Trophic Egg

A trophic egg is an egg which is not laid for reproduction but for nutrition, often for feeding the offspring hatched from a viable egg. Trophic eggs are usually unfertilised. They have been found in a hugely diverse number of species, including fish, amphibians and insects. Examples have also been found from a range of levels of parental care, from sub-social insects to the close parental care of some frogs. Trophic eggs are sometimes delivered directly to the offspring by the parents, and sometimes they are simply present in the same area as the offspring; having been laid soon after the viable offspring. The most extreme case of proximity is found in the mackerel sharks (Lamniformes), where the offspring feed on trophic eggs in utero. For more details, see Examples section. Despite the diversity of species and life strategies that make use of trophic eggs, they all share a common function, which is the sacrifice of potential future offspring in order to provide food for the survival of current offspring.