Nonadaptive radiations are a subset of evolutionary radiations (or species flocks) that are characterized by diversification that is not driven by resource partitioning. [1] [2] [3] [4] The species that are a part of a nonadaptive radiation will tend to have very similar niches, and in many (though not all) cases will be morphologically similar. [4] Nonadaptive radiations are driven by nonecological speciation. [2] [4] In many cases, this nonecological speciation is allopatric, and the organisms are dispersal-limited such that populations can be geographically isolated within a landscape with relatively similar ecological conditions. [4] For example, Albinaria land snails on islands in the Mediterranean [1] and Batrachoseps salamanders from California [2] each include relatively dispersal-limited, and closely related, ecologically similar species often have minimal range overlap, a pattern consistent with allopatric, nonecological speciation. In other cases, such as certain damselflies [3] and crickets from Hawaii, [5] there can be range overlap in closely related species, and it is likely that sexual selection (and species recognition) plays a role in maintaining (and perhaps giving rise to) species boundaries. [4]