We present a phenotypic model for the evolution of self-fertilization in an infinite population of annual hermaphrodites for the case in which fitness and inbreeding depression vary among generations (e.g., due to fluctuations in the environment from year to year). Conditions for the evolution of selfing, mixed mating, and outcrossing are derived and are compared with results from numerical cal...

BACKGROUND AND AIMS Apomictic plants maintain functional pollen, and via pollination the genetic factors controlling apomixis can be potentially transferred to congeneric sexual populations. In contrast, the sexual individuals do not fertilize apomictic plants which produce seeds without fertilization of the egg cells. This unidirectional introgressive hybridization is expected finally to repla...

We describe here rapid gamete growth and artificial fertilization method of species of the larvaceans (appendicularians), Oikopleura dioica and O. longicauda (Family Oikopleuridae: Class Appendicularia: Subphylum Urochordata). In these species, oocytes grew very rapidly from about 40 μm in diameter to about 75 μm (O. dioica) and 110 μm (O. longicauda), respectively within a few hr. Moreover, cu...

The mangrove rivulus, Kryptolebias marmoratus (Rivulidae, Cyprinodontiformes), is phylogenetically embedded within a large clade of oviparous (egg laying) and otherwise mostly gonochoristic (separate sex) killifish species in the circumtropical suborder Aplocheiloidei. It is unique in its reproductive mode: K. marmoratus is essentially the world's only vertebrate species known to engage routine...