Why haven't male wasps evolved to recognize that the flowers of an orchid are not female wasps?

When a species evolves, due to natural selection
characteristics that hinder reproduction are eliminated and the characteristics that aid
the process of reproduction are enhanced in future
generations.

Male wasps are able to recognize female wasps
by their appearance but are attracted to them primarily by chemicals called pheromones
that are released by the females and to which the males are extremely sensitive to. A
tiny amount of this chemical released by female wasps when they are ready to mate can
attract males in the range of hundreds of
kilometers.

Orchids do not have nectar to attract insects
which help in the process of pollination, instead they use other means of deception. The
flowers have a fair amount of similarity in shape to female wasps, but the most
important tool to attract male wasps is the release of chemicals similar to pheromones
that are released by the female wasps.

Orchids also have
several mechanisms to alter these chemicals to attract the right kind of wasps. The
sensitivity to pheromones is essential for wasps to be able to find females, if they
were to lose this trait reproduction would become very difficult. This is one of the
reasons why there has been no evolution to prevent the wasps from pollinating
orchids.

In addition, there is no harm caused to wasps when
they visit the orchid flowers and pollinate them, this removes the incentive for them to
be able to differentiate orchids from females from a distance. As far as energy spent in
visiting the orchids goes, it is miniscule compared to the large distances that wasps
anyway have to travel in search of food and mate.