Thermites

Larvae/Nymphs

Larval Thermites are hemimetabolous, meaning they undergo incomplete metamorphosis. This results in the larvae strongly resembling a smaller version of an adult Thermite, albeit with less hardened and melanized chitin. Similar to most other insects, Thermites have a three-part body plan with a clear head, thorax, and abdomen. They possess six legs, two antennae, and a pair of mandibles. As larvae, the chitin segments of their body have not hardened yet, making them susceptible to predation by smaller organisms until they harden as they become nymphs. Larvae possess specialized spiracles that allow for water transfer into fat-coated sacks which store and preserve moisture extremely well.

Adults

Adult Thermites possess the same morphology as the nymph and larvae with a few additional features. Males develop a series of chitinous scutes that are loosely linked to one another. When the male is agitated or displaying dominance, it vibrates its scutes at a high rate that it generates a large amount of heat and emits a loud screeching noise. They also develop more elaborate mandibles which they use for territorial disputes and mating displays.

Female Thermites retain much of their nymphal morphology save for one; their mandibles. During their final molt, they break down the hardened chitin that makes up their mandibles and it is co-opted into acting as an additional sensory organ. This sensory organ allows for females to better sense the pheromones release by the males as well as finding suitable locations beneath the soil that they can deposit their eggs.

Thermites are a hemimetabolous insect that develops from an egg to a larvae, then a nymph, then either an adult male or female. Eggs emerge into larvae within the first month and remain as larvae for two weeks as they absorb moisture from their environment. Then, the larvae develop into nymphs, which torpor for 5 months until they re-emerge and feed. After about three weeks of development, the nymphs molt into adults.

These insects are found in the northeastern plains of Kerine. Males make mounds out of soil, decayed leaves and grasses, and secretions that resemble small pillars that house only females. Only one female will ever be found in a single mound. When a Thermite leaves its mound, the compound that makes up the structure decays and provides a rich substrate for plant and fungal growth.

Every fall, male Thermites travel across the plains to try and reach the coast. During this time, they travel in swarms, causing them to vibrate their scutes intensely which result in chitinous cinders lighting the plains ablaze. This migration burns all foliage in the plains, maintaining that only grasses, shrubs, and small trees dominate the plains when spring comes. Additionally, as many males and females perish before and after this migration, the bodies of the Thermites provide nutrition to the soil, predators, and carrion feeders across the scorched plains.

As an egg, Thermites will only emerge during the first rainfall after their oviposition due to the chemical composition of their membrane. Once emerged, larvae will only absorb moisture from its environment, feeding off of the fat reserves provided by the mother when the egg was laid. In the spring, nymphs will heavily consume the vegetation of an area, typically just the roots, allowing the stalks of the plants to perish. At this time, Thermites do not absorb any more moisture.

When Thermites develop into adults, they no longer feed or drink. Male mouthparts are fully adapted for mating displays and fighting, while female mouthparts are adapted for chemosensory. Adults rely on the nutrients and moisture they obtained during their developmental stage to last them until they perish in the fall.

The eggs are laid in the fall, emerging into larvae shortly after. A few weeks later, before winter comes, the larvae develop into nymphs and go into torpor until spring. From there, the nymphs emerge and develop into adults.

Adult Thermites show a complex string of behaviors.

Their movements are sudden and almost robotic due to their need to conserve resources as an adult. Unnecessary or dramatic movements result in excess calorie burning, which, may lead to an early death due to starvation. This behavior plays into the males creating their pillar-like mounds which house the females that they try to mate with. If the female deems the quality of the nest sufficient, she will hunker down in the mound until it is time for her to lay her eggs while the male defends the mound.

Males exhibit territorial behaviors when approached by a rival male. The vibration of scutes and lifting of mandibles indicates an aggressive posture and that the male is prepared to strike. Fights between males are often lethal, as the excess burning of calories almost ensures that both fighting males will perish before arriving to the coast.

The migratory behavior is perhaps the most interesting. While the males are usually solitary, as their nutrient and moisture reserves run low, they switch their phenotype and behavior. Their scutes turn black, absorbing more heat from the sun, as well as begin to congregate with other males. During this time, it is believed that they are drawn to large bodies of water as a natal behavior retained from their larval stage. While the males are swarming together, they are still agitated by one another's presence, resulting in the intense vibration of their scutes which causes massive wildfires to break out. During this time, they emit a potent pheromone into the soil which become volatile when burned, attracting the females to follow. The females, now sensing the pheromone diffusing across the plains, follow the path the males took towards the coast. During this time, they are probing the soil trying to find a suitable location to lay their eggs. They do this by detecting the ash content beneath the soil, indicating that the soil is looser there. After they oviposit their eggs, they continue to follow the males towards the coast.

If the male and females have stored enough moisture and nutrients to make it to the eastern coast of Kerine, they attempt to drink from the saltwater of the coast, desiccating themselves and perishing shortly after.