effect of population density food level and competition on growth and metamorphosis in larval Egyptian toad, bufo regularize

ABSTRACT

Growth and metamorphosis of Bufo regularis tadpoles under two levels of population density, two levels of food and with or without competitors [the green toad, Bufo viridis] were investigated using a replicated pond system. High food supplements accelerated growth with or without competitors. The presence of competitors depressed growth, even under conditions of high food. Also, the larvae grew much better under conditions of low population density than high one in either high or low food levels with or without competitors. The tadpoles raised under high food metamorphosed earlier than those raised under low one. Survival was variable within treatments, and also was highest in high food levels. Field observations as well as laboratory treatments with competitors revealed that B. viridis commenced metamorphosis and left water before B.regularis