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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.

This week we had two caterpillars on our rush milkweeds.

stripy-2-caterpillarAt first glance they look quite similar.

stripey-3-caterpillarBoth have bands of color and filaments (also called tubercles) that look like antennae.

stripey-2-47Looking more closely, it is apparent that this caterpillar has two pairs of filaments, one pair in front and one pair in back. In addition, its bands of color are unbroken.

stripy-three-68This caterpillar has three pairs of filaments and some of the dark bands have droplets of yellow in them.

Do you know what species of caterpillars these are?

Note on the filaments (tubercles):  These threadlike projections are often mistaken for antennae. Caterpillars do have antennae, but they are only tiny bumps on the front of the head near the mandibles. The filaments vary in length and are occasionally missing.

Caterpillars like these can move their filaments, sometimes in a jerky motion.

Answers:  The caterpillar in the first and third photographs will turn into one of these. The caterpillar in the second and fourth photographs is one of these.

 

Arizona's seasons are often out of sync, especially in the Sonoran Desert. When everyone else is shutting down and getting ready for fall and winter, our wildlife is gearing up. A few weeks ago, we featured some insect eggs. Now we have caterpillars and chrysalids galore.

queen-caterpillar-small

Take this larva of a queen butterfly resting on a rush milkweed. It is taking advantage of the new growth the plants are putting out after recent rains.

queen-chrysalis-003Some of the faster developing larvae have already transformed into chrysalids. They will soon be adult queen butterflies.

skipper-on-cordiaThe skipper butterflies have already reached adulthood and are ready to lay eggs again.

Check out this post by Margarethe Brummermann who says there were 28 species of butterflies (as well as other insects) in Madera Canyon this week. She also posted an amazing video on Flickr.

 What insects did you see this week?