Butterfly Basics
Lepidoptera
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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.
There are many more species of moths than butterflies. Butterflies and skippers make up about 10% of the Lepidoptera order, while moths make up 90%.
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.
Butterfly or Moth?
Butterflies are active during the day, while moths tend to be noctural.
Butterflies tend to fold their wings vertically up over their backs. Moths tend to hold their wings in a tent-like fashion that hides the abdomen. Butterflies are typically larger and have more colorful patterns on their wings. Moths are typically smaller with drab-colored wings.
Some moths have wingless adults and some primitive moths lack a proboscis. Moths have a frenulum, which is a wing coupling device that ensures the wings travel together during flight. Butterflies do not have this.
Moths build a cocoon wrapped in a silk covering. A butterfly makes a chrysalis, which is hard and smooth with no silk covering.
The antennae of butterflies have a swelling at their end; moths have no such "club" and instead are more feathered. Moth antennae tend to be leaf or feather shaped (compare the two images below).
Butterfly  |
Moth  |
Common 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. Included on this website are some of the more common butterflies found in residential areas, nearby parks and gardens, and while hiking in the open spaces.
Common Moths
| Prometheus Moth Salt Marsh Moth Snowberry Clearwing Moth Spiny Oakworm Moth Tersa Sphinx Moth White-lined Sphinx Moth |
Butterfly Life Cycle
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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.
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).
As the caterpillar reaches maturity, it transforms itself, or "pupates", into a "pupa", or chrysalis like the Monarch chrysalis shown below.
As the Monarch chrysalis ages, it becomes dark and clear, with the butterfly evident inside, 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!
An adult Monarch butterfly
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.
Scientific Family Classification
- Papilionidae - Swallowtail butterflies, most species having prominent tails.
- Hesperiidae - Skippers - relatively small, fast-flying species.
- Lycaenidae - Blues, Hairstreaks and Coppers. Colors and patterns of sexes often differ.
- Nymphalidae - Brush-footed butterflies, contains many subfamilies.
- Pieridae - Yellows and Whites, with those predominant colors.
- Riodinidae - Metalmarks, sometimes placed in the Family Lycaenidae.
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)
Black Swallowtail butterfly (ventral view)
