ABSTRACT
A m ong invertebrates courtship is com m on only am ong the m ore advanced arthropods and molluscs. E ven in these groups i t is n o t universal: it is possible to find closely related families, some w ith elaborate courtship, others lacking it entirely. Also one m ay find a com plete range from very simple to very com plex displays w ith in one genus, such as that o f Drosophila, the fruit-flies.
