Table 3. Correlation analysis and coefficients of variation.
(A) Pearson-product moment correlations (r) between Microhyla nilphamarensis (N = 18) call properties with snout-to-vent length (SVL), mass, body condition and temperature. (B) Coefficients of variation computed among (CVa) and within males (CVw) and their ratios.
| A. Correlation analysis | B. Coefficients of variation | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Type of acoustic property | Property | SVL | Mass | Body condition | Wet bulb temperature (°C) | CVa | CVw mean (range) | CVa:CVw | ||||
| Call properties | r | P | r | P | r | P | r | P | ||||
| Temporal call properties | Call duration (ms) | −0.27 | 0.29 | 0.37 | 0.14 | 0.58 | 0.01** | 0.40 | 0.10 | 14.6 | 10.0 (3.44–18.81) | 1.46 |
| Call rise time (ms) | −0.26 | 0.30 | 0.43 | 0.07* | 0.64 | 0.00** | 0.43 | 0.07* | 44.7 | 26.05 (7.61–73.73) | 1.72 | |
| Call fall time (ms) | 0.15 | 0.54 | −0.20 | 0.43 | −0.31 | 0.21 | −0.35 | 0.16 | 32.4 | 32.1 (14.1–48.0) | 1.01 | |
| Intercall interval (s) | −0.23 | 0.37 | −0.53 | 0.02** | −0.50 | 0.04** | −0.09 | 0.71 | 116.7 | 150.6 (6.4–327.0) | 0.77 | |
| Pulses per call | −0.29 | 0.25 | 0.19 | 0.45 | 0.39 | 0.11 | 0.45 | 0.06* | 13.2 | 9.9 (3.5–19.2) | 1.33 | |
| Pulse rate (pulses/s) | −0.11 | 0.68 | −0.40 | 0.10 | −0.40 | 0.10 | 0.28 | 0.25 | 6.5 | 2.7 (1.1–7.4) | 2.39 | |
| Spectral call properties | Overall dominant frequency (peak) (kHz) | −0.05 | 0.86 | 0.06 | 0.82 | 0.09 | 0.71 | 0.04 | 0.89 | 28.8 | 16.2 (0.0–43.9) | 1.78 |
| Overall dominant frequency 1 (kHz) | −0.48 | 0.04** | −0.75 | 0.00** | −0.60 | 0.01** | 0 | 1.0 | 3.4 | 0.7 (0.0–1.6) | 4.68 | |
| Overall dominant frequency 2 (kHz) | −0.18 | 0.48 | 0.09 | 0.74 | 0.20 | 0.42 | −0.06 | 0.80 | 7.2 | 2.2 (0.0–8.3) | 3.33 | |
| Pulse properties | ||||||||||||
| First, middle and N-1 pulses | First pulse period (ms) | −0.07 | 0.79 | 0.18 | 0.48 | 0.24 | 0.34 | −0.53 | 0.02** | 8.9 | 15.8 (4.5–50.2) | 0.56 |
| Middle pulse period (ms) | 0.11 | 0.65 | 0.43 | 0.07* | 0.43 | 0.07* | −0.13 | 0.61 | 6.6 | 3.5 (1.9–14.4) | 1.88 | |
| “N-1” pulse period (ms) | 0.12 | 0.64 | 0.08 | 0.76 | 0.01 | 0.96 | −0.26 | 0.30 | 12.9 | 13.4 (6.1–27.5) | 0.96 | |
| Spectral properties maximum pulse | Overall pulse dominant frequency (kHz) | −0.14 | 0.58 | 0.20 | 0.43 | 0.30 | 0.22 | 0.24 | 0.33 | 26.1 | 18.4 (0.0–43.1) | 1.42 |
| Pulse dominant frequency 1 (kHz) | −0.62 | 0.00** | −0.66 | 0.00** | −0.42 | 0.09* | 0.21 | 0.41 | 3.3 | 2.2 (0.0–7.5) | 1.49 | |
| Pulse dominant frequency 2 (kHz) | −0.24 | 0.33 | −0.084 | 0.74 | 0.04 | 0.87 | −0.12 | 0.63 | 8.0 | 3.7 (0.9–7.6) | 2.17 | |
| Temporal properties maximum pulse | Pulse period (s) | 0.18 | 0.49 | 0.30 | 0.23 | 0.24 | 0.33 | −0.20 | 0.43 | 7.1 | 4.6 (1.9–26.9) | 1.52 |
| Pulse duration (ms) | 0.09 | 0.73 | −0.01 | 0.97 | −0.06 | 0.82 | −0.10 | 0.69 | 25.4 | 12.6 (3.2–22.3) | 2.02 | |
| Pulse rise time (ms) | −0.27 | 0.27 | 0.24 | 0.33 | 0.43 | 0.07* | −0.18 | 0.47 | 16.4 | 14.9 (1.7–42.8) | 1.10 | |
| Pulse 50% rise time (ms) | 0.25 | 0.31 | 0.50 | 0.03** | 0.43 | 0.08* | −0.30 | 0.23 | 15.2 | 14.0 (1.7–26.3) | 1.09 | |
| Pulse fall time (ms) | 0.12 | 0.65 | −0.04 | 0.89 | −0.10 | 0.68 | −0.08 | 0.77 | 32.4 | 16.9 (5.2–38.7) | 1.92 | |
| Pulse 50% fall time (ms) | 0.06 | 0.82 | −0.03 | 0.91 | −0.07 | 0.80 | −0.08 | 0.76 | 35.1 | 19.4 (8.9–37.1) | 1.81 | |
Notes.
*
For pulses/call, median and inter-quartile ranges are reported here instead of means and S.D. Sri Lanka; quartiles: q1 =12.5, q2 = 13, q3 = 13.5; Western Coast; quartiles: q1 = 9.5, q2 = 11, q3 = 11.5; New Delhi: q1 =15, q2 = 16.5, q3 = 18.75.
**
Bold type indicates statistically significant correlations (P < 0.05, p-values marked with (**), while marginally significant correlations are marked with an asterisk (*) for 0.05 < p < 0.09).