Oviparity
Oviparous animals are animals that lay eggs, with little or no other embryonic development within the mother. This is the reproductive method of most fish, amphibians, reptiles, all birds, the monotremes, and most insects, some molluscs and arachnids. Five modes of reproduction can be differentiated based on relations between zygote and parents: ▪
Ovuliparity: fecundation is external ▪
Oviparity: fecundation is internal, the female lays zygotes as eggs with important vitellus ▪
Ovo-viviparity: or oviparity with retention of zygotes in the female’s body or in the male’s body, but there are no trophic interactions between zygote and parents. In the sea horse, zygotes are retained in the male’s ventral "marsupium". In the frog
Rhinoderma darwinii, the zygotes developed in the vocal sac. In the frog
Rheobatrachus, zygotes developed in the stomach. ▪
Histotrophic viviparity: the zygotes developed in the female’s oviducts, but find their nutriments by oophagy or adelphophagy. ▪
Hemotrophic viviparity: nutriments are provided by the female, often through placenta.