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After posting about the queen caterpillars on our rush milkweeds last week, this week I came across another scene.

Yes, there's a butterfly and a caterpillar. Do you see what is unusual about this?

Let's take a closer look.

Catch it yet?

Maybe if you see the caterpillar more closely?

The caterpillar has two pairs of filaments or "tubercles" that look like antennae. That means it is a monarch butterfly caterpillar, Danaus plexippus.

The butterfly is a queen butterfly, Danaus gilippus. The queen caterpillar has three pairs of tubercles and different patterned stripes (see comparison here).

They are life stages of two different species, although they are related.

Yes, our milkweeds are busy this year.

 

We've featured queen butterfly caterpillars before, but each time we observe them, we learn something new.

How many caterpillars do you see on this young rush milkweed plant? Where are they on the plant and what are they doing?

We've noticed queen caterpillars often feed on the unopened flower buds. Those are the parts that disappear first.

This photograph has a few extra features. Let's look more closely.

What's that shiny white bump at the base of the bud on the top of the stem?

That is a hatched queen butterfly egg. Bonus points if you can find the shed exoskeleton from a previous molt.

The caterpillar in the lower middle of the first photograph of this post has finished off the flower buds. What does it have to eat?

What is the caterpillar doing?

It is crawling out to the tip of what serves as leaves on a rush milkweed.

Now it begins to eat. Any guesses why it might start at the tip?

It doesn't take long. By the time I've taken a few more photographs, the "leaf" is gone.

If you'd like to see the rest of the life cycle, try the queen butterfly emerges post.

Sacs like this appear in autumn. We found this one on a piece of firewood.

What is it?

It's a cocoon. The opening you see at one end reveals the cocoon is empty.

 

Public domain image from Wikimedia.

If we had been there at the right time, we might have seen one of these beautiful cecropia moths emerge. Wow!