The life history of the Monkey puzzle butterfly, "Rathinda amor" and larval performance in terms of food consumption and utilization, and the length of life cycle on its host plant "Ixora arborea" are described for the first time. The study was conducted during 2008 at Visakhapatnam (17°42' N and 82°18' E), South India. "Rathinda amor" completes its life cycle in 19-21 (19.80±0.84) days (Egg: 3; Larva: 8-10; Pupa: 8 days). The values of nutritional indices across the instars were AD (Approximate digestibility) 56.71-89.02%; ECD (Efficiency of Conversion of digested food) 2.61-16.83%; ECI (Efficiency of conversion of ingested food) 2.32-13.93%, measured at the temperature of 28 ±2°C and RH of 80±10% in the laboratory. These relatively high values of ECD and ECI explain at least partially the ecological success of "Rathinda amor" in the urban environment of Visakhapatnam.