Bioacoustics of Myopsalta umbra

Distribution, habitat and behaviour ( Fig. 28 ). Myopsalta umbra is restricted to south-east Queensland from Expedition Range, Isla Gorge and near Monto (Hurdle Gully) east to Lake Lenthall near Maryborough and south to Mt French near Boonah. Populations typically inhabit remnant patches of semi-evergreen vine thicket. Adults occur in the middle stratum, typically on woody vegetation. They have been found from October to January, apart from the Cracow specimens, which were collected in mid-February. This is the only species of Myopsalta known to occupy the interior of a dry rainforest habitat, specifically in a microhabitat that is almost continuously shielded from direct sunlight. Another species, M. mackinlayi , may be found on the margins of this habitat, and in disturbed or ecotonal areas (e.g. vine thicket with eucalypt canopy), but generally not in the vine thicket interior. Calling song ( Figs 32 , 33 ). The song contains a set of repeated phrases. At the onset of calling, each phrase begins with a long echeme (0.509–1.199 s duration), followed by a 0.035–0.046 s gap, a short echeme or macrosyllable (0.034–0.060 s duration) and a 0.376–2.701 s gap (all statistics, n =9 recordings). Close inspection of the beginning of the long echemes in each phrase reveals a series of discrete syllables that coalesce and increase of at least 4x in amplitude during production of the echeme. After production of several successive echemes, males typically start to lengthen the introduction of each phrase with the addition of a long sequence of syllables (each 0.007–0.011 s duration), separated by gaps of 0.030–0.080 s duration. These introductory sequences range in duration between 1.12 and 1.59 s, with the longest examples typically coinciding with particularly short gaps at the end of the preceding phrase. Field observations indicate that the female responds during the gap following the short echeme or macrosyllable at the end of each phrase. This species calls during the day and it is not known whether it also calls at dusk. The calling song maintains an even pitch throughout, with a highest amplitude frequency plateau of 10.3–16.0 kHz and a dominant frequency between 12.2 and 15.1 kHz. It is near identical to the call of M. bassiana , but differs in the greater degree of amplitude modulation in the production of each long echeme.

Calling song (Figs 32, 33). The song contains a set of repeated phrases. At the onset of calling, each phrase begins with a long echeme (0.509–1.199 s duration), followed by a 0.035–0.046 s gap, a short echeme or macrosyllable (0.034–0.060 s duration) and a 0.376–2.701 s gap (all statistics, n =9 recordings). Close inspection of the beginning of the long echemes in each phrase reveals a series of discrete syllables that coalesce and increase of at least 4x in amplitude during production of the echeme. After production of several successive echemes, males typically start to lengthen the introduction of each phrase with the addition of a long sequence of syllables (each 0.007–0.011 s duration), separated by gaps of 0.030–0.080 s duration. These introductory sequences range in duration between 1.12 and 1.59 s, with the longest examples typically coinciding with particularly short gaps at the end of the preceding phrase. Field observations indicate that the female responds during the gap following the short echeme or macrosyllable at the end of each phrase. This species calls during the day and it is not known whether it also calls at dusk. The calling song maintains an even pitch throughout, with a highest amplitude frequency plateau of 10.3–16.0 kHz and a dominant frequency between 12.2 and 15.1 kHz. It is near identical to the call of M. bassiana, but differs in the greater degree of amplitude modulation in the production of each long echeme.