Reproduction and survival of the ricefield rat Rattus argentiventer on rice plant diet

Reproduction and survival were studied in caged individuals of the ricefield rat, Rattus argentiventer on a diet of rice plants in various stages of growth. The female rat was reproductively active on diets consisting of rice plant at any stage of growth. However, the reproductive activity of the male rat was significantly influenced by the stage of the rice plant: the male was sexually active while feeding on the generative stages, but almost inactive while feeding on the vegetative stages. The percentage of males with enlarged scrotal testes began to increase on a diet of plants in the panicle primordia initiation stage and reached 100\% by the milky grain stage. The male determines the breeding pattern of this species, and this is directly influenced by the males' food source. Male rats with a scrotal sac containing testes that were larger than 30 mm (measured externally on living rats) were always reproductively active. The survival of both sexes of the ricefield rat also corresponded closely with the growth stage of the rice plant. There were no significant differences in survival values between males and females feeding on different stages of the rice plant. Overall, the milky and ripening grain stages of the rice plant provided the best foods for the reproduction and survival of the ricefield rat.