Hummingbird Moth aka Sphinx Moth

Chapter 1- The Graceful Imposter

Believe it or not, out here in the desert we see more hummingbirds hanging around than I've seen anywhere else I've lived. It's probably the wide open spaces. Once I even saw a hummingbird just sitting in a tree in our backyard. I've NEVER seen a hummingbird at rest, it's amazing how small it looks with it's wings folded against it's side. But around the time the monsoon season got underway, we started seeing them more frequently, hovering around our desert willows and birds of paradise. Really small hummingbirds, a little odd looking....


I never caught them on camera, the above photograph was 'borrowed' from the web, but after awhile we realized what we were seeing weren't hummingbirds, but the hummingbird moth:

It's hard to tell from the above photo, but these are good sized moths, with wingspans up to 5". And suddenly, they were everywhere! You notice a moth that size when it buzzes your head, or accidentally flies into your house and starts beating against the windows to get out. Our cats had a field day, we found more than one set of wings sans body on the floor of our garage. Then , without our really noticing, they quietly receded.

Chapter 2: Guilty by Association

As the monsoon season progressed, our little desert homestead blossomed. The normally brown rocky turf gave way to a tangle of green. So it was on the relatively blank slate of our gravel driveway that I first noticed a bright yellow caterpillar with a horn on the end just like the hornworms that had attacked my tomatoes. In fact they looked exactly like hornworms except for their color.

I'm normally pretty lasseiz faire about the flora and fauna around here, we don't cultivate a lawn and we let the desert pretty much go through whatever cycles it's going to go through, but I've seen hornworms strip a tomato plant down to nubs, and I had gone to SO much trouble and expense this spring to put in a garden, my first reaction to these little yellow cousins was panic. I told my girls I'd pay them 25 cents for each worm they picked off the ground and put in a bucket:

An hour later, they'd each earned $10 and it was clear this was a losing war. The driveway was crawling with them and they hung on every bush like Christmas decorations:

As it turned out, they mostly left my garden alone, if you don't count the sunflowers. The native vegetation wasn't so lucky. It seemed as if these caterpillars were specially comissioned to take down every green blade and leaf the monsoon season had brought us. It eventually got to the point where even the main road running through our neighborhood took on a yellowish hue and a creepy crawly texture. The local newspaper ran a story about it, apparently it's been about 20 years since these little guys turned out in such force. Wasps and bees are their natural predators in the larval stage, and we had such a dry spring there weren't many wasps and bees around to keep them in check.

Chapter 3: It All Comes Together

As you've probably already guessed, there is a connection between those graceful hovering moths and the caterpillar inundation. We figured out pretty early on that these little yellow guys were the progeny of the White Lined Sphinx Moth, Hyles lineata. After a couple of weeks their numbers quickly lessened, and when we did see one it was no longer munching or crawling, but turning around and around in a little circular hole in the ground. I had hoped to see thousands of little cocoons hanging from our bushes, but these guys burrow in the ground. And yesterday I spotted one of those big moths on our front porch. I wonder whether the eggs this generation of moths lays will lie dormant until the next time conditions are right, or if they'll hatch again in a couple of weeks? I always thought the natural world operated on regular cycles, but so far this has been a "make hay while the sun shines" sort of process. A live, reproduce, die, and do it all over again as fast as we can kind of thing. And it just rained again today, so weather conditions seem favorable. Time will tell.

(Thanks to Barb, who wrote a post a couple of days ago on her excellent blog The Handbook of Nature Study, about the Hummingbird Moth. I can't wait to get out my copy of the handbook and learn even more about these interesting creatures.)