Monarch Challenge Questions

From: by way of Beth Allen <ccullar@wcsonline.net>
Date: Tue Feb 21 2006 - 10:45:16 EST
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Looking at the Other Side of the Thesis:

I'd like to Challenge Question #3's presumption or hypothesis itself based on direct observations in the preserves (Reserva de la Biosfera de la Mariposa Monarca) in Central Mexico.

I've taken groups of individuals to visit the Preserves for several years. I've been in the preserves on both sunny and cloudy/cool days.

On warm days MANY thousands of monarchs are streaming up and down the mountain. The behaviors I have observed on those days (besides flying and sunning) are two: puddling and nectaring.

1) Puddling consists of locating a water source (a puddle or stream) and taking in water and minerals from the mud.

2) Nectaring I have observed on many flowers. The most common is a large bush in the daisy family (compositae). It has little yellow flowers about the size of a dime.

If I could help you visualize the region for a minute: Picture many steepsided volcanic mountains, shoulder to shoulder creating individual peaks, but some so close together that they have created ridges. Over the many thousands of years since they have erupted, these steep mountains have grown quiet and forests crept up their heights, almost to the very tops for most of them. Soil covered the jumbles of lava, pyroclastic flows, and falls of ash. These mountains rise up to 13,000 feet and then some. BUT the valley floor around them is tropical and spring-like even in the winter. The elevations in the valley floors are around 5,000 feet. There are gardens and people's yards and many flowers that bloom there during the winter.

For the monarchs to go from their tree clusters up in the cool "icebox" of the Preserve, down to the flowering valleys is a distance of no more than a mile or three. But EVEN inside the preserves I have observed flowers blooming.

*** So my caution to you is to not picture anything as 100% true or false.

It IS probably true that not every butterfly either puddles or nectars EVERY day, but it is equally UNTRUE that they never eat for the entire winter. Perhaps they take turns and only nectar once or twice a week, perhaps they only puddle once a month.

What IS important is for us to consider their behavior, observe their behavior, take measurements, record the data.

But it is also important in nature to understand that nothing is 100%. And even more important is to realize that by the time YOU become a biologist, there will still be MANY unanswered questions of this nature.

Math would tell us that if 99% of all the butterflies only eat once a month, then we would still have how many nectaring on the other 29 days of that month? How many butterflies a day could we see flying around at that rate?

* 20 million butterflies clustering in the Preserve? How many per day nectaring if 1% are active once a month?
* 100 million butterflies clustering in the Preserve?
* 180 million butterflies clustering in the Preserve?

Your answer closely represents the numbers of monarchs I have observed on sunny days at the end of February and the first week in March. Why could these observations be different than those made in December?

Carol Cullar
Executive Director
Rio Bravo Nature Center Foundation, Inc.
RR2 4915 Columbine Curve
Eagle Pass TX 78852-9605
www.riobravonaturecenter.org

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Received on Tue Feb 21 10:45:57 2006