Food intake and adult feeding behaviour in Calopteryx splendens (Harris) and Erythromma najas (Hansemann) (Zygoptera: Calopterygidae, Coenagrionidae)

The gut contents of the 2 spp. were examined at a riverine site near Oxford, U.K., during June and July 1991. Individuals were captured in the field and dissected in the laboratory. The mass of gut contents was found to be a useful measure of feeding activity for the spp. concerned. Daily food intake was highly variable within the populations. A full gut could represent a considerable addition to the fresh body weight. Most feeding occurred from 10.00-16.00 h (BST). Differences between sexes were generally small in comparison with the total variation in feeding activity. Tcnerals fed less than non-tenerals in both spp. In 9 C. splendens feeding activity increased until reproductively mature. Gut content analyses should prove useful for studying many aspects of feeding behaviour in a wide range of spp.