We examined differences in reproductive activities and intraspecific variations in advertisement calls of Duttaphrynus melanostictus (Schneider, 1799) that lives in a tropical region of central Vietnam. The snout-vent length (SVL) of sexually mature males ranged from 50.2 to 70.3 mm, while that of females ranged from 65.2 to 97.3 mm. Histological analyses of testes revealed that sperm was not present throughout the year, indicating discontinuous reproductive activity for adult males. Adult females were captured year-round, but reproductive females were observed only during months of the auxiliary rainy season (mainly April to July), indicating that females reproduce seasonally. We also estimated levels of within-male variation of each call property and the influences of the ambient temperature, humidity, and the SVL of calling males on acoustic features. The call rate and pulse rate showed intermediate levels of variation, whereas the dominant frequency and call duration were the most stereotyped properties. One-way analyses of variance for six acoustic properties showed that the call rate, pulse rate, and rise time significantly differed (p < 0.05) among localities. Advertisement calls were a series of groups of 56 to 244 (145 ± 54) pulses with an average call duration of 26.722 s, an average pulse rate of 11.69 pulses/s, and an average dominant frequency of 1.293 kHz. The results of the multiple regressions for possible effects of temperature, humidity, and SVL on the six acoustic properties indicated that the dominant frequency, pulse rate, call duration, and rise time were positively significant. In Bach Ma National Park, when air temperature in the recording area decreased to <16.6°C, and advertisement calls of adult males virtually ceased in all three populations.

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Reproductive activity and advertisement calls of the Asian common toad Duttaphrynus melanostictus (Amphibia, Anura, Bufonidae) from Bach Ma National Park, Vietnam

Geographic variation in the advertisement calls of the giant spiny frog (Paa spinosa)

Anurans often have species-specific vocalizations. To quantify and compare the characteristics of anuran calls in Gutianshan National Nature Reserve, Zhejiang Province, we recorded the advertisement calls of eight species belonging to four families (Ranidae, Microhylidae, Megophryidae and Bufonidae) from June to September 2012 using Sony ICD-FX8 IC recorders. All recordings were analyzed using the "Praat" software. Five acoustics parameters were measured, including temporal traits (call duration, number of notes or pulse number/call) and spectral traits (fundamental frequency, the first three formants and dominant frequency). The characteristic parameters of Microhyla ornate and Fejervarya limnocharis calls were different as were the calls of some populations of the same species recorded in different regions. The advertisement calls of the eight species were specific. Our study has provided a useful reference for identifying the calls of some common Chinese anurans.

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Acoustic characteristics of eight common Chinese anurans during the breeding season.

Advertisement Call Variability in the Black-spined Toad Bufo melanostictus (Anura: Bufonidae) during the Breeding Season in Lishui, Zhejiang, China: Advertisement Call Variability in the Black-spined Toad Bufo melanostictus (Anura: Bufonidae) during the Breeding Season in Lishui, Zhejiang, China

Hearing sensitivity affects survival and reproduction in animals that communicate vocally. The Chinese tiger frog exhibits sexual dimorphism in body size, reflecting the evolution of mating behaviour and life-history strategies. In this study, we recorded auditory brainstem responses (ABRs) to determine hearing sensitivity in both female and male frogs. We also compared male and female hearing characteristics with the shape of the tympanic membrane in light of previous studies showing that smaller middle ear cavities improve hearing sensitivity. We found that ABR thresholds differ significantly between males and females, with the greatest sensitivities in both sexes at frequencies close to the dominant frequency of male calls. ABR thresholds were significantly lower in females compared to males for frequencies in the 0.9–1.3 kHz range and at 1.6 kHz. The tympanic membrane diameter was significantly smaller in females (5.94 ± 0.87 mm) than in males (6.71 ± 0.49 mm). Our results indicate that sexual...

Auditory brainstem responses in the Chinese tiger frog Hoplobatrachus chinensis (Osbeck, 1765) (Anura: Dicroglossidae) reveal sexually dimorphic hearing sensitivity

We recorded and described the calls and acoustic characteristics of the male tiger frog, Hoplobatrachus rugulosus, in an artificial pond during mating season. Spectral and temporal call parameters, along with call intensity were analyzed. Three harmonics were distinguishable from the spectrogram. Four patterns of dominant frequency were found in calls produced late at night, i.e, 3 patterns in the first harmonic (located in 500 Hz section, 700 Hz section, and 800 Hz section respectively) and 1 in the second harmonic (located in 1 800 Hz section). Call duration, call duty cycle, call intensity, and pulse rate were highly variable among different patterns of dominant frequency. These call properties could provide valuable evidence for further ecological study of this species.

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MA Xiaomei

Papers

Acoustic characteristics of the tiger frog, Hoplobatrachus rugulosus, during the breeding season.

Advertisement Call Variability in the Black-spined Toad Bufo melanostictus (Anura: Bufonidae) during the Breeding Season in Lishui, Zhejiang, China: Advertisement Call Variability in the Black-spined Toad Bufo melanostictus (Anura: Bufonidae) during the Breeding Season in Lishui, Zhejiang, China

Computational Thinking: A Mediation Tool and Higher-Order Thinking for Linking EFL Grammar Knowledge with Competency