Order Lepidoptera (Butterflies and Moths)

Painted Lady butterfly (Vanessa cardui). Note the clubbed antennae.

Introduction

Douglas-fir tussock moth (Orgyia pseudotsugata). Note the plumose antennae.

Lepidoptera is a massive order with over 150,000 species worldwide. It can be easily told apart from other orders by the scales that cover the wings and bodies of adults. With a few exceptions Lepidoptera have two pairs of wings and a curled proboscis used for siphoning nectar and other fluids. Popularly the Lepidoptera are broken into two categories, butterflies and moths, although this doesn't represent a natural classification. Butterflies tend to be day flying and have clubbed antennae, while moths tend to be night flying with straight or plumose antennae (see photos, right).

Many Lepidoptera, especially butterflies, are important pollinators and generally enjoyed by the public. Many more are not beneficial or detrimental to human endeavors. Few Lepidoptera are of medical importance, the exceptions being species with stinging hairs, such as the buck moth caterpillar. However, there are quite a few species that are pests of crops, stored grains, and even fabrics. And there are several moth species that are important invasive species, such as the Gypsy moth, an important defoliator of forests in eastern U.S.

Tobacco Hornworm (Manduca sexta) with parasites. The white pill-shaped objects on the caterpillar's back are not eggs, they are cocoons that the parasitic wasps will soon emerge from.

Life Cycle

Lepidoptera are Holometabolous, their life cycle consists of four phases: egg, multiple instars, pupa, and adult. "Complete metamorphosis" is the common term for this life cycle. Insect orders with this life cycle are grouped under the term Endopterygota because immatures never have visible wing buds. The pupal stage is only found in the Endopterygota. This is typically a resting stage (e.g., the chrysalis of butterflies) where the insect undergoes a final metamorphosis from immature to adult.

Lepidoptera immatures are commonly referred to as caterpillars. Most are elongate and fleshy with three pairs of short true-legs and up to 5 pairs of prolegs. Most caterpillars eat plants and they may remain exposed on the plant, curl a leaf around themselves while they eat, mine the middle layers of leaves, or burrow into the plant while feeding. Immatures may or may not spin a cocoon while they pupate. Natural silk comes from the cocoon of the silk worm moth.

How to Photograph Lepidoptera

Butterfly photography can be incredibly rewarding and frustrating. For identification purposes it is best to photograph a butterfly from above while the wings are spread, so the pattern on the top of the wings is clearly visible. If a butterfly is perched with its wings together over its back, gently blowing down on the individual may make it open its wings so a photograph can be taken, or it may cause the butterfly to fly away, so be careful. Moths may be photographed in the same way.

Caterpillars can also be photographed for identification. Be sure coloration and markings on the side and back are clearly visible. Multiple photos should be taken as well as photos of the suspected host plant and damage caused by the caterpillar.

How to Collect Lepidoptera

Butterflies are easily collected with a butterfly trap [1] or a net. Soft aerial nets are the best to use because they minimize the likelihood of damaging the specimen. Butterflies can be killed by placing them in a freezer (if one is available), or in an ethyl-acetate killing jar (fingernail polish remover works well). Never put butterflies or moths in alcohol. Be sure to not damage the delicate scales on the wings, as this can obscure the identity of the specimen.

Caterpillars can be preserved in alcohol (80% ethyl is best, but 70% rubbing alcohol will also work), but colors will fade. Photograph the specimen before killing it if possible.

Damage from the Cabbage White, see below.

How Lepidoptera Cause Damage

Immature Lepidoptera have biting-chewing mouthparts and generally cause damage by biting off pieces of leaves, stems, flowers, roots, fruit, seeds, etc. Most damage caused by Lepidoptera is through direct consumption of the plant, not by vectoring diseases. Damage is often easily visible (although damage to roots, or internal damage may not be externally visible) but may resemble damage caused by Orthoptera and grubs.

Butterflies

Northern crescent (Phyciodes tharos).

Butterflies are important pollinators and serve as important ambassadors to the world of insects. Most immature butterflies are plant feeding. Most butterfly caterpillars do not spin cocoons, but instead make a chrysalis (plural, chrysalids).

Monarch

Family: Nymphalidae

Monarch butterfly		Caterpillar	Monarch butterflies (Danaus plexippus) are recognizable butterflies that are found throughout the United States and southern Canada. Adult monarchs are bright orange and easily visible, but are protected from bird predators by harsh chemicals (called cardiac glycosides) that they obtain from milkweed while caterpillars. An easy way to attract monarchs to your yard is to include milkweed (genus Asclepias) in your butterfly garden. Monarch migration is very interesting. Young adults fly south in the fall and overwinter in Mexico. In the spring those individuals migrate back north, perhaps as far as Texas, lay eggs, and die. It may take three or four more generations before individuals make it all the way back up to Canada.

Cabbage White

Family: Pieridae

Cabbage White		Caterpillar		Damage	The Cabbage White (Pieris rapae), is an imported pest of cruciferous plants, especially cabbage, cauliflower, and broccoli. Caterpillars are green and often remain on the underside of leaves. They overwinter as pupae and emerge as adults in early spring. Cabbage Whites may have two or more generations per year. Spraying generally does little to control caterpillars unless it coincides closely with egg hatch. Numerous parasitic wasp species have been used to control populations.

Lepidoptera Life Cycle: The most famous insect lifecycle: egg, multiple instars (caterpillars), pupa (cocoon), and adult. Modified from Comstock 1936.

Moths

Moths tend to be night flying, have straight or plumose antennae, and are usually more heavily covered in scales than butterflies. Immature moths are generally plant feeding, but many pest species also feed on stored grains and organic materials such as fabrics.

Some moth species are of medical importance, such as the Buck Moth (Hemileuca maia), which as a caterpillar possess stinging hairs that can cause painful itching and burning if touched.

Caterpillars can be photographed for identification. Be sure coloration and markings on the side and back are clearly visible. Multiple photos should be taken. Caterpillars can be preserved in alcohol (80% ethyl is best, but 70% rubbing alcohol will also work), but colors will fade.

The attraction of moths to lights at night is well known, but poorly understood. Light trapping is a good way to attract moths for collection, but many pest species can also be collected/surveyed for using pheromones specific to those particular species. Moths can be killed by placing them in a freezer (if one is available), or in an ethyl-acetate killing jar (fingernail polish remover works well). Be sure to not damage the delicate scales on the wings, as this can obscure the identity of the specimen.

Buck Moth

Family: Saturniidae

Buck Moth		Caterpillar		Eggs	Buck Moths (Hemileuca maia) are relatively large, easily recognizable moths that are found throughout eastern North America, as far west as Texas. The tip of the abdomen of males is bright red, while females have an entirely black abdomen. Adults emerge in the fall and winter and lay eggs around the branches of host trees. Buck moth caterpillars eat oak and willow. The caterpillars are covered in stinging hairs which can be very painful to touch. Caterpillars enter the soil about June to pupate and emerge in the fall as adults. There is one generation per year.

White-lined Sphinx

Family: Sphingidae

White-lined Sphinx		Caterpillar		Feeding	The White-lined Sphinx (Hyles lineata) is often referred to as a "hummingbird moth" because adults are often mistaken for hummingbirds while they feed. Adults tend to fly at dusk and hover in front of flowers while they drink nectar with their long proboscis. Immature White-lined Sphinx are occasionally pests in gardens and may eat tomatoes. This species ranges from Mexico across the United States and into Canada.

Peachtree Borer

Family: Sesiidae

Peachtree Borer- Male		Peachtree Borer- Female		Caterpillar	The Peachtree Borer (Synanthedon exitiosa) is a serious pest of peaches, cherry, plum, prune, nectarine, apricot, and some ornamental shrubs.[2] Adult females may lay up to several hundred eggs on the trunk just above the soil, or on vegetation around the base of a peach tree. Caterpillars burrow into the trunk and begin eating the live cambium under the bark. A sufficient number of caterpillars may seriously weaken a tree, allow for introduction of pathogens, and even ring and kill the tree. Larvae can be removed with a knife. Generally there is one generation every two years in Canada, one generation each year in most of the U.S. and up to two generations in the Gulf South.

Corn Earworm, Tomato Fruitworm, Cotton Bollworm

Family: Noctuidae

Adults		In Corn		In Tomato	Helicoverpa zea has many common names, (Corn Earworm, Tomato Fruitworm, and Cotton Bollworm for example) depending on what crop it's found on. Immatures of this species have been reported to eat over 100 crops. Females may lay up to 3000 eggs each and when conditions are favorable there may be up to 7 generations a year. Thus this species has a capacity to build large populations and cause devastating crop losses.

Summary and References

There are 84 families and ~11,673 species of Lepidoptera in North America North of Mexico. Many publications are available that can be used to identify butterflies and large moths by pictures of wing patterns and other characteristics. However many moths are small (2+ mm long) or difficult to distinguish, therefore Triplehorn and Johnson (2005) is a good general reference for information about the often overlooked members of this order.

Several important resources about butterflies and moths include the books: Borror and Delong’s Introduction to the Study of Insects, and Insects: Their Natural History and Diversity: With a Photographic Guide to Insects of Eastern North America. The latter is especially good, and provides many color photographs of examples of common and not so common species and families.

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Print References

First Detector Entomology Training Project