Altitudinal variations of acoustic organs in anurans: A case study from China

Abstract

Bioacoustic signals are considered to be essential to the social communication of anuran amphibians. However, some anuran species lack a vocal sac or tympanum, or both. We hypothesise that the variation of anuran acoustic organs correlates to altitude. We reviewed published literature concerning anuran species which inhabit China, and tested the general relationship between anuran acoustic organs and altitude. The result showed that both the vocal sac and the tympanum had a significantly negative trend to altitude, and that the vocal sac also significantly correlated to the tympanum. The interaction by phylogenetic relationships could be excluded. We suggested that anuran acoustic organs decline with increasing altitude. With increasing altitude, lower population density, low temperature, hypoxia and food shortage could be responsible for such degeneration. Nontympanic pathways of sound reception and ultrasonic signal system may be utilised to compensate for anuran acoustic organ degeneration.

Keywords:

• Anuran
• acoustic organs
• altitudinal variation

Introduction

Bioacoustic signals are essential to the social communication of anuran amphibians. Most anurans can be incredibly vocal, especially during breeding time, when the males advertise themselves using acoustic signals in an attempt to attract a mate. Inflation of a vocal sac characterises advertisement calling behaviour in nearly all male anurans, and the vocal sac can serve as a visual cue and is a salient part of the advertisement signal in at least some circumstances (Rosenthal et al. 2004). The sound receptor, tympanum or eardrum, are caused to vibrate by sound waves. The vibrations travel to the inner ear through the columella, which conducts the movements of the tympanum across the space of the tympanic cavity. However, some anuran species lack a vocal sac or tympanum, or both. Although such a lack usually does not cause any inconvenience for anuran vocalisation, it suggests that some factors must play a role on the variation.

Acoustic signals are considered playing a very important role on anuran activities. Males gain reproductive advantage by competing for advertisement privileges and by vocally suppressing neighbouring males (Tobias et al. 1999). There are many studies that demonstrate strong directional selection on various components of signals used to attract conspecific mates (Ryan & Keddy‐Hector 1992) and considerable variation in signals and receivers among populations of the same species (Claridge et al. 1988; Verrill & Arnold 1989; Ritchie 1991; Ryan & Wilczynski 1991; Ryan et al. 1992; Rowe 1999; Rosenthal et al. 2004). Mating success has been shown to be positively correlated to an individual's chorus tenure in some species (Murphy 1999). Combinations of acoustic and visual cues can also enhance spatial localisation (McDonald et al. 2000). The acoustic signals that most anurans produce are accompanied by inflation of a conspicuous vocal sac. The specificity of female response to vocal sacs, and the great diversity of form, colour and pattern in these structures (Duellman & Trueb 1986; Hödl & Amézquita 2001; Narins et al. 2003), suggests that these cues might play a role in conspecific mate recognition and mate preference.

Attracted by the fact that the communication systems of some arthropods show strong analogies with those of anurans, we tried to investigate the extension of such parallelisms and focused on the relation with altitude. Arthropods were found to be reduced and lacking wings with both increasing altitude and increasing latitude (Downes 1965; Mani 1968). The elytra and wings of the grasshoppers in the Tibetan Plateau had degenerated or were even found to be lacking (Yin 1984). As a grasshopper relies on the elytra and wings to make sound, the degeneration or lack of these lead to a default, which in turn resulted in a degeneration of their auditory organ, and it was positively correlated to altitude.

Being ectothermal animals, anurans are particularly sensitive to environmental factors. The reduction of arthropods' wings and auditory organ provides a cue for us to explore the variation of anuran acoustic organs. Along with the increasing altitude, environment changes rapidly. There is an underlying process of deterioration that is more rapid and severe the greater the altitude. Anurans had to adapt to this pressure by adjusting their behaviour and physiology, and this must be followed by changes in morphology. According to the literature (Hu et al. 1987; Yang 1991; Ye et al. 1993; Zhao and Yang 1997; Liu et al. 2000), there are more than 200 anuran species in China, which being distributed from sea level to 5100 m above sea level (a.s.l.) provide good material for our study. Our aim is to test whether anuran acoustic organs decline with increasing altitude. We tested whether the acoustic organs of the species within anuran orders correlate to altitude, and briefly discussed processes that may account for the results.

Materials and methods

We reviewed literature that concerned about 250 anuran species in China. To avoid confusion caused by different taxonomic systems, we dealt with anurans according to the publication that listed the most anuran species which belong to four suborders: Opisthocoela, Anomocoela, Procoela and Diplasiocoela (see Appendix I). Other publications were also referred in case of possible bias on species description.

Data analysis is usually reasonable for interpreting a result, so we transformed the characteristics described in the literature into data. We recorded the characteristics according to papers that clearly described the vocal sac and tympanum of each species. We collected information on 199 species out of 250 (79.6% of total) for which both vocal sac and altitude information were available, and 162 species (64.8% of total) for which both tympanum and altitude information were available. Each character was turned into a number: ‘2’ stands for external vocal sac, ‘1’ for internal vocal sac and ‘0’ for lack of or inconspicuous vocal sac. For tympanum, ‘2’ represented a tympanum larger than half the diameter of the eye, horizontal tympanum diameter less than half the horizontal eye diameter or with an indistinct tympanum was marked ‘1’, and no tympanum or a barely visible tympanum was marked ‘0’. The altitudes as indicated by the literature were adopted. When it appeared in a range, we used the average value. Those with no clear description of both vocal sac or tympanum and altitude at the same time were excluded for purposes of calculating the relationship between vocal sac and tympanum.

Because we hypothesised that the anuran acoustic organs vary along with altitude, we tested the general relationship between anuran acoustic organs and altitude by using the nonparametric correlation test. In this procedure, altitude was treated as the independent factor and the characteristics of anuran acoustic organs as dependent factors. Altitude range was divided into four categories (1⩽1000 m; 1000 m<2⩽2000 m; 2000 m<3⩽3000 m; 4<3000 m). We also tested whether tympanum was influenced by vocal sac using bivariate correlation analysis.

Anuran families in China have different altitudinal ranges (Figure 1). The association between altitude and both vocal sac and tympanum might be an artefact and could be explained by phylogenetic relationships rather than by natural selection acting independently on all the species considered. Loglinear analysis is useful in order to classify subjects based on values of a set of predictor variables, so the data were dealt with according to such a procedure. Genus was also introduced as one of the variables at family level, and all the species were grouped into six categories according to their families.

Figure 1 Altitudinal range of anuran families in China. The six families are Discoglossidae(DIS), Pelobatidae (PEL), Bufonidae (BUF), Ranidae (RAN), Rhacophoridae (RHA) and Microhylidae (MIC).

Since the responses had been aggregated, the cases were weighted by frequency first. Hierarchical loglinear analysis could remove some effects while evaluating the full model. The first model evaluated was the saturated model, which included all effects (altitude, family, vocal sac and tympanum) and thus perfectly fits the data. With our data, the quadruple and the triple interactions showed no significant effect (P values were larger than 0.577), so the quadruple and the triple interactions were removed. After a six‐step simple effect deletion, the final model was generated. Two remaining interaction terms were altitude–vocal sac and altitude–tympanum, and the interaction of phylogenetic relationships could be excluded. Then, two‐way interaction of altitude–vocal sac and altitude–tympanum were tested with General Loglinear Analysis.

Statistics were achieved by SPSS 12.0.

Results

The results of the nonparamatric test showed that anuran auditory organs showed a significant difference at different altitudes (Table I). As expected, the median test indicated that both vocal sac and tympanum showed a negative trend along with increasing altitude (Table II).

Table I. Kruskal–Wallis test for testing distribution of anuran auditory organs to different altitude.

		χ^2	df	P
Altitude	Vocal sac	55.99	3	<0.001
	Tympanum	38.44	3	<0.001

Table II. Frequency of vocal sac and tympanum above and below the median.

		Altitude				χ^2	P
		<1000	1000–	2000–	3000–
Vocal sac	>Median	42	45	11	0	42.49	<0.001
	< = Median	14	40	23	24
Tympanum	>Median	12	18	2	0	11.18	0.011
	< = Median	29	55	26	20

Loglinear analysis also reached the conclusion that vocal sac and tympanum each had a significant association with altitude. The results showed a likelihood ratio chi‐square value of 18.80 (df = 16, P = 0.279), a Pearson's chi‐square value of 15.34 (df = 16, P = 0.500), so the model fitted the data adequately. It confirmed the hypothesis that anuran acoustic organs changed along with altitude.

In addition, bivariate correlation analysis showed that vocal sac and tympanum are positively correlated (r = 0.343, P<0.001, n = 188), and it could be inferred that the degeneration of the vocal organ led to the same trend in the auditory organ.

Discussion

Physical characteristics of the environment may influence the evolution of call characteristics related to morphology and physiology (Bosch & De la Riva 2004). Although some reports showed that differences in call structure could be more readily explained by differences among species in body size or by phylogenetic relationship than by differences in natural calling environment (Penna & Solis 1998; Kime et al. 2000), our results showed an association between acoustic organs and altitude instead of phylogenetic relationships.

High‐altitude populations are less resilient than low‐altitude populations (Morrison & Hero 2003). It was considered that, when calling in areas isolated from others, a male would tend to produce simple calls (Ryan & Rand 1999). Altitude, per se, had a negative effect upon species densities (Rogers 1976). Increasing with the altitude, lower‐density anurans will not make as much noise as those at low altitude; as a result, female detection of the male acoustic signal becomes somehow easier at this stage. Because individuals at high altitudes are not in such densities as those as at low altitudes, it is no longer necessary for them to keep either the complex call or diverse vocal sac.

Exhibiting the signal requires energy, whether the animal is displaying a morphological character in a courtship dance or producing a sound, pheromone, or electrical discharge (Ryan & Rand 1993). An increase in the signal to noise ratio increases the signal's conspicuousness, and complex, long calls appear to be more attractive to some females, but incur higher energy costs and oxygen consumption (Ryan & Rand 1993; Rosenthal et al. 2004). Taigen and Wells (1985) indicated that calling can be metabolically very expensive, and during high levels of calling a large amount of oxygen can be consumed, with an increased metabolic rate of 10–20 times that of resting.

The fact is that there is less oxygen at higher altitudes. At 4000 m a.s.l., for example, the partial pressure of oxygen decreases by about 40% in comparison to pressure at sea level. In addition, it is common for anurans to suffer from food shortage. Those could not match the need for anuran calling. It is disadvantageous for anuran metabolic activity as well as calling. Marler and Ryan (1996) stated that males given supplemental food were significantly more likely to call than males not given supplemental food. Anurans at high altitude must prevent continual calling and conspicuous vocal sac inflation in order to meet the limited food supply.

Temperature also decreases rapidly with increasing altitude, accompanied by low air pressure and lack of oxygen. Vocal activity becomes physiologically harder. Severe environments forced frogs and toads to distribute their energy more carefully. They had to adapt the pressure by adjusting their behaviour, physiology, and morphology.

Pough et al. (1998) indicated that temperature affects several properties of the advertisement call of frogs and toads. The magnitude of a temperature effect, however, may differ between populations that live in different climates (Sullivan 1989; Navas 1996), and frogs from colder climates and higher elevations call at lower temperatures than frogs from warmer climates and lower elevations (Narins & Smith 1986; Schneider & Sinsch 1999). It could be inferred that frogs from colder climates had adjusted their physiological strategy to cope with a low‐temperature environment, although vocal activity is also physiologically harder at lower temperature, and high‐elevation tropical species use thermal niches to reduce exposure to the cold, as well as restricting maximum vocal activity to just after dusk, before temperatures become too low (Navas 1996; Murphy 1999). They will shorten the chorus period as much as possible. At the same time, temporal visual cues may be redundant with acoustic cues in localising and evaluating a call (Rowe 1999), so vocal sac degeneration or absence occurred.

It is often assumed that the evolution of an animal communication system involves co‐evolution of a signal and receiver (Ryan 1986; Ryan & Rand 1999). Within a taxon, signals and receivers are ‘congruent’ if the response and signal are either both present or both absent (Hill 1994). As a response to reduced vocal activity, tympanum degeneration followed.

The vocal sac and tympanum degeneration could be compensated by other means of sound transmission. Anuran amphibians can utilise nontympanic pathways of sound reception (body wall, head surface, and dorsal shoulder surface) (Hetherington 1992). So the reduction or lack of vocal sac and tympanum will not affect the communication of anurans inhabiting high‐altitude regions. It should be noted that males of the concave‐eared torrent frog (Amolops tormotus), whose tympana are recessed and invisible from the outside, living in or near noisy streams, reliably produce acoustic signals that contain prominent ultrasonic harmonics (Narins et al. 2004), and their unusual morphological features enable them to respond to ultrasonic signals (Feng et al. 2006). This is a sound evidence of frog species evolution resulting from natural selection.

We conclude that anuran acoustic organs declined with increasing altitude. Low population density, hypoxia, low temperature, and food shortage might be responsible for such a decline. Nontympanic pathways of sound reception or an ultrasonic signal system will efficiently maintain their communication.

Acknowledgements

We are particularly grateful to Massimo Delfino and an anonymous reviewer for their comments on the manuscript.

Appendix

Table

Species	Vocal sac	Tympanum	Altitude	Sources
OPISTHOCOELA
DISCOGLOSSIDAE
Bombina fortinuptialis		0	1420	Liu et al. 2000
Bombina maxima	0	0	3050	Yang 1991, Zhao & Yang 1997
Bombina microdeladigitora	0	0	2015	Yang 1991, Zhao & Yang 1997, Liu et al. 2000
Bombina orientalis	0	0		Zhao & Yang 1997
ANOMOCOELA
PELOBATIDAE
Oreolalax chuanbeiensis		1	2000	Liu et al. 2000
Oreolalax jingdongensis	0	0	2400	Liu et al. 2000
Oreolalax liangbeiensis	0	1	2950	Ye et al. 1993
Oreolalax lichuanensis		2	1700	Liu et al. 2000
Oreolalax major	0	1	2500	Zhao & Yang 1997, Liu et al. 2000
Oreolalax omeimontis		2		Liu et al. 2000
Oreolalax Pingii	0	1	3000	Ye et al. 1993, Zhao & Yang 1997
Oreolalax popei	0	1	1500	Ye et al. 1993, Zhao & Yang 1997
Oreolalax puxiongensis	0	1	2750	Ye et al. 1993
Oreolalax rhodostigmatus		2	1420	Liu et al. 2000
Oreolalax rugosus	0	0	2500	Ye et al. 1993, Zhao & Yang 1997
Oreolalax schmidti	0	1	2050	Zhao & Yang 1997, Liu et al. 2000
Oreolalax xiangchengensis	0	0	2990	Ye et al. 1993, Zhao & Yang 1997
Scutiger brevipes	0	0	3100	Ye et al. 1993
Scutiger glandulatus		0	3475	Zhao & Yang 1997, Yang 1991,
Scutiger gongshangensis	1	0	3150	Zhao & Yang 1997, Yang 1991, Liu et al. 2000
Scutiger mammatus	0	0	3500	Zhao & Yang 1997, Yang 1991, Ye, Fei & Hu 1993
Scutiger muliensis		0	3225	Liu et al. 2000
Scutiger tuberculatus	0	0	3175	Ye, Fei & Hu 1993
Scutiger boulengeri	0	0	3900	Hu et al.1987, Ye et al. 1993, Zhao & Yang 1997
Scutiger chintingensis		0	3050	Liu et al. 2000
Scutiger liupanensis		0	2200	Liu et al. 2000
Scutiger maculatus	0	0	3400	Hu et al.1987, Zhao & Yang 1997, Liu et al. 2000
Scutiger ningshanensis		0	2500	Liu et al. 2000
Scutiger nyingchiensis	0	0	3600	Hu et al.1987, Ye et al. 1993
Scutiger pingwuensis		0	2200	Liu et al. 2000
Scutiger ruginosus	0	0	3400	Zhao & Yang 1997
Scutiger tuberculatus	0	0	3175	Zhao & Yang 1997
Scutiger sikkimensis	0	0	3450	Hu et al. 1987, Liu et al. 2000
Scutiger weigoldi		1		Liu et al. 2000
Leptobrachium chapaensis	1	1	1415	Zhao & Yang 1997, Yang 1991, Liu et al. 2000
Leptobrachium hainanensis	1	2	315	Ye et al. 1993
Leptobrachium hasseltii		1		Liu et al. 2000
Vibrissaphora ailaonica	0	1	2350	Ye et al. 1993
Vibrissaphora boringii	0	1	1200	Ye et al. 1993
Vibrissaphora leishanensis	0	1	1300	Ye et al. 1993
Vibrissaphora liui	1	1	1000	Ye et al. 1993
Vibrissaphora yaoshanensis	1	1	1250	Ye et al. 1993
Leptolalax liui	1	2	1065	Liu et al. 2000
Leptolalax oshanensis	1	2	1260	Ye et al. 1993
Leptolalax pelodytoides	1	2	1100	Zhao & Yang 1997, Yang 1991, Liu et al. 2000
Brachytarsophrys carinensis	1	0	1375	Zhao & Yang 1997, Liu et al. 2000
Brachytarsophrys feae	2	1	1220	Ye et al. 1993, Zhao & Yang 1997
Megophrys boettgeri	1	2	675	Liu et al. 2000, Lin & Zheng 2003
Megophrys brachykolos				Liu et al. 2000
Megophrys gigantica	1	1	1900	Yang 1991, Ye, Fei & Hu 1993
Megophrys glandulosa		2	2000	Liu et al. 2000
Megophrys jingdongensis		2	2060	Liu et al. 2000
Megophrys kempii		2	600	Hu et al. 1987, Liu et al. 2000
Megophrys kuatunensis	1	2	1250	Liu et al. 2000, Lin & Zheng 2003
Megophrys lateralis	1	2	2050	Yang 1991, Ye et al. 1993, Zhao & Yang 1997
Megophrys mangshanensis		2	1000	Liu et al. 2000
Megophrys medogensis		2	1100	Liu et al. 2000
Megophrys minor	1	2	1700	Yang 1991, Hu et al. 1987, Ye et al. 1993, Zhao & Yang 1997
Megophrys nankiangensis		0	1700	Liu et al. 2000
Megophrys omeimontis	1	2	1550	Yang 1991, Ye et al. 1993
Megophrys pachyprocta	1	2	1215	Yang 1991, Hu et al. 1987, Liu et al. 2000
Megophrys palpebralespinosa	1	2	1650	Yang 1991, Liu et al. 2000
Megophrys parva	1	2	650	Yang 1991, Liu et al. 2000
Megophrys shapingensis	0	0	2600	Ye et al. 1993, Zhao & Yang 1997
Megophrys spinata	1	2	1371	Yang 1991, Liu et al. 2000
Ophryophryne microstoma		2	710	Ye et al. 1993
Ophryophryne pachyprocta	1	2	950	Ye et al. 1993
PROCOELA
BUFONIDAE
Bufo ailaoanus	0	0	2550	Yang 1991, Liu et al. 2000
Bufo andrewsi	0	1	1725	Yang 1991, Zhao & Yang 1997, Liu et al. 2000
Bufo burmanus	0	0		Yang 1991, Liu et al. 2000
Bufo cryptotympanicus	0	0	1650	Yang 1991, Liu et al. 2000
Bufo cyphosus	0	1	1400	Hu et al. 1987, Liu et al. 2000
Bufo galeatus		2	305	Liu et al. 2000
Bufo gargarizans	0	2	1100	Ye, Fei & Hu 1993, Lin & Zheng 2003
Bufo himalayanus	0	1	2040	Hu et al. 1987, Yang 1991, Zhao & Yang 1997, Liu et al. 2000
Bufo melanostictus	1	2	1625	Yang 1991, Ye et al. 1993, Zhao & Yang 1997
Bufo minshanicus	0	1	3300	Zhao & Yang 1997, Liu et al. 2000
Bufo raddei	1	2	1650	Ye et al. 1993,
Bufo stejnergeri		0	450	Liu et al. 2000
Bufo tibetanus	0	1	3300	Hu et al. 1987, Yang 1991, Ye et al. 1993, Zhao & Yang 1997
Bufo tuberculatus	0	1	2650	Hu et al. 1987, Liu et al. 2000
Bufo viridis	1	2	2750	Hu et al. 1987, Ye et al. 1993
Pelophryne scalpta	1	1	1075	Ye et al. 1993
Hyla annectans	2	2	1725	Yang 1991, Ye et al. 1993, Zhao & Yang 1997
Hyla arborea	2	2		Ye et al. 1993
Hyla chinensis	2	1	600	Ye et al. 1993, Lin & Zheng 2003
Hyla japonica	2			Liu et al. 2000
Hyla sanchiangensis	2	1	900	Ye et al. 1993, Lin & Zheng 2003
Hyla simplex	2	2	125	Ye et al. 1993
Hyla tsinlingensis	2	2	1400	Liu et al. 2000
Hyla zhaopingensis	2	2	140	Liu et al. 2000
DIPLASIOCOELA
RANIDAE
Rana altaica	0	2	1400	Ye et al. 1993
Rana amurensis	0	2		Liu et al. 2000
Rana asiatica	1			Liu et al. 2000
Rana chaochiaoensis	0	2	2245	Yang 1991, Liu et al. 2000
Rana chensinensis	1	2	2105	Ye, Fei & Hu 1993
Rana chevronta	0	2	1800	Liu et al. 2000
Rana huanrenensis	0			Liu et al. 2000
Rana japonica	0	2	1005	Liu et al. 2000
Rana longicrus				Liu et al. 2000
Rana omeimontis	0	2	1310	Ye, Fei & Hu 1993
Pelophylax hubeiensis	0	2	565	Ye et al. 1993
Pelophylax narins	2	2		Liu et al. 2000
Pelophylax nigrolineata	2	2		Liu et al. 2000
Pelophylax nigromaculata	2	2	1005	Ye et al. 1993
Pelophylax plancyi	1	2		Ye et al. 1993
Pelophylax pleuraden	2	2	1725	Ye et al. 1993
Pelophylax ridibunda	2	2	700	Ye et al. 1993
Pelophylax shuchinae	1	1	3400	Liu et al. 2000
Pseudorana sangzhiensis	0	2	1350	Liu et al. 2000
Pseudorana sauteni	1	2		Liu et al. 2000
Pseudorana weiningensis	0	1	2325	Ye et al. 1993
Hylarana adenopleura	2	2	915	Ye et al. 1993
Hylarana daunchina	2	2	1000	Ye et al. 1993
Hylarana guentheri	2	2		Ye et al. 1993
Hylarana latouchii	1	2		Ye et al. 1993
Hylarana macrodactyla		2	250	Liu et al. 2000
Hylarana nigrovittata	1	2		Liu et al. 2000
Hylarana spinulosa		2	365	Liu et al. 2000
Hylarana taipehensis	0	2		Ye et al. 1993
Hylarana varians	1	2		Liu et al. 2000
Euphlycyis cncrivora	2	2	75	Ye et al. 1993
Euphlycyis limnocharis	2	2	1700	Ye et al. 1993
Hoplobatrachus rugulosus	2	2		Ye et al. 1993, Lin & Zheng 2003
Rugosa emeljanovi	1	2	250	Ye et al. 1993
Rugosa tientaiensis	1	2		Liu et al. 2000
Glandirana minima	1	2	330	Ye et al. 1993
Odorrana andersonii	1	1	1130	Liu et al. 2000
Odorrana anlungensis	2	2	1515	Liu et al. 2000
Odorrana grahami	1	2	2460	Ye et al. 1993
Odorrana kuangwuensis	0	2	1650	Liu et al. 2000
Odorrana livida	2	2	775	Ye et al. 1993
Odorrana lungshengensis		2	1250	Liu et al. 2000, Lin & Zheng 2003
Odorrana margaratae	0	1		Liu et al. 2000
Odorrana schmackeri	2	2	850	Ye et al. 1993, Lin & Zheng 2003
Odorrana swinhoana	2	1		Liu et al. 2000
Odorrana tiannanensis	2			Liu et al. 2000
Odorrana versabilis	1	1	805	Liu et al. 2000
Odorrana wuchuanensis	0	2	700	Liu et al. 2000
Limnonectes fragilis	0	0	595	Ye et al. 1993
Limnonectes kuhlii	0	0	760	Liu et al. 2000
Paa boulengeri	1	1		Ye et al. 1993
Paa chayuensis	1	1	1650	Ye et al. 1993
Paa maculosa	1	0	2200	Ye et al. 1993
Paa shini	1	1	1000	Ye et al. 1993
Paa spinosa	1	1	1000	Ye et al. 1993, Lin & Zheng 2003
Paa yunnanensis	1	1	1950	Ye et al. 1993
Paa quadrana	0	1	1750	Ye et al. 1993
Paa unculuana	0	1	2000	Ye et al. 1994
Paa cpmaemsos	1	0	3150	Liu et al. 2000
Paa exilispinosa		1	1050	Liu et al. 2000, Lin & Zheng 2003
Paa feae	1	2		Liu et al. 2000
Paa jiulongensis	1	0	800	Liu et al. 2000
Paa liebigii	1	0	2890	Liu et al. 2000
Paa muta	0	2	2375	Liu et al. 2000
Paa yadongensis		1	3150	Liu et al. 2000
Platymantis liui	0	2	655	Liu et al. 2000
Platymantis reticulatus	0	2	890	Hu et al. 1987, Liu et al. 2000
Platymantis xizangensis	0	2	2300	Hu et al. 1987, et al. 1993
Nanorana parkeri	0	1	3850	Zhao & Yang 1997
Nanorana pleskei	0	1	3750	Ye et al. 1993, Zhao & Yang 1997
Nanorana ventripunctata	0	1	3600	Yang 1991, Ye et al. 1993, Zhao & Yang 1997
Altirana parkeri	0	0	3775	Hu et al.1987, Ye et al. 1993
Micrixalus borealis	1	1	400	Hu et al. 1987, Ye et al. 1993
Micrixalus liui	0	2	655	Yang 1991, Zhao & Yang 1997
Amolops afghanus	2	1	1100	Yang 1991, Zhao & Yang 1997,Liu et al. 2000
Amolops chunganensis	2	2	1200	Yang 1991, Ye et al. 1993, Zhao & Yang 1997, Lin & Zheng 2003
Amolops daiyunensis	1	1	1050	Liu et al. 2000, Lin & Zheng 2003
Amolops gerbillus		1	330	Liu et al. 2000
Amolops granulosus		1	1500	Liu et al. 2000
Amolops hainanensis		2	465	Liu et al. 2000
Amolops hongdongensis		1		Liu et al. 2000
Amolops lifanensis	0	1	1615	Zhao & Yang 1997, Liu et al. 2000
Amolops loloensis	0	1	2650	Zhao & Yang 1997, Liu et al. 2000
Amolops macrorhynchus	0	1		Yang 1991, Liu et al. 2000
Amolops mantzorum	0	2	2400	Yang 1991, Ye et al. 1993, Zhao & Yang 1997
Amolops monticola		1	1600	Zhao & Yang 1997, Liu et al. 2000
Amolops nasicus		1		Liu et al. 2000
Amolops ricketti	0	1	1100	Yang 1991, Ye et al. 1993, Lin & Zheng 2003
Amolops tormotus	2	2	540	Liu et al. 2000
Amolops torrentis	1	2	430	Liu et al. 2000
Amolops viridimaculatus		1	1370	Yang 1991, Zhao & Yang 1997, Liu et al. 2000
Amolops wuyiensis	1	1	950	Liu et al. 2000, Lin & Zheng 2003
Occidozyga lima	1	1	290	Yang 1991, Ye et al. 1993
Occidozyga martensii	1	2	505	Yang 1991, Ye et al. 1993
RHACOPHORIDAE
Buergeria japonica		2		Liu et al. 2000
Buergeria oxycephala	1	2	290	Liu et al. 2000
Buergeria prasinata		2		Ye et al. 1993
Buergeria robusta		2		Liu et al. 2000
Philautus albopunctatus		1	1100	Hu et al. 1987, Liu et al. 2000
Philautus argus		2	650	Hu et al. 1987, Liu et al. 2000
Philautus asper		2	400	Hu et al. 1987, Liu et al. 2000
Philautus cavirostris	1	2	875	Zhao & Yang 1997, Liu et al. 2000
Philautus gracilipes	1	2		Yang 1991, Liu et al. 2000
Philautus jinxiuensis	1		1300	Liu et al. 2000
Philautus longchuanesis	2	2	1475	Yang 1991, Zhao & Yang 1997, Liu et al. 2000
Philautus medogensis	1	2	1500	Hu et al. 1987, Ye et al. 1993
Philautus menglaensis	1	1	900	Liu et al. 2000
Philautus ocellatus	1	2	550	Liu et al. 2000
Philautus palpebralis	1	1	1040	Yang 1991, Liu et al. 2000
Philautus rhododiscus	0	2	1350	Liu et al. 2000
Philautus romeri	0			Liu et al. 2000
Philautus tuberculatus		2	400	Hu et al. 1987, Liu et al. 2000
Philautus vittatus	1	2	1200	Hu et al. 1987
Chirixalus doriae	2	1	1335	Yang 1991, Liu et al. 2000
Chirixalus eiffingeri		1		Liu et al. 2000
Chirixalus idiootocus		1		Liu et al. 2000
Chirixalus vittatus	1	1	1200	Yang 1991, Liu et al. 2000
Theloderma kwangsiensis	0	2	1350	Ye et al. 1993
Theloderma moloch		2	650	Hu et al. 1987, Liu et al. 2000
Polypedates chenfui	2	2	2000	Liu et al. 2000
Polypedates dennysi	1	2		Ye et al. 1993
Polypedates dugritei	2	1	2300	Yang 1991, Zhao & Yang 1997, Liu et al. 2000
Polypedates gongshanesis		2		Liu et al. 2000
Polypedates hungfuensis	2	2		Liu et al. 2000
Polypedates leucomystax	1	2	840	Yang 1991, Ye et al. 1993
Polypedates maso		2	650	Liu et al. 2000
Polypedates megacephalus	1	2	840	Zhao & Yang 1997, Liu et al. 2000
Polypedates mutus	0	2	820	Yang 1991, Zhao & Yang 1997, Liu et al. 2000
Polypedates nigropunctatus	1	1	1367	Zhao & Yang 1997, Liu et al. 2000
Polypedates omeimontis	1	2	1350	Ye et al. 1993, Zhao & Yang 1997
Polypedates yaoshanensis		2	800	Liu et al. 2000
Rhacophorus bimaculatus	1	2	400	Zhao & Yang 1997, Liu et al. 2000
Rhacophorus cavirostris	1	2	1150	Hu et al. 1987
Rhacophorus feae		2	1000	Liu et al. 2000
Rhacophorus gongshanensis	1	2	1600	Zhao & Yang 1997
Rhacophorus leucomystax	1	2	1140	Hu et al. 1987
Rhacophorus maximus	1	2	850	Hu et al. 1987, Liu et al. 2000
Rhacophorus moltrechti		2		Liu et al. 2000
Rhacophorus reinwardtii	1	2	1000	Yang 1991, Ye et al. 1993
Rhacophorus rhodopus	1	2	1090	Hu et al.1987, Yang 1991, Zhao & Yang 1997, Liu et al. 2000
Rhacophorus smaragdinus		2		Liu et al. 2000
Rhacophorus taipeianus			90	Liu et al. 2000
Rhacophorus translineatus	1	1	1350	Hu et al. 1987, Liu et al. 2000
Rhacophorus tuberculatus		2	650	Hu et al. 1987, Liu et al. 2000
Rhacophorus verrucopus	0	2	1175	Hu et al. 1987, Liu et al. 2000
MICROHYLIDAE
Calluella yunnanensis	2	2	1460	Yang 1991, Ye et al. 1993, Zhao & Yang 1997
Microhyla butleri	2	1	860	Yang 1991, Ye et al. 1993, Zhao & Yang 1997
Microhyla fowleri		1		Yang 1991, Liu et al. 2000
Microhyla heymonsi	2	1	1050	Yang 1991, Ye et al. 1993, Zhao & Yang 1997
Microhyla inornata		2		Yang 1991, Liu et al. 2000
Microhyla mixtura	2	1	950	Liu et al. 2000
Microhyla ornate	2	1	1100	Yang 1991, Ye et al. 1993, Zhao & Yang 1997
Microhyla pulchra	2	1		Yang 1991, Ye et al. 1993
Kaloula borealis	2	1		Ye et al. 1993
Kaloula pulchra	2	1	1620	Yang 1991, Ye et al. 1993, Zhao & Yang 1997
Kaloula rugifera	2	1		Ye, Fei & Hu 1993
Kaloula verrucosa	2	1	1350	Yang 1991, Ye et al. 1993, Zhao & Yang 1997
Kalophrynus interlineatus	2	2		Liu et al. 2000
Kalophrynus pleurostigma	2	1	1040	Yang 1991, Liu et al. 2000