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🧬 Gut Microbiome Competition

Multiple bacterial species compete for a shared, replenished nutrient pool under generalized Lotka-Volterra competition — watch competitive exclusion or stable coexistence emerge from the interaction matrix.

Biology & Life2DEasy60 FPS

How it Works

Each bacterial species i has a population Ni that grows logistically toward a carrying capacity Ki set by the shared nutrient inflow, but that capacity is eaten into by every other species present, weighted by a competition coefficient αij. When αij values are small relative to each species' self-limitation, niches barely overlap and every species finds room to persist — stable coexistence. When αij values are large, the fastest-growing or highest-capacity species consumes so much of the shared resource that rivals are pushed toward zero — competitive exclusion, mirroring how a single opportunistic gut species can crowd out others after antibiotic disruption.

The simulation numerically integrates the generalized Lotka-Volterra competition equations with a small explicit Euler timestep every animation frame, so you can watch trajectories curve in real time as you drag the sliders. The petri-dish view underneath renders each species as a colored circular patch whose area is proportional to its current population, giving an intuitive spatial read of who is winning the shared gut environment.

dNi/dt = ri · Ni · (1 − (Ni + Σj≠i αij·Nj) / Ki)
Ni(t+dt) = Ni(t) + dt · dNi/dt, clamped to Ni ≥ 0
αij = competitionStrength (uniform off-diagonal coupling, i≠j)
Ki = baseCapacity · resourceInflow

Frequently Asked Questions

What is the Lotka-Volterra competition model?

The generalized Lotka-Volterra competition model describes how multiple species sharing a resource grow logistically while also suppressing each other's growth. Each species' growth rate depends on its own population plus a weighted sum of competitors' populations, scaled by competition coefficients.

What is competitive exclusion?

The competitive exclusion principle states that two species competing for the exact same limiting resource cannot stably coexist indefinitely — the species with even a marginal fitness advantage will eventually drive the other to local extinction.

How can multiple bacterial species coexist in the gut?

Coexistence becomes possible when interspecific competition coefficients are weaker than intraspecific self-limitation, meaning each species limits its own growth more than it limits its rivals — often because species specialize on slightly different nutrients or gut niches.

What does the competition coefficient alpha represent?

The coefficient alpha-ij measures the per-capita effect of species j on species i's growth, expressed in units of species i's own carrying capacity. An alpha of 1 means a competitor individual suppresses growth exactly as much as one of your own species; higher values mean stronger suppression.

What is carrying capacity in this simulation?

Carrying capacity (K) is the maximum population a species could sustain alone on the available nutrient inflow. It sets the ceiling each species' logistic growth curve approaches in the absence of competitors.

About this simulation

Every bacterial species in this simulation is racing to grab a share of the same replenished nutrient pool, and every frame its population edges toward a logistic ceiling that shrinks the moment a rival species crowds in. Push the competition slider up and watch the interaction matrix decide, in real time, whether one strain sweeps the gut or several settle into an uneasy truce — the same dynamic that plays out after antibiotics wipe the slate clean in a real intestine.

🔬 What it shows

Three to five bacterial species integrating generalized Lotka-Volterra competition equations frame by frame, rendered as both a population time-series chart and a proportional-area petri-dish view.

🎮 How to use

Adjust Species Count, Competition Strength and Resource Inflow, hit Randomize Initial Ratios to reshuffle starting populations, and use P/R to pause or reset.

💡 Did you know?

A single course of broad-spectrum antibiotics can collapse gut microbial diversity so sharply that opportunistic species like Clostridioides difficile face almost no competition, letting them bloom unchecked — real-world competitive exclusion.

Frequently asked questions

What is the Lotka-Volterra competition model?

What is competitive exclusion?

How can multiple bacterial species coexist in the gut?

What does the competition coefficient alpha represent?

What is carrying capacity in this simulation?

⚙ Under the hood

Canvas 2DMicrobiomeCompetitive ExclusionLotka-VolterraEcology

2D · HTML5 Canvas 2D · 60 FPS target · runs fully client-side, no install