The fact that the milkweed plant is essential for the survival of the monarch butterfly is well known. Monarch butterflies can be seen taking nectar from a variety of flowering plants, but the larvae are only found eating milkweed. Adult female monarchs deposit their eggs on milkweed leaves, and as soon as the tiny caterpillar hatches until the time it enters its chrysalis stage, it is totally reliant on milkweed for sustenance.

The monarch is not the only insect that is reliant on the milkweed plant; a few different species can be seen on milkweeds at various times of the year. One thing that is common with the majority of insects that utilize milkweed is that they are, for the most part, easy to spot. They are brightly colored, with red or orange being their colors of choice.

Nature has equipped these various species that rely on milkweed with bright conspicuous colors and pin striping for a reason. Milkweed plants contain a chemical defense in the form of naturally occurring chemicals known as cardiac glycosides. This group of chemicals can cause gastric irritation to animals that might try to eat milkweed, and in certain cases of consumption of a sufficient quantity of milkweed, death. The insects that partake of milkweed absorb this chemical during feeding on the plant and suffer no adverse effects. In nature, bright colors on an insect can mean, “Don’t eat me!” The bright color patterns that adorn these insects serve as a warning to would- be predators that they risk ill effects from eating them.

Even as fall comes, and milkweed plants start to turn yellow and lose leaves, some of these critters may be found on the plants. The monarch migration winds down in October, but they are always a few stragglers, especially on milder days. Milkweed is providing food and a degree of protection from predation for this group of insects. See the images included with this column for the more common critters that utilize milkweed plants.