Inter-sexual Mate Competition in Humans: A Historical Example from Seventeenth Century Portugal.

Inter-sexual mate competition occurs any time opposite-sex individuals simultaneously seek to acquire or maintain exclusive access to the same sexual partner. This underappreciated form of mate competition has been anecdotally documented in several avian and mammalian species, and systematically described among Japanese macaques and humans. Here, we extend the concept of inter-sexual mate competition by reassessing a remarkable series of Portuguese letters, penned in 1664 and later discovered and translated by Mott and Assunção (J Homosex 16:91-104, 1989). The letters comprise one side of a correspondence between two males, former lovers who were scrutinized by the Portuguese Inquisition. After ending the relationship, the recipient of the letters was betrothed to a woman, which provoked a jealous response from his jilted male lover and pleas to reunite. We argue that the letters portray a prolonged sequence of inter-sexual mate competition in which a male and female competitor vied for the same man. An established taxonomy of mate competition tactics was applied to the behavior of both competitors illustrating many parallels with contemporary examples of inter-sexual mate competition. Through this comparison, we show that modern mate competition taxonomies can be fruitfully applied to historical texts and that inter-sexual mate competition occurred hundreds of years before the present. Other examples of inter-sexual mate competition are likely to exist in the historical record, providing a rich source of scientific information if appropriate theoretical frameworks are employed. Indeed, any time individuals are attracted to sexual partners who behave in a bisexual manner, then inter-sexual mate competition can ensue with members of the other sex.