This is an example of sympatric speciation. This type of speciation occurs when the individuals in a population are not separated by a geographical barrier such as a river. Instead, other barriers such as behavior arise.
The male dance is an example of such a barrier. In this case it is a prezygotic barrier as it prevents some individuals of this species to mate with each other and thus, to produce a zygote. A zygote is a single-celled embryo which will develop into a new individual.
This type of speciation is most controversial and some scientists don't believe it exists. However, there are examples of this process, which is most common in plants. A good example of animal sympatric speciation is the North American apple maggot, whose common ancestor fed on hawthorn trees. With the introduction of apple trees by European settlers, some individuals in the population have started feeding on apples instead.
