Frogs as potential biological control agents in the rice fields of Chitwan, Nepal

Khatiwada, Janak Raj; Ghimire, Subarna; Khatiwada, Shanta Paudel; Paudel, Bikash; Bischof, Richard; Jiang, Jianping; Haugaasen, Torbjørn

doi:10.1016/j.agee.2016.06.025

Cited by 47 publications

(27 citation statements)

References 44 publications

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“…Three (VDCs) namely Bachhauli, Ghyalchok, and Ghanapokhra from the Chitwan, Gorkha, and Lamjung districts, respectively, were selected for the case study ( Figure 2). The study areas stretch from 190 to 2700 m above sea level (hereafter m) and from the sub-tropical to cool temperate climatic zone representing three different agroecological regions (inner terai, mid hill, and high hill) of Nepal [39,40]. Smallholder subsistence farming with a mixed crop-livestock production system is a common source of livelihood, but the level of agricultural dependency and its importance to overall household income varies across the area.…”

Section: Study Areamentioning

confidence: 99%

Household Livelihood Strategies and Implication for Poverty Reduction in Rural Areas of Central Nepal

Khatiwada

Deng

Paudel³

et al. 2017

Sustainability

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137

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Abstract:Understanding household livelihood strategies is pivotal to minimize rural poverty in the least developed countries like Nepal. This study is an attempt to assess livelihood strategies pursued by rural households, investigate the most remunerative strategy, and identify the factors that influence a household's choice of better strategies in rural Nepal. Primary data collected in 453 households from three villages of central Nepal are analyzed quantitatively within a sustainable livelihood framework. This study categorized households into five main livelihood strategy groups. The results showed that the majority (61%) of the households diversified their income to non-farm sources. Livelihood diversification to business/enterprise strategies adopted by 16% of the households is the most remunerative strategy followed by commercial farming that includes 13% of the sample and are more relevant to poverty reduction. Land holding, education, agriculture and skill training, access to credit, and proximity to the road and market center are the major influencing factors on the adoption of higher returning livelihood strategies. Stimulating poor households to follow market-oriented farm and non-farm activities by improving access to education, vocational training, rural credit, and rural infrastructures is momentous for reducing poverty in the rural areas of central Nepal.

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Section: Study Areamentioning

confidence: 99%

Household Livelihood Strategies and Implication for Poverty Reduction in Rural Areas of Central Nepal

Khatiwada

Deng

Paudel³

et al. 2017

Sustainability

Self Cite

137

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“…However, recent studies have shown that frogs are important predators of BPH, potentially having a larger contribution to BPH mortality than arthropod natural enemies (Khatiwada et al, 2016;Zou et al, 2017). That the role of frogs in biocontrol of BPH has been underappreciated until recently can be explained by the widespread use of techniques for measuring predation rates that are unsuitable to quantify predation by frogs, for instance use of immobilized prey (Zou et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

Survival analysis of brown plant hoppers (Nilaparvata lugens) in rice using video recordings of predation events

et al. 2018

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The brown plant hopper, Nilaparvata lugens Stål, is a major rice pest in SouthEast Asia. While brown plant hopper (BPH) populations can be regulated by natural enemies, there is limited quantitative information available about the contribution of different predator species to BPH mortality. Our study has three aims: (i) assess the relative contribution of different predator species to BPH mortality in rice fields, (ii) assess diurnal patterns in BPH predation, and (iii) assess the seasonal variation in BPH predation. We quantified predation of live mobile BPH in three rice fields using video recording and assessed densities frogs, a major predator group, by direct counts. In 864 hours of video recording, 102 mortality events were observed. Frogs (Ranidae), wolf spiders (Lycosidae) and jumping spiders (Salticidae) were the main predators, accounting for 76%, 13% and 9% of the BPH predation events, respectively. There were large differences in frog density across fields, and there was more predation during the evening (63% predation events) than during the day (37%). Survival analysis indicated that predation risk quickly decreased with time after the onset of recording sessions and that most predation happened within the first 10 minutes. The results confirm the often overlooked contribution of frogs to BPH predation, but also highlight the substantial variation in predator pressure and frog abundance across farmers' fields. While camera observations provide compelling information on the identity and relative importance of natural enemies in predation of pests, further development of methods is needed to minimize possible biases resulting from disturbance when making camera observations to quantify predation risk.

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“…This large bodied frog (up to 160 mm) has high reproductive potential (up to 5750 eggs per clutch, Oliveira et al, 2017) and is uncommon or absent in forested and coastal regions but occurs as a human commensal in plantations and agricultural fields (Daniels 2005). It is considered a dietary generalist, feeding on invertebrates and even large anurans such as Duttaphrynus melanostictus (Padhye et al, 2008;Datta & Khaledin, 2017); however, quantitative diet assessment with adequate sample size across habitats and seasons is lacking (but see Khatiwada et al, 2016 for diet of H. tigerinus in rice fields of Nepal).…”

Section: Introductionmentioning

confidence: 99%

Peer Review #2 of "What’s for dinner? Diet and potential trophic impact of an invasive anuran Hoplobatrachus tigerinus on the Andaman archipelago (v0.2)"

2018

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Amphibian invasions have considerable detrimental impacts on recipient ecosystems. However, reliable risk analysis of invasive amphibians still requires research on more nonnative amphibian species. An invasive population of the Indian bullfrog, Hoplobatrachus tigerinus, is currently spreading on the Andaman archipelago and may have significant trophic impacts on native anurans through competition and predation. We carried out diet analyses of the invasive H. tigerinus and native anurans, across four habitat types and two seasons; we hypothesized that i) small vertebrates constitute a majority of the H. tigerinus diet, particularly, by volume and ii) the diet of H. tigerinus significantly overlaps with the diet of native anurans, thereby, leading to potential competition. We assessed the diet of the invasive Hoplobatrachus tigerinus (n = 358), and individuals of the genera Limnonectes (n = 375) and Fejervarya (n = 65) and found a significant dietary overlap of H. tigerinus with only Limnonectes. Small vertebrates, including several endemic species, constituted the majority of H. tigerinus diet by volume, suggesting potential impact by predation. Prey consumption and electivity of the three anurans indicated a positive relationship between predator-prey body sizes. Individuals of Hoplobatrachus tigerinus and Fejervarya chose evasive prey, suggesting that these two taxa are mostly ambush predators; individuals of Limnonectes elected sedentary prey; although a large portion of its diet consisted of evasive prey, such electivity indicates 'active search' as its major foraging strategy. All three species of anurans mostly consumed terrestrial prey. This intensive study on a genus of newly invasive amphibian contributes to the knowledge on impacts of amphibian invasions, and elucidates the feeding ecology of H. tigerinus, and species of the genera Limnonectes and Fejervarya. We also stress the necessity to evaluate prey availability and volume in future studies for meaningful insights into diet of amphibians.

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Frogs as potential biological control agents in the rice fields of Chitwan, Nepal

Cited by 47 publications

References 44 publications

Household Livelihood Strategies and Implication for Poverty Reduction in Rural Areas of Central Nepal

Household Livelihood Strategies and Implication for Poverty Reduction in Rural Areas of Central Nepal

Survival analysis of brown plant hoppers (Nilaparvata lugens) in rice using video recordings of predation events

Peer Review #2 of "What’s for dinner? Diet and potential trophic impact of an invasive anuran Hoplobatrachus tigerinus on the Andaman archipelago (v0.2)"

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