Bioacoustics of Myopsalta crucifera

Calling song (Figs 9, 10). The song of this species contains simple, repetitive buzzing phrases, each beginning softly then rising sharply to a constant amplitude for the remainder. Each phrase commences with a long echeme of 0.800–6.150 s duration, followed by a brief gap (0.008–0.040 s) and a syllable or macrosyllable of 0.006–0.028 s duration (all statistics, n= 49 recordings). Occasionally, an additional syllable or macrosyllable is produced at the end of the phrase. Each phrase concludes with a gap of 0.021–0.191 s duration. When short gaps occur, the phrases often appear to follow on continuously. In the absence of direct observations, it is presumed that the female would respond with a wing flick during longer gaps at the end of each phrase. Close inspection of the structure within the long echeme at the start of each phrase often reveals that the beginning of this echeme contains a series of discrete syllables, although in some cases these syllables at the beginning of each long echeme may be entirely coalesced. Indeed, there is a progression from isolated short syllables to isolated longer syllables, to coalesced syllables. The calling song typically exhibits a highest amplitude frequency plateau between 12.0 and 18.6 kHz. There appears to be no dramatic modulation in frequency during production of the calling song.

Distribution, habitat and behaviour ( Fig. 4 ). Myopsalta crucifera is found from near Cooktown south through coastal and subcoastal Queensland to Kyogle in northern New South Wales . It has also been recorded further inland in the vicinity of Mount Surprise and from near Carnarvon Gorge in northern and central Queensland respectively. Populations occur in open grassland, grassy woodland, paddocks, crops (e.g. Sugarcane; see Moulds, 1990 ), in mangrove communities and in open forest where the adults are typically found on low vegetation including grass. Adults have been found from September to April. Males sing frequently during warm, sunny conditions. Calling song ( Figs 9 , 10 ). The song of this species contains simple, repetitive buzzing phrases, each beginning softly then rising sharply to a constant amplitude for the remainder. Each phrase commences with a long echeme of 0.800– 6.150 s duration, followed by a brief gap (0.008– 0.040 s ) and a syllable or macrosyllable of 0.006– 0.028 s duration (all statistics, n= 49 recordings). Occasionally, an additional syllable or macrosyllable is produced at the end of the phrase. Each phrase concludes with a gap of 0.021– 0.191 s duration. When short gaps occur, the phrases often appear to follow on continuously. In the absence of direct observations, it is presumed that the female would respond with a wing flick during longer gaps at the end of each phrase. Close inspection of the structure within the long echeme at the start of each phrase often reveals that the beginning of this echeme contains a series of discrete syllables, although in some cases these syllables at the beginning of each long echeme may be entirely coalesced. Indeed, there is a progression from isolated short syllables to isolated longer syllables, to coalesced syllables. The calling song typically exhibits a highest amplitude frequency plateau between 12.0 and 18.6 kHz. There appears to be no dramatic modulation in frequency during production of the calling song.