The calling song of P. camellifolia is a succession of chirps (Shaw 1968). Each chirp consists of 2 or more repetitions of a characteristic pulse train group (PTG): minor plus following major pulse train. The human ear cannot discriminate major from minor pulse trains, so each PTG is perceived as a unitary sound emission. The occurrence of 3 such PTGs per chirp is the basis of the collo quial name 'kate-ee-did' (Caudell 1906). Four such groups are rendered onomatopoetically as 'kate-ee-she-did'. These variations in chirp length are associated with geography and with aggressive acoustic interactions between neighbouring males (Shaw 1968). P. camellifolia south of the Appalachian Mts typically produce chirps of 5-7 PTGs (Alexander 1967, see his Fig. 16). The rate of tegminal movement is much slower in P. camellifolia than in Lophaspis; compare the oscillogram records of Fig. 3 which all have the same time base.
P. camellifolia has a sound level of 105 dB at 5 cm, calculated from Shaw (1968) by considering only spreading loss. Our measure ments of Lophaspis are also very high: L. hebardi at 110 dB and L. scabricula at 113 dB (Table 1). However such high intensity signals are not unique among Tettigoniidae. For example Dumortier (1963) gives Tettigonia viridissima L., a common katydid of western Europe, as 90-95 dB at lm; this converts to 116-121 dB at 5 cm! [1]
References
- . Song Structure and Description of Some Costa Rican Katydids (Orthoptera: Tettigoniidae). Transactions of the American Entomological Society. 1982;108(1/2):287-314. Available at: http://www.jstor.org/stable/25078301.