Thief pigeons are worth further study. The second example of promiscuity was one Darwin (1871) cited in Descent. The information came from his cousin

William Darwin Fox and involved the two species of geese he kept. In one season, a male Chinese goose seduced a white domestic goose, causing her to abandon her domestic gander: when the female’s clutch hatched, it was immediately evident from the appearance of the goslings that both the Chinese gander and the white gander had fathered offspring: promiscuity and multiple paternity in a single, striking example. With such clear evidence in front of him, it is easy (with the benefit of hindsight) to ask how Darwin could have overlooked the potential for promiscuity and sperm competition. In this instance, I think Victorian prudery won out over science (Birkhead, 1997), but Smith (1998) MAPK inhibitor Selleck KU-57788 offers

some other possibilities. He suggests that Darwin (and many of his successors) were psychologically predisposed to presume that females are monogamous. If so, the few explicit examples of female promiscuity that Darwin was aware of were then viewed as exceptions and could be ignored. Darwin may also have assumed pre-copulatory choice to preclude the necessity of female promiscuity. Finally, Smith (1998) suggests that during Darwin’s lifetime, knowledge of sexual reproduction was both amorphous and confused, creating an intellectual barrier that prevented Darwin from considering the implications of female promiscuity. As far as I am aware, there is no synthesis of what Darwin understood or did not understand about sexual reproduction in animals. He wrote extensively about the process of fertilization in plants, and so it is almost inconceivable that he did not have an interest in animal reproduction, and yet our understanding of Darwin’s knowledge of sexual reproduction remains Astemizole unclear. He knew a great deal about the reproductive anatomy of the barnacles

he spent so long dissecting. We also know from his notebooks (Barrett et al., 1987) that he had read Spallanzani’s (1769) ingenious study from the late 1700s that erroneously concluded that spermatozoa had no role in fertilization. As Smith (1998) points out, Spallazani’s account of fertilization must have confused Darwin, and continues: ‘Perhaps it was this confusion that pressed Darwin to his own fuzzy “gemmule” theory of inheritance [pangenesis], which despite its own vagaries at least restored a heritable male contribution to reproduction’. Smith then says: ‘Ideas about fertilisation and heredity remained extremely amorphous through the eighteenth and most of the nineteenth centuries …’. While it is certainly true that ideas about heredity remained amorphous, it is less clear why Darwin should have remained confused about sexual reproduction.