Research Article: Deyatima Ghosh, Vikram Aditya, and Neelavar Ananthram Aravind (2024) “Farmland Herpetofauna: What Do They Do for Us?,” Journal of Herpetology 58(2), 1-15,

Blog Author: Shashank Dalvi

Key Takeaway:

  • Herpetofauna refers to a group of organisms that includes both amphibians and reptiles
  • Studies have shown that amphibians consume more insects than reptiles.
  • Lack of data on how herpetofauna helps in pest control with relatively more studies on amphibians than reptiles.
  • Climate change can alter the efficiency of pest regulation by herpetofauna.
  • Reptile hatchlings incubated at higher temperatures can forage better.
  • Using herpetofauna as natural pest regulation is a sustainable solution.

How often do we observe chequered keelback snakes (Xenochrophis piscator) in our backyard or farmland? It is considered a ubiquitous snake in the Indian countryside or even in the lakes of every city in the country. There is a popular belief that they only feed on fish. However, their diet also consists of agricultural pests like grasshoppers. Similarly, amphibians such as Indian bullfrogs and skittering frogs also show a strong preference for pests, particularly during the dry season. Studies have shown that frogs can consume up to 13 prey items per day, and their feeding rates are generally higher than those of lizards. This particular service they provide to us is often referred to as ‘Ecosystem Services’.

Herpetofauna (reptiles and amphibians) play a critical yet underappreciated role in biological pest regulation, especially in farmlands. A systematic review of 27 studies highlights the lack of data on this topic, with most research focusing on amphibians rather than reptiles. Despite this, amphibians and reptiles have a broad dietary range, consuming a variety of crop pests and contributing significantly to pest control.

Role of body size in pest regulation

The size of both the predator and prey plays a critical role in pest regulation. Larger lizards, like Erhard’s Wall Lizards, prefer larger prey such as grasshoppers and caterpillars, which improves their biocontrol efficiency. The relationship between predator body size and prey size also influences how herpetofauna contributes to pest control across different seasons.

Role of temperature and sex in pest regulation

Temperature and sex can also impact pest regulation efficiency. For example, female Mongolian racerunners have higher prey consumption rates than males, while in other species, no significant difference between sexes is observed.

The impact of reptile sex ratios and climate change on pest control

In quite a few reptile species, the determination of sex in newborn hatchlings depends on at what temperature they hatch. Hence an increase in temperature can result in skewed sex ratios and consequently, sex reversals. This can significantly impact pest control efforts. Additionally, climate change, with projected temperature increases of 1.1–6.4 °C by 2100, could alter the efficiency of pest regulation by herpetofauna. Studies show that reptiles incubated at higher temperatures tend to perform better in foraging tasks, which could influence pest control outcomes in a warming world.

Using exotic vs native amphibians for pest control

Introducing exotic species for pest control has its risks. While Chinese bullfrogs have successfully reduced rice pests in China, the infamous introduction of cane toads in Australia caused widespread ecological damage, leading to declines in native predators. Conservation biological control, focusing on native species, offers a more sustainable and balanced approach to pest management in farmlands.

A roadmap to improve ecosystem services through herpetofauna: maintaining the diverse community of herpetofauna

To enhance ecosystem services and biodiversity in agriculture, conserving a diverse predator community is essential. Different species of herpetofauna (reptiles and amphibians) specialize in preying on various pests. For example, certain frog species target leafhoppers, while other reptiles prefer ground-dwelling insects. Thus, maintaining a diverse assemblage of predators can improve pest regulation across multiple environments and pest species.

One challenge is ensuring that predators can access pests in all parts of crops. Amphibians often focus on ground pests, while reptiles hunt both ground-dwelling insects and those in the air or on plants. To overcome this, researchers recommend integrating amphibians and reptiles with other pest-predator communities, such as arthropods, birds, and mammals. Understanding the life cycles and habitats of target pests can also make biological pest regulation more effective.

Threats to herpetofauna, particularly due to intensive farming practices, are another key consideration. Conventional agriculture has been shown to reduce amphibian and reptile populations. Strategies like preserving natural vegetation, hedgerows, and water bodies near farmland can support herpetofauna and improve pest control. Additionally, habitat features such as leaf litter, shrubs, and fallow lands can create more suitable environments for these species.

A critical factor in promoting biological pest control is engaging stakeholders, including farmers and policymakers. Biological control offers long-term benefits, but these may take longer to become evident compared to chemical pest control. However, the economic and environmental advantages of biocontrol far outweigh those of chemical methods. In developing countries, introducing natural predators into farming systems has already shown promising results, improving yields and reducing costs.

Unlocking the potential of herpetofauna for biological pest regulation

A key gap in research is the lack of data on the pest control efficiency of herpetofauna. While there are examples like the study showing Anolis lizards reducing coffee berry borer infestations by up to 83%, there is a need for more field trials to validate such results on a larger scale. Another overlooked group is snakes, which play an important role in controlling rodent populations that cause significant crop damage, but their biocontrol potential remains underexplored.

One critical aspect that needs attention is the economic value of the ecosystem services provided by herpetofauna. The benefits of natural pest control by birds, for instance, have been quantified, but similar assessments for amphibians and reptiles are missing. Attaching a monetary value to these services can drive conservation efforts, increase funding, and engage stakeholders more effectively.

As agricultural intensification increases, so will the need to balance crop production with biodiversity conservation and ecosystem health. Reducing dependence on chemical pesticides and harnessing natural pest regulation is a sustainable solution. By conserving species and their habitats, we can start utilizing herpetofauna alongside traditional pest predators like arthropods and birds.

Keywords: Herpetofauna, Natural pest control, Climate Change, Ecosystem Services, Sustainable Farming

 

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