Rice Frog Research Articles

Japanese Rice Frog Fejervarya kawamurai is Absent from Available Archaeological Faunal Assemblages of the Kinki District of Honshu, Japan

Japanese Rice Frog Fejervarya kawamurai is Absent from Available Archaeological Faunal Assemblages of the Kinki District of Honshu, Japan

Advertisement Call Variation of Two Frog Species along an Urban–Rural Gradient in Shanghai, China

Urbanization has a significant influence on amphibian communities, populations, and individuals because of habitat loss, degradation of habitat quality, and habitat fragmentation. Advertisement calls of anurans are used for communication and play an important role in reproduction; however, how anthropogenic noise and habitat change caused by urbanization affect anuran advertisement calls is less well known. In this study, we examined changes in the advertisement calls of two frog species, the ornamented pygmy frog (Microhyla fissipes) and rice frog (Fejervarya multistriata), during the breeding season along an urban–rural gradient in Shanghai, China. We used the percentage of impervious area (including buildings and roads) in each 2 km-radius landscape to represent the urbanization index of 34 study sites. We then measured five advertisement call parameters (call duration, call interval, call rate, pulse rate, and dominant frequency) of these two species (100 males of F. multistriata and 89 males of M. fissipes) in each study site from May to July in 2020 and 2021. We explored how the urbanization index and other variables (air temperature, snout–vent length and calling situation (one frog species calling, or two frog species calling together)) in each study site affected these call parameters. The results showed that the dominant frequency of M. fissipes was significantly negatively related to urbanization index, and call duration and call interval were significantly negatively related to air temperature; furthermore, call rate and pulse rate were significantly positively related to air temperature, and call duration was also significantly positively related to snout–vent length. For F. multistriata, pulse rate was significantly negatively related to urbanization index, snout–vent length, and situation (two frog species calling together), but significantly positively related to air temperature; by contrast, call interval was significantly positively related to snout–vent length. We suggested that these two frog species had different responses to urbanization, which could help us to better understand the change of anuran breeding behaviors and reproductive life-history strategies in the face of rapid urbanization.

Microbe-mediated reduction of methane emission in rice-frog crop ecosystem

Rice–frog crop ecosystem (RFCE) can significantly reduce CH4 emission from paddy soils to mitigate global warming. However, information on the correlation of soil microbial communities with paddy soil CH4 emission in RFCEs remains limited. This study evaluated the influence of frogs on CH4 flux, paddy soil/water properties, and abundance/community composition of methanogens and methanotrophs in an RFCE between 2018 and 2019. The study parameters were compared between “with frogs” (RFCE; 15,000 frogs ha−1) and “without frogs” (control check [CK]) conditions. Frogs in paddies significantly decreased the CH4 flux during the rice-growing seasons (p < 0.05) but increased the paddy water/soil dissolved oxygen (DO) concentration, redox potential (Eh), and soil organic carbon (SOC) content. Compared with the CK, the RFCE significantly decreased the relative abundance of the soil methanogen species Candidatus Methanoperedens nitroreducens and Methanocella arvoryzae, genera Candidatus Methanoperedens and Methanocella, and families Methanoperedenaceae and Methanocellaceae (p < 0.05); however, it significantly increased the abundance of the soil methanotroph species Methylosinus sp. LW2, Methylocystis sp. KS3, and Methylocystis sp. KS30; genera Methylosinus and Methylocystis; and family Methylocystaceae (p < 0.05). Furthermore, variation partitioning analysis revealed that oxygen (DO and Eh) explained 41.2% of the variation in the abundance of soil methanogens, which was greater than the effects of C/N (38.2%) and SOC content (38.1%). For soil methanotrophs, oxygen (DO and Eh) explained 45.6% of the variation, which was more than the effects of C/N or pH. Oxygen concentration in the paddy soil/water was the driving factor for the change in the composition of soil methanogenic and methanotrophic microbial communities. Bioturbation due to the frogs increased oxygen availability in the paddy soil, decreased CH4 production by soil methanogens, and increased CH4 oxidation by type II methanotrophs, all of which reduced CH4 emission. Thus, this study provides strong evidence for the microbial mechanisms underlying the reduction of CH4 emission from RFCE.

Genome-Wide SNP Analysis of Male and Female Rice Field Frogs, Hoplobatrachus rugulosus, Supports a Non-Genetic Sex Determination System

Sex determination systems (SDSs) in anurans are diverse and have undergone independent evolutionary transitions among species. The mode of sexual reproduction of the rice field frog (Hoplobatrachus rugulosus)—an economically viable, edible amphibian species—is not well known. Previous studies have proposed that threshold temperature conditions may determine sex in these frogs. To elucidate the SDS in H. rugulosus, we karyotyped 10 male and 12 female frogs, and performed fluorescence in situ hybridization combined with sequencing analyses using DArTseq™. Our results revealed a highly conserved karyotype with no sex chromosome heteromorphism, and the sequencing analyses did not identify any consistent sex-linked loci, supporting the hypothesis of temperature-dependent sex determination. The results of this study, and others, on SDSs in the rice field frog and related species also provide support for the theory that heteromorphic sex chromosomes may lead to an evolutionary trap that prevents variable SDSs. These findings add important information to the body of knowledge on H. rugulosus and are likely to have a significant impact on the productivity and economic success of rice field frog farming.

Genetic diversity of the Pegu Rice Frog, Microhyla berdmorei (Anura: Microhylidae) based on mitochondrial DNA

The Pegu Rice Frog, Microhyla berdmorei is distributed across ten Asian countries. However, the DNA barcoding information (COI gene) is restricted to only Southeast Asian countries. Here, we sampled a specimen of M. berdmorei in Mizoram state, northeast India to allow the genetic diversity of the species across its range. We generated both COI and 16S ribosomal RNA sequences of the studied species to check the population genetic diversity. The Bayesian analyses clearly discriminate M. berdmorei from its sister species Microhyla pulchra. The present datasets of M. berdmorei also revealed 11 and 19 haplotypes with high uncorrected pairwise genetic distances in COI (3.8–11.8%) and 16S rRNA (0–4.6%) gene, respectively. Owing to the high intra-species genetic distances and different haplotypes with sufficient mutational steps in both mitochondrial genes, this study affirms the existence of M. berdmorei species complex or cryptic diversity within its range distribution in South and Southeast Asia.

The effect of integrated rice–frog ecosystem on rice morphological traits and methane emission from paddy fields

Integrated Rice–frog Ecosystem (IRFE) has the potential to reduce methane (CH4) emission and maintain yields from paddy fields. However, the quantitative relationship between rice morphological traits and CH4 emission remains to be explored. In this study, a 2-year field experiment was conducted to evaluate the effect of IRFE on rice morphological traits and CH4 emission from paddy fields and the ecological mechanisms. This study was conducted to analyze twelve aboveground and eight underground rice morphological traits, rice yields, and CH4 flux and emission from the paddy fields with six frog densities (0, 3750, 7500, 15,000, 30,000, and 60,000 frogs ha−1). The results showed that IRFE reduced CH4 emission by 24.70%–41.75% and 21.68%–51.21% in the 2018 and 2019 rice growth seasons, respectively. Moreover, CH4 emission decreased with the increase of frogs. Frogs also increased the diameter, biomass, and volume of rice roots, thus promoting rice growth. Root biomass, thousand-grain weight, and harvest index were also closely related to the yield. Root porosity and oxygen secretion capacity were negatively correlated with CH4 flux. Frogs increased root porosity and oxygen secretion, thereby reducing CH4 emission. The present study demonstrated that reducing CH4 emission and improving rice yields could be simultaneously achieved by altering rice morphological traits in IRFE.

Rice-frog Planting and Raising Mode and Its Sustainable Development Strategy

Rice-frog Planting and Raising Mode and Its Sustainable Development Strategy

Effects of landscape heterogeneity and breeding habitat diversity on rice frog abundance and body condition in agricultural landscapes of Yangtze River Delta, China.

Amphibians play a key role in structuring biological assemblages of agricultural landscapes, but they are threatened by global agricultural intensification. Landscape structure is an important variable influencing biodiversity in agricultural landscapes. However, in the Yangtze River Delta, where a "farmland-orchard-fishpond" agricultural pattern is common, the effects of landscape construction on anuran populations are unclear. In this study, we examined the effects of agricultural landscape parameters on the abundance and body condition of the rice frog (Fejervarya multistriata), which is a dominant anuran species in farmland in China. Employing a visual encounter method, we surveyed rice frog abundance for 3 years across 20 agricultural landscapes. We also calculated the body condition index (BCI) of 188 male frog individuals from these agricultural landscapes. Landscape variables, comprising landscape compositional heterogeneity (using the Shannon diversity index of all land cover types except buildings and roads), landscape configurational heterogeneity (using landscape edge density), breeding habitat diversity (using the number of 5 waterbody types available as breeding habitats), and areas of forest were also measured for each 1-km radius landscape. We found that the amount of forest in each agricultural landscape had a significant positive relationship with rice frog abundance, and breeding habitat diversity was positively related to the BCI of male rice frogs. However, body condition was negatively impacted by landscape configurational heterogeneity. Our results suggested the importance of nonagricultural habitats in agricultural landscapes, such as waterbodies and forest, to benefit rice frog population persistence.

Native and non-native frogs responded differently to modernization at Japanese paddy fields

Rice farming modernizations, especially changes in the irrigation system, have been accused as one of the reasons of frog population decline in Japan. Here, we examined responses of native frog, Daruma pond frog (Pelophylax porosus porosus) and non-native frog, Rice frog (Fejervarya kawamurai) population to the modernization in Japanese paddy field. We tested the following two hypotheses: 1) native frog’s density will be lower in the modernized paddy field, and 2) non-native frog density will not be affected by modernization. After two periods of field studies (2017 and 2018), we found that native frog’s density is indeed lower in modernized paddy fields, and the non-native frog’s density is lower in the non-modernized sites. Presumably, changes of shallow soil ditches to concrete ditches in modernized paddy fields act as a death trap for Daruma pond frog. Ditch depth and the distance from forest also significantly affecting the density of Daruma pond frog. On the other hand, the population of Rice frog did not show any negative response to the modernizations. The non-native frog population remained stable because they may have high fecundity.

Histological Differences in the Livers and Kidneys of Two Populations of Rice Frog (Fejervarya limnocharis) Naturally Exposed to Different Environmental Cadmium Levels

Histological observation has always been important in the study of sentinels. In this research, histological differences in the liver and kidney of two wild populations of Fejervarya limnocharis exposed to different environmental cadmium levels were observed. Liver and kidney samples from 30 rice frogs caught from reference site (Mae Pa) and contaminated site (Mae Tao) were sectioned and stained with Haemotoxylin and Eosin and then observed under light microscope. It was found that liver sections from frogs caught from Mae Tao had higher hepatic macro-melanophage count (MMC) (0.949 ± 0.267 cells/1000 µm2) as compared to those from Mae Pa (0.672 ± 0.299 cells/1000 µm2 ). Other observable histological features found in frog’s liver from Mae Tao include possible necrotic areas, cellular swellings and chromatin margination. The kidney sections from frogs caught from Mae Tao showed the presence of tumor-like cell aggregation and hemorrhage. However, the proportion of tumor-like cell aggregation and hemorrhage were not significantly different than were expected from random occurrences. The result of the histological study revealed that F. limnocharis caught from Mae Tao had higher hepatic MMC and higher prevalence of renal tumor-like aggregation and renal hemorrhage than the rice frogs caught from Mae Pa. Cellular swelling, possible necrotic area and possible apoptotic cell could also be observed in the liver of contaminated frogs. DOI : http://dx.doi.org/10.17576/JSKM-2019-17SI-09

Histological Differences in the Livers and Kidneys of Two Populations of Rice Frog (Fejervarya limnocharis) Naturally Exposed to Different Environmental Cadmium Levels

Histological observation has always been important in the study of sentinels. In this research, histological differences in the liver and kidney of two wild populations of Fejervarya limnocharis exposed to different environmental cadmium levels were observed. Liver and kidney samples from 30 rice frogs caught from reference site (Mae Pa) and contaminated site (Mae Tao) were sectioned and stained with Haemotoxylin and Eosin and then observed under light microscope. It was found that liver sections from frogs caught from Mae Tao had higher hepatic macro-melanophage count (MMC) (0.949 ± 0.267 cells/1000 µm2) as compared to those from Mae Pa (0.672 ± 0.299 cells/1000 µm2 ). Other observable histological features found in frog’s liver from Mae Tao include possible necrotic areas, cellular swellings and chromatin margination. The kidney sections from frogs caught from Mae Tao showed the presence of tumor-like cell aggregation and hemorrhage. However, the proportion of tumor-like cell aggregation and hemorrhage were not significantly different than were expected from random occurrences. The result of the histological study revealed that F. limnocharis caught from Mae Tao had higher hepatic MMC and higher prevalence of renal tumor-like aggregation and renal hemorrhage than the rice frogs caught from Mae Pa. Cellular swelling, possible necrotic area and possible apoptotic cell could also be observed in the liver of contaminated frogs.

Feeding Habits of the Japanese Rice Frog, Fejervarya kawamurai, as an Invasive Species

Fejervarya kawamurai (Dicroglossidae) is an invasive species occurring in several populations in the Kanto region, including Fujisawa City, Kanagawa Prefecture, Japan. To estimate the ecological impacts of this frog, we investigated the food habits of invasive populations. We collected 119 individuals of F. kawamurai. Of these, 108 (90.8%) had stomach contents that included various small animals. Therefore, this invasive frog might influence the ecosystem via predation pressure on small native animals.

Breeding habitat influences abundance and body condition of rice frog (Fejervarya multistriata) in agricultural landscape of Shanghai, China

Amphibians are threatened by the intensification of agriculture throughout the world. Several studies have considered the morphology of animals to be an indicator of the health of a population, but differences in anuran morphology (especially body condition) in different breeding habitats in agricultural landscapes remain largely unknown. In this study, we investigated differences in the abundance and morphology of the rice frog (Fejervarya multistriata) in three waterbody types (ten farmland irrigation ditches, ten fruit forest drainage ditches, and ten lotus ponds) in agricultural landscapes in Shanghai, China. We sampled the snout–vent length, body mass, and body condition index for 206 individual rice frogs from the three types of waterbody. Our results showed that the abundance of rice frogs was higher in farmland irrigation ditches than in the other two habitats, whereas the snout–vent length, body mass, and body condition index of rice frogs were lower in farmland irrigation ditches than in the other two habitats. Our results suggest that breeding habitats in agricultural landscapes have different effects on rice frog abundance and morphology, and that constructing diverse waterbodies (other than farmland irrigation ditches) in the same agricultural landscape might benefit the condition of rice frogs.

Be Godogan Kuliner Tradisional Bali Di Ambang Kepunahan

One of the almost extinct BTC is Be Godogan (rice field frog meat). The purpose of this article is to describe the gastronomy of the Balinese cuisine and obtain a strategy to maintain the existence of its main ingredients. To achieve the goal, gastronomic theory and the theory of cultivation are used. The data collection technique used in this study is through interviews and literature study. The results of the research show that be godogan has a high source of animal protein and tastes, so it is aligned with chicken meat. Some people believe that frog meat can cure several diseases and increase male vitality. The use of pesticides in processing rice fields has threatened the life of this frog as it has dramatically dropped its population. The strategy to maintain the existence of the biological resources is to preserve rice field frogs for the continuity of this BTC. Keywords: Traditional Culinary, Be Godogan, Extinction, Bali

Tadpole of Microhyla picta Shenkel (Anura: Microhylidae), an endemic narrow-mouthed frog from Vietnam.

The Painted Rice Frog, Microhyla picta Schenkel, is one of the least studied species among narrow-mouthed frogs of the genus Microhyla. To date it is known only from Vietnam, where it is distributed mostly in eastern coastal areas in central and southern parts of the country (Nguyen et al. 2009; Nguyen Hoang 2013). The species was also found in Con Dao archipelago (Poyarkov Vassilieva 2011). No data are available on the ecology and reproductive biology of the species, and its larval morphology is also not described. Microhyla frogs are widespread and numerous in terrestrial ecosystems and microhylid tadpoles are known to play an important role in the aquatic communities of temporary waterbodies of monsoon ecosystems in Southeast Asia (Heyer 1973; Vassilieva et al. 2017). The ability to identify microhylid tadpoles in the field is pertinent for biodiversity and ecological studies. We provide a description of larvae of M. picta from various areas in southern Vietnam.

The Diversity of Birds and Frogs Species at Perdana Botanical Lake Garden, Kuala Lumpur, Malaysia

Unbalance urban development would affect the ecosystem and environment of the people and living things. Declining and loss of flora and fauna species occurs because of landscapes and living habitat changes. Urban biodiversity is a part of ecological elements and ecosystems services of the urban environments. Thus, it is important to be maintained or preserved in urban planning and design. The lack numbers of study focusing on the field of urban wildlife such as birds and frogs around the globe. Thus, the aim of the study is to understand the scientific data on urban wildlife mainly focus on birds and amphibian. This study will provide significant information pertaining to urban biodiversity issues. Birds is chosen as the best example that will act as an indicator for the inland environment while frogs as the amphibian for the urban lake garden. Birds can be the best indicator for inland environment while frogs can be indicator for the aquatic environment of the urban lake garden.The study was conducted at Perdana Botanical Lake Garden in Kuala Lumpur, Malaysia. The observation survey includes in details of the name of the species, number of species, habitat, data observation on time and dates, remarks and reference notes. The survey method on birds used the transect lines in order to observe the bird species within a measured line. The observation includes calculations and records of all the birds species, while walking along the transect route at average speed of 15 m/min within 30 m distance. The survey usually conducted either early in the morning and late evening. Meanwhile, the amphibian observation on frogs survey based on ‘Quadrant Sampling’ which is the standard quadrant being set in metre (m), in which 5×5 m and 10×10 m. The amphibian observation begin during the night time for 3 days duration started from 7.00 pm to 9.00 pm. Based on the observation at Botanical Perdana Garden, 8 species of birds has been identified. The most common is Acridotheres Tritis/Common Myna (n = 19) and the least is Geopelia Strata/Zebra Dove shows (n = 1) During the observation, a total of 6 species of frogs were found. The highest species of frogs recorded were Hylarana erythraea/Green Paddy Frog with (n =80), while Fejervarya limnocharis/Indian Rice Frog (n = 1). The result concludes that the park need to have more species of birds that share the same eating diet such as frugivorous and nectarous. The lake garden should restructured especially the pond with ecological approach to attract more types of frogs.

Metamorphic strategies of the Indian rice frog, Fejervarya limnocharis, in response to irrigation regimes

Metamorphic strategies of the Indian rice frog, Fejervarya limnocharis, in response to irrigation regimes

A Case of Scavenging Behavior by the Japanese Rice Frog,Fejervarya kawamurai(Amphibia: Anura: Dicroglossidae)

Abstract: Most of metamorphosed terrestrial frogs feed only on moving organisms and rarely exhibit scavenging behavior in nature. We here report a case of scavenging by the Japanese Rice Frog, Fejervarya kawamurai, which fed on a dead Black-spotted Frog, Pelophylax nigromaculatus at the edge of paddy field in central Japan. This observation is the first case of Fejervarya, feeding on a dead animal in nature and is an important addition to the cases of this unique behavior, which has been reported only for limited number of anuran species so far. In contrast, the behavior is more often reported for frogs in captivity, and F. kawamurai may be a useful species for examining scavenging behavior in post metamorphic anurans.

Unusual sex-ratios and developmental mortality in the rice frog Fejervarya kawamurai

Unusual sex-ratios and developmental mortality in the rice frog Fejervarya kawamurai

Cytotoxic evaluation of rice field frogs (Fejervarya limnocharis) from gold mine area with arsenic contamination

The objectives of this study were to investigate chromosomal aberrations in rice field frogs (Fejervarya limnocharis) from gold mine area compared to those from non-affected area. Three frogs were collected from each site, and chromosomal aberrations were studied in their bone marrow. Arsenic (As) was also measured in water and sediment from both areas. The average As concentrations in samples from the gold mine and the non-affected areas were 0.03 ± 0.003 mg/L and not detected in water and 351.59 ± 5.73 and 1.37 ± 1.07 mg/kg in sediment, respectively. The values in the gold mine were still higher than that allowed by the water and soil quality standards; however, the As concentrations in the samples from the non-affected area were acceptable. The average concentrations of As in the frog samples from the gold mine and the non-affected areas were 0.35 ± 0.33 and 0.07 ± 0.01 mg/kg, respectively, which were both lower than the standard of As contamination in food. The diploid chromosome number of frogs in both areas was 2n = 26, and the percentage of chromosomal aberrations in rice field frogs in the gold mine area was higher than in the non-affected area. There were seven types of chromosomal aberrations observed: single chromatid gap, isochromatid gap, single chromatid breaks, deletion, fragmentation, centric fragmentation and polyploidy. The most common chromosomal aberration in the samples from the affected area was the single chromatid gap. The difference in the percentages of chromosomal aberrations in rice field frogs from each area was statistically significant (p < 0.05).