sound production

We monitored electromyographic activity of flight and respiratory muscles in relation to biosonar vocalization in the bat Pteronotus parnellii (Microchiroptera:  Mormoopidae). Signals were recorded from the blank muscles (lateral abdominal wall), rectus abdominis, diaphragm, pectoralis and serratus ventralis. Signals were telemetered from flying bats with a small FM transmitter modified to summate the low frequency myopotentials with audio signals from a crystal-ceramic microphone. Activities of all muscles were correlated with vocalizations. A discrete burst of activity in the flank muscles accompanied each vocalization. Myopotentials in the diaphragm occurred between groups of calls and did not coincide with activity of the blank muscles or with vocalizations. Flight muscles were inactive prior to the initiation of fliqht. In Sight, vocalizations and the abdominal muscle activity that accompanied them coincided with myopotentials of the pectoralis and serratus ventralis muscles. We propose that contractions of the flank muscles provide the primary power for the production of intense biosonar vocalizations. Synchronization of vocalization with contractions of the pectoralis and serratus ventralis cooperate in pressurizing the thoracic and abdominal cavities. The use of pressure normally generated in flight facilitates respiration and allows the production of intense vocalizations with little additional energetic expenditure.

We present the first description of the calls and stridulatory structures of males and females of an Indian weta species from the Western Ghats of Southern India. Calls of males and females produced by femoro-abdominal stridulation were recorded and call features such as chirp duration, chirp period, syllable period and syllable duration were characterised. The calls of males were highly stereotyped with regular chirp periods and durations whereas chirp rates in the female calls were more variable. The number of syllables per chirp was constant for males and females and the fine temporal features such as syllable periods and syllable durations showed low inter-individual variation in both males and females. The arrangement of femoral stridulatory structures was different from the previously described anostostomatid species. The high stereotypy of calls of males and females indicates that the signal could serve for identification of species and sex