Direct development

Direct development is an idea in biology. An animal does direct development if the baby animal looks like a small adult and not a larva.^[1] A frog that hatches out of its egg as a small frog has direct development. A frog that hatches out of its egg as a tadpole does not. An insect that hatches out of its egg as a small adult does direct development. An insect that hatches out of its egg as a caterpillar or grub does not.

Direct development is the opposite of complete metamorphosis. An animal does complete metamorphosis if it becomes a non-moving thing, for example a pupa in a cocoon, after being a larva but before being an adult.^[2]

Examples

• Most frogs in the genus Callulina hatch out of their eggs as small frogs. They are never tadpoles.
• Springtails and mayflies are never larva. They are called ametabolous insects.^[3]