Back when Laurie and I lived in Tucson, Arizona, we planted some Desert Milkweed (Asclepias subulata) in our backyard. The Milkweed wasn’t much to look at for most of the year, just a clump of vertical stems. But oh! When it bloomed! The Milkweed had magnificent, showy flowers that exuded nectar, which attracted clouds of pollinators. Bees, ants, Queen Butterflies, Monarchs and best of all, Tarantula Hawks.
Some of the Tarantula Hawks were enormous…at least two inches long. I would often hear them flying even before I’d see them. They made a loud, deep buzzing noise, and every time I’d wonder – what is that sound?? Then I’d see these impossibly large creatures slowly wending their way through the air. Their long legs would be dangling behind them, making them seem even larger.
And each time I saw them, it was like witnessing a miracle. They were that spectacular.
In the shade, their bodies were a shiny black. But when the sun shone on them, they sparkled with metallic blue reflections. Their wings were a deep burnt orange color. They were striking, startlingly beautiful creatures.
The Tarantula Hawks were so large that didn’t so much land on the clusters of Milkweed flowers as drape themselves over them. Then they would probe at the Milkweed flowers, drinking their nectar.
They would never show signs of defensiveness, except to move away if I became too intrusive. But they were very much aware of me. As I’d stare at them, I could feel them looking back at me.
I think most insects look back at us as we watch them, But the Tarantula Hawks are just so physically large that you can actually see them doing it.
Here’s something I found out years later – one way that you can often tell male from female Tarantula Hawks is by the way they hold their antennae. A female’s antennae are often curled, as in the photo below.
A male’s antennae, though are usually held straight, as in this photo:
I’d often see yellow ‘pollinia’ – pollen packets – stuck to the Tarantula Hawk’s legs. One of the interesting things about Milkweed is that it doesn’t have loose pollen, like a lot of other plants. Rather, it keeps its pollen in these packets, called ‘pollinia’. These pollen-packets stick to flower visitors such as the Tarantula Hawks, moving with the pollinators from flower to flower and plant to plant.
If you look at the legs and feet of the Tarantula Hawks in these images, you can see the pollinia hanging off of the Tarantula Hawks like clusters of sticky keychains.
I’ve circled one batch of them in the photo below.
Sometimes as the Tarantula Hawk walks over the flowers, the pollina get stuck in the ‘slots’ on the Milkweed flowers, and they’ll get detached from the Tarantula Hawk. And then, Hey presto! – the Milkweed has successfully transferred its pollen from one Milkweed to another.
The pollinia must feel awkward to the Tarantula Hawks – sometimes the Hawks will stop and try to groom the packets away.
The Milkweed plants were swarming with life, all interacting. The Monarch and Queen Butterflies and their caterpillars, the beetles, the aphids, the ants, the multitudinous species of bees and wasps…it was staggering.
It’s funny how, as I write this, I find that I’m so very earnestly trying to convey bits of information, little factoids. But if I’m honest, those facts are secondary to me. The real thing I’m trying to convey is the sense of awe, the feeling of stunned grace that I felt at seeing all of this overwhelming complexity and beauty.
When I watched the Tarantula Hawks and other creatures on the Milkweeds, I was catching bare glimpses of so much beauty, so many interactions between the creatures, so many stories, taking place.
And I was only seeing the barest fraction of them.
Words fail me.
Sources:
As usual – Bugguide.net has wonderful information both Pepsis and Hemipepsis. You may note that I’m calling the wasps “Tarantula Hawks” throughout this post. According to Bugguide, there are a eight? nine? species of “Tarantula Hawks” in Arizona, spread between two genera. And it’s not always easy to tell which you’re looking at in the field. So…discretion being the better part of Taxonomy, “Tarantula Hawks”, Thank you, Bugguide.
And thank you, Eric Eaton. Once again – Eric Eaton’s blog is a wealth of information. This post was especially helpful . but he has a number of other great posts about Tarantula Hawks.
The Sabino Canyon Volunteer Naturalists Tarantula Hawk page has some great photos of a Tarantula Hawk with a Tarantula.
The Virginia Tech Insect Collection blog (here) has a really good article on the anatomy of Milkweed flowers and pollinia.
