a similar phenomenon occurs in the sea urchin, "strongylocentrotus droebachiensis". urchin mothers in nutrient rich environments produce a large number of small eggs. offspring from these small eggs grow at a faster rate than their large egg counterparts from nutrient poor mothers. again, it is beneficial for sea urchin larvae, known as planula, to grow quickly to decrease the duration of their larval phase and metamorphose into a juvenile to decrease predation risks. sea urchin larvae have the ability to develop into one of two phenotypes, based on their maternal and larval nutrition. larvae who grow at a fast rate from high nutrition, are able to devote more of their energy towards development into the juvenile phenotype. larvae who grow at a slower rate with low nutrition, devote more energy towards growing spine-like appendages to protect themselves from predators in an attempt to increase survival into the juvenile phase. the determination of these phenotypes is based on both the maternal and the juvenile nutrition. the epigenetic mechanisms behind these phenotypic changes is unknown, but it is believed that there may be a nutritional threshold that triggers epigenetic changes affecting development and, ultimately, the larval phenotype.