New Butterfly or Old?
Watching the Wings for Clues
Butterfly wings become worn and faded over time. Therefore,
the condition of a butterfly's wings is a clue to its age. Each spring we ask observers to look carefully at the
condition of a monarch's wings. Here are some examples of what this can
indicate about monarchs:
- By the month of March, monarchs that have over-wintered in Mexico are about
7 months old. We expect their wings to be very worn, tattered and faded.
- All monarchs do not go to Mexico for the winter. For
example, many years some are present in Texas and breed, especially along the Gulf Coast. When these monarchs produce offspring,
the young butterflies have fresh, new wings.
- Breeding butterflies only live for a few weeks. Their wings typically do not have
time to get as old, torn, and faded as those that over-winter in Mexico.
monarchs that over-winter in Mexico are dead by the end of April.
Fresh new butterflies — children of those that
overwintered in Mexico — continue the journey north.
Using a technique
developed by Dr. Karen Oberhauser and Dr. Bill Calvert, you can
estimate how old and worn a monarch is. The three monarchs below were captured in
Texas in the spring
in the Aschen family's backyard. They
show monarchs at various stages of wing-wear.
the descriptions of wing conditions (indicated by "fade value")
below. Which description
do you think matches monarchs #1, #2, and #3?
Click to enlarge the image for a closer look.
your skill, then check the answers.
holes, no tattering, but beginning to have missing scales to cause
faded, some tattering and holes. Orange beginning to turn gray, black
just beginning to turn charcoal, but not yet transparent or "ghostly".
butterfly do you think could be from Mexico?
might be a young butterfly from Texas?
- If you
saw a torn and tattered monarch in Oklahoma on April 1st, where would
you think it came from?
- What happens
to a monarch to make its wings fade and are damaged over time? What
things might touch their wings? How might the sun and weather affect
them? Write a short story and describe the misadventures in the day-to-day
life of a butterfly.