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Butterfly life cycle

Butterfly lifecycle stages from egg to caterpillar, chrysalis and butterfly.


A female butterfly may lay between 100-200 eggs. She detects a possible host plant and tastes the leaves with her feet to ensure it’s the correct plant before attaching the eggs with a special adhesive fluid.

The egg has a hard outer layer lined with a wax coating to keep the inside moist and viable. The caterpillar will hatch within a week or two.


The butterfly larva is also known as a caterpillar. Its entire life consists of eating its own weight in leaf material every day. 

Caterpillars and butterflies do not have a nose or lungs - they breathe through tiny holes on their sides called spiracles

As the caterpillar grows it will fill its skin tightly and moult about four times until it sheds for the final time. Each phase between shedding is called an instar.


The caterpillar now starts an amazing transformation and pupates. It sheds its final caterpillar skin to reveal a chrysalis underneath.

The caterpillar attaches itself to a twig or leaf and forms a chrysalis around itself. This chrysalis is a hard shell encasing the caterpillar as it undergoes its metamorphosis into an adult butterfly. 

The caterpillar’s tissues and cells break down inside the chrysalis and the adult butterfly structures are formed. This last chrysalis stage can last weeks, months and sometimes years, depending on environmental conditions. 

You can often see the structures of the butterfly forming inside the chrysalis.


When the final stages are complete, and the conditions are right, the newly formed adult butterfly will split its pupal case and emerge. 

Its wings are soft, velvety, pliable and filled with veins. The butterfly will pump its haemolymph (butterfly blood) into its wings until they expand to their full size. They require a few hours to dry their wings so they are ready to take flight. 

The butterfly no longer has a mouth, but a long straw-like structure called a proboscis, which unfurls during feeding. When emerged the proboscis is in two parallel halves and the butterfly needs to mould them together to make the single long tube ready for drinking nectar from flowers. 

The butterfly has six legs, two large compound eyes with a large visual field and extreme colour vision, and  two antennae which help with navigation and detecting the aromas of host plants and prospective mates.

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