Bioacoustics of Yoyetta repetens

Distribution, habitat and behaviour. Populations are known to occur from the Greater Sydney region southwest to Goulburn in central New South Wales ( Figure 18 ). Open eucalypt forest, woodland and parkland are inhabited with cicadas usually 1–5m from the ground on trees, bushes and posts. Males typically call while stationary and will fly between singing stations when approached. Adults have been collected between October and March. Calling song. The song of Y. repetens sp. nov. is a very simple, repetitive series of low-pitched macrosyllables ( Figure 19 ). Each macrosyllable ranges between 65 and 90 ms duration ( n = 3 recordings; Figure 20 ) and contains 7–9 syllables, each between 4 and 6 ms duration. A period of silence between 240 and 340 ms duration occurs between each macrosyllable. The macrosyllable repetition rate for the call ranges from 2.4 to 3.0 Hz. The frequency spectrum of the calling song ranges from 4.2 to 14 kHz, with the highest energy between 6.5 and 11.5 kHz, and a dominant frequency of approximately 9.5 kHz ( Figure 19 ).

Etymology. From Latin repetens , meaning “repeating”. This name has been chosen because of the distinctive and repetitive “zrrpp-zzrrp-zrrpp”chirping song of this cicada species. Distinguishing features. Yoyetta repetens sp. nov. , can be distinguished from Y. aaede (Walker) , Y. abdominalis , Y. hunterorum and Y. denisoni by the absence of the prominent, white hind wing plaga, characteristic of these latter four species. It is distinguished from Y. landsboroughi , Y. nigrimontana sp.nov. , Y. incepta , Y. fluviatilis sp.nov. , and male Y. hunterorum by possessing fore wings with length> 22 mm . Y celis has a more greenish-brown coloration, with 2 distinct black spots over the scutal depressions, whereas Y. repetens exhibits a broad area of dark brown to black coloration anterior to the cruciform elevation. In addition, the ovipositor of female Y. repetens does not extend past the end of the abdomen (c.f.>1.0 mm beyond in Y. celis ). The colour surrounding the cruciform elevation in Y. repetens is not noticeably paler or brighter than the remainder of the mesonutm, which differentiates this species from Y. tristrigata . In male specimens, the presence of a transparent, spine-like apex to the theca is an additional feature of Y. repetens that is absent in the Y. tristrigata . Dark male specimens of Y. repetens sp. nov. , which are the typical colour form in western Sydney and Goulburn, can easily be distinguished from Y. cumberlandi sp. nov. , which exhibits predominantly brown thoracic markings. Paler coloured males of Y. repetens sp. nov. found in the inner western and northern suburbs of Sydney are more difficult to distinguish. However, there is a useful feature that is consistently different between the two species in timbal structure. In Y. repetens sp. nov. , long rib 5 is considerably narrower than the widest portion of adjacent long rib 4. In Y. cumberlandi sp. nov. , long rib 5 is approximately equal in width to adjacent long ribs. Paler female specimens of Y. repetens sp. nov. from western Sydney can also be difficult to distinguish from Y. cumberlandi sp. nov. ; however, in the former species, the lateral markings on the tergites appear diffuse and faded, whereas these markings are contrastingly prominent in Y. cumberlandi sp. nov.