What about non-adaptive radiation?

The use of the epithet ‘adaptive’ in the popular denotation ‘adaptive radiation’ suggests that radiation as such does not imply adaptation. Without trying to define radiation more sharply than is usually done in textbooks, emphasis is given to what might be called non-adaptive radiation, a kind of diversification not accompanied by adaptation into various significantly different niches and, therefore, resulting in a group of allopatric species which are isolated because of competitive interactions.