Answers From Monarch Butterfly Expert, Karen Oberhauser
Julie BrophyTo: Journey North
From: Karen Oberhauser
Thanks to all of the students who asked me questions. Often your questions make me feel like maybe I'm not so much of an "expert"; there are some that I still can't answer! But maybe being an expert means that you know very well just what it is that you don't know! I hope you all see lots of monarchs this spring, and that you let me know what you learn about them this year.
If there are any teachers who would like information on our
"Monarchs in the Classroom" curriculum, please let me know
A. Mariposa means butterfly in Spanish. So Mariposa Monarca means Monarch Butterfly. In Spanish, the adjective often goes after the noun, which makes a lot of sense to me.
Q. How do the Monarch butterflies know that Arizona is a northerly direction?
A. Now this is a very interesting question. From my perspective,
Arizona is in a southerly direction, and this is true for Monarch
Butterflies in Minnesota too. If you are asking how do the butterflies
know what is north, the answer is that this is not yet completely
understood. They may use the location of the sun in the sky, or they may
use the earth's magnetic field.
A. When it's raining, monarchs do not fly. They usually rest on a tree, bush or something else (like the side of my research cage if they happen to be inside the cage during a rainstorm). They do get wet, however, and they simply remain still until their wings dry. They often bask in the sun to dry their wings. If they're too wet, they can't fly because their wings are too heavy.
Q. How dow monachs breathe? Jeffrey@Sunderland Elementary Grade 2
A. Monarchs, like other insects, breathe through tiny holes in their cuticle (like our skin) called spiracles. These holes open into a sytem of tubes in their body (called trachea) that carry the oxygen all over their body. This is different from the system that we and other mammals use. We breathe air into our lungs, and special cells in our blood pick up the oxygen carry it to the rest of our body.
Q. How many Monarchs travel together at the same time and how do they travel such far distances? Lydia@Sunderland Elementary Grade 2
A. The number that travels together varies with where they are. In Minnesota, we often see one or a few traveling together. South of here, it is not uncommon to see dozens or even hundreds at a time (although we did see concentrations this big in Minnesota last fall).
They are very smart about where and when they fly. They choose
altitudes at which they can take advantage of the wind to help them on
their long migratory flights. And they don't fly when there's a strong
wind blowing in the wrong direction. They also store up a lot of energy
for these long trips. This energy comes from the food they eat as
caterpillars, and also from the nectar they get from flowers.
A. These mice have somehow overcome the monarchs' chemical defenses enough to use them as an important food source during the winter. I'm not sure just what effects the toxins have on the mice, but they can't be too bad, since the species that eat the monarchs (Peromyscus melanotis, the scansorial black-eared mouse) seem to do very well eating them. In fact, one mouse can eat about 37 monarchs a night.
Q. Approximately how long does it take preditors bodies to eliminate/reduce the toxin levels to a safe level or to where they can eat again?
A. If you're talking about the bird predators here, the orioles that eat
the monarchs actually avoid the toxins by not eating the cuticle (skin)
where most of the toxins are stored. The grosbeaks do eat the cuticle,
but they prefer males, who have fewer toxins. While scientists have
studied the timing of bird predation (it occurs twice a day in the
overwintering colonies), I'm not sure if anyone has actually followed a
particular bird to see if it eats monarchs twice a day. Maybe individual
birds do need to wait a while after eating monarchs.
A. This isn't completely understood yet. They may use the sun, or the earth's magnetic field to tell them which way is north.
Q. Why do they hang in trees?
A. The trees offer the monarchs protection from extreme temperatures, predators, and precipitation (rain and snow). Many people, particularly Alfonso Alonso, Lincoln Brower, Eneida Montesinos, and Eduardo Rendon, are studying how important the trees in the overwintering sites are to the monarchs. Eneida once said to me that she loves the monarchs, but she loves the forest even more, because without the forest there could be no monarchs. It is very clear that the trees are absolutely necessary to the survival of the monarchs.
Milkweed plants and healthy habitats in their northern homes are also very important, so people all over North America need to work hard to preserve what the monarchs need wherever they live!
Happy Monarch Watching! Karen