The effect of adult nutrition on the reproduction and development of the estuarine nudibranch, Tenellia adspersa (Nordmann, 1845)

Egg size is broadly correlated with development time, development mode and organic content for many marine invertebrates. Variation in egg size and organic content may be related to the adult nutritional state and may translate into differences in larval, juvenile or other life history characteristics. This study examined the role of adult nutrition on reproduction, egg size and offspring development in the estuarine nudibranch, Tenellia adspersa (Nordmann, 1845). I compared adult nudibranchs that were fed on an ad libitum diet of the hydroid, Cordylophora lacustris (Allman), to nudibranchs that had been starved for four to seven days. Adult size, reproductive output, size and weight of eggs, developmental time and developmental mode were measured daily. This experiment was replicated at 20 degrees C and 25 degrees C with similar results. In both experiments, adult size and reproductive output rapidly decreased with starvation. Eggs produced by starved adults developed faster and spent more time in the plankton than within the egg capsule. All of the spawn masses produced by starved adults had pelagic lecithotrophic development, whereas 10-15% of the eggs produced by fed adults developed into capsular metamorphic juveniles. This study demonstrates that in T. adspersa, egg size is plastic and related to the adult's nutritional regime. Variation in egg size is related to variation in early life history of the offspring and, as such, may represent a ''bet-hedging'' strategy, allowing some progeny to survive in an unstable estuarine environment.