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Bushcrickets are one of the vocal insects which communicate through conspicuous calls. In most bushcrickets it is the adult male who produces sound to attract females in order for them to mate. The Phaneropterine subfamily is one of the largest and most widely-distributed of bushcricket family (family: Tettigoniidae) (~2400 species). Unlike other bushcrickets, phaneropterines show duetting where the female responds to the calling male. To avoid predation and boost signal reach of their songs bushcrickets may select specialized microhabitats and calling sites. Even though such patterns of the roost site fidelity have been studied previously in bushcrickets, calling site fidelity has not been explored much in case of bushcrickets. The current study was undertaken with the objective to describe the call of a commonly heard bushcricket, at various locations in Delhi, India (28° 24’ N, 28° 53’ E, 216 MASL). The calling individuals were recorded during March-April 2018 between 1900-2230 IST by ultrasonic recorder, Bat Detector D1000X (Petterson Electronik, Frequency response 5-235 KHz). Isopsera pedunculata was found to be narrow band caller, with a peak frequency of 8.42(±0.98) kHz and a very low duty cycle (4.4±2 phonatomes per min). We calculated resource selection function (RSF) to check if the calling males had selective preference for any particular tree as a calling site. Belt Transects of 40 × 20m were laid so as to include maximum number of trees with a GBH of ≥25cm. Out of 33 tree species in a total of 25 transects that were laid, the species was observed calling only from Neem trees (Azadirachta indica) (RSF value=1), signifying its selective preference for the tree. This preference of calling exclusively from Neem could be attributed to the relative abundance of Neem trees in transects (abundance=0.4). Other reasons for this preference could be the height of trees available to the insect for calling as microhabitat selection plays a crucial role in boosting communication and improving signaling. Further investigations are necessary to explore other possible reasons of this selective preference of I. pedunculata. This paper brings the first acoustic account and calling-site fidelity of phaneropterine I. pedunculata from Delhi. Keywords- Bioacoustics, Orthoptera, Phaneropterine, Calling site fidelity, Resource Selection Function.
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