Predators: I’m the same bug that made you sick
- John Lorson: The Rail Trail Naturalist
- October 17, 2023
- 542
The red milkweed beetle feeds on the leaves and flowers of the common milkweed, drawing the plant’s toxicity into its own body to use as a defense mechanism. The bright coloration of the insect reminds all would-be predators “this is the bug that made you sick that time you tried it,” and monarch butterflies, a species that peacefully coexists with the beetle on the milkweed plant, use the very same means of defense.
Out and about on a crisp October day, you’re certain to notice the dramatic shift of green to red, yellow, orange and even brown. One of the more subtle changes that might be overlooked in this explosion of color is the slow fade to pale gray or brown of the milkweed seed pod. That change signals the plant’s seeds are ready, and the pod in which they’ve spent the past few months developing is just about to split down the side and release a cloud of snowy fluff into the surrounding countryside.
Overlooking the drab hue of the milkweed seed pod is easily excusable, but if the pods are inhabited by the strikingly vibrant red milkweed beetle, the sight is a tough one to miss — and that’s by design.
The red milkweed beetle is among the many organisms that have developed a survival mechanism that can most easily be described as the opposite of camouflage. Such creatures bear some sort of tangible defense mechanism, be it a foul taste, horrible smell, a tough exterior — think spikes, spines or quills — or some other characteristic that makes for a difficult meal for would-be predators.
To advertise this to the world, these critters display bright colors, or at the very least striking contrasts in color — like the black and white of a skunk — to let predators know they’re not worth their time in the making of a meal. This survival strategy is known as aposematism, which is roughly translated from ancient Greek as “away sign” or a signal to keep away.
The red milkweed beetle, just as its more famous neighbor, the monarch butterfly, spends its youth feeding on milkweed, therefore acquiring the plant’s inherent toxicity into its own body. A predator that snacks on one red milkweed beetle — or monarch caterpillar or butterfly for that matter — is unlikely to try it again. Though rarely fatal, a bird that gags on a bright red or orange bug quickly learns there are other much easier meals to be had and avoids the practice from there on out.
While the presence of the adult beetles on a cluster of milkweed pods may appear to be a catastrophic infestation, and the insects can interrupt the life cycle of the plants to a certain degree, it’s often best to let nature take its course, as any chemical efforts to destroy the beetles is just as likely to harm the monarch butterfly.
This time of year marks the annual drive to collect seed pods from the common milkweed plant as conservation groups work to enhance feeding opportunities for struggling monarch butterfly populations throughout the Midwest. Pods collected by citizen volunteers can be turned in at local Soil & Water Conservation District offices — both Wayne and Holmes counties are participating — where they will be processed and used to enhance habitat statewide.
Pods should be dry and gray or pale brown in color. It’s best to collect and store using paper bags so moisture is allowed to escape, preventing mold from forming on the pods. Store the pods in a cool, dry place until you have the opportunity to drop them off. Remember to leave a few undisturbed pods on the plant’s stalks so natural dispersal can continue, and don’t be shy about knocking those bright red milkweed beetles off the pods you’re collecting. I don’t need those things crawling around my office at the Wayne SWCD.
Check the websites at www.WayneSWCD.org or www.HolmesSWCD.com for more details or call 330-263-5376 (Wayne SWCD) or 330-674-2811 (Holmes SWCD). Collection turn-in will end Oct. 30.
If you have comments on this column or questions about the natural world, write The Rail Trail Naturalist, P.O. Box 170, Fredericksburg, OH 44627, or email John at jlorson@alonovus.com. You also can follow along on Instagram @railtrailnaturalist.