Effect of density and food level on the growth, development and survival of larvae of the green toad (Bufotes variabilis, Pallas 1769), Amphibian: Anura

Growth, development and survival have important effects on life-history and population dynamics, as they interact to determine an individual's size and age at particular life cycle transitions (e.g. metamorphosis and maturity). For many amphibians, density and food are the primary biotic environmental factors affecting growth, development and survival rates. In this study, the independent and interactive effects of density and food levels on growth, metamorphosis, and survival were studied in larval of Green toad Bufotes variabilis. We designed a 2 × 2 factorial experiment in which larvae were raised either at high and low density of conspecifics and fed either a high and low level of food that carried out within 112 days. Food level had a significant effect on growth, metamorphosis, and survival. However, density did not significant influence on growth, survival and metamorphosis time but showed a significant effect on metamorphosis size and percentage of metamorphosis. Growth, metamorphosis size, percent of larval metamorphosed, and survival were all highest in the low density / high food. The lowest growth and metamorphosis size, the greatest age of metamorphosis were in the high density / low food. The lowest survival rate and percentage of metamorphosis were in the low density / low food. Combined effects of food level and density showed significant effects on growth, metamorphosis size, percentage of metamorphosis and metamorphosis time over time but this interaction was not significant for survival.