PREDATION ON POMACEA & RADIX SNAILS DURING NON-RICE GROWING PERIODS BY THE PHILIPPINE RICEFIELD RAT, RATTUS TANEZUMI TEMMINCK

摘要

Predation preference by the principal rodent pest species, the Philippine ricefield rat, Rattus tanezumi Temminck (formerly known as Rattus rattus mindanensis), for the invasive alien freshwater snail, the golden apple snail, Pomacea canaliculata; native non-pest freshwater snail, Radix quadrasi; and other alternative food resources, was studied at the experimental lowland ricefields of PhilRice at Maligaya, Science City of Munoz, Nueva Ecija, during the rice fallow months. Based on the free-choice field tests, R. tanezumi dined mostly on small snails, and preferred P. canaliculata over R. quadrasi. In contrast, the large-shed P. canaliculata were carried more often by R. tanezumi into their burrows and consumed. Irrespective of the snail species, predation was highest at lower elevations (closer to water source) and almost always at night. It was difficult to establish field prejerence(s) for milled rice grains either with or without rodenticide, due to the interference by fire ants, Solenopsis germinata and house sparrows, Ploceus philippinus.