Readers’ wildlife photos

Okay, my photo tank is getting quite low, so I’m putting out a call for readers to send me GOOD photos (in focus, high quality, and so on). Thanks!

Today we have a life-history story of a caterpillar from reader Mark Sturtevant. His notes are indented:

Here I describe the process which I like to call summoning the devil, but it is really about raising a batch of hickory horned devil caterpillars. It was my pleasure to once again take on this task last summer. The hickory horned devil (Citheronia regalis) is famous for being our largest caterpillar (at least by length). These Saturniids eventually become the beautiful ‘regal moth’, or ‘walnut royal moth’, which is our heaviest moth although it is not the moth with the largest wingspan. That designation generally goes to the cecropia moth, which is a species that I have reared out many times and have shown here before.

I had first “summoned” a batch of devils over four years ago, but I was not really taking WEIT-worthy pictures back then. Now pretty everything can be documented. The eggs were purchased by mail order, and by the time they arrived they were already showing signs of late-stage embryos inside.

The first four pictures show the emergence of pigmentation in an embryo, starting with the mandibles and antennae, followed by darkening of the head capsule. The later pictures in this group shows development of pigment over the entire body.

Next comes hatching, as shown in the next two pictures. Several eggs were lined up for the big event. I was hoping to photograph several emerging larvae, but it all happened rather quickly. After nibbling an opening in the shell for a time, the larvae pretty much came charging out! Not at all like the slow, unhurried process that I had expected. The above pictures showing the eggs and hatching were taken with an inexpensive ‘super-macro’ lens that I had built from various bits and pieces. A basic description of this contraption can be found here.

The next four pictures show the changes in the hatchlings. The peculiar array of quills on the first instar larvae expand fairly quickly over about an hour after hatching. They were ready to start eating many hours later.

Like most Saturniids, hickory horned devil larvae will accept a wide range of food plants. However, most species of caterpillars will pretty much starve to death rather than switch to an alternative kind of plant once they have accepted a particular diet. My preferred food for this species is black walnut as that tree is exceedingly common around here. As they grew and molted, the larvae changed their appearance with each molt. But very early in their youth I was forced to go on a family vacation to San Francisco (too cold for bugs!). As was planned, a friend from work kindly took over caterpillar care until my return. When I got back, how they had changed! Most were now in their fourth and final (fifth) instars! These giants grow quickly. The next picture shows a two inch long fourth instar larva. Although this is a staged picture taken out doors, I always raise my babies indoors in large containers. Fourth instar larvae will grow a little larger, but the real transformation into the jolly green giants happens later in their fifth larval instar.

One of my goals for this whole activity was to photograph a larva while it molted to the fifth instar. I had done this with a cecropia larva, as shown here, so when a devil larva was getting ready to molt I would set it up in the dining room with a camera on a tripod. Once in pre-molt they will not willingly move, so there was ample time to prepare everything for the big moment. After a few test shots to make sure everything was just right I would then wait. And wait…. and … wait. I had the worse luck with this plan! I could be tied to the house for 3 or 4 days, checking at all hours of the day and night, and I would miss the molt anyway. At one point there were three pre-molt larvae at the same time. Missed every #%()#%$%# one of them.

The absolute worst moment is shown in the last pictures. Here I had monitored events through the night, waking up with an alarm every couple hours to check, and by early in the morning it was beginning to show the characteristic wrinkles that meant the old cuticle had loosened and a new cuticle had formed underneath. I expected it would molt a couple hours later since that had happened before. So I sat next to it, eating breakfast and surfing the web (most certainly checking out WEIT). After a short time I turned to check it and.. well … the last picture shows what I saw not three feet away. It was a very low point.

There were only two fourth instar larvae left. So are there pictures of The Molt? Stay tuned for the next installment!

JAC: Here’s a photo of the adult: the royal walnut moth (photo from Project Noah):

22 Comments

  1. Posted February 9, 2018 at 8:02 am | Permalink

    I’m a bit of a Luddite. How can I send you amazing video of Phyllodesmium rudmani, a sea slug that imitates an entire coral polyp colony?

    • Posted February 9, 2018 at 8:47 am | Permalink

      Near the top of the page are links about Jerry, including his University of Chicago email.

  2. ThyroidPlanet
    Posted February 9, 2018 at 8:03 am | Permalink

    Good work!

  3. Debbie Coplan
    Posted February 9, 2018 at 8:10 am | Permalink

    Great photos and documentation.
    Thanks for all the details in the description and the photos! amazing….

  4. Colleen Milloy
    Posted February 9, 2018 at 8:23 am | Permalink

    Wow, absolutely amazing pictures. Thank you for sharing!

  5. Posted February 9, 2018 at 8:41 am | Permalink

    And thanks from me also. Terrific.

  6. Posted February 9, 2018 at 9:06 am | Permalink

    Great photo sequence! Thanks!

    • Glenda Palmer
      Posted February 9, 2018 at 10:26 am | Permalink

      +1

  7. Posted February 9, 2018 at 9:59 am | Permalink

    That moth would feed a bat family for a week!

  8. nicky
    Posted February 9, 2018 at 10:32 am | Permalink

    These were indeed GOOD photos, in focus where it matters, high quality and so on 🙂
    Seriously great photographs!

  9. rickflick
    Posted February 9, 2018 at 10:44 am | Permalink

    Those worms look so unappetizing. Yet, look at the beautiful moth. There’s a moral to this story.

  10. Posted February 9, 2018 at 12:11 pm | Permalink

    Beautiful embryos!

  11. Posted February 9, 2018 at 12:44 pm | Permalink

    The larvae go through some amazing changes. Great photos.

  12. Paul Doerder
    Posted February 9, 2018 at 1:45 pm | Permalink

    Great photos, story. Obviously, both larval and adult forms are known for many moths, including this spectacular one. But, field guides claim that for many moths, the larvae are unknown. Thus, they encourage folks to rear any found larvae to see what kind of adult moth emerges, and, of course, to make a photographic record.

  13. Mark R.
    Posted February 9, 2018 at 2:18 pm | Permalink

    These are all terrific. I always enjoy your caterpillar photos and commentary. Man, that sucks not catching the (seemingly) quick molt! Dedication that isn’t rewarded. Either way, the two pictures of pre- and post-molt still tell a good tale.

  14. Posted February 9, 2018 at 3:15 pm | Permalink

    Well done! Thanks.

  15. Posted February 9, 2018 at 4:58 pm | Permalink

    These are stunning! Thanks, Mark.

  16. Posted February 10, 2018 at 8:34 am | Permalink

    Nice photos!

  17. Posted February 10, 2018 at 2:19 pm | Permalink

    Brilliant!

  18. Diane G.
    Posted February 10, 2018 at 10:59 pm | Permalink

    Wow! What fantastic pics!

    And thanks for the natural history lesson. I’ve seen the adults around here but to the best of my knowledge, never a caterpillar. (I think had I seen one of any of those instars I would remember it!)

    So looking forward to the rest of the story!


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