ABSTRACT
Previous studies have demonstrated that at low concentrations of food, echinoplutei develop longer arms; at high concentrations of food development of the echinus rudiment is accelerated. Predictions for larvae of other classes of echinoderms depend on the causes of this developmental plasticity. (1) Allocation of early growth to the larval apparatus for capturing particles when food is scarce and to postlarval structures when food is abundant may be adaptive. Then similar developmental plasticity is expected for larval asteroids, which develop a postlarval rudiment while retaining the larval body, but might not be advantageous for larval ophiuroids and holothuroids, which have little development of postlarval structures until the larval structures are resorbed or transformed at metamorphosis. (2) Ophiuroid and holothuroid larvae might also advantageously switch allocation between ephemeral larval structures and other nutrient stores in response to abundance of food.
