🐛 Termite Mound Construction

Termite agents drop pheromone-laced mud pellets and preferentially build where pheromone is strongest, an emergent stigmergic process that grows pillars into connecting arches — no blueprint, no foreman.

Life ScienceInteractive
Watch pillars emerge and bridge into arches · P pause · R reset

How it Works

The ground is a grid of cells. Amber termite agents random-walk across it, each step biased toward the neighbouring cell with the highest pheromone reading rather than moving perfectly randomly. When a termite is adjacent to existing mud or the ground floor, it may drop a mud pellet there; the chance of dropping rises with local pheromone concentration through a logistic threshold function, so termites overwhelmingly build where scent is already strong rather than at empty, unscented ground.

Every dropped pellet also deposits fresh pheromone into that cell, and the whole pheromone field diffuses to neighbouring cells and evaporates a little each frame. This creates a positive feedback loop: a lucky early deposit raises local pheromone, which attracts more termites to deposit nearby, which raises pheromone further — concentrating mud into tall pillars instead of a flat smear. When two pillars grow close enough that their pheromone plumes overlap, the gap between them crosses the drop threshold too, so termites bridge it, and the pillars fuse into an arch, exactly the mechanism believed to produce real Macrotermes mound pillars and arches.

Move bias: P(dir) ∝ exp(pheromone(dir)) mixed with uniform randomness
Drop probability: P(drop) = 1 / (1 + exp(-k · (pheromone - threshold)))
Deposit: pheromone(x,y) += depositRate on successful drop
Field update: pheromone = blur3x3(pheromone) · (1 - evapRate)

Frequently Asked Questions

What is stigmergy in the context of termite building?

Stigmergy is coordination through the environment rather than direct communication. A termite that drops a mud pellet laced with pheromone changes the local environment, which then influences the building decisions of other termites that pass by later.

Why do isolated pillars appear instead of a flat wall of mud?

Random early deposits create small pheromone peaks. Because drop probability rises with local pheromone, those peaks attract more deposits, which raises the peak further, a positive feedback loop that concentrates mud into a few tall pillars rather than spreading it evenly.

How do two separate pillars end up joining into an arch?

As a pillar grows taller its pheromone plume diffuses outward. When two plumes from nearby pillars start to overlap, the combined pheromone in the gap between them exceeds the drop threshold, so termites are drawn to build there too, bridging the gap into an arch.

What does the pheromone evaporation rate control?

Evaporation rate sets how quickly deposited pheromone fades each frame. Low evaporation lets scent linger and spread, encouraging fewer, larger structures, while high evaporation keeps signals localized and short-lived, favouring many small, slow-growing pillars.

Is this how real termites build mounds?

Yes, in principle. Field and laboratory studies of species such as Macrotermes show workers depositing pheromone-marked mud pellets and preferentially building near existing pheromone-rich structures, a stigmergic process that produces pillars, arches, and eventually chimneys without any centralized plan.

About this simulation

Written by MySimulator Team · Reviewed by MySimulator Editorial Review

Last updated: 11 July 2026

No termite in this simulation knows it is building a pillar, let alone an arch — each one is only ever answering the question "is the mud beside me smelly enough to add to?" That single local rule, repeated by hundreds of amber dots wandering a pheromone-scented grid, is enough for random early deposits to snowball into towers, and for two nearby towers to reach out and fuse into an arch purely because their scent plumes started to overlap.

🔬 What it shows

Termite agents random-walking with a bias toward higher pheromone, occasionally dropping mud pellets near existing structure and reinforcing the local scent, producing emergent pillars that can bridge into arches.

🎮 How to use

Increase Termite Count or Pheromone Deposit Rate to speed up construction, raise Drop Threshold to force more concentrated single pillars, and raise Evaporation Rate to see structures stay small and scattered instead of merging.

💡 Did you know?

Real Macrotermes mounds can rise several metres above ground, built from millions of individual pellet-sized mud deposits, and their internal chimney networks passively regulate temperature and gas exchange for the colony below, all without any termite having a blueprint.

Frequently asked questions

What is stigmergy in the context of termite building?

Stigmergy is coordination through the environment rather than direct communication. A termite that drops a mud pellet laced with pheromone changes the local environment, which then influences the building decisions of other termites that pass by later.

Why do isolated pillars appear instead of a flat wall of mud?

Random early deposits create small pheromone peaks. Because drop probability rises with local pheromone, those peaks attract more deposits, which raises the peak further, a positive feedback loop that concentrates mud into a few tall pillars rather than spreading it evenly.

How do two separate pillars end up joining into an arch?

As a pillar grows taller its pheromone plume diffuses outward. When two plumes from nearby pillars start to overlap, the combined pheromone in the gap between them exceeds the drop threshold, so termites are drawn to build there too, bridging the gap into an arch.

What does the pheromone evaporation rate control?

Evaporation rate sets how quickly deposited pheromone fades each frame. Low evaporation lets scent linger and spread, encouraging fewer, larger structures, while high evaporation keeps signals localized and short-lived, favouring many small, slow-growing pillars.

Is this how real termites build mounds?

Yes, in principle. Field and laboratory studies of species such as Macrotermes show workers depositing pheromone-marked mud pellets and preferentially building near existing pheromone-rich structures, a stigmergic process that produces pillars, arches, and eventually chimneys without any centralized plan.