Feeding Ecology of a Tropical Litter-Dwelling Frog, Chaperina fusca (Microhylidae) from Borneo
We analyzed the diet of a litter-dwelling microhylid frog, Chaperina fusca, from the lowland rainforest of Borneo. We flushed the stomachs of 194 frogs: 94.8% had contents and 5.2% were empty. Although the diet composition of C. fusca was diverse, with 27 prey categories, we found that ants, mites, beetles, and springtails, in that order, dominated its diet both numerically and volumetrically. Among these four categories, however, ants were by far the most frequently consumed in both number (63.5%) and volume (82.6%) and in higher proportion than in the leaf litter. A novel aspect of our study, conducted in only a limited number of studies of anuran diets, was to determine the ant genera consumed. We identified 41 ant genera consumed by C. fusca whereby the genera Lophomyrmex, Pheidole, and Tetramorium were the most prominent. We also recorded a significant relationship of prey volume and number with both body size and mouth width of frogs. Our data provide circumstantial evidence that C. fusca is an ant-specialist feeder and active forager. These results are in line with the dietary characteristics of many terrestrial microhylid frogs in subtropical and tropical Asia, the Neotropics, and the Afrotropics. Kami telah menganalisa komposisi diet katak microhylid Chaperina fusca yang menghuni serasah daun di hutan hujan pamah rendah Borneo. Kami mengepam air ke perut 194 ekor katak: 94.8% mempunyai kandungan dan 5.2% adalah kosong. Komposisi diet C. fusca adalah pelbagai dan mengandungi 27 kategori mangsa, mengikut susunan ini kami mendapati bahawa semut, hama, kumbang dan springtails mendominasi komposisi diet yang mempunyai kiraan dan isipadu yang tinggi. Walau bagaimanapun, di antara empat kategori ini, semut adalah yang paling kerap dimakan dari segi bilangan (63.5%) dan isipadu (82.6%). Satu aspek baru kajian kami adalah untuk menentukan genera semut yang dimakan. Kami telah mengenalpasti 41 genera semut yang mana genera Lophomyrmex, Pheidole dan Tetramorium adalah yang paling menonjol yang dimakan oleh C. fusca. Kami juga merekodkan hubungan signifikan diantara isipadu dan bilangan mangsa dengan kelebaran mulut katak tetapi tidak dengan panjang badan. Data kami membuktikan bahawa C. fusca merupakan pemakan semut khusus dan pemburu aktif. Hasil kajian ini selari dengan ciri-ciri pemakanan kebanyakan katak microhylid yang terdapat di Neotropika dan Afrotropika.Abstract
Abstrak
Map of the study site in the Temburong district of Brunei Darussalam showing the location of the three streams: Apan, Baki, and Belalong.
Accumulation curve of prey categories consumed by Chaperina fusca in the Ulu Temburong National Park, Brunei Darussalam, Borneo. Inset: Image of a male Chaperina fusca.
Proportions of index of relative importance (% IRI) of five prey categories with the highest importance in the diet of Chaperina fusca in the Ulu Temburong National Park, Brunei Darussalam, Borneo.
Proportions of index of relative importance (% IRI) of 10 ant genera with the highest importance in the diet of Chaperina fusca in the Ulu Temburong National Park, Brunei Darussalam, Borneo.
Relationship between prey size (in volume) and prey number with snout–vent length (SVL) and mouth width (MW) of Chaperina fusca. Dotted lines indicate 95% confidence intervals.
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