Nudibranch life cycles in the Northwest Atlantic and their relationship to the ecology of fouling communities

摘要: 1. The most abundant nudibranchs in southern New England are small aeolids and sacoglossans. These gastropods characteristically sub-annual species with asynchronous growth, continuous egg production recruitment. Growth of individuals is notably rapid for molluscs, probably related to the possession cerata, which appear be an adaptation permitting increased rates assimilation metabolism. characteristics represent adaptations transient food sources early microsuccession fouling communities. Larger species, almost entirely dorids, have slower restricted periods production, synchronous growth cycles, lower metabolic rates. feed on more stable, longlived characteristic later successional stages. 2. The cerata convergent four major taxa (Sacoglossa, Dendronotacea, Arminacea, Aeolidacea) increase nonhomeostatic respiration. This accomplished by both respiratory digestive surface area. 3. The component recruitment nudibranch populations due allochthonously-produced larvae. may great value repopulation areas similar England, where temperature instability preclude survival a population than few months. 4. High thermal sensitivity western Atlantic, as indicated high Q10 values. does not always cause mortality natural populations, but changes activity, further prey-species' life cycles. The interaction wide environmental range, however, limit zoogeographic ranges accounts low diversity west Atlantic littoral fauna. Thermal also explains scarcity intertidal vernal disappearance species. 5. Most type 1 (planktotrophic) development, dispersal exploitation new growths. Some evidence given that proportion development higher eastern relate greater species. 6. The widely-reported sudden appearances arrival large numbers larvae, followed visible size. A critical stimulate settling metamorphosis. 7. Sudden disappearances adult several causes. Small exploitist normally overgraze supplies following peak periods. leads destruction microhabitat reduction absolute size, apparent individuals. Annual die physiological weakening caused extreme gonad output.