Flightlessness and rapid terrestrial locomotion in tiger beetles of the Cicindela L-subgenus Rivacindela van Nidek from saline habitats of Australia (Coleoptera: Cicindelidae)

Tiger beetles of the genus Cicindela L. subgenus Rivacindela van Nidek from saline habitats of Australia display great variation in locomotory behavior. A total of 30 species have been described, nine of which are flightless. A notable consequence of brachyptery in Rivacindela is the evolution of very rapid terrestrial locomotion. Brachypterous beetles reach significantly higher cursorial velocities than macropterous ones. The running speeds attained by flightless Rivacindela are the fastest ever recorded for insects. The large species, Cicindela hudsoni Sumlin, reaches a maximal speed of 2.5 m.s-1, whereas the small-sized Cicindela eburneola Sumlin, attains the remarkable relative velocity of 170 body length.s-1. The evolution of flightlessness in Australian Cicindela occurred only in Rivacindela species and in Cicindela (Macfarlandia) arachnoides Sumlin, a mimic of lycosid spiders. Correlation between flightlessness and stable and isolated habitats is noted and discussed.