The Remarkable Monarch

Meet Danaus plexippus - the monarch butterfly.   

click on images to enlarge

It’s a remarkable butterfly when you consider that it is a long distance traveler. Monarchs migrate up to several thousand miles from Canada to Mexico and back.  

Adult butterflies feed on the nectar of flowers but in its larval stage of life the monarch feeds exclusively on milkweed.  This endows it with a unique defense mechanism.  The monarch is poisonous to predators as a consequence of dining upon milkweed.  Toxic chemicals found in milkweed build-up and remain in the critter even after it metamorphoses into a butterfly giving it a chemical defense system.  It is remarkable.  

The caterpillar will form a chrysalis from which an adult butterfly will emerge.  The entire process of egg, caterpillar, chrysalis, and adult butterfly takes about four to five weeks with multiple generations born over the course of a year.  

Beginning in the spring - migrating females head north in relays laying their eggs along the way with new generations of butterflies replacing the old.  Each butterfly will migrate once with its great-grandchildren migrating the following year.  The science behind the migration supposes that the monarchs use the earth’s magnetic field to navigate and the position of the sun to signal when to depart for Mexico.   

Since the butterfly only lives a few weeks it is the last generation of monarchs born in late summer or early fall that make the return migration.  As the temperatures begin to fall and the days grow shorter this generation of butterflies doesn’t mature enough to reproduce - allowing them to live up to eight or nine months.  They’ll make the migration south for the winter and return next year to reproduce.

The teensy-tiny egg that you spy above found its way into the house on July 11 when the milkweed it was laid-upon was accidentally removed from the flower bed alongside the porch.  Aghast - Jill rescued it from the compost bin.

 July 11

It hatched later that day and became our silent houseguest.  Captive to the indoors it’s been a treat to observe its development over the past five weeks. 

July 15

We’ve never parented a monarch but Jill’s peninsula pal Cathy has been a surrogate mom for rescued eggs over the years and provided guidance for the foster mom.  

 July 20

Frass (caterpillar poop) was removed and fresh milkweed supplied daily.   

 July 22 took all day to molt

As our caterpillar grew it went through five molts (called instars) where it shed and replaced the previous skin it had outgrown. 

July 23

This caterpillar was a hungry one and eventually bulked-up to 45 mm in size.  Following the fifth instar and overnight on July 26-27 it formed a chrysalis.

 July 28

The houseguest hung around as a chrysalis on top of the bookcase for nine days.  Beginning the evening of August 5^th it started to darken and by Sunday morning, August 6^th it looked like this.  

Then suddenly this happened Sunday afternoon.  Remarkable.

 August 6

It’s a girl.  She was released to the wild yesterday morning to do her butterfly thing.   

Monarch numbers are in decline as a consequence of pesticide and herbicide use and loss of habitat.  If you’re inclined to lend a hand - plant milkweed and nectar producing flowers for this remarkable critter.

Our unscheduled visitor was indeed a remarkable houseguest.  Quiet too.