‘Hopeless’ pairings – why do they do it?

Following Dr David Shuker’s talk to the Dutch Entomological Society in December, Dutch Biology paper ‘bionieuws’ published a piece about his analysis of ‘hopeless pairings’. That is to say, why do some animals form pairings between individuals of different types or at different  developmental stages that cannot result in offspring?  Dr Shuker questions the meaning of these behaviours, and considers the insights into evolutionary mechanisms that studying them can bring.