Secondary Production and Its Trophic Basis of Two Mayfly Species in a Subtropical Stream of China

Abstract

During June 2003 to June 2004, an investigation on life cycle, production and trophic basis of two species of mayfly in a second-order river of Hanjiang River Basin, Hubei, China was conducted. The results showed Epeorus sinensis UMLER and Caenis nigropunctata WU both developed two generations a year. The mean annual production and P/B ratio of E. sinensis were 9.154 g m ‐2 a ‐1 dry weight and 16.0, and those of C. nigropunctata were 1.554 g m ‐2 a ‐1 and 9.6, respectively. For E. sinensis, the proportions contributing to secondary production of the main food types were: amorphous detritus 33.46%, fungi 10.8%, vascular plant detritus 1.8%, diatoms 53.9%; for C. nigropunctata, the proportions were 70.8%, 6.90%, 3.5% and 18.8%, respectively. Compared with those species reported in North America and Europe, although land use mode and local climate were greatly different in China, life history and trophic basis of the mayflies seemed roughly similar, yet secondary production appeared to be much higher.