Study of the water balance in larvae of Aeshna cyanea (Müller) by means of measurement of changes in total body weight, with special reference to the method (Anisoptera: Aeshnidae)

As urine collection in the anisopteran larvae is very difficult, due to the respiratory function of the rectum, a study of the water balance is made by means of measurement of changes in the total body weight. A new, simple and accurate weighing method has been elaborated and tested. Drinking appears as an important factor in the regulation of water balance in larvae of Aeshna cyanea (Miill.).