Sample Monarch Vital Statistics
Introduction | Monarch Size & Condition
| Sex Ratios | Researchers
| Further Questions | Vital
Statistics
This
section includes samples of the kinds of vital statistics that are of interest to
monarch researchers. Our goal is to illustrate a few patterns that we have observed,
with the hope that these patterns will lead to questions and research projects—by
you!
One of the most amazing things we have found by measuring monarchs in different
locations and times is that they are so variable. For example, the smallest wild
monarch we have measured was a male in Mexico, who had a forewing length of 40.0
mm. The largest was a female in Mexico with a winglength of 58.2 mm. Figure 1 illustrates
this variation, showing a frequency distribution of winglengths for males and females
measured during the summer of 1997. While the average male is larger than the average
female (52.2 mm vs. 51.5 mm), you can see that many males are smaller than an average
female. For example, in the picture on the right, the male (bottom) is much smaller
than the female (top).
We hope that you are encouraged to collect similar data, or to think of new ways
to study monarchs using observations of size, condition, numbers observed, and sex
ratios. If you would like to submit your data, we will publish it here. For descriptions
of how to measure monarch size and condition, click to our
Measuring Monarchs section.