The 'waterfall spectacle' of Libellula quadrimaculata-aggregations (Odonata: Libellulidae)

摘要

A hitherto unknown swarming flight behaviour of Libellula quadrimaculata that included spectacular waterfall-like manoeuvres was observed and photographically documented in May and June 2015 in the steppes of the Kazakh Uplands. This unusual flight behaviour was connected to communal roosting aggregation. It is analysed and compared with common hypotheses and literature on communal roosting and swarm dynamics in Odonata and other animals.