Variations of the level of the digestive enzymes during the intermolt cycle of Palaemon serratus: Influence of the season and effect of the eyestalk ablation

Abstract

1. 1. Measurements of digestive enzyme activities in Palaemon serratus during each intermolt cycle show that, at different periods of the year, the variations follow three different schemes. 2. 2. A rhythm of monophasic activity is observed during the spring; the maximum is situated at the premolt. 3. 3. A rhythm of diphasic activity is predominant during the summer months; the maxima are situated at the end of the intermolt and the middle of the premolt. 4. 4. This rhythm persists in the autumn, but the amplitude is less pronounced. 5. 5. A rhythm of monophasic activity is characteristic of the winter months; the maximum is situated at the end of the intermolt and the beginning of the premolt. 6. 6. Ablation of the eyestalks provokes different responses according to the stage of the intermolt cycle when the ablation is effected and also according to the period of the year.