EFFECTS OF FOOD AVAILABILITY, LARVAL SOURCE AND CULTURE METHOD ON LARVAL DEVELOPMENT OF BALANUS-AMPHITRITE AMPHITRITE DARWIN - IMPLICATIONSFOR EXPERIMENTAL-DESIGN

Effects of food concentration on larval development of Balanus amphitr ite amphitrite Darwin (Crustacea: Cirripedia) were studied in three ex periments designed to examine plasticity of survival, time of developm ent, and size: I, larvae from a single brood, cultured individually; I I, larvae from multiple broods, cultured individually; III, larvae fro m multiple broods, cultured in groups (batch cultures). Nauplii were f ed the diatom Skeletonema costatum (Grev.) Cleve at six concentrations ranging from 0 to 10(6) cells.ml(-1) at 24 degrees C and 30 parts per thousand salinity. Food concentration had a clear impact on larval su rvival and development time for B. a. amphitrite and larvae showed the same trends in survival, duration of development, and growth whether they were obtained from single or multiple parents and whether they we re cultured individually or in batches. Nauplii of B. a. amphitrite fa iled to reach the cypris stage at algal concentrations less than or eq ual to 10(3) cells.ml(-1). Development stopped at nauplius II when lar vae were reared at 0-10(2) cells.ml(-1) and stopped at nauplius III wh en larvae were reared at 10(3) cells.ml(-1). Survival at 10(5) and 10( 6) cells.ml(-1) was higher than at 10(4) cells.ml(-1). Larvae reared a t the three highest food concentrations developed to the cypris stage. Development time from nauplius II to cyprid was similar (p > 0.10) wh en larvae were maintained at 10(5) or 10(6) cells.ml(-1), but was sign ificantly longer when reared at 10(4) cells.ml(-1). The sizes of B. a. amphitrite larvae at a particular stage were similar regardless of fo od concentration, developmental rate, larval source (from single vs. m ultiple broods) and the method of culture. In future studies that invo lve B. a. amphitrite larvae, larval source and method of culture can b e selected solely on the basis of questions to be addressed. (C) 1997 Elsevier Science B.V.