equation

Lotka-Volterra equation

The Lotka-Volterra equations are a pair of first-order nonlinear differential equations used to model predator-prey interactions in biological systems.
23 related articles · 1 formulas

Description

In the 1920s, American mathematician Alfred Lotka and Italian physicist Vito Volterra independently derived a system of two differential equations describing the dynamics of interacting populations. Lotka was interested in chemical reactions and extended the idea to ecology, while Volterra responded to a zoologist's request to explain strange fluctuations in fish catches in the Adriatic after World War I. The equations are simple: the growth rate of prey is proportional to their numbers but decreases proportionally to encounters with predators; the growth rate of predators is proportional to their numbers and the number of prey, but there is also natural mortality. The solution yields neutral cycles: the amplitude of oscillations depends on initial conditions, and the slightest perturbation changes the trajectory forever. This is an idealization: in reality, cycles often dampen or become chaotic due to external factors.

History

Alfred Lotka in 1920 published a paper on chemical oscillations, where he presented equations for autocatalytic reactions, and in 1925 in his book 'Elements of Physical Biology' applied them to ecology. Vito Volterra in 1926, inspired by fish catch data shown to him by his son-in-law, zoologist Umberto D'Ancona, derived the same equations and investigated their properties. Interestingly, Volterra initially considered the model as an argument against overfishing: he showed that a proportional increase in fishing of both species paradoxically increases the proportion of predators. Later, the model was extended to competition, mutualism, and systems with delays.

How it works

Applied for qualitative analysis of ecological systems: predicts cyclicity, estimates extinction thresholds, and helps design biocontrol strategies. For example, in fisheries, the model explains why intensive harvesting of predators can lead to outbreaks of low-value species. Limits of applicability: assumes a homogeneous environment and instantaneous population response, which is violated in real ecosystems with seasonality, migrations, and evolutionary adaptation.

In practice

Forecasting pest population outbreaks in agriculture and assessing the stability of rare species populations in nature reserves.

Fun fact

Volterra arrived at his model while pondering fishing: during the war, fishing ceased, and the proportion of predatory fish in catches increased. He realized that reduced harvesting of prey led to an increase in predators — pure mathematics.

Concept graph →

Formulas

$$\alpha = \frac{4K - 1}{2K}$$
Exponent alpha expressed in terms of Luttinger parameter K.
What is in the formula
αvariableScaling exponent (same as in power law)
KvariableLuttinger parameter — luttinger parameter
α=\frac{4k-1}{2k} · 2606.31659

Related articles · 23

Quantum Gases2026-08-081 minarXiv:2608.08124express
Quantum Pendulum: Why Superfluid Strings Tremble in Unison
A superfluid gas is like a crowd of people marching in step: each atom knows where to go and doesn't fall out of the common rhythm. But this crowd has three 'valleys'—three different directions it can take. In a new experiment, physicists made one valley slightly more 'favorable' than the others and watched how the crowd darted between them.
nlin.AO2026-07-161 minarXiv:2607.14914express
How Spite Replenishes Resources
Two gardeners haggle over water from a magical well. One proposes how many buckets to take, the other can agree or refuse. If the deal goes through, the water decreases; if not, the well gradually refills. This haggling repeats hundreds of times, and the gardeners' habits sometimes change randomly, as if they're trying new tactics.
Cosmology2026-07-162 minarXiv:2607.15020
The Cosmic Score is Silent: Dark Matter and Neutrinos Don't Play a Duet
Light from distant quasars, breaking through billions of years, leaves a pattern of dark absorption lines on the cosmic film — the spectroscopic Lyman-alpha forest. Each line is like a note in a grand score, written by the hydrogen of the intergalactic medium.
Machine Learning2026-07-161 minarXiv:2607.15180express
Neural Cartographer: Recovering the Invisible Laws of Nature
Many natural processes are described by differential equations, but scientists often have only fragmentary data — a sort of torn map. The new computational method works like a cartographer who reconstructs a complete map of the terrain from a few landmarks.
q-bio.PE2026-07-151 minarXiv:2607.14360express
Disease in the Food Chain: The Predator Seesaw
In the web of life, predators and prey exchange carbon and water, and each act of eating slightly increases the universe's disorder. But the intrusion of disease turns this system into a giant seesaw. When a mid-level predator gets sick, its hunting abilities decline, and it becomes easy prey.
q-bio.PE2026-07-141 minarXiv:2607.13281express
A Predator, Two Prey, and the Population Dance
Ecosystems are not chaos but a complex dance where every species plays its part. Scientists modeled such a dance: two prey compete for carbon and water (the building blocks of cells), while a predator eats both. Sixteen scenarios emerged — from predator extinction to a steady rhythm for all three species.
q-bio.PE2026-07-051 minarXiv:2607.04204express
Extinction in every world, but life in switching
A runner loses on both a smooth track and sticky sand. Seems hopeless. But if the surface underfoot starts changing every few seconds (track, then sand) the runner suddenly stops falling behind. He doesn't get faster; the environment just doesn't get a chance to 'crush' his weakness. That's exactly what the authors found when studying a simple predator–prey model.
q-bio.PE2026-07-052 minarXiv:2607.04456express
How Life Learns to Survive
Molecules float in a pot of broth. Some copy themselves, others help their neighbors, and still others just get in the way. This isn't soup: it's a model of early life: a replicator system. Usually, we assume the rules of the game are fixed once and for all: whoever reproduces fastest wins. But the authors of this study proposed something different — the rules can change too, just very slowly.
Entropic Tuning Fork of Evolution: Proteins and Notes of Complexity
Biological complexity has long eluded us: you can count genes, cells too, but how do you grasp the organization of the proteome itself — a multi-thousand ensemble of proteins woven from carbon, oxygen, and hydrogen?
Statistical Mech2026-06-242 minarXiv:2606.25660express
Hidden Symmetry in a Quantum Spin Chain
A quantum spin chain is like a string of beads, where each bead is a microscopic magnet pointing up or down. In the XXZ model, these little magnets interact differently along the three axes, and at special parameter values, roots of unity, the system awakens with a hidden memory.
Molecular Ballet Without a Choreographer
A dance of hundreds of particles: some pairs spin slowly and gracefully, others twitch in a frantic rhythm. To understand the essence of the dance, you need to watch the slow movements: they are the main choreography of the system. In molecular science, such slow movements are called 'slow modes,' and they determine how a protein folds into a ball or how a drug binds to its target.
HEP Phenomenology2026-06-101 minarXiv:2606.12404express
How Neutrinos Get Entangled in Stellar Cores
In the scorching heart of a dying star, an invisible stream is born — a neutrino gas. The particles race through matter almost without stopping, but when their density is enormous, they start to feel each other. Old calculations described this as a jostle in a crowd: each shove changes direction, but no connection arises between passersby.
General Relativity2026-05-181 minarXiv:2605.18376express
Wormholes Without Exotic Matter
A wormhole is a tunnel through the fabric of spacetime, an idea expanded by John Wheeler and Kip Thorne. Just as a mountain passage tends to cave in, the throat of a wormhole wants to snap shut.
Biological Physics2026-04-302 minarXiv:2604.27937express
Why a monkey outlives a cat
An eight-kilogram rhesus macaque can live up to forty years. A cat of the same weight rarely sees its twentieth birthday. This difference is no accident: across all primates, from tiny marmosets to gorillas, lifespan is markedly longer than in other mammals of similar body mass. Standard models linking lifespan to metabolic rate fall short here.
Biological Physics2026-03-271 minarXiv:2603.26226express
The Ant Trap: When the Shortest Path Becomes a Roadblock
In urban planning, Braess's paradox is well known: adding a new road to a transport network can worsen traffic rather than ease it. For a long time, it was explained by the selfish behavior of drivers, each seeking personal gain. However, ant colonies, acting as a single coordinated superorganism without personal interests, exhibit the same trap.
Exoplanets2026-03-231 minarXiv:2603.22491express
How Bacteria Battle on Water Planets
Simple equations that describe fox and rabbit cycles have been turned to bacteria on distant exoplanets, like K2-18 b. These worlds hold deep oceans under thick hydrogen skies. Like duckweed on a pond, light-eating microbes cover the sunlit water surface, stealing light from those below.
Exoplanets2026-02-042 minarXiv:2602.04806express
How Stars Kick Out Their Guests
Interstellar wanderers are rocks and icy chunks that have broken free from their home planetary systems and now drift through the Galaxy. The first such visitor, 'Oumuamua, zipped past the Sun in 2017, followed by Comet Borisov and the ATLAS object. Where do they come from?
Biological Physics2026-01-262 minarXiv:2601.18669express
Swimming Cells Choose Their Viscosity
A swimmer in a pool of syrup moves differently than in clear water: each stroke is harder, but you can push off more strongly. Roughly the same goes for single-celled organisms — tiny rowers that propel themselves through fluid using flagella.
q-bio.PE2026-01-201 minarXiv:2601.13947express
How the Weak Win: Fleeing a Neighbor Saves the Species
Two species of bacteria share a single Petri dish. Both eat the same food, and by all rules, one should outcompete the other. But in reality, they often live together for years. The secret lies in knowing when to leave. Bacteria don't stay put. When a stranger appears nearby, they start moving faster.
Physics and Society2026-01-171 minarXiv:2601.12114express
How Peer Pressure Shapes Vaccination Decisions
An infection is spreading through a city, and residents are watching each other: some have already been vaccinated, others are hesitant. Every day, they update their decisions — whether to imitate neighbors or friends who support vaccination.
Quantum Physics2025-10-301 minarXiv:2510.26295express
Quantum Predator-Prey Games
In nature, everything is cyclical: hares multiplied — foxes thrived — hares ran out — foxes died off — and the cycle repeated. This 'predator-prey' model was invented a century ago, and it works everywhere: from chemistry to economics. Physicists have now brought this storyline to the atomic stage.
The Climate Symphony: How Random Jolts Produce a Predictable Response
The orchestra plays the symphony of climate. Each violin, each wind instrument carries its own part: these are the Kolmogorov modes, the system's natural rhythms. Suddenly, a thunderclap bursts into the hall: a sharp jump, like a gust of wind or a downpour. Previously, we could only listen to the smooth sound, but we couldn't decipher such chords. In the new work, mathematicians have completed the score.
Chaos That Vanishes: How to Tell a Storm from a Mirage
A traveler in the desert sees a lake. It shimmers, beckons with coolness, but as you approach, the water recedes. So it is in mathematics: the computer draws chaos, lines dart across the screen, and it seems we are witnessing a real storm. But if you wait long enough, the storm subsides, and the trajectory settles into a simple equilibrium.