Asian Herpetological Research 2021, 12(2): 250–260 DOI: 10.16373/j.cnki.ahr.200069 ORIGINAL ARTICLE 1. Introduction Anuran amphibians are traditionally described as generalist predators, with opportunistic foraging behaviour (Santos et al. , 2004). A majority of the invertebrates reported in adult frog diets are arthropods, including arachnids, crustaceans, orthopterans, coleopterans, and especially, ants and mites (Cogălnicueanu et al. , 2000; Hirai and Matsui, 2001; Kovacs et al. , 2010; Maneyro et al. , 2004; Ogoanah and Uchedike, 2010; Toft, 1980a, 1980b; Van Sluys et al. , 2006). Small vertebrates, such as fish and frogs, may be occasionally eaten, especially by large- growing species (Santos et al. , 2004; Measey et al. , 2015), and cannibalism has also been documented (Inger, 1966a; Ogoanah and Uchedike, 2010). Plant material and stones may sometimes occur in stomach samples in small amounts, and are probably taken incidental to food (Berry, 1966), except in a couple of species (Das, 1995; da Silva et al. , 1989). Taking into account the number of prey items consumed and the contribution of each prey item to the overall diet, anuran amphibians can be organized in a feeding behaviour gradient, from generalist to specialist (da Rosa et al. , 2002). Many species show some degree of dietary specialization and recognized as specialist feeders that are often associated with high proportions of a particular food from the food spectrum available (Toft, 1980a; Santos et al. , 2004). Te two widely considered ends of the dietary continuum in tropical anurans include the “ant specialists”, which tend to be toxic to potential predators and active searchers of prey, taking many small prey that usually show a clumped distribution, such as ants and termites, and the “non-ant specialists or generalists”, that are cryptic, sit-and-wait foragers, which take relatively few, but larger prey types (Toft, 1980a). Ants and other small insects make up the diet of probably all Ansonia species (Inger et al. , 2017), as in the bufonidae in general, as well as in members of the family Microhylidae (Ahmad Sah et al ., 2019). Amphibians Trophic Ecology of Ansonia latidisca at Gunung Penrissen, Sarawak, North-Western Borneo Jia Jet ONG and Indraneil DAS Keywords Ansonia latidisca , Borneo , diet, ecology, Malaysia, Sarawak Institute of Biodiversity and Environmental Conservation, Universiti Malaysia Sarawak, Kota Samarahan 94300, Sarawak, Malaysia * Corresponding author: Prof. Indraneil DAS, from Institute of Biodiversity and Environmental Conservation, Universiti Malaysia Sarawak, with his research focusing on taxonomy, ecology and conservation biology of amphibians and reptiles. E-mail: idas@unimas.my Received: 14 June 2020 Accepted: 19 January 2021 Abstract Dietary data on Ansonia latidisca, the little known Bornean Rainbow Toad, are presented, through an investigation of a population at Gunung Penrissen, Sarawak, Malaysia (north-western Borneo), at elevations between 1,100–1,229 m asl. Standard sampling techniques, including visual encounter surveys, were employed and individuals encountered stomach-flushed, marked, and released. The volume of food ingested by adults, apart from large females, did not vary monthly, and there was no significant difference between wet and dry periods, the dominance index between the two periods showing no significant difference, indicating that seasonal variation does not affect the dietary constitution of the species across months. The mean longest prey was recovered from a female in March, during the end of the wet season. Larger individuals did not consume larger prey in the species, although larger females did harvest the largest insects, and as may be expected, had fewer prey items in their stomachs at the time. Males fed on fewer prey items than females, the adult male diet predominantly comprised of members of the Hymenoptera, including formicids (ants), as indicated by percentage frequency of occurrence of 78.69, while for adult females, equivalent figure was 90.70. Coleopterans (beetles) were found secondary in importance (48.8% in females, 5.85% in males), the rest categorized as tertiary. Plant items (including bryophytes) had a high frequency of occurrence (23.3% in females, 4.64% in males). Females examined in the month of July had voluminous stomach contents, and may have eaten more to increase fat reserves for breeding in the upcoming wet season. Since the diet of all size classes consisted of hymenopterans (ants) and coleopterans, the study species is here considered to have a narrow food preference, and consequently, is a dietary specialist.