Butterflies and Moths - biology.

Butterflies and Moths - biology. I INTRODUCTION Butterflies and Moths, insects distinguished by four wings covered with tiny, shingle-like scales and by mouthparts that form a hollow, flexible tube like a drinking straw. Most butterflies and moths use their distinctive mouthparts to feed on the nectar of flowers. The insects have proportionately small bodies and large wings, and a pair of antennae on their heads. Butterflies and moths together make up the second largest order of insects, called Lepidoptera (Greek lepis, "scale"; ptera, "wing"). Butterflies and moths are similar animals, but they have some general differences. The main difference is that butterflies have knobs, or clubs, on the tips of their antennae. Moths may have threadlike, feathery, or blunt antennae, but their antennae lack clubs. In addition, most moths tend to fly chiefly at night, while butterflies are active during the day. When at rest, most moths hold their wings folded flat over their backs, while butterflies hold their wings upright over their backs or bask with them spread flat out to the side. Many species of moths have dull gray or brown wings, and butterflies often have wings with colorful patterns. But numerous exceptions exist. For example, many moths fly during the day and are brightly marked, and many butterflies have soft, brown wings. Throughout history, lepidopterans--especially the colorful butterflies--have been admired for their delicate beauty. They have a prominent place in art and literature as symbols of freedom, creativity, and the beauty of nature. The animals are also crucial parts of the ecosystems in which they live. Their most important ecological role is in pollination, the transfer of pollen from one flower to another, which helps plants to reproduce. Butterflies and moths pollinate many wild plants as well as important crops grown by humans for food. By far the majority of lepidopterans are moths. Scientists have identified some 200,000 species of moths and suspect there may be many more not yet discovered, perhaps amounting to a million or more species. By contrast, the approximately 18,500 known types of butterflies probably account for most of the world's butterfly species. Lepidopterans probably arose between 200 million and 300 million years ago from insects similar to present-day caddisflies, night-flying insects that live near water. After flowering plants, on which butterflies and moths depend for food, arose about 130 million years ago, the insects developed and diversified rapidly. The earliest known fossils of primitive moths, found in Lebanese amber and Siberian sediments, are 100 million to 130 million years old. The oldest known butterflies in the fossil record date from about 48 million years ago, and many butterfly fossils are found in shale about 38 million years old from the Florissant Fossil Beds of Colorado. Some of these fossil butterflies closely resemble present-day species. II RANGE AND HABITAT Butterflies and moths are native to almost every part of the globe except Antarctica and the oceans. Different biomes, such as forests, grasslands, deserts, and alpine highlands, each support distinctive arrays of butterfly and moth species. Like many groups of animals, lepidopterans reach their greatest diversity in the tropics. More than 6,000 species of butterflies make their home in Peru, a largely tropical nation in South America with a variety of habitats from rain forest to mountain summits, while only 6 types of butterflies live in Greenland's high arctic environment. In general, wooded habitats are more hospitable to moths, while butterflies prefer open, sunny settings. Butterflies may be found in flowery fields, meadows, and hillsides; along stream banks, roadsides, and the edges of woods; and in clearings, glades, and nature reserves of all sorts. Especially large numbers of butterflies can be found in prairies, arctic and alpine tundra, and deserts following spring or summer rains. Although the best way to see butterflies and moths is to visit places where human settlement has not greatly disrupted native habitats, the insects are also present in urban settings such as city parks, gardens, and vacant lots. Some gardeners plant flowers, herbs, and shrubs to attract colorful butterflies of a great variety of species. III PHYSICAL CHARACTERISTICS As do all insects, butterflies and moths have a hard outer covering, or exoskeleton, that supports and protects the body. Also typical of insects, lepidopterans possess a body divided into three main parts--head, thorax, and abdomen--and have three pairs of jointed legs. The small, round head protects the lepidopteran's brain and bears the insect's sensory organs and mouthparts. Butterflies and moths have a pair of large, oval, compound eyes, each made up of thousands of individual lenses, or ommatidia. In spite of the many lenses, the lepidopteran eye is thought to see a single, reasonably clear image. In addition to the spectrum of colors from red to violet that humans can see, butterflies and moths can perceive ultraviolet wavelengths of light. Two antennae protrude from the head. The antennae are covered with many small pits that serve as smelling organs, enabling the butterfly or moth to locate food sources by scent. Scent also plays a role in lepidopteran mating. The antennae of many male moths, equipped with elaborate side bristles, resemble feathers or ferns and are thought to give the moths a particularly sharp sense of smell, enabling them to locate females from several kilometers away. The function of the knobs on the ends of butterfly antennae is not fully understood. But butterflies lacking one antenna tend to fly in circles, which suggests that the knobs may play a role in orientation. The lepidopteran's mouth is located between its eyes. When it is not feeding, the butterfly or moth keeps its tongue, or proboscis, curled up below its face. The animal can uncoil the proboscis, which functions like a drinking straw, and insert it into flowers and other food sources. The proboscis may vary in length from a fraction of an inch to a foot or more. A few moths, such as the giant silk moths, have no functional mouthparts, and one family of tiny moths has jawlike structures called mandibles instead of a proboscis. These moths use their mandibles for chewing pollen grains. The thorax, or middle body part, of a butterfly or moth is the thickest of the body segments. It contains the powerful flight muscles and bears the legs and wings. The six legs are attached to the underside of the thorax. Each lepidopteran foot bears a pair of claws, used for clinging to perches, and hairlike structures responsible (along with the proboscis) for the sense of taste. If the front feet of a butterfly are touched with a small brush dipped in a very weak sugar solution, the butterfly will uncoil its proboscis and attempt to feed because the tasting hairs on its feet sense food. The wings--two forewings and two hind wings--originate from the sides of the thorax. A lepidopteran's wings are large in proportion to its body and very thin. The wings are made of two membranes with a network of stiff veins between the layers. The scales covering the wings give butterflies and moths their distinctive colors and patterns. Scales may contain pigments like those found in skin or fabric that give them their color. Ridges and furrows on the scales may also diffract light like a prism, producing metallic and iridescent hues called structural colors. The scales rub off easily when a lepidopteran's wings are touched. The third body part, the abdomen, is tubelike in shape and usually consists of ten segments. Inside the abdomen are the lepidopteran's heart, respiratory and digestive systems, and reproductive organs. The heart, a muscular tube that runs the length of the abdomen, pumps blood toward the front of the body. Oxygen enters the body through six to seven pairs of breathing holes known as spiracles, located on the sides of the abdomen. The spiracles are connected to a network of tubules called tracheae, which deliver oxygen to the tissues. In females, the reproductive organs take up most of the abdomen. Their abdomens tend to be fuller and blunter than those of the males because of the large number of eggs inside. The smallest butterflies are certain blues that have wingspans of a mere 0.7 cm (0.25 in). The largest are the female giant birdwings of Papua New Guinea, which measure up to 30 cm (12 in) across. Moths range in size from tiny Microlepidoptera, several groups of small moths with wings no more than 0.16 cm (0.06 in) across, to giant silk moths, such as the atlas moth, which may exceed 30 cm (12 in) in wingspan. IV REPRODUCTION AND LIFE CYCLE Butterflies locate potential mates by sight, identifying the wing colors and patterns characteristic of their species. In some types of butterflies, males and females display different patterns on their wings. In other species, the wing markings look the same to the human eye. But either the males or females often have scales on their wings that reflect ultraviolet light, producing patterns that enable the butterflies to distinguish one sex from the other. During the breeding season the males of some species stake out territories, where they perch and watch for females. Once a male and female butterfly locate each other, the male initiates a courtship dance. Scientists believe that this ritual exposes the female to pheromones, chemical signals released by the male that induce the female to mate. Males of many species have patches of specialized scales called androconia on their wings, thorax, or abdomen that release pheromones. Females also release pheromones from their abdomens. The butterflies sense each other's pheromones with the smelling organs on their antennae. During the courtship ritual, the male may flutter around the female or bump her with his wings or body. The pair may also alight on a plant or other perch and stroke each other with their antennae. In some species the courtship ritual is elaborate, but in most it is simple and brief. Moths, creatures that are often drab in color and active at night, rely primarily on smell to find mates. In many moth species the female releases pheromones, and the chemicals become plumes of scent on the wind that advertise her presence. When a male detects a female's pheromones with his sensitive antennae, he responds by flying directly upwind toward the source of the scent. Some silk moths are able to detect the scent of the females from 10 to 20 km (6 to 12 mi) or more away. Lepidopterans mate by perching and bringing the tips of their abdomens together. The male holds the female tightly with handlike structures on his abdomen called claspers, and if threatened the pair can fly away while still maintaining their embrace. Mating lasts from several minutes to several hours, depending on the species. The male uses his penis to pass to the female a spermatophore, a package containing sperm (male sex cells) and nutrients. The spermatophore's weight may be up to 10 percent of the male's body weight. The generous supply of nutrients it contains helps sustain the female as she lays her eggs. After mating, sperm are stored in the female's reproductive tract. Fertilization, or union of the sperm and egg, takes place just before each egg is laid. Female butterflies and moths usually lay their eggs on or near plants suitable for the young to eat. Many species deposit their eggs singly on the plant's leaves. Others, such as tiger moths and checkerspot butterflies, lay their eggs in large clusters, often ringing the stem. Most eggs hatch from two or three days to a month or more after they are laid. Some eggs laid in the fall do not hatch until the next spring. The egg hatches into a larva called a caterpillar, which has a cylindrical body and mouthparts designed for chewing. Like an adult lepidopteran, a caterpillar has three pairs of legs on its front segments. Most types also have five pairs of leglike structures called prolegs on the rear segments. After hatching, the caterpillar usually consumes its eggshell and then begins feeding on the leaves, buds, or flowers of its host plant. Some species have more unusual habits, boring into the stems or roots of plants or feeding on stored grain. A few types of caterpillars eat other insects, especially aphids or ant larvae. Some caterpillars are tended and protected by ants, and in return provide the ants with honeydew, a sweet, nutritious substance that the ants use as food. Caterpillars are voracious eaters and grow rapidly. Most types molt, or shed their skin, four or five times as they grow. Each time they molt they enter a new growth phase, called an instar. When a caterpillar reaches its full size, it prepares to complete its metamorphosis, the radical change in body form that turns a caterpillar into a butterfly. Metamorphosis takes place inside the pupa, or chrysalis, a hard, sometimes thorny, oval structure. Most caterpillars pupate by attaching themselves to a twig or other support. To anchor themselves to the support they spin a button of silk from their mouthparts, then grasp the silk button with the cremaster, a clawlike structure at the end of the abdomen. Hanging from the twig, the caterpillar sheds its skin to reveal the pupa underneath. Most moth caterpillars spin a cocoon of silk around their bodies before becoming a pupa. The cocoon helps protect the pupa from predators and from drying out. Within the pupa, the tissues and organs of the caterpillar break down into a soupy liquid, and then reassemble into the tissues and organs of the adult butterfly. Groups of cells known as the imaginal discs remain complete, and the adult butterfly's structure takes shape as directed by these cells. The imaginal discs work in tandem with hormones, chemical messengers that carry information between different parts of the body, to program the insect's development, much as silicon chips direct the operation of a computer. The pupal stage may last anywhere from one week to several years, depending on the species and the weather. When its development is complete, the adult butterfly or moth splits the pupal shell and crawls out. It unfolds its wings and pumps blood into the veins, then holds the wings spread out like a kite until they dry and harden. The animal is then ready to fly off, feed, and mate. Most adult butterflies and moths live just one or two weeks. A few types, such as anglewings and the migratory generation of monarchs, may live six months or more. V DIET Adult butterflies and moths feed mainly on flower nectar and other sugars, such as those contained in the sap of wounded trees, rotting fruit, and fluids excreted by certain vines. The males of many butterfly species have additional nutritional requirements. They commonly flock to mud puddles to suck up dissolved salts. They also feed on vertebrate feces and dead animals in order to obtain nutrients such as carbon, nitrogen, and amino acids. Some groups of lepidopterans have unusual eating habits. A few species, such as silk moths, have no functional mouthparts and do not feed as adults. Longwing butterflies found in tropical regions of the western hemisphere and a group of moths called micropterygids live on pollen as well as than nectar. Longwings collect a ring of pollen around the proboscis, then moisten the pollen with saliva and swallow it. This diet is rich in protein and enables the longwings to live for several months--much longer than most butterflies--and to continue to produce eggs and sperm throughout their lifetimes. Butterflies and moths locate flowers and other sources of food by vision, smell (using their antennae), and taste (using the hairlike structures on their feet). Once a butterfly or moth finds a food source, it uncoils its strawlike proboscis and sucks the nectar or other food into its mouth. The length of a lepidopteran's proboscis determines which flowers it relies on for food. When nectar is located deep in a flower, as in nasturtiums, columbines, and many lilies, the only lepidopterans that can reach it are those with long proboscises, such as hawk moths (also known as hummingbird moths or sphinx moths). Many butterflies and moths naturally serve as pollinators for the plants they visit for nectar, playing a key role in the life cycle of these plants (see Pollination). As they move from flower to flower gathering nectar, butterflies and moths often transfer pollen grains, which contain a plant's male sex cells, from one flower to another. In this way, as the insects find food, they help the plants to reproduce. Over thousands of years, close relationships have evolved between some flowering plants and certain species of butterflies and moths. For example, yucca plants of the southwestern region of the United States are pollinated only by yucca moths, and each species of yucca is pollinated by a particular species of moth. After entering a flower, a female yucca moth assembles a sticky mass of pollen with her mouthparts. While laying an egg in the flower, she rubs the pollen on the stigma, or female part of the flower. When the caterpillar hatches it eats some of the yucca flower's seeds, and the remaining seeds grow into the next generation of yucca plants. This arrangement benefits both species. Without yucca moths, yuccas would be unable to reproduce; without yuccas, yucca moth caterpillars would be without food. VI ENEMIES AND DEFENSES Adult butterflies and moths are preyed upon by birds, bats, lizards, spiders, and various insects, including dragonflies, ambush bugs, robber flies, and praying mantids (see Mantis). Birds are the most important enemies of butterflies, while moths suffer heavy predation by bats. Lepidopterans have evolved many strategies to evade their predators. One strategy, particularly common among moths, is camouflage or cryptic coloration. The wings of many moths blend in with the tree trunks where the moths perch during the day. The color patterns of both the bark and the lichens or mosses that grow on the bark may be copied in detail on the moth's wings. Many moths settle most often on the kinds of trees they most closely resemble, frequently with an orientation that matches the up-and-down pattern of a tree trunk. Once settled, the moths are practically invisible to birds and other daytime predators. Other species have evolved mechanisms to startle or confuse potential predators. Perched at rest on a tree trunk, anglewing butterflies display the underside of their wings and underwing moths show the upper surface of their forewings. In this position, each species is elegantly camouflaged against the bark. But if a bird comes too close, anglewings flash the bright, rust-colored upper side of their wings, and underwing moths move their forewings aside to reveal crimson, orange, or yellow hind wings. This surprise show of color startles the bird long enough for the insect to make its getaway. Many lepidopterans, such as swallowtails, hairstreaks, and urania moths, have tail-like shapes on their hind wings; others, including wood nymphs and ringlets, have bright eyespots near the outer edges of their wings. These tail-like shapes and spots serve as decoys--birds tend to strike at these wing shapes rather than at the vital parts of the lepidopteran's body, so the insect is more likely to survive a bird attack. In certain species, such as owl butterflies and io moths, the eyespots may be large enough to intimidate predatory birds. Some species deter birds and other predators because they are poisonous or not tasty to eat. Butterflies of this sort are often marked with yellow, orange, or red on a dark background to warn predators of their unpalatability, and birds learn to avoid these patterns. A familiar example of warning coloration is the striking rust and black pattern on the wings of the monarch butterfly, which is distasteful to birds because it feeds on poisonous milkweed plants as a caterpillar. Another form of defense in butterflies and moths involves mimicry. In Batesian mimicry, a perfectly tasty species, the mimic, closely resembles a distasteful type, the model, that birds have learned to avoid. In Muellerian mimicry, two distasteful species resemble each other, and predators need to learn only one danger-signaling pattern to avoid. The most familiar example of butterfly mimicry is that of the monarch and viceroy, which have similar rust and black markings. The monarch-viceroy mimicry was once considered Batesian, but scientists now know that it is Muellerian, with the viceroy as well as the monarch being distasteful to birds. In the tropics, many complex relationships known as mimicry rings have evolved. A mimicry ring involves many species of lepidopterans and sometimes other insects--some unpalatable, some not--that all have similar patterns and colors on their wings. Many moths have developed sensory organs to help them evade bat predators. They have hearing organs often located near the middle of the body or elsewhere and are able to detect the high-pitched sounds bats use to navigate and find prey in the dark. Some moths even produce sounds that interfere with the bats' navigation system, which is known as echolocation. Birds consume a great many caterpillars of both butterfly and moth species. However, the greatest enemies of caterpillars are parasites. Certain wasps and flies lay their eggs on caterpillars, and sometimes on eggs and pupae as well. When the parasites hatch they burrow into the caterpillar and consume the caterpillar's tissues from within, eventually killing it. Caterpillars have evolved numerous defenses against birds and parasites, including many of the same strategies used by adults. Many caterpillars are colored brown or green to blend in with the plants where they live. Caterpillars may also have markings on their bodies that look like large, reptilian eyes. These eyespots may intimidate potential predators. Monarch caterpillars, like the adults, taste bad to birds because they feed on milkweed, a plant that contains chemicals that are poisonous to birds. Swallowtail caterpillars have orange, strong-smelling, antlerlike structures called osmeteria behind their heads that they protrude when bothered. Other caterpillars have stinging hairs to deter predators. Some pupae vibrate rapidly to repel parasites. VII HIBERNATION AND MIGRATION Butterflies and moths are dependent on outside warmth for most of their body temperature and the vegetation they depend on dies off in winter, so species that live in temperate regions adapt to cold weather either by hibernation or migration (see Animal Migration). Lepidopterans that pass the winter in cold regions enter a state of reduced metabolism called diapause, in which their body systems all but close down. They may enter diapause in any life stage, depending on the species. Species that overwinter as eggs or caterpillars accumulate chemicals similar to antifreeze inside their bodies when the weather begins to turn cold. The chemicals prevent ice crystals from forming in their cells and damaging tissues. Other species spend the winter as pupae, butterflies as a naked chrysalis and many moths within a silken cocoon. A few moths and butterflies hibernate as adults, such as anglewings, tortoiseshells, and the brimstone butterfly of Europe and Asia. Taking shelter in a hollow tree, a shed, or under a bank, these hardy species may fly on unseasonably warm days in midwinter. Often they are the earliest of all butterflies to reappear in the spring. Only a few lepidopterans conduct a regular, back-and-forth, birdlike migration. The most famous butterfly migrant is the monarch. It lives throughout the continental United States and southern Canada during the summer. In the fall, adult monarchs migrate to overwintering sites in the mountains of central Mexico or the California coast. An individual monarch may fly 3,000 km (2,000 mi) or more on this journey. The adults mate in the spring and begin to fly northward, the females laying their eggs along the way. Most of these butterflies die before reaching their old summer grounds, but the next generation of monarchs hatches from the eggs laid on the way by returning females and continues the flight north. In this way, the children and grandchildren of the overwintering monarchs recolonize the continent. The monarch's annual exodus and return is one of the most spectacular and poorly understood migrations of any animal. Many butterflies and moths emigrate from tropical and subtropical latitudes into temperate regions each year. For example, during the winter painted lady butterflies are found in North Africa and Mexico. In the spring, the butterflies begin to move northward, colonizing the northern hemisphere over the course of several short generations much as monarchs do. In summer painted ladies can be found as far north as northern Finland and Alaska. Migrating painted lady populations vary in size from year to year because of changes in the butterflies' food supply and other factors. The butterflies migrate in such huge, low-flying groups that their migrations may close highways and cause other disruptions. Most of these individuals perish when cold temperatures return in the autumn rather than flying south again. VIII IMPORTANCE AND CONSERVATION Moths (and, to a lesser extent, butterflies) are a major component in many food chains because they are so numerous. Many songbird and bat populations depend in large part on moth caterpillars and adults for nourishment. Certain human cultures also harvest caterpillars for food. Lepidopterans are also an important part of many countries' economies. The cultivation of domestic silk moths for the fiber in their cocoons has been a major industry in Asian countries for many centuries. When unraveled, each silk moth cocoon yields hundreds of meters of strong, durable silk fiber that absorbs colors beautifully and weaves into a soft, glossy fabric. More recently, butterfly farming to provide specimens for collectors and live pupae for butterfly houses has become an important source of income in tropical countries, particularly Papua New Guinea and Costa Rica. Ecotourism by butterfly watchers has become common in developing countries, especially Mexico. There, tourists drawn by the overwintering monarchs provide a source of income for local residents who might otherwise log the trees where the butterflies roost during the winter. Perhaps the greatest economic and ecological importance of lepidopterans comes from their worldwide function as pollinators of crops and wild plants. Only a few butterflies are considered destructive. The cabbage butterfly damages cabbage, broccoli, and related crops. The caterpillar of the giant swallowtail, known as the orange dog, feeds on citrus plants and sometimes damages commercial citrus crops. Many more moths than butterflies are regarded as pests. The caterpillars of some moths attack grain and other stored food. The larvae of clothes moths chew holes in clothing made of wool and other natural fibers. Cutworms destroy the roots of many different crops, including cabbage, corn, cotton, and tomatoes. Spruce budworms strip the needles from spruce and other conifer trees, and codling moths destroy apple crops. Tent caterpillars make ugly webs in ornamental trees. Many lepidopteran pests are species that have been introduced to a new area by humans and grow into large populations because they lack natural enemies in their new home. The gypsy moth, native to Europe, was accidentally introduced into New England during the late 1860s. Since then, gypsy moth caterpillars have caused widespread damage, devouring the leaves of trees in parks, gardens, and woodlands throughout North America. Although some moths are destructive pests, many more species are benign or beneficial to humans. Human activities such as farming, logging, and development threaten many butterfly and moth species. The Xerces blue, the first North American butterfly to die out because of human activities, became extinct in San Francisco in 1943 (see Extinction). It gave its name to the Xerces Society, the international organization for conservation of rare invertebrates and their habitats. Today, several West Coast butterflies related to the Xerces blue are endangered due to human population growth. Other endangered lepidopterans in the United States include the Oregon silverspot, native to oceanfront habitats that have been developed for human use; the Uncompahgre fritillary, which lives in the San Juan Mountains of Colorado and is threatened by livestock grazing and, perhaps, by global warming; and Schaus' swallowtail, at risk due to coastal development and heavy use of pesticides to control mosquitoes in Florida. In tropical rain forests, where lepidopterans reach their highest diversity, logging and burning to clear forests for agriculture place many different species in jeopardy. Queen Alexandra's birdwing, the largest butterfly in the world, is gravely endangered because of the destruction of forests on the coast of Papua New Guinea for timber and oil palm plantations. The annual migration of monarch butterflies is a threatened phenomenon. Logging and development threaten the monarch's winter roosts in Mexico and California. Meanwhile, the butterfly's North American breeding grounds are being destroyed to build roads, houses, and shopping malls. Pesticides kill milkweed, the plant monarch caterpillars depend on for food, and also kill the monarchs themselves. IX BUTTERFLY COLLECTING, WATCHING, AND GARDENING Many people enjoy collecting butterflies, a hobby that offers close contact with the outdoors, exercise, and a means of gaining firsthand knowledge of nature. Collectors help scientists learn about lepidopterans by documenting the whereabouts of native butterflies, which helps scientists understand the insects' conservation needs. Butterfly collectors commonly use a net to capture adult butterflies in the wild, carefully observing and stalking the insects in sunny spots where nectar flowers grow or around mud puddles or streams. When the butterfly alights to sip nectar or bask in the sun, the collector swings the net quickly, flipping it to trap the insect within. Moths are usually hunted at night, using ultraviolet lightbulbs or syrupy baits to draw them. Many scientists believe that moths fly toward light because the light disorients them, not because they are attracted to it as is often said. After a moth or butterfly is caught, it should be placed in a protective envelope with tweezers to prevent damage to the wings, then frozen overnight to kill it. This method avoids the use of poisons to kill the specimen. The butterfly or moth is then mounted on a grooved board with a long insect pin inserted through the thorax. Collectors typically label their specimens with the location and date of capture and the name of the collector, and often record additional information about the insect's habitat and behavior. Lepidopterans reproduce very quickly and in large numbers, so butterfly collecting usually poses no threat to butterfly populations. However, collectors need to be aware of collecting guidelines recommended by associations such as the Lepidopterists' Society and the Xerces Society. These common-sense guidelines call for collectors to take no more specimens than are needed, collect fewer females than males, and use care to minimize disruption of butterfly habitats. Collectors must also observe all relevant laws and regulations. Permits to collect butterflies and moths are required in many United States parks and reserves and in many foreign countries, and they should be obtained before netting a single insect. Endangered species should never be collected. Another rewarding activity is to raise butterflies and moths from eggs or larvae. Lepidopteran eggs and caterpillars can often be found on the food plants eaten by each species--for example, red admiral caterpillars are found on nettles and black swallowtails on fennel. The caterpillars can be reared in a netted enclosure with a plentiful supply of their food plant and fresh air to avoid mold. Raising butterflies and moths this way enables a person to observe caterpillars molting and adults emerging from the chrysalis. After the adult emerges, it may be frozen for a collection or released into the area where the egg or caterpillar was found. In recent years, butterfly watching, photography, and gardening have become popular as hobbies that do not require killing the admired insects. Butterfly watching is much like birding, with the watcher tracking and observing the insects with close-focusing binoculars. Some watchers capture the butterflies with a net and then release them after examining them up close. The butterfly watcher's techniques of tracking and careful observation also lend themselves to photographing butterflies, which may be approached closely with care. Butterfly gardeners attract the desired insects to visit and breed in their own yards by planting nectar flowers--such as butterfly bush, verbena, and zinnia--and larval host plants--such as hollyhock, sassafras, and willow--suitable for native butterflies. Scientific classification: Butterflies and moths comprise the order Lepidoptera within the class Insecta and the phylum Arthropoda. Butterflies are broken down into two main groups, or superfamilies: the Hesperioidea (skippers) and the Papilionoidea (true butterflies or scudders). Together, these two superfamilies are called Rhopalocera. Swallowtails are members of the genus Papilio in the family Papilionidae. The Xerces blue (Glaucopsyche xerces) and other blues, coppers, and hairstreaks are all grouped together in the family Lycaenidae. The painted lady is classified as Vanessa cardui, the viceroy as Limenitis archippus, and the monarch as Danaus plexippus. All three are members of a large family called the Nymphalidae. Moths as a group include 21 superfamilies, known collectively as Heterocera. Microlepidoptera is a general term applied to many families of small moths, including the pollen-chewing family Micropterygidae, clothes moths (genus Tineola), and yucca moths (genus Tegeticula). The domestic silk moth, classified as Bombyx mori, is in the family Bombycidae. Underwing moths (genus Catocala) and cutworms belong to the family Noctuidae. The gypsy moth (Lymantria dispar) is classified within the family Lymantriidae. Contributed By: Robert Michael Pyle Microsoft ® Encarta ® 2009. © 1993-2008 Microsoft Corporation. All rights reserved.