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HNUE JOURNAL OF SCIENCE Natural Sciences 2018, Volume 63, Issue 11, pp. 162-168 This paper is available online at http://stdb.hnue.edu.vn DOI: 10.18173/2354-1059.2018-0085 ADVERTISEMENT CALLS AND MATING BEHAVIOUR OF Chiromantis doriae (BOULENGER, 1803) (ANURA: RHACOPHORIDAE) FROM NORTHWESTERN VIETNAM Tran Thanh Tung1, Nguyen Song Thao2 and Le Trung Dung2 1 Vinh Phuc College Faculty of Biology, Hanoi National University of Education Abstract. We present new data on the vocalization and mating behaviour of Chiromantis doriae (Boulenger, 1803), a narrowly distributed frog from Vietnam. A new population of C. doriae was discovered during field surveys in the upland forest in Dien Bien Province in 2017. The complex vocal repertoire of C. doriae included only one type of tonal, wideband and pulsed calls and several transitional signal types differentiated by frequency and amplitude parameters. Calls were uttered as singular signals (pulsed calls). The complex structure of the advertisement call markedly distinguishes C. doriae from other members of the genus Chiromantis. We give the spacing of calling males, presence of multiple males near breeding sites. C. doriae mated only at night but males began calling immediately after dusk. The amplectant pair frequently moved around the branch for approximately 10-15 minutes. The female attended to the eggs that were attached to the branch. Keywords: Chiromantis doriae, advertisment calls, mating behaviour, Pa Thom forest, Vietnam. 1. Introduction A critical component of reproductive behaviour for most anuran amphibians is the acoustic signal (Wells, 2007) [1]. The main sound produced by males during the reproductive season is the advertisement call, which is utilized for species recognition, sexual selection, and territory defense (Wells, 1977 [2]; Gerhardt & Davis, 1988 [3]; Toledo et al., 2014 [4]). For these reasons, many of the acoustic properties of the advertisement call operate as prezygotic reproductive isolation mechanisms, and consequently are important for taxonomic inferences (Littlejohn, 1965 [5]; Duellman & Trueb, 1994 [6]; Goicoechea et al., 2010 [7]). Examining the variation in acoustic properties of advertisement calls at different organization levels (individuals, populations, species) contributes to efforts for taxonomic delineations among species and generates hypotheses about the biological meaning of acoustic traits (Giacoma & Castellano, 2001 [8]). Knowledge of the calls and reproductive biology of the anurans inhabiting Vietnam is scarce. Yet our understanding of the ecology and evolution of anuran reproduction is far from complete, as suggested by observations of peculiar behaviour and natural history in some species (Wells, 2007 [1]). Detailed field research of frog behaviour may even change current thoughts on the evolutionary biology of anurans. Altogether, these findings suggest that breeding behaviour is still Received July 30, 2018. Revised October 19, 2018. Accepted October 26, 2018. Contact Le Trung Dung, e-mail address: letrungdung_sp@hnue.edu.vn 162 Advertisement calls and mating behaviour of chiromantis doriae (boulenger, 1803) (anura: rhacophoridae)… poorly understood in many anurans even within relatively well-studied lineages [9]. Therefore, our study aimed to describe the advertisement call of C. doriae based on more robust sampling and using recordings taken within and near the typelocality; to present an analysis of the variation in call properties within and among individual males; to evaluate the effect of air temperature on the dynamic properties of the advertisement call. 2. Content 2.1. Materials and methods Collecting of data and specimens. Our samples included calls from males of Chiromantis doriae from Pa Thom forest, Pa Thom district, Dien Bien province. We first recorded the vocalization, then recorded calling site data including perch type (emergent plants, water surface), height relative to water surface, and horizontal distance from water. Our digital recordings were made with a Zoom H1 Handy Recorder recorder at a sampling rate of 48 kHz and 16 bit of sample size, and a Movo VXR40 Supercardioid Broadcast Shotgun Condenser Microphone positioned about 0.3 m from each calling male. For each recorded call sequence, the air temperature and humidity were measured with an electronic thermal hygrometer Nakata NJ-2099-TH. Recorded individuals were immediately collected to be retained as voucher specimens, fixed in 90% alcohol, and later preserved in 70% alcohol (Simmons, 2002 [10]). We deposited voucher specimens and recordings in the vertebrate collection of Museum of Biology, Hanoi National University of Education (HNUE). Morphological analysis. Measurements were taken with a digital caliper to the nearest 0.1 mm. Abbreviations are as follows: SVL, snout-vent length; EL, eye length, from anterior corner to posterior corner of eye; EN, distance from anterior corner of eye to posterior edge of nostril; HL, head length, from posterior corner of mandible to tip of snout; HW, maximum head width at the angle of jaws; NS, distance from anterior edge of nostril to tip of snout; SL, distance from anterior corner of eye to tip of snout; FLL, forearm length, from elbow to base of outer palmar tubercle; HAL, hand length, from base of outer palmar tubercle to tip of third finger; FL, thigh length, from vent to knee; TL shank length; TW maximum shank width; a.s.l., above sea level. For webbing formula we followed Glaw and Vences (2007) [11]. Acoustic analysis. Calls were analyzed by using Raven Pro, version 1.3 (Cornell Laboratory of Ornithology, Ithaca, NY, USA) at resolution of 16 bit and frequency of 44.1 kHz. Spectrograms were performed with Hann window type, frame length of 1024 samples, and corresponding 3 dB filter bandwidth of 67.4 Hz; frame overlapped 50% with time-grid resolution of 512 samples and fre- quency-grid resolution of 46.9 Hz. For each acoustic signal, the following parameters were measured: call duration (s): duration of time between beginning and end of a call; call repetition rate (calls/sec): (total number of calls–1)/duration of time between beginning of the first call and end of the last call; inter-call interval(s): duration of time between end of the first call and beginning of the second call; number of notes per call: total number of notes in a call; number of pulses per note: total number of pulses within a note (in some cases); dominant frequency of call (kHz): the emphasized harmonic in the spectrum (after Duellman and Trueb, 1994 [6]; Cocroft and Ryan, 1995 [12]). The first 10 notes of each call were removed according to research by Pröhl (2003) [13]. We calculated the coefficients of variation (CV = [SD/mean] × 100%) of the acoustic features measured in calls. We employed the criteria of Gerhardt (1991) [23] and classified as static those acoustic properties with average within individual CV < 5% and dynamic those with CV>12%, and CV from 5 - 12% was intermediate level of within-individual variation. To test the effect of air temperature and humidity on call rate, total number of notes per call, call duration, and dominant frequency, we used a linear regression analysis. Our data met the 163 Tran Thanh Tung, Nguyen Song Thao and Le Trung Dung assumptions of parametric tests. To perform the regressions, the acoustic characteristics were considered dependent variables and air temperature and humidity were considered the independent variable. Statistical tests were performed in JASP 0.8.6 (JASP Team, 2015 [14]; https://jasp-stats.org/) with a significance level of α = 0.05. Figure 1. Map showing the geographical location of Pa Thom forest (black circle) in Dien Bien Province, Northwestern Vietnam 2.2. Results and discussion New finding of C. doriae from Pa Thom forest, Dien Bien Province Chiromantis doriae (Boulenger, 1893) (Fig. 2a, b) Doria's asian treefrog / Nhai cay do - ri Specimens examine (n = 9). Six adult males (HNUE PT.2017.183-186, 211, 212) and three adult females (HNUE PT.2017.201, 209, 210) collected on 8 August 2017 by Le et al., near Pa Xa Lao Village, Pa Thom Commune, Dien Bien District, Dien Bien Province (N21⁰18.045’ E102⁰54.418’, 600 m). Morphological characters of specimens from Pa Thom forest agreed with the descriptions of Bourret (1942) [15], Taylor (1962) [16], and Neang and Jeremy (2008) [17]. However, it slightly differs from the description of Taylor (1962) [16] by having a small size in females (SVL 30.3 - 32.6 mm versus 29 - 35 mm). 164 Advertisement calls and mating behaviour of chiromantis doriae (boulenger, 1803) (anura: rhacophoridae)… Figure 2. Chiromantis doriae (HNUE PT.2017.201, adult female): a, Dorsal view and b, Ventral view Description. Body slender and long, males smaller than females (SVL 25.3 - 26.7 mm in males, n = 6 and 30.3 - 32.6 mm in females, n = 3); head longer than wide (HL/HW 1.04 - 1.37 in males and 1 - 1.1 in females); snout obtusely pointed, shorter than the diameter of the orbit (SL/EL 0.76 - 0.97 in males and 0.74 - 0.86 in females); nostril closer to the tip of snout than to eye (NS/EN 0.54 - 0.83 in males and 0.50 - 0.86 in females); loreal region concave; tympanum distinct; tongue large, notched posteriorly; vomerine teeth present. Forelimbs shorter than the length of hand (FLL/HAL 0.61 - 0.73 in males and 0.77 - 0.88 in females), fingertips with disc clutches, free of webbing. Hindlimbs slightly robust, long, thigh shorter than tibia (FL/TL 0.80 -0.89 in males and 0.89–0.91 in females); toes slender, relative toe lengths I

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