Bioacoustics of Ewartia roberti

Distribution and habitat . This species occurs from near Monto and Isla Gorge in south-east Queensland south to near Macksville, Spring Ridge and the Warrumbungle National Park in northern New South Wales ( Fig. 10 ). Adults are present from late August until April. It occurs in association with various wattles ( Acacia spp.) in dry sclerophyll forests, heathlands and also in urban environments, including road verges. Acacia fimbriata is a major adult food plant in Brisbane. In Brisbane Forest Park, A. glaucocarpa is inhabited. In the inland, specimens have been collected from A. spectabilis . Other wattle species with small phyllodes tend to be favoured. Acacias with large, fleshy phyllodes (e.g. A. concurrens ), are only utilised occasionally. In most seasons, E. roberti n. sp. is a common species throughout its range. Local congregations of singing males are often prominently scattered throughout areas of suitable habitat. Adults are active from Late August or September to May, being most common from October to February. This species overlaps in geographical distribution with E. oldfieldi and E. lapidosa n. sp. , and sometimes occurs in sympatry with each of these taxa. Calling song . The complex calling song mode of E. roberti n. sp. ( Figs 11–13 ) contains repeated, exceptionally long subphrases (25.3– 36.6 s duration; all statistics n = 70 recordings). Each subphrase is composed of a long series of discrete macrosyllables (each 2–5 syllables, 0.029– 0.080 s duration), each separated by a (typically increasing) set of 1–5 discrete syllables (each 11–13 ms duration, gaps 0.053– 0.092 s duration), which is then followed by series of 3–4 echemes of increasing duration (0.107– 0.441 s ), each punctuated by syllable sequences of decreasing duration (each between 0.337 and 1.234 s , containing intersyllable gaps of 0.009– 0.045 s duration), a climatic echeme (0.296– 2.351 s duration) and, finally, a long syllable sequence (4.416– 7.407 s duration, with intersyllable gaps of 0.031– 0.084 s duration). An accentuation then follows the syllable sequence at the end of most subphrases. This comprises typically 3–4 macrosyllables (each containing 2–5 syllables), each separated either by a syllable sequence (1–5 syllables, with intersyllable gaps of 0.031– 0.086 s duration) or, more rarely, an uninterrupted gap (0.142– 0.201 s ), and followed by a final gap (0.123– 0.155 s duration). This calling song mode is typically produced at intervals throughout the day. The simple calling song mode of this species ( Fig. 14 ) contains monotonously repeated phrases (0.3– 1.1 s duration). Each phrase typically contains a single echeme (0.25– 1.07 s duration) followed by a gap (0.053– 0.118 s duration); however, as the call progresses, the long echemes may be preceded by 1–2 discrete syllables or macrosyllables (each 0.011– 0.062 s duration), each followed by gaps (0.026– 0.064 s duration). This calling song mode predominates at dusk and is also produced occasionally at intervals during the day. The presentation of the frequency spectra does not change between song modes. In each mode the calling song typically has a highest amplitude frequency plateau between 10.0 and 14.5 kHz, with a dominant frequency between 11.3 and 13.5 kHz (mean=12.3, n =22; e.g. Fig. 7 B). The structure of the calling song of E. roberti n. sp. is remarkably consistent across its wide distribution. The echeme, syllable sequence and subphrase durations do exhibit some variation, but this variation appears to be present within and among individuals in the broader population, without exhibiting any clear spatial pattern. Much of this variation considered likely to be at least partly temperature dependent.