Special thanks to Dr. Karen Oberhauser for providing her time and expertise in
responding to your questions.
Q. I saw ants crawling out of a tiny hole in the pupa. Did the ants dig the hole? or did another preditor poke it and withdrew fluids and the ants were just finishing the job? It happened all summer. I gathered the pupa so no more could be destroyed. But something did make a hole in some of these too. What could it be?
A. This could be many things. Ants will eat a dead pupa, but if you saw a hole in it, it is possible that the monarch had been parasitized by a wasp, who had already crawled out. Another predator, like a mouse or a predatory wasp, might also have attacked the pupa from the outside and the ants were just finishing the job. Or, you may have seen tiny parasitoid wasps that had developed inside the pupa that just looked like ants. Are you positive they were really ants?
North Albany Elementary
Q. Do Monarchs breath in their chrysalis, and if they do, how do they? If they don't, why don't they need air?
A. The pupa "breathes" just like the larva and adult, through tiny holes in the side of the abdomen and throax called spiracles. The reason that I put quotes around the word breathes is because this is very different than the kind of breathing you do. The air goes into these holes and through a whole series of tubes in the body called trachea. The trachea carry oxygen throughout the monarch's body. They don't have lungs.
Q. How come only male monarchs have a big black dot on their wings?
A. These dots are made of specialized scales which produce a chemical during courtship. Even though this chemical does not appear to be important in monarch courtship, the males still have the spots. The spots are much larger on close relatives of monarchs.
St. Patrick School
Q. Last year, we did not see any monarchs up here. There are milkweed plants here. When I went to Bancroft in the summer, there were monarchs everywhere. How come they are not here? How can we encourage them to return to here? From Mrs. Livingston and her Grade 4 class
A. We don't know what causes the big changes in where monarchs can be found each summer, or how many there are. We see the same things in Minnesota. Some years there are a lot in certain places, some years we don't see any. We are tyring to study this very thing with a large monitoring project all over the US and southern Canada. The best thing you can do is just have a spot that is "monarch friendly." Keep lots of milkweed, flowers, and open space available, and hopefully they'll come back.
Q. I have been gathering larva in the fall the past 25 years for classes. It seems that I have noted a very distinct drop in larva found in August to early September (in northeastern Ohio). Is this a pattern for this area? Are there reasons why we may be seeing fewer Monarchs?
A. See my answer to the above question. We really need consistent, long-term data to answer this question. Insect populations are notorious for large fluctuations, and we don't know if the low numbers we've been seeing lately are just a "natural dip" in population density, or if they mean that humans have changed or usurped monarch habitat, or caused other environmental changes that have harmed the monarchs. If you (or anyone else) would like to help in our monitoring project, you can. This involves weekly monitoring of a site that has milkweed, and takes about 2-3 hours per week. For more information, you could e-mail Michelle Prysby, who is directing this project (Michelle.D.Prysbyfirstname.lastname@example.org).
Griswold Middle School
Q. Are there monarchs living on other continents?
A. Yes. I'll copy the answer I gave above. Monarchs are found in many places throughout the world, but they probably originated in the Americas, and were spread either with the help of humans or on their own to other places. They are found in Australia and New Zealand, and many islands east of these countries (most islands between Australia and Tahiti have monarchs). They are also found in Hawaii, most islands in the Caribbean, and even sometimes in western Europe.
Q. Can you tell the differance between a male and female monarch when they are in the larval state?
A. Only if you dissect them and look for the male's testes. In some butterfly species you can see these testes from the outside, but not monarchs.
Q. Do the males look for food more than the females?
A. I don't think so, but I've never studied this nor read about anyone else's study of this question. How could YOU answer it?
From: NEW YORK
Locust Valley Intermediate School
Q. If the female mates and is ready to lay her eggs and can't locate milkweed plants ,what does she do? Does she lay them on any plant she finds? If that is so, what becomes of the caterpillars?
A. Females will wait a long time to find milkweed. Sometimes in our cages we keep mated females without milkweed, and VERY rarely, we will find a few eggs on other plants or the sponges we use to feed the females. The caterpillars then die. That's a bad situation for females to be in, and their reproductive cycle is closely coordinated with their environment so that it doesn't happen too often. We have done studies here at the University of Minnesota that have shown that having milkweed around actually speeds up egg development in females that were overwintering in Mexico.
Q. When the monarchs go to Mexico how do they know where they are going?
A. This is a question that scientists are still working to answer. People working at the University of Kansas with Chip Taylor have shown that they use the sun, and also probably the earth's magnetic field to know which way is south during the fall migration. But we don't know how they find the specific spots in Mexico. Personally, I'm not sure that we'll ever be able to answer this one - which I think is kind of nice. I like mysteries!
Q. Did you ever tag and track a specific group or colony of monarch butterlies to see where they are taking their journey to? If so, what were the results of your tagging?
A. No, I haven't done this. People working in the California colonies have, though. Just recently, Paul Cherubini from CA, made the following statement on the Monarch Watch listserve. "Monarchs tagged in the Santa Barbara area overwintering colonies have been recovered in all possible directions (e.g. in extreme southern California, Arizona, Nevada and throughout northern California)."
Q.With the recent logging practices in Mexico what impact do you feel will result in future monarch population numbers ?
A. I think that unless the rate of logging decreases, future monarch population numbers will be much lower. It is VERY important that the overwintering sites in Mexico are preserved. Of course, it is also VERY important that suitable breeding habitat and migratory routes in the US and Canada are preserved. We all need to work together to ensure that your children will still be able to study monarchs in their classrooms twenty or thirty years from now.
Department of Ecology, Evolution and Behavior University of Minnesota
1987 Upper Buford Circle
St. Paul MN 55108
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