Bioacoustics of Oxyecous lesnei

( Figs. 36 A–G, 54G–I) Diagnostic remarks. A medium-sized katydid that exhibits a distinct sexual dimorphism. Males have long, nearly translucent tegmina and hind wings that surpass the tip of the abdomen by over half their length whereas in the female the wings surpass the tip of the abdomen by only about a fifth of their length ( Figs. 36D, E ). Males of O. lesnei are easily identifiable by the presence of conspicuous cuticular folds (auriculae) on the inner sides of the tympana; these folds are much smaller but still noticeable in the females. The costal and median fields of the male tegmen have reduced venation, resulting in large, membranous areas in the proximal half of the wing ( Fig. 36A ). Bioacoustics. O. lesnei , along with Debrona cervina Walker, 1870 , are unique among known katydids in being able to stridulate in flight. This interesting behavior, its mechanism, and potential adaptive advantage will be discussed in an upcoming publication (Naskrecki, in prep.). The in-flight stridulation usually has a different temporal pattern than the stationary stridulation, which the males engage in later at night. While stationary on tall bushes and lower branches of trees, the males produce long series of single syllables every 0.38– 0.60 s , which are occasionally followed by a short series of 2-syllable echemes; mean syllable duration is 0.067 s (SD=0.0267, n=44); the peak frequency of the call is 5.9–7.6 kHz ( Figs. 54 G–I), making it easily audible from a distance of several meters.