2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/114169In this paper we prove the existence of non-stationary periodic solutions of delay Lotka-Volterra equations. In the proofs we use the degree for $S^1$-equivariant maps.Classical Analysis and ODEs34C25, 34l30Existence of periodic solutions for the Lotka-Volterra type systemstext