Networks with a modular structure are expected to have a lower risk of global failure. However, this theoretical result has remained untested until now. An experimental microarthropod (Folsomia candida) metapopulation was used to test the effect of modularity on the response to perturbation. One local population was perturbed and the spread of the impact of this perturbation was measured, both within and between modules. Results show the buffering capacity of modular networks. To assess the generality of these findings, then a dynamical model of the system was analyzed. In the absence of perturbations, modularity is negatively correlated with metapopulation size. However, even when a small local perturbation occurs, this negative effect is offset by a buffering effect that protects the majority of the nodes from the perturbation. informacion[at]ebd.csic.es: Gilarranz et al (2017) Effects of network modularity on the spread of perturbation impact in experimental metapopulations. SCIENCE 357: 199-201 DOI 10.1126/science.aal4122