So, this is a speculative evolution project, while many aspects of this come from extant and extinct species, this animal does not exist (as far as we know). The general setting is Terra Nova, a hypothetical India sized piece of land that fragmented off of Gondwana (Africa, Australia, South America, India and Antarctica) in the Cenozoic Period. Terra Nova is in the tropical latitudes within the Pacific Ocean and has a mixture of rainforests, dry scrub, grassland, wetland, and montane habitats.
This week’s issue covers one of the habitats present on Terra Nova and some of the flora and fauna that don’t warrant a full issue on them. A list of species included in within the provenance at the bottom of this document.
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#43 – Spartoi Ant Nests and their hangers on
A common sight within the dry seasonal woodlands of Terra Nova, the two-foot tall mounds produced by Spartoi ants (Velesparta myrmidon) as temporary nests. During the daylight hours, trails of inch long Spartoi worker ants can be seen radiating out in the search of food. These minor workers are shadowed and protected by majors which are double the size and have large mandibles and a pair of venomous stingers on the tip of the abdomen. With the leading edge of the workers lying down a pheromone trail to navigate to and from their nest, a continuous parade of seeds, fruit and pieces of arthropod is carried back. On occasion Spartoi ants can be seen dragging the eggs, larvae and pupae back to their nest. These ‘hostages’ come from smaller species such as little canopy ant (Attica attica) and will be raised by their captors to become a slave workforce, controlled by pheromones, even going as far as participating in raids on the nest where they were born. Smaller then their Spartoi commanders, the little canopy ants are easy to spot in the column, however not all the small ‘ants’ in the column are part of this species, close examination will reveal that these ants have an additional pair of legs, and are Colchis jumping spiders (Myrmimic colchis), who mimic the ant body plan and produce identity pheromones to avoid detection so they can enter the ant’s nest.
The jumping spiders are entering the Spartoi ants to feed on the sugary solutions produce by the Spartoi ant grubs, massaging them until they produce the syrup. Among the ant grubs are other insect larvae, those belonging to the ant-mark moth (Formicomimus raptorus) which mimic the ant grubs but don’t produce the sugary syrup but do produce pheromones that prevent the ants from attacking them. Upon pupating the flightless moths crawl to the surface, typically tying their emergence to a glut of fallen fruit that they feed on, before returning to a nest to lay their own eggs. The larvae, regardless of their origin, are among the most precious resource within the Spartoi ants, and any member who doesn’t have the identity pheromone scent is attacked, torn apart and fed to the larvae. There are parasites too small for the ants to detect however, the fairyfly Mymar terranovam, reaches a body length of 0.2mm and sneaks in past the guards and inject their eggs into the larvae. From their the fairyflies larvae hatch and begin to feed on the grubs internal organs before pupating in the larvae’s corpse before emerging as tiny adults.
Dead ants, and dead larvae including those killed by fairyflies are thrown into a communal refuse tip. This glut of corpses attracts scavengers that can manage to enter the nest and evade the aggressive defenders. Growing from the corpses is the ant garden fungus (Leucoagaricus hesprides), that produce small wart like fruiting bodies across the exoskeleton, whose spores were inhaled by ants that were undertaking cadaver removal duty. The spores remain dormant until a certain humidity is reached before fruiting, and typically only grows in the lowest parts of the nest. Other scavengers include the millipede Armidraco curris that uses its heavily armoured carapace to withstand attack as it meanders down into the lower chambers. These millipedes eat both the decaying ant corpses and the fungus growing on them. When food sources are scarce, these millipedes are not above heading into the upper chambers and hunting ants, spraying toxic foam from its ventral pores to kill prey and fend off retaliation as it eats its meal where it dropped.
Other predators are present in the nest, the guillotine beetle (Deltochilum robespierre) is larger than even the majors of the Spartoi ant. Despite its size, the guillotine beetle feeds almost exclusively on Armidraco millipedes, and is tolerated by the ants, in part due to its ability to produce a pheromone that smells close enough to those they produce. Despite the amour of Armidraco, the guillotine beetle uses its mandibles to grip its prey, before popping the head plate forward causing the horns above the millipede’s armour plating to smash through the armour, to the point where it sometimes decapitates the prey animal. Other beetles are also present within the nest, Xu’s rove beetle (Jiǎchóng communis) is a scavenger that feeds on deceased ants, as well as the waste products produced by the ants, and are valued as a cleaning crew that reduces the amount of disease organisms present within the nest. Their diet of faeces and carrion passes on a passive pheromone scent to the beetles, and along with the beetle’s ability to mimic the ant’s identification antenna movement, keep the ants from attacking them, and sometimes even going so far to protect this scavenging species.
When displaced, usually by flooding, the Spartoi ants translocate the entire colony, forming a column defended by the majors, and includes allied species within the column such as their enslaved little canopy ants and Xu’s rove beetle, with guillotine beetles and Armidraco lumbering behind the main column. Within their nests Spartoi ants are almost untouchable, save for by large predators such as Dinoscutum or infiltrators able to enter the nest undetected, but outside they are vulnerable, particularly those carrying eggs, larvae and pupae. Fortunately, the ants have additional defenders outside the majors in the form of the valiant ant bird (Sipia ajax), small birds that typically follow ant columns looking for insects and lizards spooked into fleeing by the approaching ants. Able to recognise the movement of eggs and larvae, the birds become incredibly territorial of the ants, mobbing would be disruptors to the column.
Not all the external retinue are helpful to the Spartoi ant’s progress through the forest floor. Multiple kleptoparasites such as the centipede Formicovenator ferox and the macabre thorny roach hopper (Pseudogryllus viliscanthum) are fast enough or armoured enough to snatch food transported by the ants and escape before being torn apart. Ant specialist predators are also present, and some, such as the Cadmus dragon (Cadmus microdraco), a two foot long legless lizard can decimate colonies, in part due to chemicals in the dragon’s skin producing chemicals that neutralize most of the ant’s distress pheromones, allowing the lizard to eat for longer before being disturbed. Spartoi ants are also at risk of attack by the ant-decapitating fly (Pseudacteon tricuspis), that lays its eggs on the thorax of the ant, with the hatched maggot biting through the thorax and pupating in the head of the host insect.
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Species List
Species highlighted in bold are real world species, species with an underline will be receiving their own entry;
If you have any recommendations for Terra Nova’s fauna and flora please leave a suggestion, and if you want to take part with this ‘New World’s’ exploration, send me a message.
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