Roosting and resting site selections by coenagrionid damselflies

Field observations on adult Ischnura elegans, Coenagrion puella and Enallagma cyathigerum show that plant stems are frequently adopted as roosting sites and that the species differ in the mean stem diameters selected. Ischnura roosts on narrower stems than Enallagma, and Coenagrion appears to prefer stems of intermediate diameter. This ranking of the species is demonstrated experimentally for both roosting and resting sites, and a relationship is shown between eye spacing and preferred stem diameter. Damselflies use supports that are sufficiently wide to conceal most of the body whilst allowing unimpeded vision.