Interspecific Scaling Relative Size Change Of Wing Beat Frequency And Morphometrics In Flying Beetles Coleoptera

Abstract

In 126 species of beetles (Coleoptera) average wing beat frequency (n) in free flight, body mass and length, elytron and ala length (1), and ala area were determined. The range of body mass covered four orders of magnitude. Most morphological parameters were significantly correlated with n but ala aspect ratio and ala loading did not influence n. With the exception of elytron length, all morphological parameters were geometrically similar. Wing beat frequency scaled with ala length-1/2, a relationship significantly departing from that predicted by the harmonic oscillator model of GREENEWALT (1960) and WEIS-FOGH's (1977) interspecific rule (n .alpha. l-1). Comparison with other insect orders indicated that geometric similarity in wing length occurred only in Coleoptera. Based on Newton's second principle, n .alpha. l-1/2 implies that beetles over the entire size range use the same wing mass specific force to drive their wings and that similar lift coefficient result. Furthermore, in order to enable n .alpha. l-1/2 over a large size range, a large part of the kinetic energy of wing movement must be conserved, implying considerable elastic storage.