Psammechinus miliaris - chapter 27

Psammechinus miliaris occurs in a diverse range of habitats, frequently at high densities, particularly in shallow or littoral locations. There is now a significant body of literature examining its reproduction, diet, trophic ecology, and biochemical gonad deposition. Hence, the species lends itself well as a model to better understand a variety of processes of the inshore ecosystem. Its omnivory is well documented, comprising a diet rich in encrusting invertebrates which support high gonad indices. It is likely the grazing activity of P. miliaris has a profound impact on the biodiversity and distribution of subtidal and intertidal encrusting communities. This species shows phenotypic plasticity in response to changes in diet and environmental conditions. This is relevant to our wider understanding of how sea urchins persist through ecosystem phase shifts from macroalgal-dominated communities to urchin barrens. The fate of ingested carotenoid pigments and their transformation and expression as gonad color have been investigated furthering the commercial potential for P. miliaris. As it is relatively robust in culture, P. miliaris is increasingly used as a model for the study of developmental embryology, the impact of climate change, and environmental pollutants.