For a moth life begins as an egg. Female moths lay eggs sometimes in large numbers, typically on surfaces that are suitable for larva to feed upon once they've hatched. Moth eggs are usually very small and may have varying shapes and colors, often blending in with their surroundings. The durations of the egg stage can vary greatly on environmental conditions like temperature.

Once the eggs hatch, the larva will enter the feeding stage of their life cycle. The caterpillars consume large amounts of food, often the leaves of plants or other organic material in preparation for their metamorphosis. While some larvae are considered pests to crops, they are also known for regulating certain plant populations. As they grow in size and weight they will also go through a series of shedding their skin. This stage can last from a few weeks to several months depending on the species.

After reaching a certain size and maturity, the caterpillar transforms into a pupa. This stage is a reorganization and transformation, where the caterpillar's body is broken down and reformed into an adult moth. During this stage some larvae will develop their pair of wings, antennae, and reproductive organs. The organism is also generally immobile and may be enclosed in a cocoon made from silk or a harder chrysalis. The length of this stage can vary from a few weeks to longer then a year in some cases.

Once the adult moth has emerged from the pupal case, often undergoing a period of expansion and drying of its wings before it can fly. Unlike the larval stage, some adult moths don't eat at all and instead rely fully on the energy they already stored. The adult life span is often very short, sometimes only for a week or two. This stage is mainly focused on mating, and for females, laying eggs to begin the next generation.