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Bats Act As Natural Defenders Against Rice Crop Pests In Southeast Asia

by Achim Dobermann
Bats Act As Natural Defenders Against Rice Crop Pests In Southeast Asia

Scientists from the Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW) and Prince of Songkla University in Thailand have shown that Wrinkle-lipped free-tailed bats not only travel long distances but also hunt at high altitudes—up to 1,600 meters.

This is the same height where planthoppers, major rice crop pests, fly. Traditional insecticides are ineffective at these heights, making these bats an important natural pest control, helping to protect food security in South and East Asia. The study, published in Oecologia, highlights the importance of conserving this bat species.

Rice is a staple for more than half the world’s population, with Southeast, South, and East Asia being key production areas. Planthoppers cause severe damage to rice fields, leading to major crop and financial losses. These insects travel long distances using winds at altitudes between 300 and 1,000 meters.

Led by Prof. Dr. Christian Voigt from Leibniz-IZW, researchers discovered that the Wrinkle-lipped free-tailed bat (Mops plicatus) hunts at these high altitudes.

“Mops plicatus is an expert hunter, catching insects in open air above vegetation,” says Voigt. “Until now, little was known about their hunting patterns during peak planthopper activity, so we used miniaturized GPS loggers to track them.”

This bat species is common in Southeast Asia, roosting in large caves with populations reaching millions. Previous studies found that Mops plicatus feeds on planthoppers, including the brown planthopper (Nilaparvata lugens) and the white-backed planthopper (Sogatella furcifera).

Planthoppers migrate at high altitudes to spread to new rice fields and reproduce. The study coincided with the annual planthopper migration in Thailand.

Scientists captured several adult bats from a cave in Lopburi province, central Thailand, attaching lightweight GPS loggers (0.95g) with medical glue. These loggers recorded the bats’ 3D movements every 10 minutes. After a few days, the devices naturally detached and were retrieved.

“We found that Mops plicatus has vast foraging areas—up to 1,743 km², about twice the size of Berlin,” Voigt explains.

“No other vertebrate weighing just 18 grams has been recorded with such a large range. Some bats flew over 200 km in a single night, staying in flight for up to 11.5 hours. More than 50% of their time was spent above 150 meters, often reaching over 1,600 meters.”

Dr. Supawan Srilopan from Prince of Songkla University, the study’s lead author, adds: “Our research provides new insights into how these bats select their hunting grounds. They prefer rice fields, even when other crops are closer, likely due to the abundance of planthoppers.”

The scientists stress the need to protect the bats’ natural habitats and roosting caves. Despite their large population, only a few caves are occupied year-round. Preserving these caves from disturbances like tourism is crucial for farmers in Thailand and even in distant regions like China, Korea, and Japan.

“The ecosystem services provided by Mops plicatus extend far beyond Thailand, contributing to sustainable rice production across Asia,” says Prof. Sara Bumrungsri from Prince of Songkla University, a co-author of the study.

This research was conducted as part of a four-year project funded by the National Research Council of Thailand (NRCT).

Journal Reference: Supawan Srilopan, Daniel Lewanzik, Sara Bumrungsri, Christian C. Voigt. Large and high-altitude foraging ranges suggests importance of Wrinkle-lipped free-tailed bats (Mops plicatus) for consuming dispersing pest insects. Oecologia, 2025; 207 (2) DOI: 10.1007/s00442-025-05671-x

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