Bioacoustics of Chrysocicada trophis

Ecology. Males sing from within grass tussocks. A female was observed ovipositing in a live grass stem, facing head downwards. Individuals produce an alarm call when handled, but they are reluctant to fly and instead will drop to the base of a grass clump and remain still when disturbed. One instance of pair-formation was observed, in which a female walked toward a singing male, stopping when the male stopped singing. The male moved toward the female when she was near, eventually found a way to her grass stem and began copulation. No wing-flicking was observed from the female. A perched male would often begin moving toward the hand of a careful collector, as if mistaking it for an approaching female.

Measurements. Range and mean (in mm) for 10 males and 3 females (includes smallest and largest of available specimens). Length of body (including head): male 13.9–15.8 (14.9); female (including ovipositor) 13.2–14.2 (13.8). Length of forewing : male 13.4–15.7 (14.7); female 14.5–16.2 (15.2). Width of head (including eyes): male 3.4–3.7 (3.6); female 3.2–3.7 (3.5). Width of pronotum (across lateral angles): male 3.8–4.5 (4.1); female 3.3–4.0 (3,7). Distinguishing features. Males of Chrysocicada trophis sp. n. can be distinguished from all other Australian species by their brown suffused wing tips, small size (forewing less than 16 mm long) swollen abdomen (clearly wider than thorax), narrow head (narrower than the mesonotum), and lack of fusion of forewing veins M and CuA at the basal cell. Further, forewing vein CuA 1 is divided by crossvein m-cu so that proximal portion is consistently longest. Females are more difficult to distinguish but their brown suffused wing tips and small size (forewing less than 16.2 mm long), narrow head and forewing veins M and CuA unfused at basal cell, in conjunction with forewing vein CuA 1 being divided by crossvein m-cu so that proximal portion is longest separate them from all others. Chrysocicada trophis sp. n. differs from C. franceaustralae in having a head that is narrower than the mesonotum instead of about equal, five hindwing apical cells instead of six, and tergites 2 and 3 just a little wider along their midline than any of tergites 4–7 instead of being about equal. Song ( Figs 26a–d ). Recordings were examined from the type locality, including song from the holotype male which is illustrated. The calling song consists of a smooth, whining buzz that is produced for indefinite periods of time, usually while the male faces head upward with the wings angled outwards alongside the body and with the abdomen distinctly elevated. The song contains closely spaced or coalesced 4–5 pulse syllables repeated at about 150/s. The within-syllable pulse rate is approximately 700/s. In some samples the syllables cannot be distinguished and the pulse rates become irregular, yet the spectral profile does not change markedly. Most sound energy is contained within the range 7–12 kHz, and the peak sound frequency is about 9.5 kHz. The sound spectrum is not modulated over time, except that the pitch may drop with the approach of a recordist. Males occasionally hesitate in song production for ca. 0.1– 0.2 s . The song of Chrysocicada trophis sp. n. is similar to that reported for the type species C. franceaustralae , which sings from grasses with a similar posture ( Boulard 1989 ). C. trophis differs in having a somewhat lower frequency spectrum (dominant frequency ca. 10 kHz instead of 12 kHz in franceaustralae ). Additional very low frequency sound components reported by Boulard for the type (<2.2 kHz, and a fundamental signal band at 0.1–1.3 kHz) are not present in the song of C. trophis . A spectrogram generated from an unfiltered sample is shown in Fig. 26b to demonstrate this. Such spectral frequencies are not usually found in the songs of small-bodied Cicadettinae and they might have been caused by the likely teneral (newly emerged) condition of the singers, reported by Boulard, or by microphone distortion. The two spectrograms published for C. franceaustralae do not allow unambiguous measurement of the underlying pulse and/or syllable rates.

Etymology. Named from the Greek adjective trophis meaning well-fed, fat, stout, and pertaining to the inflated male abdomen of this species. Tribe. Pictilini , Moulds & Hill, in Marshall et al. , 2018 . Types . Holotype male (Simon Lab. molecular voucher 06.AU.WA.MDE.01, song recorded), Meda Stn , 53 km E of Derby , Western Australia , 17º25.090’S 124º05.825’E , 24 m , 7.ii.2006 , Hill , Marshall , Moulds ( WAME 113425 ) ( WAM ) . Paratypes as follows: WESTERN AUSTRALIA : 2 males , 1 female , same data as holotype (DE). 2 males , same data as holotype ( LP ). 6 males , 2 females ( 2 males genitalia preps. CHR3 and CHR4 ), same data as holotype ( MSM ). 1 male , same data as holotype ( PH ). 1 male , same data as holotype (molecular voucher 06.AU.WA. MDE .02) ( UCONN ). 5 males , same data as holotype ( WAME113426-113430 ) ( WAM ).