a taste for spilled blood, seeking out sites of violence where it can easily find its food spattered across the ground. Like all dustflies, it has lost the ability to pierce with its proboscis, so it eats by slurping up liquids from surfaces. Sometimes a blood-lapping dustfly will arrive at the scene of a fight or predation event to find that all the accessible blood has already congealed, so it will vomit up a bit of its gut contents to begin the digestion process, then drink the resulting soupy blood-saliva mixture. 

5: Northlox Drillbird

The temperate climate of Northlox is ill-suited to the this species' year-round reproductive cycle, so until very recently they had no presence here. In the past, whenever drillbirds migrated too far north, they would find success during the summer but stop reproducing when it got too cold. The previous season's helpers would grow up and move on by spring, making it impossible to rear any chicks the next year. However, a single population has developed a new strategy that allows it to survive. A mutation has arisen that renders homozygotes unable to become sexually mature, so they instead remain lifelong helpers, never abandoning their parents. These individuals are crucial to restarting the reproductive "conveyor belt" when spring comes. Though these homozygotes can't reproduce, they allow their heterozygotic parents to do so successfully. Unfortunately, this population is small, inbred, and unstable. Individuals with two copies of the non-mutant allele are unable to produce permanent helper offspring, so they inevitably face the same fate as earlier drillbird pioneers in this area. Even worse, they are impossible to visually distinguish from heterozygotes, who often mate with them, unaware that they are dooming their own reproductive prospects. This puts a massive hindrance on the reproductive success of the entire community, which has entered a steady decline. Over the next handful of millennia, either the Northlox Drillbird will stumble upon some genetic solution to this problem, or Apterra's first instance of burgeoning eusociality will dwindle to nothing.

6: King Springtail

Though the first springtails brought to Apterra were purely detritivores, the line between detritivore and scavenger can be a blurry one, and several different springtail genera have recently produced members with traits that make them more effective in the latter niche. Of this subgroup, the largest and most widespread is the King Springtail (Retrorsunguis rex), which sometimes exceeds a centimeter long and whose forelimbs have been modified into backward-facing, snatcher-like claws for cutting into flesh. These are effective offensive weapons, and some of the king springtail's relatives use them for active predation, but in this case their purpose is to cut off chunks of flesh from already-deceased targets. 

Like the squashtoad, the king springtail's first response when faced with danger while feeding is to flee. Its furcula is strong, and it has evolved an instinct to swing its forelegs opposite to the direction it finds itself tumbling through the air. This allows it to stop its rotation in midair and always land on its feet. It can then assess the threat from a safe distance using its large ocelli, which have increased in number and formed a cup-like indentation in its face, granting the springtail a very limited sense of sight, with the ability to form only the simplest images at a distance.

Scavenging diets provide an easy route for many lineages to experiment with new lifestyles and features. The creatures on this list came from many evolutionary backgrounds, all of which proved amenable to being co-opted for this way of life. For example, the ancestors of the gleanerfly were near-obligate herbivores, king springtails originated from tiny detritivores, and blood-lapping dustflies evolved from highly specialized nectarivores. With their newfound scavenger identities, some of these animals are pre-adapted to expand further into many of Apterra's many remaining unfilled niches. The vomit-lapping behavior of Corvoculex might, in future ages, result in a descendants occupying traditional Dipteran niches, and the Northlox drillbirds (if they survive) could be poised to occupy a whole world of possible roles for eusocial tetrapods.