Diet of the Wrinkle-Lipped Free-Tailed Bat (Chaerephon plicatus Buchannan, 1800) in Central Thailand

Abstract

Brown planthopper is one of the major insect pests of rice field. They have been widely acknowledged for significantly causing yield losses of rice production. Using wrinkle-lipped free-tailed bat (Chaerephon plicatus Buchannan, 1800) as a biological pest control agent for planthoppers were previously reported, however, it was unprecedented for brown planthoppers. The objective of this study to determine the diet of C. plicatus in the areas where brown planthopper is common. To accomplish this objective, we analyzed the diet of C. plicatus from two caves that differed in the percentage of surrounding land area occupied by rice fields (70% vs. 22%). A year round fecal samplings were carried out monthly. The total of 720 fecal pellets was collected and analyzed, the results revealed that C. plicatus fed on at least 8 insect orders belonging to Coleoptera, Homoptera, Hemiptera, Diptera, Lepidoptera, Odonata, Hymenoptera and Orthoptera. Surprisingly, Homoptera made up a greatest diet volume in period of active rice field where as Coleoptera was the most abundant in the diet during inactive rice period. Most Homoptera were identified as brown planthopper, an important economic pest in rice field. The number of male brown planthopper genitalia was counted and it showed the greatest number during rice planting period, an average of four males genitalia per pellet were recorded. Assessment of percent volume and percent frequency revealed that the diet of C. plicatus was not significantly different between the two study caves (p > 0.05), even though the proportion of surrounding active rice fields was different. According to the results, this study further suggests that at least ten millions individuals of brown planthopper are consumed by this bat colony each night. The highly importance of C. plicatus as a biological control against the brown planthoppers in rice fields is emphasized.