The Unsung Heroes of Rice Farming

By hunting at high elevations where chemical insecticides are ineffective, wrinkle-lipped free-tailed bats (Mops plicatus) contribute significantly to pest control, according to a recent study conducted by researchers from Thailand's Prince of Songkla University and the Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW). The study, which was published in Oecologia, emphasises how the bats might prevent planthoppers—one of the main insect pests that harm rice fields in Southeast Asia, South Asia, and East Asia—from spreading. The results highlight how crucial it is to preserve this bat species for both ecological and agricultural reasons.

More over half of the world's population depends on rice as a staple grain, and Southeast Asia is one of the key production regions. Rice fields are severely damaged by planthoppers, such as the brown planthopper (Nilaparvata lugens) and the white-backed planthopper (Sogatella furcifera), which costs farmers money. At elevations between 300 and 1,000 meters, these insects can fly great distances, rendering conventional pest management techniques useless. According to the study, many of these pests fly up to 1,600 meters in the air, where Wrinkle-lipped free-tailed bats prey. These bats contribute to the region's food security by acting as a natural pest management service by limiting the spread of high-flying planthoppers.

In order to trace the activities of adult Wrinkle-lipped free-tailed bats, researchers fitted them with portable GPS recorders after capturing them in a cave in the Lopburi district of Thailand. According to the statistics, these bats have vast hunting grounds that span up to 1,743 km2, or about twice the area of Berlin. Some flew for up to 11.5 hours straight, covering more than 200 km in a single night. They hunted at elevations above 150 meters more than half the time, often exceeding 1,600 meters. Due to the quantity of planthoppers and other prey, the study also discovered that rice fields were a popular hunting location.

Even though they are very common, Wrinkle-lipped free-tailed bats only use a few caves for roosting—less than a dozen are known to be inhabited all year round. Since maintaining these caves' environments is essential to maintaining their pest control functions, the researchers stress the urgent necessity to shield them from disruptions like tourism. These bats have an impact on agricultural regions in China, Korea, and Japan in addition to nearby rice farms because of their great travel distances. They assist stabilise rice output and lessen the demand for chemical pesticides by controlling planthopper populations.

In order to guarantee long-term food security, the study emphasises how crucial it is to incorporate bat conservation into agricultural plans. Farmers and ecosystems throughout Asia could gain from the sustainable and economical pest management strategy of protecting wrinkle-lipped free-tailed bats and their habitats. The National Research Council of Thailand (NRCT) provided funding for the study, which was carried out over the course of four years.

Source: Oecologia
Credits: Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW), Prince of Songkla University