Nitrogen Excretion in Nymphs of Aeshna Cyanea (Müll.) (Odonata, Anisoptera)

Abstract

1. The excretion of ammonia and uric acid has been studied in nymphs of Aeshna cyanea (Odonata, Anisoptera). 2. Ammonia is the main nitrogenous component of the excreta of nymphs during fasting and after feeding on a protein-rich diet. Only a small proportion of the total nitrogen excreted is present as uric acid. 3. Retention of uric acid in the body is at most trivial. 4. When fasting nymphs are fed on a protein-rich diet in the form of egg-white there is a large, temporary increase in the amount of ammonia excreted, but the output of uric acid remains constant. 5. It has been estimated that nymphs excrete a quantity of nitrogen within 24-48 hr. after feeding equivalent in amount to 60% or more of the total nitrogen absorbed during that period.