Speaking of Nature: The red milkweed beetle
As we move into August, we transition into the time of the year that I call the “deep summer.” This is a time distinctly different from the days of June and July, but this year the differences have been amplified by the extreme shift in the weather. Gone is the rain of June and the punitively hot and humid weather of early July. The past three weeks have seen days more typical of late September.
It feels different, but it also sounds different. Gone is the dawn chorus, that explosion of avian optimism that marks the true beginning of summer in my book. There are still birds aplenty in our fields and forests, but they haven’t got the same motivation to belt out a song as they used to.
But life still abounds around us. You simply have to go out and look for it a little harder because the main characters in Act II of summer’s great play are the insects. It just so happens that this shift in actors coincides with the sudden blooming of a certain level of anxiety. August is here, which means September cannot be far. School looms on the horizon and, like birds preparing for migration, we find ourselves in a bit of a panic. Did we do everything we wanted to do this summer? Will there be time to finish things that are, as yet, undone?
We may feel a compulsion to do something extraordinary during our time off, but that leaves a lot to interpretation. Just what grand adventure awaits us? Should it be some epic discovery of a new place, or could it be some equally epic discovery of a hitherto unknown facet of the place we call home? Both choices can be meaningful, but the later is a bit less damaging to the old wallet.
On July 25, I felt the panic, so I had to choose — far or near? Since I’m always extolling the virtue of finding something new in your own yard, I decided to lead by example. So I stepped out the door, camera in hand, and took “a tour of the estate.” But I didn’t disappear into the primeval forest that borders my yard (in my dreams). Instead, I sort of puddled down the hill, like rainwater following the path of least resistance, and I ended up at the “flat spot,” a euphemistic term I invented for my leach field.
This spot is profoundly different from the rest of my yard. The sand that so effectively filters water is also poor in nutrients. As a result, there are plants that grow there that cannot be easily found elsewhere. I have taken advantage of this situation and actually encouraged the growth of several types of flowering plants by implementing a carefully planned mowing schedule.
Some of the plants I have encouraged are milkweeds and as I walked among their stems, I noticed that many were inhabited by red milkweed beetles. Never heard of them before? Well, I suppose I’m not surprised. After all, I’m using one of this species’ alternate names. Surely you’ve heard of the eastern milkweed longhorn. I’m guessing that most of you are thinking, “Eastern milkweed longhorn? Why didn’t you say so in the first place?”
At a half-inch in length, the red milkweed beetle isn’t one that jumps out at you. To be honest, if it weren’t for the contrast between the red of the beetle’s shell and the green of the milkweed’s leaves, I probably wouldn’t have noticed they were there. But when I did take notice of these beautiful creatures, I was instantly made aware of just how small they really are.
I had selected a lens for the butterflies and dragonflies that I had anticipated seeing. For smaller quarry, however, it was a little less useful. Tiny creatures tend to require the closest focus, which exaggerates “hand jiggle” while holding a camera. The shutter was snapping aplenty that day my friends, but to no avail. All of the photos were useless.
I returned the next afternoon with the right stuff. Tripod (to cut down on vibrations) and my 105 mm macro lens. This combination of gear would surely do the trick, right? Nope. Neither the beetles, nor the weather, felt like cooperating. It was cloudy (perfect for macro photography), but windy (awful for close up work). I did manage to get an obligatory copulation shot, but the rest were sub par.
Finally, on Monday, I was able to get the photos I was looking for. So, after hours of photography, and hundreds of images captured, I can finally present the red milkweed beetle in all of its glory.
This species is a milkweed specialist, which explains its bright coloration. Like monarchs that feed on the toxic leaves, the beetles spend their entire lives feasting on their host plants and become toxic as a result. The bright color is a warning to would-be predators: “eat me and you’ll get sick.”
Eggs laid at the base of the milkweed plants hatch into larvae that tunnel underground and tap into the roots. The larvae remain underground through the winter, pupating in the spring and then emerging as new adults in the early summer. The adults continue to feed on the leaves, stems and flowers of the milkweed plants, but they have to be careful. Milkweeds protect themselves with an arsenal of chemical weapons, one of which is a healthy dose of latex in the sap. If a milkweed beetle bites a stem and gets a face full of latex, it has to clean itself quickly before the latex hardens and glues its mouth shut.
The solution to this problem is one that is also used by monarch caterpillars. The beetles find a large vein on a milkweed leaf and sever it below the area they want to feed on. This reduces the pressure in the vein and allows them to feed. So, safe from the defenses of their food source, and relatively safe from predators, the milkweed beetles are free to court and mate right out in the open.
The graceful, long antennae of the milkweed beetles are what help to identify them as longhorn beetles. Some species have antennae that are actually longer than their bodies, but they all have the same common trait of having these gorgeous protrusions emerge from the head right next to the eye. The red milkweed beetle has taken this trait to an extreme, however, which has produced an amazing characteristic in this species.
The antennae are so close to the eyes that they have actually bisected the visual organs. As a result, the beetles have not two, but four eyes. The species name for the red milkweed beetle (Teraopes tetraophthalmus) is a not-so-subtle reference to this characteristic. The Greek word “tetra” means “four,” while anyone who has ever paid a visit to the ophthalmologist will recognize this as the fancy term for the “eye doctor.” In the human world calling someone “four eyes” is a cruel taunt, but in the world of the red milkweed beetle, it’s just unimaginative and boring.
One last thing before I sign off. You may remember that I did a column on fireflies last month and made reference to the dual purposes of the wings in beetles. Like many insects they have two pairs of wings, but unlike many insects they (through the process of evolution) have seen the front pair of wings fashioned into protective shells.
Well, after taking hundreds of photos, I finally managed to capture one of these beetles exposing this little secret. The photo clearly shows the outer wings (or elytra) being held out of the way of the inner pair of wings so they don’t interfere with flight. It was this accomplishment that was the icing on the cake of my backyard adventure. I encourage you to step out the back door and find whatever treasures that nature has hidden in your yard.
Bill Danielson has worked as a naturalist for 16 years. In that time, he has been a national park ranger, a wildlife biologist and a field researcher. He currently works as a high school chemistry and biology teacher. To contact Bill, or to learn more about his writing, visit