It is not at all uncommon for me to see some fairly interesting things on my regular morning walk down to my Thinking Chair. I do my best to remember to scan my surroundings as I mosey along, but I have to admit that there are mornings when I am simply focused on getting where I’m going. It is easy to become blind to the regular, daily commute; it doesn’t seem to matter if the commute is in a car or on foot.
I am usually up too early to do much in the way of insect observation. The dim light before sunrise and the cooler temperatures of early morning generally keep most insects calm and quiet. So, I suppose I can forgive myself from focusing more on the fresh coffee in my travel mug than on the wide variety of wildflowers that I stroll past. This sort of carelessness actually came to bite me (literally) when I passed too close to a very tall thistle plant along my route. The plant is about as tall as I am and is covered with gorgeous flowers, but I wasn’t really paying attention to its proximity and I was made aware of this when the plant’s formidable spines stabbed through the sleeve of my shirt.
My annoyance at this little episode of pain faded quickly and the morning’s observations were delightfully familiar. A family of chickadees took great interest in the food that I put out, as did a large collection of song sparrows. The one issue that was unavoidable was the time of year. In early August there simply isn’t much going on in the world of the birds. Nests have already been built, eggs laid, chicks fed and then fledged; all of the hard work has been done. So, though there are plenty of birds around, they tend to be quietly going about their own business. No need to draw unnecessary attention to one’s self, after all.
On my way back up to the house I was much more alert. Bumblebees were buzzing happily in the Joe-Pye weed and I even saw a monarch butterfly in their company. A tiger swallowtail flew by and the chicory flowers were covered with all sorts of interesting little flies. All of the distractions were purged from my brain as I approached the mean old thistle plant that had stung me earlier. It was worth looking at, but it definitely needed to be respected. Thus it was that a memory of recent discomfort had me looking in just the right direction at just the right time to see a gorgeous and curious little insect.
The hummingbird clearwing (Hemaris thysbe) is probably a creature that you have seen in your flower gardens from time to time. Smaller than a ruby-throated hummingbird, this moth is an example of convergent evolution. Two vastly different types of living things happen to look somewhat the same because they do the same things in the same places and in the same ways. Hummingbirds are famous for their ability to hover in front of flowers as they feed. Well, it turns out that there is a group of moths (the clearwings) that have been shaped by natural selection to look more like a bird than a moth. In this way, the moths are able to go about their business in broad daylight without attracting too much unwelcome attention from predators.
The hummingbird clearwing is particularly fond of pink flowers, which probably explains this individual’s interest in the thistle plant. The big problem was that I didn’t have the correct lens to get the photo, but I took a chance and retrieved it from my desk. Upon returning to the thistle I was happy to find that the moth was still infatuated with the flowers. The photo gods (Nikonus and Iso) had smiled upon me.
This particular moth species is one that appears early in the spring. Adults emerge from the ground and then start the process of finding food and laying eggs. The caterpillars will feed on a variety of host plants, but two of the species that you may have in your yard are cherry trees and honeysuckle bushes. The caterpillars are a light, leafy green and they have a long, white “thorn” extending off their rear ends. The main challenge is simply putting in the time to actually find one. We’re talking about an animal that relies on its ability to blend in for survival. In more than 25 years of poking around, I have been unable to find one.
The caterpillars will feed for about a month and then, when they have reached full size with sufficient energy stored in their bodies, they will bury themselves in the ground and transition from the larval form (the caterpillar) into a pupa. This is a stage in the lives of insects in which the larva transitions into the full adult. What is really interesting about the hummingbird clearwing is the fact that the insect goes dormant and spends the winter in the soil. Only in the spring will the rising temperatures signal that it is time to finally change into a moth.
If you have gardens in your yard, and especially if you happen to have a selection of pink and purple flowers, then you will most likely have this curious little imposter visiting them for nectar. This will often happen in the middle of the day when the temperature is high. Perhaps you can walk out to the mailbox and stop to admire the flowers. Chances are that you will eventually see one for yourself. If you start looking now, then you will have about a month left to find one.
Bill Danielson has been a professional writer and nature photographer for 28 years. He has worked for the National Park Service, the US Forest Service, the Nature Conservancy and the Massachusetts State Parks and he currently teaches high school biology and physics. For more information visit his website at www.speakingofnature.com, or go to Speaking of Nature on Facebook.