Bioacoustics of Popplepsalta tremula

Distribution and Ecology ( Figure 19 ). This species occurs in southern Queensland from Carnarvon National Park east to Cooyar, Benarkin near Blackbutt and Eidsvold, and south to Boggabilla in far northern inland New South Wales . These cicadas are associated with eucalypts of the subgenus Symphyomyrtus , including Eucalyptus populnea (section Adnataria ) and E. camaldulensis (section Exsertaria ). Adults occur high on the upper branches from where the males sing. They do not fly between calling sites as actively as some of the other Pauropsalta species dealt with here, but do fly if approached closely. Geological and Pedological Associations . Found in association with sandy loam soils on flats derived from highly weathered sandstone, granite and occasionally laterite. Calling Song ( Figs 2E , 20–21 ). This species typically produces only the lilting song component, but individuals occasionally emit a brief succession of short echemes that could be interpreted as a brief buzzing component. The lilting component includes a long echeme (6–13 syllables, 0.043 –0.104 s) followed by a silence ( 0.043 –0.098 s), then a short echeme (2–3 syllables, 0.018 –0.034 s) and another silence ( 0.051 –0.104 s) (all statistics, n=47 individuals). phrase repetition rates vary between 0.160 –0.340 s, and typically fall within the range of 0.200 –0.300 s. The rhythm of the calling song is characterised by silences of about equal duration between each long and short echeme and vice versa, giving it a maraca-like quality. Two cases of male–female duets have been recorded, with females responding only during the silence at the end of each lilting phrase, 0.021 –0.030 s after production of the short echeme. The calling song has a frequency plateau between 7.0–12.0 kHz, with a highest amplitude dominant frequency between 7.2–9.2 kHz and a syllable repetition rate of approximately 90–110 Hz.

Diagnosis ( Figs 4F , 5F , 6F , 18A–B ). Pauropsalta tremula differs from P. annulata as follows. Eyes red (live specimens) to brown (dried specimens), never white or grey. Mesonotum with apparent yellow-brown to reddishbrown fasciae surrounding the submedian sigilla and adjacent to the lateral sigilla, along the lateral margin; submedian sigilla, lateral sigilla and area posterior to lateral sigilla, black; dorsolateral fasciae meeting medially, or occasionally separated with black colouration extending along sagittal plane. Abdominal sternites mainly black with thin areas of pale brown to medium brown colouration on lateral margins of sternites II–V (rarely VI) and on extreme lateral posterior margins of remaining sternites. Theca apex relatively blunt when viewed laterally, without obvious dorsal and ventral posterior projections; fine to medium sized spine ornamentation present. Females similar in appearance to males, with mesonotum generally showing more extensive yellow-brown to brown colouration apart from submedian and lateral sigilla and areas surrounding scutal depressions, which are black. Ovipositor sheath does not extend significantly beyond the apex of the abdomen (< 0.5mm ). Distinguishing features: Males and females can be distinguished from all others in the P. annulata group except for P. blackdownensis , in having the unique combination of distinct dorsolateral and lateral mesonotal fasciae surrounding the lateral sigilla, with abdominal sternites that are black apart from the lateral edges of sternites II–V (rarely VI) and extreme posterior lateral margins of remaining sternites. Males differ from P. blackdownensis in having a rather blunt apex of the theca, when viewed laterally (rather than an apex with apparent dorsal and ventral projections). Females differ from P. blackdownensis by their ovipositor sheath, which does not extend significantly beyond the apex of the abdomen. Notes on Geographical Variation . Specimens recently collected from Mount Moffatt section in Carnarvon National Park by A. Ewart could represent another population of this species. They key out to this species morphologically, but appear melanistic. The calling song has yet to be recorded from these insects, so their species status remains unclear.