The Influence of some Physical and Chemical Conditions of Water on May-fly Larvae (Cloëon dipterum, L.)

Abstract

Numerous experiments have been performed to study the specific effect of hydrogen ion concentration, CO₂ and oxygen content of water on may-fly larvae, which warrant the following conclusions :—1. While hydrogen ion concentration is a factor of great significance, the carbon dioxide pressure is of greater importance and should afford a very reliable index of the suitability of water as a habitat for true aquatic insects.2. May-fly larvae, and presumably other insects as well, can stand a very low concentration of oxygen, below 1·0 cc. per litre. In view of the fact that in nature oxygen content seldom goes down to such a low figure, insects should not, as a rule, die of lack of oxygen.