Influence of temperature on the starvation threshold of nauplii of barnacle Balanus amphitrite (Cirripedia: Thoracica)

Abstract

An evaluation of starvation threshold of the newly hatched Balanus amphitrite nauplii (instar; II) has been made at three different temperatures (5, 15 and 25°C). Earlier studies on starvation in crustacean larvae demonstrated Point of No Return (PNR) as an index of starvation. PNR is the state from which no larvae exposed to stress conditions can recover and complete metamorphosis. In this-study Ultimate Recovery Point (URP) has been used as a new index of starvation threshold. URP denotes the number of hours of starvation after the end of which larvae can recover and continue development. Larvae starved at 5 and 25°C had URP of 204 hand 24 h respectively. The larvae starved at 5°C for 12 h showed reduced II instar duration (1 d) compared to control II instar duration (1.8 d). At 15 and 25°C reduction in instar duration was not evident.