Packing Up and Yard Observations

(click on photo to enlarge)

This could be my last post from Tucson. Our house is just about ready for occupancy and we’re very excited. The downside is the packing. So, as a pleasant way to avoid boxing up more stuff, I’ve decided to bring things up-to-date on yard happenings.

Tecoma stans ‘Orange Jubilee’

One of the native shrubs that grows in the yard here in Tucson, that we’ll be planting in the Dragoons, is Yellow Bells (Tecoma stans var. angustifolia) and the orange flowered variety ‘Orange Jubilee’ (which is actually my favorite and the subject of most of this post).

Tecoma stans ‘Orange Jubilee’

Belonging to the Bignoniaceae Family, which includes Desert Willow (Chilopsis linearis), the nectar-rich flowers are insect magnets plus it’s a host plant for the Rustic Sphinx Moth (Manduca rustica).

Rustic Sphinx Moth caterpillar (Manduca rustica)

These caterpillars can get as thick as a man’s thumb and exceed 4 inches in length. The “horn” at the rear end is why these caterpillars are sometimes called hornworms. The caterpillar above was not happy about being disturbed and was rearing up to make itself look even larger to scare me off. This posture is how the moths in this family came to be called Sphinx Moths. If all goes well and the caterpillar is not infested with parasitic wasps like every single caterpillar I tried to rear last summer, it will eventually leave the host plant to look for a place to pupate. This wandering is how I collected most of my caterpillars last year — they were all rescued from certain death as they crossed a busy road.

A few weeks ago, another road rescue successfully made the transition to pupa. The caterpillar excavated a shallow tunnel in loose soil and constructed a protective shell of hardened soil. I don’t know how it does this because it’s hard to see what’s going on underground, even in a terrarium. After a few days of inactivity, I could see that the green caterpillar had turned into a shiny brown pupa with the shed skin next to it. I made a careful excavation of the cavity and found this:

Rustic Sphinx Moth pupa

Notice the long extension at the top of the pupa. It’s the future proboscis (mouth part) of the adult moth. Rustic Sphinx Moth adults have a very long proboscis. This enables them to feed from long tubular flowers that other insects can’t get to. So for now my story ends. The pupa will overwinter and next spring I hope to show you an adult moth.

There are many more insects that visit the Tecoma stans shrub and I thought I’d show you some of them.

I mentioned above that the Rustic Sphinx Moth has a long proboscis so it can feed from long tubular flowers. Other insects have figured out how to raid these flowers for nectar even though they have very short mouthparts. It appears that bees are capable of making a slit at the base of the tubes right where the nectaries are located. I’ve never seen a bee actually doing this but they are the most frequent visitors to the flowers. Notice the honey bee below sipping nectar.

Honey Bee raiding flower for nectar

I suspect the real culprits may be the large, jet black Carpenter Bees that also frequent the flowers. Their mouthparts could probably easily slit the flower.

Carpenter Bee — slit-maker in action?

Other nectar-loving insects take advantage of this easy nectar source, including butterflies. For the last month or so the Tecoma shrubs have been loaded with American Snouts (Libytheana carinenta).

American Snout (Libytheana carinenta)

One morning I was more than pleased to find two Great Purple Hairstreaks at the slits. Their larvae feed exclusively on mistletoe which is pretty common in mesquite trees. The hairstreaks are not so common however.

Great Purple Hairstreak (Atlides halesus)

Hairstreaks rarely land with open wings so a glimpse of that bright metallic blue on the uppersides can only be seen when they fly. You can get the idea from this artsy flight shot.

Great Purple Hairstreak on the wing

My first migrant Rufous Hummingbird (Selasphorus rufus) showed up at the Tecoma flowers. Unlike the “cheaters” who don’t enter the flower the “right” way and help with pollination, the Rufous gives evidence that it’s been quite an effective pollinator judging by the yellow coating of pollen on its bill.

Rufous Hummingbird (Selasphorus rufus)

You might think you have to get into a car and drive some miles before you can enjoy nature. Not so. Perhaps you could just sit by a flowering plant for an hour or two and see what you can find. You might be surprised!