This week we had two caterpillars on our rush milkweeds.
At first glance they look quite similar.
Both have bands of color and filaments (also called tubercles) that look like antennae.
Looking 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.
This 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.
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.
Some of the faster developing larvae have already transformed into chrysalids. They will soon be adult queen butterflies.
The 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?
Fresh from the camera, today we have a stripy-faced caterpillar. (Yes, we still have insects out and about here in Arizona.)
Yum, the buds of the rush milkweed flower are tasty.
The structures that stick out behind the head that look like they might be antennae are actually called tubercles. Queen caterpillars have three pairs of tubercles, for a total of six. Similar monarch larvae have two pairs of tubercles, one set at each end. The tubercles are thought to help protect caterpillars from predators.
Where are the real antennae? Butterfly larvae do have two buds in the lower front of the face that will become the long antennae of the adult. Can you see the tiny light-colored "fingers" that the project on either side of the mouth?
When you start to look around the photograph, you start to notice other things. Take the winged aphid, for example. That is an oleander aphid.
Notice anything else in this photograph? If you chose to, please feel free to leave a comment if you spot something. (I didn't notice it until I had the photograph on the computer screen).