Monarch Butterflies: Answers From the Expert

Monarch Butterflies: Answers from the Expert
Dr. Karen Oberhauser, University of Minnesota
April 13, 1995

To: All the students who asked questions.

Thanks for your great questions. I hope that my answers help you understand a little more about this wonderful insect. You'll notice that a lot of my answers are -"I don't know." There are a lot of things that no one knows about monarchs. Some of you asked questions that I've thought of a lot, but either they would be so expensive to study that no one has done it, or no one knows just how to answer the question. A few of you asked questions that I'd never thought of, and those were great! Maybe I'll study how mating affects flying ability, thanks to Farrah from Mrs. Capluzzi's class in Rochester, NY. That was a great question!

Anyway, I think that the fact that there are so many unanswered questions should make you all happy. In case you decide to study monarchs, or other butterflies, when you're older, there will be plenty of things left for you to do! Maybe you'll think of amazing questions that no has thought of before, or maybe you'll think of amazing ways to answer questions that no has figured out how to answer. That's really all scientists do.

Have a great spring, all of you. I hope you all see monarchs!

Karen Oberhauser

From MINNESOTA: Q. How do monarch butterflies breath? (Laura and Jessalyn)

A. When you breathe, oxygen goes into your lungs and is picked up by your blood which carries it to cells throughout your body. Because vertebrates are generally pretty big, we need this complicated system. But insects are so small that tiny air tubes (called tracheae) can carry air from the outside directly to body tissues. Air enters and leaves these tubes through small holes (called spiracles) on the outside of the thorax and abdomen (the two body parts behind the head). This is true of the larvae, pupae and adults in monarch butterflies.

Q. Why do butterflies have the same design on there wings? (Laura)

A. Do you mean all monarchs, or all butterflies? Butterflies have an amazing variety of designs on their wings, but in some cases different species may look similar to humans. In some cases one species may mimic another one that tastes bad to predators. In other cases closely related species may look similar - the queen butterfly is closely related to monarchs and is very similar. If you mean why do all monarchs have the same design, it is because they are genetically programmed to have this design.

Q. Why don't they chew? (Miguel)

A. All butterflies and most moths can only take in liquid food through their long tongue, called a proboscis. They do not have the right mouthparts for chewing.

Q. Hello we would like to know how manarchs get those little scales on there wings? (Mike & Scott)

A. The scales form during the pupal stage of butterflies and moths. This groups of insects, the Lepidoptera, is actually named after the presence of scales - their name means scaly wings. They actually have scales on other parts of their body as well. Only the Lepidoptera have so many scales - their nearest relatives, caddisflies, have a few scales, but nowhere near as many. The scales give the color patterns to butterflies, help to insulate them from cold temperatures, and make it easier for them to fly.

Q Do butterflies have bones? (John, Daniel and Jenna)

A. No. All insects have an exoskeleton which provides support and protects them.

Q. Why do monarch butterflies have little black marks on their wings? Are they there for a special reason? (Callie)

A. We don't know the function of all of the marks on monarch wings. We do know they are due to black scales in those spots. I think that one of the neatest mysteries in the world is why butterflies have the amazing designs and patterns on their wings. What's even more amazing is that there are parts of these patterns that we can't even see - many butterflies have ultraviolet paterns that are only visible to other butterflies. Humans can't see these patterns.

Q. Why do butterflies have to be in cocoons before they are born? Your Puzzled Writers, Ashley,Megan,and Ashley

A. Butterflies and moths have what is called complete metamorphosis, which means they have four separate life stages: egg, larva (or caterpillar), pupa (or chysallis in butterflies), and adult. The pupa stage that you're asking about is sort of like a resting stage. So many things have to go on during this time as the caterpillar changes into an adult that they spend this time not moving. Also, dveloping such big wings would be hard if it kept moving around.

Q. How do butterflies form antenas? Korey

A. The antennae develop from special cells in the larva's head. This actually starts happening in the larva, but the antennae are only on the outside after the adult emerges.

Q. Why do Monarch butterflies rest in groups on branches after migrating south for the winter? Your friend, Nichole, Kristin

A. There is a limited amount of space on the trees for so many butterflies, so they need to be pretty close together. They might also gain some protection from severe cold by being so close together, and an individual butterfly might have a lower chance of being eaten by a predator in a big group.

Mr. Lawrence's 5th Grade Class,Eagle Lake Elementary Eagle Lake, MN lswing01@eagle.isd77.k12.mn.us

From NEW YORK: Hi. We are students in Mrs. Capluzzi's class at Sherman school in Rochester, NY. We are fifth graders working with the school's enrichment teacher to follow the Journey North project.

Q. How fast can a Monarch fly? from Edith

A. This is a hard question to answer because it is so variable. The speed such a small organism can fly will depend a lot on the wind and other weather variables, especially temperature. Monarchs flap their wings realtively slowly, about 5 to 12 times per second, compared to other butterflies and moths, but they also take advantage of wind a lot during their flight. Monarchs have been measured to fly 40 km per hour, but they may not be able to do this for very long. Some recapture data of tagged monarchs has shown that they can fly 129 km in a day. We do know that they start ariving in the colonies near Mexico city during the first few weeks of November, and start leaving Minnesota late in August. How could you measure this? You could try timing them with a stop watch!

Q. How long does it take them to migrate? from Kevin

A. It depends on where and when they start, and how the weather is a long the way. From where I live in St. Paul, it probably takes them about 2 1/2 months, but I'm sure there's a lot of variation.

Q. Why do Monarchs cling to trees in bunches? from David

A. As explained above, perhaps because there's limited space and they can avoid predators and cold temperatures.

Q. How high can a monarch fly? Frankie

A. People have observed monarchs flying up to 1250 meters above the ground. (That's about 3/4 of a mile!) They might actually take advantage of air currents and soar in air currents, like human hang-gliders do! This would save them some energy on their long trip.

Q. How far does a monarch travel in a day? Tabatha

A. It varies, for the reasons mentioned above in response to Kevin's question.

Q. Do the monarchs rest? How long do they sustain flight? Zandy

A. They rest at night and when the wind is blowing hard against them. They seem to be able to sustain flight for longs periods of time, but it's really hard to follow an individual butterfly to figure this out!

Q. When do the monarchs mate and how does this effect their flight? Farrah

A. The monarchs that migrate to Mexico don't mate before they leave the north, but most females do mate before they leave the colonies to come north in the spring. I don't think that anyone has ever studied how this affects their flight. During mating, males transfer more material than just sperm to females - the sperm are packaged in a bundle called a spermatophore that can weigh up to 10%, but usually about 5% of the female's total wieght. This might be hard to carry, but it also provides her with some energy. I actually study mating behavior and the effects of this spermatophore in monarchs, and I've never thought to learn how it affects their flight. Maybe I'll do that. Maybe you can do it sometime!

Mrs. Chislett read one of the questions posed in the teachers manual. It made her think. What would the sighting of a monarch in Rochester (where we live) in April mean? I am guesssing, it would mean we are having an early Spring. Q. Is that correct?--Mrs. Chislett

A. It would also require an early spring all the way from Mexico to here. I would actually be skeptical of this sighting.

Q. One more question--Is the validity of the studies involving student contributed data effected by misinformation? Is this accounted for at all? ---Mrs. Chislett Thank you from us all. FDYT89C@prodigy.com (SHERMAN SCHOOL)

A. This is a very good point. Elizabeth did a good job of answering this question previously in the March 27th monarch update. Basically, each person using the data must decide which sightings they feel are dependable.

From MAINE: Dear Expert, I am from Bar Harbor, Maine. My name is Kate.

Q. What are the Monarch's preditors? Sincerely, Kate Ms. Clixby's 3rd grade Class sclixby@emerson.u98.k12.me.us

A. Monarchs actually have quite a few predators. Probably the most important ones are some that we usually don't think about, parasites and other diseases. There are very small wasps and flies that lay their eggs on monarch caterpillars or pupae, and the wasp larvae actually eat the living tissue of the monarch until they kill. Often when I collect a caterpillar from the wild and rear it in my lab, I get little wasps and flies instead of an adult monarch. There are also bacteria and other micro-organisms that can kill monarchs. We are studying one in my lab that lives in the gut of the caterpillar and is passed from a female to her offsrping on the surface of the eggshell.

But, also the more "typical" predators also eat monarchs. Even though the milkweed they eat may make them taste bad to some birds, some kinds of milkweed aren't as potent. There are several species of birds that eat monarchs, and people have watched birds eat dozens in the overwintering colonies in California and Mexico. Mice also eat them - one summer a mouse got into one of my cages and ate 6 pupae in one night.

From WISCONSIN: Our names are Tracy Johnson and Becky Sowinski from Merrill Senior High, Merrill, WI. We would like to know the following information please:

Q. How long is a monarch's life span?

A. This is a good question, one that many of people have! See answer below.

Q. How did you become interested in monarch butterflies? Hope to hear from you soon...thanks. THermanek@aol.com

A. I started studying them because they are easy to rear in captivity and seem to behave fairly normally under captive conditions. I was especially interested in working with an insect that mated in captivity. But I've always been interested in them because they're so amazing!

From MINNESOTA:

Hi, we're from Mrs. Eigner's 6th grade at Lily Lake Elemetary, in Stillwater, MN. We're in the monarch group. We would like to ask you some questions, that we have about monarchs.

Q. How do humans influence monarchs?

A. Unfortunately, much of our influence is bad. We spray pesticides that either kill the milkweed that they must eat, or kill monarchs along with pest insects. We destory prairies that have lots of good flowers for nectaring and larval foodplants. We destroy the sites they have used for overwintering for a long time - in California houses, parking lots, and shopping centers have been built on monarch overwintering spots. We might even be changing the climate in ways that will hurt monarchs and other butterlies - they can't stand very hot weather, and if it gets hot too fast in the spring in the southern part of the US, they might not be able to get north fast enough.

This is pretty depressing, but I think that if we understand the impact we have on monarchs and other species, and if we learn to care about these other organisms, we can change this. Lots of people really do care. You should try to find out about groups that are trying to learn about and save insects. There is actually a group just for kids, called the Young Entomologists Society, in Lansing, Michigan. (1915 Peggy Place, zip 48910)

Q. How do people mark monarchs?

A. I use a magic marker to write on their wings in my research. Every butterfly gets a unique number. When we tag them for the fall migration, we use tiny stickers that we glue onto the wing. These have a number and an address on them, so that if someone finds them it is possible to track down just when and where they were tagged. We will tell you how to get tags so that you can do this some time later this spring.

Q. What are monarchs' behavior?

A. They have so many behaviors, I would have to write a whole book to answer this question. How about if I just say that most of their behaviors are concerned with finding food, avoiding being eaten, finding a mate, laying eggs on the right kinds of plant, and, for some, migrating.

Q. Besides milkweed, what do monarchs eat?

A. The larvae only eat plants in the milkweed family, although some of these plants are not actually called milkweed. The adults eat nectar from flowers. They will also feed from a hummingbird feeder or slices of watermelon! I feed mine a mixture of honey and water. They drink plain water too.

Q. How long does a monarch live?

A. As adults, 4 to 6 weeks during the summer. The ones that migrate live up to nine months. If you count the other life stages, you need to add about a month to both of these estmates. The fact that they live so much longer over the winter tells us something about how costly it is for them to reproduce - they only start reproducing at the end of this long life, whereas summer ones start at age 4 to 5 days.

Q. How long does it take for the monarchs' journey south?

A. This can vary as explained above.

I hope you can answer our questions about the monarchs. Thanks a ton!! Sarah Fioritto, Lisa Isenberg, and Stephanie Roth Lily Lake Elementary School Stillwater, MN 0834llel@informns.k12.mn.us

From NEW YORK: We are Mrs.Hogan's fifth grade class from Henrietta, NY We have some monarch questions: Q. Do Monarchs act human and protect their own?-Frank

A. No. But females are careful to lay their eggs on the right hostplant - this is protecting their offspring, in a way.

Q. We read something about a tagged monarch in an update, do scientists tag monarchs, how and why?- Jessica

A. We tag them to learn more about their migration - where they go and how fast they go.

Q. Is there a special tag they use? Justin

A. We use a tiny sticker, that measures about 1 cm by 1 cm.

Q. Does the presence of pollen effect monarch migration? - Dan

A. Monarchs don't eat pollen, but they do need nectar. If you mean nectar, they need it to fuel the trip. An early freeze that kills flowers could have a devastating effect.

Q. Is there a correlation between flower pollen and monarch migration? Has this been studied? We are thinking of looking at this question in our own study.-Mrs. Hogan

A. As in response to Dan's question, it's nectar availability that can influence migration

Q. Does pollution effect monarch migration, how and why?- Erik

A. I talked a little about pesticides in a previous answer. I'm not sure if anyone has studied the effects of other pollutants on adults. People have looked at the effects of ozone pollution on larvae, and have gotten variable results. These things are actually very hard to study. Maybe you can figure out a way to do this!

Q. Do the same number of butterflies come back each year?- Joe

A. Your class asks hard questions! There seems to be quite a bit of variation in butterfly numbers from year to year, but it's hard to count them very accurately! There is a group of people that do 4th of July butterfly counts (like Christmas bird counts) every year, and they are collecting interesting long term data on numbers of many butterfly species, including monarchs.

Q. What are the main things related to habitat that effect migration?- Frank

A. Probably the most important is safe places to roost at night during the migration, and adequate food at the beginning of the trip, and possibly along the way.

Q. How does unexpected weather effect migration?- Shanna

A. Strong winds and cold weather can be devastating.

Q. If water gets on a monarchs wings, does their color comeoff? -Mike

A. As long as they don't get stuck to something they will usually dry off pretty well. I am careful never to handle wet butterflies

Thank you for your answers, Mrs. Hogan, Mrs. Chislett and class SHERMAN SCHOOL, FDYT89C@prodigy.com

From MAINE: Hi, we're fifth and sixth graders in Mr. Galin's class at Bowdoinham Community School in Bowdoinham, Maine.

Q.How do monarch butterflys know were to migrate?

A. Nobody knows! What do you think?

Q.What did Monarch butterflys evolve from? Thank you. From Mr. Galin's class. dgalin@bruin.bowdoin.edu

A. Lepidoptera first occurred about 210 million years ago. There are a lot of different groups of Lepidoptera, most of them moths. The first butterflies occurred about 100 million years ago, so butterflies really evolved from moths. Monarchs are part of a big family of butterflies called Nymphalidae, and their ancestor was some ancient butterfly that we don't know much about. It's hard to study the evolution of butterflies, because there aren't a lot of fossils.

From COLORADO: The First and Second grade classes at Deer Creek Elementary in Bailey, Colorado have been studying the Monarch Butterfly and following it's migration. Here are some questions that we have for the experts:

Q. How many eggs do the Monarchs lay at a time?

A. One. But one monarch can lay many eggs.

Q. During what months do the eggs hatch?

A. April and May in the southern US, and June, July, and August in the north.

Q. Do Monarchs have brothers or sisters?

A. Yes - they can have up to 1000 of them!

Q. Are there more males or females?

A. The same numbers of each.

Q. How do you tell the males from the females?

A. The ends of their abdomens are different, and the males also have a little patch of scales on their hind wings that females don't have. This patch looks like a little dot on one of the wing veins.

Q. Do Monarch Butterflies like Water?

A. They do drink water, but they probably don't like to fall into water!

Q. Who are the ancestors of the Monarch Butterflies?

A. See the answer to a similar question above from Mr. Galin's class in Maine.

Q. Do the adult butterflies eat the same thing (milkweed) as the catapillar

A. They do get nectar from milkweed flowers, but from many other flowers as well.

Q. Why don't the Monarch butterflies fly at night? (We thought it might be because animals, like owls, would eat them, but then we read that Monarchs don't taste good and can make animals that eat them sick.)

A. Butterflies are very visual insects, and they don't fly in the dark. This is why we call them diurnal (active during the day).

Q. Do Monarchs have different designs on their bodies?

A. Except for the difference between males and females, they all look pretty much alike.

Q. Why do the Monarch Butterflies all stick to the same tree?

A. It seems many students are wondering about this. I mentioned several reasons above.

Here are some questions from Mrs. McGrath's First grade class: Q. Are Monarchs the only butterflies who migrate?

A. No, actually many butterflies migrate. But, as far as we know, no others migrate as far as monarchs.

Q. How did they get named Monarch? What does Monarch mean?

A. The word monarch means king. Maybe they got that name because someone thought that they should be the king of insects!

Q. Do they fly at night or sleep?

A. They only fly during the daytime.

Kristy Dudley, Technology Teacher, Deer Creek Elementary Bailey, CO kdudley@dash.com

From MINNESOTA: We are Ms. Appel's 3rd grade class from Deephaven.We have some questions for the expert.

Q. When was the 1st Monarch on Earth?[What year?]

A. I don't know the exact year, but it was sometime from about 70 to 80 million years ago.

Q. What is the most unusual course taken?

A. Do you mean back and forth from the overwintering grounds? We aren't sure of the exact courses. It is possible that some of them might migrate across the Gulf of Mexico, or it may be that monarchs observed there have been blown off course.

Q. How many butterflies are still alive?

A. I don't know. Billions!

Q. Are there monarchs in S. America?

A. Yes, there are a lot of them north of the Amazon.

Q.How can you tell a male and female butterfly apart?

A. See description above.

Q.How do they know when to migrate?

A. We don't know for sure, but daylength and temperature probably provide cues.

Q.How do they know where they are going?

A. We don't know this either! They may use the earth's magnetic field, or angles of the sun.

Q. How long does it take to cross a state?

A. It depends on the size of the state! See above answers for how far they can fly in a day.

Q. Can they fly when it rains?

A. No.

Deephaven Elementary 0276del@InforMNs.k12.MN.US

From MINNESOTA: Q. I want to know what butterflys eat? Nat5011878@aol.com

A. Adults eat nectar, usually. There are some that eat rotting fruit, mud, dung, or pollen. One moth even sucks blood!

From MINNESOTA: Q. On what host plant does the female monarch lay her eggs? (Wa Meng, 2nd grader)

A. On plants of the milkweed family.

Q. How did you get interested in butterflies? (Michaela, 2nd grader) Hale Elementary 0001hel@InforMNs.k12.MN.US

A. Can you imagine anyone NOT being interested in butterflies!!!

From MARYLAND: We are a group of second graders who are interested in butterflies because we raised American Painted Lady butterflies this fall in our classroom. We are reading the email printouts about the monarch migration and posting the information on a map to share with the school.

Q. What we want to know is how do you put a tag on a butterfly's wing?

A. Look for information on doing this later in J. North communications.

Thank you, Ellen Jay Media Specialist mejay@umd5.umd.edu

Journey North 125 North First Street Minneapolis, Minnesota 55401 Phone: (612)339-6959