Horizontales Schlüpfen bei mitteleuropäischen Zygopteren (Coenagrionidae)

Whereas most European Anisoptera emerge hanging down, Zygoptera and Gomphidae during emergence assume the upright position, and thus are able to emerge on horizontal substrates. Both Erythromma species are known to emerge on floating Nymphaea and Hydrocharis leaves, E. viridulum on weeds floating on the water surface. Only the top of the head and thorax of the larvae may be in the air during emergence. Present observations confirm this procedure for Enallagma cyathigerum on floating Elodea, and new records are added for Cercion lindeni and Ischnura elegans. All species however prefer vertical stems or flowers; emergence from floating weeds in Zygoptera seems to be typical of individuals living in open fields of weeds far from the bank, constituting a protection from predation by fish.