Caterpillar (is it a Monarch?)
Location: Leitchfield, Kentucky
May 5, 2011 11:31 am
I am an avid Monarch fan. I have Milkweed in my flower bed for them. I also have several Butterfly Weed plants for all butterfly…I noticed several Monarch caterpillars on my milkweed…was so delighted at this sight. Couple of days later as I was stalking up the Butterfly Weed, I saw to my amazement what appeared to be lots of caterpillars that look to be Monarch. I thought Monarchs only(strictly) ate Milk Weed…
Signature: JoAnn

Monarch Caterpillar

Dear JoAnn,
This is most certainly a Monarch Caterpillar, and we are not entirely convinced that your “butterfly weed” is not a Milkweed.  We are not botanists, though we are also not entomologists and that doesn’t stop us from trying to identify insects, but we do know that there are many species of Milkweed.  The plant in these photos has a developing flower head that seems to resemble the inflorescence of a milkweed.  Check with the nursery where you purchased the Butterfly Weed to see if they can provide a scientific name and then check that it may be in the milkweed subfamily Asclepiadoideae.

Monarch Caterpillar

Dear Daniel
I did some checking as you suggested.  You are 100% correct.  My Butterfly-Weed is Asclepias tuberosa. It is a member of the Common Milkweed family.  It does not have the milky sap as the others or the opposite whorled leaves.  This is what threw me for a loop (absence of the milky sap) when I saw the caterpillars.
I thought the Butterfly-Weed was just one of the plants that all butterflies loved for nectar.  Never entered my mind to check it out further.  To my delight, I now have another plant for the Monarch to feast upon.  As I have the other types of milkweed readily available to me, I plan on expanding my garden.  The fragrance of the common Milkweed is heavenly and the plants can be controlled by removing the fruit(follicle) right before it pops open or immediately after.   Should your bed get to big, as it will in time…just dig up the straggling plants moving outside your bed in the spring.
Thank You very much for you rapid reply.
Have a Great Day!

Location: Kentucky

2 Responses to Monarch Caterpillar, but is that Milkweed??? Yes, it is!!!

  1. Vickie Roberts says:

    We were excited to see that we had smallish caterpillars eating on our milkweed, thinking that they were Monarch. But, after viewing your pictures, I see that ours are smaller and have lots of sparse long “hairs”. They have the colors of a Monarch; What could they be?

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