If they have evolved (and are now distinct) from functionless by-products of failed reproduction, then trophic eggs should be more easily available and provide more nutrients to the offspring than their evolutionary predecessors. There seems to be clear evidence of this adaptation in many species. This can be seen in mothers making an effort to distribute trophic eggs to their offspring; and/or eggs which are specialised for the nutritional needs of the offspring. However, in many species, the two types of egg are indistinguishable. Various hypotheses could potentially be tested to determine whether trophic eggs are indeed an evolved phenotype.