Effects of the duration and timing of starvation during larval life on the metamorphosis and initial juvenile size of the polychaete Hydroides elegans (Haswell)

The larvae of the polychaete Hydroides elegans were exposed to different feeding schedules to evaluate the effects of starvation on metamorphosis and initial juvenile volume. The timing of starvation (early or late in development) and the total number of days of feeding (3, 5 or 8 days) at 24 degreesC had significant effects on the percentage of larvae that successfully completed metamorphosis and on the volume of the post-metamorphic juveniles. However, the duration of starvation (2, 4, 6 or 8 days) did not influence metamorphosis or juvenile volume. For larvae that had fed for 3 or 5 days, those that were starved at the beginning of development had a higher percentage of successful metamorphosis and produced larger juveniles compared with those starved after an initial 3-day feeding period, Larvae that had been allowed to feed for a total of 8 days were not affected by the timing of starvation. The percentage metamorphosis was lower in larvae that had fed for 3 days (16%), but was not significantly different between those that fed for 5 days (47%) compared to 8 days (47%). However, juvenile volume increased with the number of days of feeding from 0.95 nl after 3 days to 1.35 nl after 5 days, to 1.91 nl after 8 days of feeding. Discontinuous feeding reduced the proportion of larvae undergoing metamorphosis and juvenile volume compared to larvae continuously fed for only 5 days, but had no effect on larvae that fed for 8 days. The larvae of this extremely successful fouling species are remarkably tolerant of starvation and seem to require approximately 5 days of continuous feeding to achieve high levels of metamorphic success and large initial juvenile volume. (C) 2001 Elsevier Science B.V. All rights reserved.