The Second Stage of a Butterfly's Life Cycle

Butterflies have a 4-stage life cycle, in which they complete a metamorphosis from a caterpillar to butterfly. The four stages are called egg, larva, pupa or chrysalis, and imago. The life of the butterfly in the adult stage can range from a week to almost a year, depending on the species. The length of the other stages also varies, some butterflies spending longer in the pupal or egg stage, to allow for survival through the winter months.

  1. Physical Characteristics

    • The butterfly starts the second stage of its life when it hatches from an egg in larva form. The caterpillar has a segmented body, with a recognizable head. The adult butterfly keeps the three pairs of short, jointed legs on the thorax, but loses the additional unjointed, fleshy prolegs. These prolegs are present on some of the abdominal segments and have clusters of minute hooks to enable gripping.

    Progression

    • Most caterpillars are herbivores, but some species feed on insects. Often, host plants contain chemicals that are toxic to most insects, but caterpillars are able to ingest and retain these substances. This provides the caterpillars with protection from predators, due to their inedibility. Caterpillars eat almost continuously to allow growth. They shed their hard outer skin, the exoskeleton, most often molting about 4 to 5 times during the larva stage. At the time of the final molt, the caterpillars' wings start developing rapidly.

    Silk

    • Caterpillars produce silk that they release from the spinneret. Initially, they use these silk threads for swinging when they descend from a height. At the end of the larva stage, caterpillars wrap themselves in these silk strands to create the cocoon where they pupate.

    Relationship With Ants

    • Some caterpillars, such as the Lycaenidae, have mutual interactions with ants. Communication is possible by sending out vibrations or emitting chemicals. Caterpillars release a sweet substance from glands in their tail end that the ants collect. In some cases, ants offer protection to the caterpillar, even letting it into their nest to form its chrysalis. Other times, caterpillars will live in the ant nest as parasites, consuming baby ants.