Feeding experiments were conducted under light and dark
conditions, and larvae aged between 12 and 17 days (postflexion
stage) were used. Prior to the experiments, the larvae
were starved for 24 h and each larva was transferred to a
500 ml beaker containing 300 ml fresh water. The larvae
were left for 20 min to recover from the stress of handling.
Following the recovery period, 30 Artemia (0.1 individual/ml,
the same density as in the previous study of Mukai et al. [15])
were placed in each beaker, and the larvae were left in the
beakers to feed for 30 min. Larvae were subsequently anesthetized
with Transmore (Nika Trading Co.) to stop ingestion,
and the remaining Artemia were counted in order to determine
the number consumed by each larva (n = 30). Experiments
performed under dark conditions were carried out in a dark
room (n = 30). The number of Artemia eaten by a larva was
expressed as the ingestion ratio of Artemia per 30 min.