Tuesday, November 30, 2004

The adults have arrived!

Last I wrote (way back in October), my Manduca sexta caterpillars had all pupated, and I wasn't sure if they were going to diapause or not. Well, it turns out the moths must like our Southern California winters, because over the past few weeks they've been eclosing (coming out of their pupal cases). For those keeping track of time, the first eclosing I observed was approximately November 5, and the moth pictured below eclosed on November 16. See my posts on 1st instars, 3rd instars, 5th instars, wanderers, and pupation, for more information on moth development.

Manduca sexta adult
Classic view of a M. sexta adult.

One of the things you'll most likely notice is that the animal no longer looks like a caterpillar (well, ok, it looks a bit like a caterpillar with wings from the top, but it's a stretch). No longer do we find the soft, hairless body, prolegs, and very hardened, obvious head capsule of the larva. The caterpillar has lost its hardened mandibles that are adapted for consuming leaves, and has instead grown a long proboscis that it uses to drink nectar, which you can see in the image below.

Blue Manduca sexta
A M. sexta adult seen from the bottom/side.

The caterpillars did not have large, noticeable eyes, and realistically don't need large eyes to survive (they live on their food, and do little but eat). However, the adults moths fly, primarily at night, and thus their compound eyes are much larger.

From the top it can look like the moths have only two wings (one pair), but they actually have four wings (two pairs). The picture below shows the two pairs relatively clearly - the larger pair that lies on top are the forewings, while the smaller pair that are held underneath are the hindwings. In the first picture I posted (the top view) the hindwings are visible near the middle two yellow/orange dots on the abdomen.

Bottom view of an adult Manduca sexta
A M. sexta adult from the bottom, showing its two pairs of wings.

After eclosing, the adults would normally find and mate with a member of the opposite sex, and then the female would lay fertilized eggs on suitable host plants. I don't have a setup capable of keeping adult moths happy enough to mate, and thus this post completes my Manduca sexta development series. I hope you've enjoyed it!

Side view of an adult Manduca sexta Closeup of blue Manduca sexta Manduca sexta on a branch Manduca sexta side
More pictures of the M. sexta adult - larger versions are on Flickr.

Note: While I was collecting tomato leaves for my M. sexta caterpillars, I collected some caterpillars from the wild and reared them as well. Thus, it is possible that this moth is a Manduca quinquemaculata, whose range overlaps that of M. sexta in this region; adults of the two species look quite similar.

1 comment:

Radagast said...

Importing comments:


Thanks Your site (the Manduca Project) is a great one, and it sounds like a very neat program (I've actually used your site for information before).

I'll respond about the picture permissions in more detail in an e-mail, but in general it's fine if you use my pictures for non-commercial purposes as long as you give me credit and link back to the site.
January 6, 2005, 6:04:40 PM PST – Like – Reply

Hi There!

I just wanted to let you know that you have some of the best M. sexta pictures that I've ever seen! Very impressive!

I run an elementary science ed outreach program (The Manduca Project) at the U of Arizona. I was wondering if you would mind if I used some of your photos in our teacher training materials and/or let us post some on our website (with full credit and flowery thanks, of course). Please let me know!

January 6, 2005, 10:20:11 AM PST