Butterfly Basics


Buckeye Butterfly on Hydrangea in Texas

Butterflies and moths belong to a group of insects called Lepidoptera. Like all insects, butterflies and moths have a head, thorax, abdomen, two antennae, and six legs.

Additionally, moths and butterflies have four wings that are almost always covered by colored scales, and a coiled proboscis for drinking liquids such as flower nectar. Of course there are exceptions; some moths have wingless adults and some primitive moths lack a proboscis.

Butterflies are active during the day, while moths tend to be noctural. The antennae of butterflies have a swelling at their end; moths have no such "club" and instead are more feathered.

Butterfly Species

It is estimated that there are about 20,000 species of butterflies in the world. In North America, there are 725 species (north of Mexico), with about 575 of these occurring regularly in the lower 48 states of the United States.

Butterfly Life Cycle

The life cycle consists of four stages:

  • Egg - A butterfly starts life as a very small, round, oval or cylindrical egg laid on the leaf of a "host plant"
  • Larva (caterpillar) - once the egg hatches, the larva eats the host plant on which it was placed. As the larva grows, they "molt" several times, becoming larger through each step, or "instar". 
  • Pupa (chrysalis) - as the larva reaches its full size, it transforms itself into sack in which it will make the final transformation into an adult.
  • Adult butterfly

After mating, the female butterfly lays small round or oval eggs on a “host” plant as shown below. Butterflies lay their eggs on plants that will be eaten by the caterpillar when it hatches from its egg. For example, the Monarch butterfly lays her eggs on Milkweed, while the Black Swallowtail will usually lay eggs on dill or fennel.

Monarch Butterfly egg carefully laid in the heart of a Milkweed plant

The eggs hatch into caterpillars within a few days, or within months or even years, depending on the species and weather conditons.

Monarch Butterfly caterpillar ... 7 days from egg laying ... size compared to a straight pin (below).

Monarch Butterfly caterpillar ... 7 days from egg laying ... size compared to a straight pin


Monarch Butterfly caterpillars ... nearing maturity



As the caterpillar reaches maturity, it transforms itself, or "pupates", into a "pupa", or chrysalis like the Monarch chrysalis shown below.

Monarch Butterfly caterpillar in its chrysalis ... carefully blending with nature!


As the Monarch chrysalis ages, it becomes dark and clear, with the butterfly evident inside, ready to emerge.

Monarch chrysalis ... dark and clear, with the butterfly ready to emerge


After several days or weeks, the adult butterfly emerges, completing the amazing life cycle!

In the photo below, we see a beautiful new Monarch Butterfly ... minutes after emerging from 10 days in its chrysalis!

A beautiful new Monarch Butterfly ... minutes after emerging from 10 days in its chrysalis

An adult Monarch butterfly
Monarch Butterfly at the Charlotte Rhoades butterfly Garden in Southwest Harbor, Maine

Life Span

Different butterfly species have different life spans. An average butterfly species has an adult life of 2-4 weeks, or less.

Some live much longer, like the Mourning Cloak, which may live almost a year. Monarchs and Swallowtails typically live no longer than a month. Others overwinter in the adult stage.

The Butterfly Diet

Most adult butterflies drink nectar from flowers through their tongues. A smaller number of butterflies never visit flowers, but gaining sustenance from tree sap, rotting animal matter, and other organic material.

Butterfly caterpillars almost all eat plant matter.

Studying the Butterfly: Dorsal and Ventral Views

When studying about butterflies, and reading books about them, you will often see references to "dorsal view" (wings open) and "ventral" view (wings closed). See example photos below.

Tiger Swallowtail Butterfly (dorsal view)
Male Tiger Swallowtail Butterfly on Butterfly Bush


Black Swallowtail butterfly (ventral view)
Black Swallowtail butterfly (ventral view) gathering nectar from a Milkweed flower


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