2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/177059We consider neutrinos with varying masses which arise in scenarios relating neutrino masses to the dark energy density in the universe. We point out that the neutrino mass variation can lead to level crossing and thus a cosmo MSW effect, having dramatic consequences for the flavor ratio of astrophysical neutrinos.8 pages, 1 figure, more detailed discussions, version to be published by Mod. Phys. Lett. AAstrophysicsHigh Energy Physics - Phenomenologytext