Avoidance behaviour in Odonata

H.B. WHITE (1979, Notul. odonatol. I: 75- 76) recorded Zoniagrion exclamationis (Sel.) moving behind stems to avoid observation by a presumed predator during climatic conditions suboptimal for flight. I have seen similar behaviour in Xanthocnemis zealandica(McL.) and Ischnura aurora (Br.) in New Zealand on many occasions and, during May 1980, 1 witnessed the same response in Ischnura elegans (Vander L.), Pyrrhosoma nymphula (Sulz.) and Coenagrion puella( L.) in England and Wales, and in I. elegans and Erythromma najas (Hans.) in the Netherlands. R.J. T1LLYARD (1917, The biology of dragonflies, Cambridge Univ. Press, p. 323) mentioned that zygopterans are as likely to hide from an enemy as to flee and C.O. HAMMOND (1977, The dragonflies of Great Britain and Ireland, Curwen Press, London, p. 13) comments briefly on orientation behind stems in United Kingdom damselflies. This type of behaviour may be more widespread in the Insecta: I have seen the hemipteran Nezara viridula (L.) behave similarly; and some salticid spiders follow the same pattern. In X. zealandica and I. aurora, avoidance behaviour of this type occurs not only in mature specimens during inclement weather but also in tenerals which have not attained flight capability. Another anti-predatorcontrivance used by insects is to drop and feign death (thanatosis) (M. EDMUNDS, 1974, Defence in animals. Longman, Harlow, p. 172). Attempts on 31 May 1980 to net I. elegans and E. najas at rest during rainy conditions elicited first the hiding response and then, when the pursuit was continued, the specimens would fall from their support. These damselflies continued to move the legs and abdomen after they had fallen which would deny the behaviour as thanatosis.