Wednesday, April 12, 2017

Monarch Eggs

From Shae Johnson:

Sunday, April 10, 2017, North of Ozark
I spotted my first Monarch while I was mowing grass. Ran in house to get my camera. I kept seeing the Monarch, but it flits from here to there so quickly, cannot get its picture yet. I kept trying, but never got its picture. When it first appeared, it zeroed in on my emerging common milkweed right away!!

I am sure I heard it say, "Hey, didn't I see you in Mexico in February?" recalling my visit to Sierra Chincua, a Monarch sanctuary in the state of Michoacan, Mexico.  Whether she came from Mexico or had been born from one of my friends from the trip, I could tell she was old and tired by her wings which had lost some of her color from the loss of scales.

Monarch egg 4-12-17 - REK
I also now know it was a female, "Senora Monarch."  As I was hoeing this area after getting the grass mowed, I looked down, and look what I found on this 2 inches tall milkweed.  She had been laying eggs!

I hope the milkweed grows fast in the next two weeks, or the caterpillars won't have enough to eat!!  I have more common milkweed in another garden. Checked there, and there are more eggs on those two plants, though not as many as on those young, emerging common milkweed.  - Shae Johnson
Monarch laying an egg - REK
Thanks, Shae.
So how does a Monarch find a milkweed?  The best information I could find is that they use a combination of visual and chemical clues. Their antennae have chemoreceptors that could pick up airborne clues.  Like many butterfly species, they have chemoreceptors on the legs.  Watch a butterfly on a plant and you may see it probing around with its legs.  The Monarch even has even has spines on its legs to pierce the plant for sampling.

Their compound eyes don't work like ours and pick up a different spectrum of light.  They see thousands of small individual images.  What ever they see, they are able to pick out a milkweed faster than I can.  Not so with Barb who knows her milkweed and showed me eggs on her milkweed in the backyard.

Egg on swamp milkweed 4 -12 -17 - REK
Egg on common milkweed 4-12 -17 - REK

Update April 14, 2017
We have been getting excited reports of Monarch butterflies arriving last Sunday from lots of friends and neighbors.  A question at the WOLF School resulted in a show of hands of over 30 students who had seen them at the first of the week.

Barb had a chance encounter at the school with Jason Jenkins, director for Missourians for Monarchs.  He explained that their sudden dramatic arrival was due to the the strong winds coming up from Oklahoma, carrying the new butterflies rapidly to their next stop on their Journey North

** Further update
Sudden early migration north may be bad for monarchs when milkweed is too small and cold weather can still occur - some arrived in Lincoln, Nebraska by April 9!  Read this for details.

*** More update
1st instar - note dinner hole near fingertip
April 20 - Barb called me out to check the first hatch.  At first I only found the little 2nd instar caterpillars until I got her and my reading glasses and found the little first instars.  In the short time they had been out of the eggs they had already eaten heartily and it showed. 

Second instar leaving huge divots in the leaf
The second instars were easier to find but still required getting on my hands and knees.  The missing chunks of leaves were impressive when compared to the size of the "hungry little caterpillar."

An interesting race is on between the cats and the milkweed.  In a normal competition, one contestant wins.  In this case however, if the milkweed's growth can't keep up with the cat's appetite they will both lose.

Stay tuned for the final race results.

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