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Butterfly Frequently Asked Questions
Questions answered by Dr. Paul Opler, Biological Resources Discipline, U.S. Geological Survey
Ask a Question about ButterfliesNOTE: Please carefully read through the questions listed below before you submit a question. Your question(s) may have already been answered below.
Questions:
1- What are butterflies and moths?
2- How many kinds of butterflies and moths are there?
3- What is the difference between butterflies and moths?
4- What is the life cycle of butterflies and moths?
5- Where can I find butterflies and moths?
6- How can I catch a butterfly or moth?
7- Why are butterfly and moth wings so delicate? How are they made?
8- Why do some butterfly and moth wings have such brilliant colors?
9- Are there endangered butterflies and moths?
10- Where can I find out more about butterflies and moths?
11- How can I raise a caterpillar?
12- Where can I buy caterpillars?
13- How do butterflies go to the bathroom?
14- Are butterflies poisonous?
15- Do caterpillars have teeth?
16- How does a caterpillar turn into a butterfly?
19- Where do butterflies go when it rains?
20- Do caterpillars have ears? Do butterflies have ears?
21- Why are butterflies and moths such good insects? Why does everyone love them?
23- Why do caterpillars turn into butterflies?
24- Why do they have dust on their wings?
25- How do butterflies communicate? Is it like honeybees?
26- How high do butterflies fly? How fast do butterflies fly?
27- Why do butterflies look the same on both sides?
28- Which butterflies are poisonous?
29- Can butterflies be damaged by handling? Can you damage a cocoon by handling it?
30- How did butterflies get their name? Why are they called "butterflies"?
31- How much do butterflies weigh?
32- How long do butterflies live?
33- How does one tell the difference between male and female butterflies?
34- Do butterflies have brains and hearts?
35- Do caterpillars drink water?
36- Do butterflies sleep or take brief naps? What is sleep to a butterfly?
38- How do caterpillars "know" when its time to turn into a chrysalis?
39- Do caterpillars hide somewhere at night or are they eaten by birds?
40- How many legs does a caterpillar have?
41- How do I identify a caterpillar?
42- Are butterflies pollinators?
Did you find the answer to your
question? If not, you can submit a question to Dr. Opler our Lepidopteran
expert who replies to your butterfly and moth questions via e-mail at:
paulevi@webaccess.net.
Please note that Dr. Opler has recently "retired" and is frequently
in the field working on butterfly research around the world. Because
he is out of the office for extended periods, there will be a 1-2 week
minimum delay in answering your questions. In addition,
since we receive so many questions on a daily basis we are no longer
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Please do not submit your questions via the FORT comment form.
Q1: What are butterflies and moths?
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A1: Butterflies and moths are 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. Lepidoptera is derived from the Latin "lepido"= scale + "ptera" = wing. Of course there are exceptions; some moths have wingless adults and some primitive moths lack a proboscis.
Q2: How many kinds of butterflies and moths are there?
A2: Butterflies and moths are found on all continents except Antarctica, and scientists estimate that there are approximately 12-15,000 species of butterflies and 150-250,000 species of moths. There are still thousands of moth and butterfly species that have not been found or described by scientists. In the United States and Canada, more than 750 species of butterflies and 11,000 species of moths have been recorded. Many species of moths and a few kinds of butterflies are still being discovered. There is much to be learned.
Q3: What is the difference between butterflies and moths?
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A3: Butterflies are mostly brightly colored day-flying insects with long clubbed antennae and most moths fly at night and lack clubs at the end of their antennae. A group of tropical "moths" has been found that are closely related to butterflies but they lack clubs on their antennae; they are now considered to be butterflies. Perhaps the best answer that matches our current knowledge is just to say that butterflies are "fancy moths."
Q4: What is the life cycle of butterflies and moths?
A4: View The Butterfly and Moth Life Cycle Page
Q5: Where can I find butterflies and moths?
A5: Butterflies and moths are found during the warmer months of the year in many different environments. In most places, May to August are the best months, and you will do well looking in sunny exposed places with low plants. Many national parks, wildlife refuges, or other wild places are usually rich in butterfly species. Your local city or county park may have planted a butterfly garden to attract butterflies in the summer or you may want to visit the nearest insect zoo or butterfly house where hundreds of living exotic insects and butterflies are on display.
Q6: How can I catch a butterfly or moth?
A6: The best way to "catch" a butterfly or moth is to raise it from the caterpillar stage. Then when the butterfly or moth hatches out you can observe it and then let it go. Some stores provide kits that have a net with them, and you can go into fields or mountains and catch butterflies or moths. Since most moths are attracted to lights, you can find moths at porch lights (if you use a white bulb--not yellow) or other lights. Keeping a butterfly or moth collection requires that you follow special techniques and lots of care. The best way to learn about insect collections is to join a local 4-H club*. Today, many people prefer to watch butterflies and moths with small close-focusing binoculars or to photograph the living insects. Photographing a live butterfly in nature can be more challenging than netting one, and you can keep your "collection" in a photo album or color slide tray.
See the National 4-H Council Homepage. Some sample on-line resources:
4-H Entomology Projects: Leader's Guide
Agricultural Education, Communication, & 4-H Youth Development at Oklahoma State
Iowa State University Extension to Youth and 4-H
Q7: Why are butterfly and moth wings so delicate? How are they made?
A7: Butterfly and moth wings are made of thin layers of chitin--the same hardened protein that makes up their outside body--and are covered with thousands of tiny scales that lend color to the wings. The wings are strengthened by a system of veins. The wings have to be strong enough to support the body in the air, but still flexible enough for flight movements.
Q8: Why do some butterfly and moth wings have such brilliant colors?
A8: The colors of butterfly and moth wings may serve several purposes. Colors are often used in courtship, so that male and female butterflies recognize each other as the correct species. Bright colors may also serve to warn birds or other predators that a particular butterfly, such as a Monarch, is bad-tasting. Other butterflies and moths, although perfectly edible, may have colors that "mimic" the bad-tasting species and thereby gain protection for themselves. Finally, certain color patterns may help the butterfly or moth blend into its background and be protected from birds or other would-be predators by "background resemblance."
Q9: Are there endangered butterflies and moths?
A9: There are more than 20 butterflies and moths listed as endangered by the U.S. Fish and Wildlife Service. Most of these species are found in the United States and may become extinct due to loss of their habitat. Some butterflies from other countries, such as some rare birdwing butterflies from New Guinea, are endangered by loss of habitat and by collection of specimens for international trade. Several individual states list and protect declining butterflies and moths in their state. Contact your local wildlife or conservation office to find out what you can do to conserve butterflies and moths.
Q10: Where can I find out more about butterflies and moths?
A10: I don't think there is too much on the web about Lepidoptera that would give you a basic view of the group outside our website. There is nothing now on the group as a whole. If you want an introduction try the introduction to Covell's Peterson Field Guide to eastern Moths or the introductory chapters to my Field Guide to Eastern Butterflies. More inclusive would be the introduction to my book Butterflies East of the Great Plains. The very best now would be Malcolm Scoble's book Lepidoptera.
See the Children's Butterfly Site Butterfly Related Websites.
Q11: How can I raise a caterpillar?
A11: To raise a caterpillar through the chrysalis or pupa to the adult moth or butterfly is an excellent lesson about insect metamorphosis. All you need is a caterpillar, some of its favored food, and a suitable container. You can find caterpillars on most plants during the spring and early summer. Put the caterpillar and a few fresh leaves in a wide mouth jar or plastic shoebox. Cover the jar mouth with netting or a piece of nylon. Every day change the leaves and provide dry paper towels to help prevent mold. You can put in pencil-size twigs upon which the caterpillar can attach its chrysalis or silken cocoon (with the pupa inside). The insect will hatch in 10-14 days, if it does not over winter. Before releasing it you can photograph your prize. Don't be disappointed if small wasps or flies--natural parasites--hatch out instead. These insects keep the butterfly and moth populations under natural control.
Additional information on how to Raise a Caterpillar.
Q12: Where can I buy caterpillars?
A12: If you can't find a caterpillar or need to provide caterpillars for an entire class, there are several places where they may be purchased together with an artificial food source. Monarch caterpillars and rearing instructions may be purchased from Monarch Watch , and Painted Lady caterpillars are available from several commercial sources listed at the "Butterfly Website."
Q13: How do butterflies go to the bathroom?
A13: Adult butterflies do not go to the bathroom. Caterpillars do all of the eating and almost continually defecate. Occasionally adult butterflies drink so much they must emit a fine liquid spray from the tip of their abdomen but it is almost pure water.
Q14: Are butterflies poisonous?
A14: Some butterflies such as the Monarch and Pipevine Swallowtail eat poisonous plants as caterpillars and are poisonous themselves as adult butterflies. Birds learn not to eat them. Other good-tasting butterflies (called "mimics") come to resemble them and thus benefit from this "umbrella" of protection.
Q15: Do caterpillars have teeth?
A15: Caterpillars have opposable toothed mandibles to chew their food. These can be seen with a magnifying glass.
Q16: How does a caterpillar turn into a butterfly?
A16: This is not easy to explain. You can say that inside the chrysalis the caterpillar changes clothes and turns into a butterfly. (An esoteric explanation: Inside the chrysalis the caterpillar structures are broken down chemically and the adult's new structures are formed).
Q17: Do butterflies eat bugs?
A17: As I mentioned the caterpillars do most of the eating. Almost all caterpillars eat plant parts, but a few are carnivorous. Caterpillars of the carnivorous Harvester butterfly of the eastern U.S. eat wooly aphids. The adult female butterfly lays her eggs in the middle of aphid masses.
Q18: What do butterflies eat?
A18: With few exceptions, adult butterflies eat only various liquids to maintain their water balance and energy stores. Most butterfly adults sip flower nectar, but other imbibe fluids from sap flowers on trees, rotting fruits, bird droppings, or animal dung. Many adult butterflies are found drinking fluids at wet sand or mud, especially along stream courses or the edges of dirt roads or trails. Some exceptions are the adults of longwing butterflies such as the Zebra are able to collect pollen from certain flowers with their proboscis and to break it down and absorb amino acids (proteins) which contribute to the ability to survive, mate and lay eggs for long periods (6 months or so). With their short proboscis (tongue) the adults of Harvester butterflies can actually pierce the bodies of woolly aphids and drink their fluids--this would be the only bugs that adult butterflies eat. The caterpillar of almost all butterflies eat various parts of plants. Each species may specialize of only a few kinds of plants or plant parts. The caterpillars of the Harvester butterfly and its relatives are exceptions in that they feed solely on aphids.
Q19: Where do butterflies go when it rains?
A19: Butterflies hide when it rains. They usually go to the same places they do for the night. Some butterflies hide under large leaves, some crawl down into dense leaves or under rocks, and some just sit head down on grass stems or bushes with wings held tightly. If the rains are exceptionally hard or of long duration many of the butterflies become tattered or die.
Q20: Do caterpillars have ears?
A20: (Kristi Crawford's Second Grade Class asks, "Do caterpillars have ears? If so, where? Can we see them?") No, caterpillars do not have ears. In fact only some moths have "ear." These are not easily seen. Many adult moths and butterflies have motion stability sensors in their antennae.
Q21: Why are butterflies and moths such good insects? Why does everyone love them?
A21: I can only answer for myself not everybody! But my guess is that butterflies are obvious bright-colored objects in our environment. They are believed to be free spirits in their flight and lack on constraints. They are also thought of as harmless, innocent creatures. They also contribute significantly to pollination of many wildflowers.
Q22: How do butterflies fly?
A22: Butterflies have strong muscles in their thorax which force their wings up and down on a fulcrum basis. They actually go in a slanted figure 8 motion that propels them forward through the air in the same principle as an airplane.
Q23: Why do caterpillars turn into butterflies?
A23: Caterpillars are the eating and growing stage for the butterfly, but they cannot mate and reproduce. The adult butterfly is both the mating and egg-laying stage of the beautiful insect. Also adult butterflies can disperse by flight, sometimes long distances, to either colonize new areas with fresh plants for the caterpillars or even migrate long distances to escape our freezing winters, such as Monarchs flying to Mexico or coastal California for the winter.
Q24: Why do they have dust on their wings?
A24: The dust on butterfly wings are modified hairs called scales. The scales have at least 4 functions, not necessarily on the same butterfly species:
(a) They form patterns of bright colors, sometimes with hidden ultraviolet pattern, that are used as signals to the other sex in attraction for mating.
(b) The bright colors are used to advertise particular butterfly's bad tastes to predators. This protects them from being eaten.
(c) The scales may form patterns that help the butterflies blend into their background and thus escape being eaten by birds or other animals by background resemblance.
(d). Dark colors formed by the scales can be used by butterflies to soak up warmth from the sun that allows their bodies to warm up to flight temperatures in cool seasons or cool environments. Remember butterflies are cold-blooded.
Q25: How do butterflies communicate? Is it like honeybees?
A25: Butterflies do not communicate like honeybees but they use some of the same kinds of communication. Butterflies can communicate with each other [same or different species] by color, chemicals, sound, and physical actions. Color patterns are used to signal their sex or species to each other. Chemical pheromones are used by both sexes of some butterflies to attract the opposite sex or to signal species identity in courtship. A few butterflies make clicking sounds [males of genus Hamadryas] to protect their space. Some chrysalides [gossamer wings family] make clicking sounds to attract ants that in turn protect them. Physical actions such as aggressive flight or postures are used in courtship or to protect resources such as an important flower. Caterpillars of some species produce sugary substances for ants which in turn protect the caterpillars.
Whole books have been written on this topics. This is the briefest, simplest answer I can give.
Q26: How high do butterflies fly? How fast do butterflies fly?
A26: I don't think they've been clocked but certainly some fast-flying skippers can fly 30 mile per hour or faster. Slow flying butterflies probably fly 5 mph or a little more.
During fall migration migrating Monarchs have been seen flying by tall buildings such as the Empire State Building at 1,000+ ft. Butterflies are picked up by storm fronts and moved 100's of miles, probably at altitudes of several thousand feet.
Q27: Why do butterflies look the same on both sides?
A27: Butterflies have very different patterns on the upper and undersides of their wings. Does the questioner mean right and left halves? Just as with people, the right and left halves of butterflies are not exactly the same.
Q28: Which butterflies are poisonous?
A28: No butterflies are so poisonous that they kill people or large animals, but there is an African moth whose caterpillar's fluids are used to poison the tips of arrows. When shot by one of these arrows an antelope can be killed in short order (see recent National Geographic). Other butterflies whose caterpillars eat poisonous plants such as milkweeds, pipevines, and passion vines, are distasteful and can cause birds who eat them to vomit or spit them out--never to try another.
Q29: Can butterflies/cocoons be damaged by handling?
A29: Medium to large butterflies can be safely handled and released by persons who know how to do it. Any butterfly can be fatally damaged by being handled improperly. For example, the vein on the front wing if broken will cause the butterfly to be flightless evermore. Their internal organs can be injured. Although the loss of some wing scales does not harm the butterfly, I personally prefer not to see butterflies in butterfly conservatories with thumb prints on their wings.
Cocoons, a stage in the moth life cycle, are pretty tough as long as nobody squeezes them. Handle them carefully by the silk part. Don't handle a chrysalis though, the butterfly's metamorphic stage. They are much more delicate.
Q30: How did butterflies get their name? Why are they called "Butterflies"?
A30: No one knows for sure, since the word has been in the English language for centuries (the word was "buterfleoge" in Old English, which means butterfly in our English today). Because it is such an old word, we don't really know who or when someone said "That 'thing' over there is a 'butterfly'." One story is that they were named so because it was thought that butterflies, or witches that took on the shape of butterflies, stole milk and butter. (Someone else wondered if the word was really meant to be "flutter-by" <smile>). In other languages, the word for our fluttery friends has no such derivation as "butter" + "fly". One can only speculate on why the English language uses such an unlikely name.
Q31: How much do butterflies weigh?
A31: I have some information on butterfly weights but not exact weights for the largest and smallest butterflies. However, I can make pretty good guesses. I have weights ranging from 0.3 gram for a large swallowtail to 0.04 gram for a small butterfly called the elf. My guess is that the female Queen Victoria Birdwing, the world's largest butterfly, would weigh 2 or 3 grams and one of the World's smallest butterflies, the Pygmy Blue, would weigh only a few thousandths of a gram.
Q32: How long do butterflies live?
A32: Different butterfly species have different adult potential life spans. By marking butterflies then recapturing or sighting them later scientists gain information on how long butterflies can live. An average butterfly species has an adult life span of 2 weeks or less. For example one butterfly studied in Costa Rica had a life expectancy of about 2 days, and live 10 days at the most. No adult butterfly can live more than a year. The Mourning Cloak adult and some related tortoiseshells and anglewings that hatch in early summer may live almost a year. It over winters as an adult and then waits to court, mate and lay eggs the following spring or early summer. Monarchs and Swallowtails may live about a month in the summer, but the Monarchs that migrate to Mexico or the California coast may live up to 6 months. Some long-lived tropical butterflies live up to 6 months as adults. The long-life champion is a tiny yucca moth that feeds on Banana Yucca (Yucca baccata). Dr. Jerry Powell of the University of California at Berkeley has found this moth's caterpillar may be able to wait up until 30 years to form a pupa and emerge as an adult.
Q33: How does one tell the difference between male and female butterflies?
A33: The color pattern on the upper wing surfaces often differs in many species of butterflies. For example the males of Blues is often bright blue, whereas that of females has lots of brown.
Another good way is by behavior. Males are often perching or patrolling in search of females, and females spend a lot time searching out plants to lay their eggs on.
The final and definitive way is to examine the abdomen. That of females tends to be rounder. Males have a slit at the tip and females have a round holes where the eggs are laid. It is especially difficult to separate the sexes of some brushfoots such as mourning cloaks and tortoiseshells.
Q34: Do butterflies have brains and hearts?
A34: Yes butterflies and all other insects have both a brain and a heart. The center of a butterfly's nervous system is the subesophageal ganglion and is located in the insect's thorax, not its head. The butterfly has a long chambered heart that runs the length of it's body on the upper side. It pumps hemolymph (it lacks the red color of blood) from the rear of the insect forward to bathe its internal organs. It has other functions similar to our blood.
Q35: Do caterpillars drink water?
A35: Caterpillars don't drink water. They normally obtain sufficient fluids from food plants. Sometimes for over wintering caterpillars, such as tiger moth caterpillars, it is good to add a few drops of moisture to keep them from drying out too much.
Q36: Do butterflies sleep or take brief naps? What is sleep to a butterfly?
A36: When butterflies cannot keep their temperatures at activity levels, when its cloudy, or at night they become quiescent. This quiescence, or resting, is not equivalent to human sleep. Butterflies always have their eyes open, since they do not have eyelids and they probably do not dream. Certainly, I don't know of anyone who has heard of a snoring butterfly! It's probably best just to consider that they become inactive.
Q37: How do butterflies mate?
A37: Male butterflies find females by sight, and use chemicals called pheromones at close range. If the female accepts the male, they couple end to end and may go on a short courtship flight. They may remain coupled for an hour or more, sometimes overnight. The male passes a sperm packet called a spermatorphore to the female. The sperm then fertilize each egg as it passes down the female's egg-laying tube.
Q38: How do caterpillars "know" when its time to turn into a chrysalis?
A38: Caterpillars have a chemical called juvenile hormone in their bodies that is made by their brain. Whenever a caterpillar sheds its skin and the juvenile hormone level is high it goes to the next caterpillar stage. When the juvenile hormone level is low the caterpillar wanders to find a site to make a chrysalis (or a cocoon if its a moth), then it becomes a chrysalis and not another caterpillar stage.
Q39: Do caterpillars hide somewhere at night or are they eaten by birds?
A39: The full-grown caterpillars usually wander off the plant some distance to find a place to make their chrysalis. During the feeding and growth stage they just remain under leaves.
Q40: How many legs does a caterpillar have?
A40: The number of legs that caterpillars can have varies with the kind of caterpillar and sometimes with it's stage. Usually all of the butterflies or moths in the same family will have the same number of legs on their caterpillars, but this is not always the case. The caterpillars of some tiny leaf-mining moths may have no legs at all. Most caterpillars of the larger moths and butterflies have 3 pairs of true legs, and most have 5 pairs of prolegs on their abdomen. So the best answer would be that most often they have 16 legs.
Q41: How do I identify a caterpillar?
A41: The only readily available books are the Peterson First Guide to Caterpillars by Amy Wright published by Houghton Mifflin, and the Golden guide to Butterflies and Moths by Robert T. Mitchell. There are some photos of caterpillars on the Butterflies of North America and the Moth of North American websites served by the USGS Northern Prairie Wildlife Research Center
There are thousands of kinds of moths and over 700 kinds of butterflies in North America and only a few of the caterpillars are illustrated in these sources.
Q42: Are butterflies pollinators?
A42: Actually, most butterflies are not good pollinators of flowers. Pollen does not regularly stick to their legs or tongue (proboscis) and the butterflies do not make proper contact with the flower's stigma. There are probably some notable exceptions to this such as the pollinia (a coherent mass of pollen grains often with a stalk bearing an adhesive disk that clings to insects) of the milkweed flowers sticking to the tongue and legs of Monarch butterflies.
Hope this helps!
Dr. Paul A. Opler
U.S. Geological Survey
Emeritus Scientist
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