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It’s your nature: Keep your distance

I believe that everyone who reads this column is quite aware of the striped skunk and strong scent it sprays from glands near its “business end.”

Unfortunately, your family dog, at least after its first nighttime encounter, had to learn the hard way.

The skunk makes no effort to blend in. Its striped pattern is meant as an advertisement: “Keep your distance.” It is using warning coloration.

Many insects such as mosquitoes rely on their nighttime foraging to offer some protection. Grasshoppers, crickets, and aphids depend on their colors blending in with the surroundings in which they live.

However, there are quite a few insects that have a bad taste, odor, or even stinging spines that rely on “advertising their defenses.”

Lady bird beetles (lady bugs) exude a pungent odor that discourages potential predators. That odor actually emanates from their feet. They certainly aren’t colored to blend in.

Monarch butterflies are bad tasting. (not that I’ve tried one) and their bright wing scales discourage avian predators from eating them.

These are just a few examples of warning coloration.

My reminders of warning coloration may help you avoid a nasty rash, itchy skin, or other skin irritations. But to birds that would feed on insects using warning coloration, it is much more important.

The common milkweed plant, as you may have seen, releases a milky liquid from its leaves when broken or being eaten by a caterpillar.

Two rather common caterpillars feast on the milkweed almost exclusively. The monarch butterfly caterpillar and the milkweed tussock moth caterpillar (also called the milkweed tiger moth caterpillar) do just that.

The “sap” of the milkweed contains a toxic cardiac glycoside. This is a toxin that would affect the heart. For a bird, eating one monarch caterpillar will probably make the bird vomit to immediately get rid of that chemical. Surprisingly, the caterpillars and adults of both of these species are not affected by having this toxin in their bodies. It does remain in the adult after they leave the pupa stage. The orange and black colors are warning colorations used by these insects. In fact, the milkweed bug that also feeds on milkweed, is itself, orange and black too.

Yellow and black are also nature warning colors. Yellow jackets and bumblebees display those colors to warn of their stingers. Even honeybees, although a dull yellow, are giving the same warning. I’ve included photos of many of our “stinging and distasteful insects” to help make you familiar with them. But don’t let that stop you from getting outdoors the next few weeks in one of the best nature times of the year.

Test Your Outdoor Knowledge: You should notice large patches of two-four-foot-tall flowers blooming along the roadsides or along some damp paths or trails on your drives or nature walks. They are topped with white, pink, or lilac, four petaled flowers and are called: A. Dame’s rocket B. bleeding hearts C. day lilies D. forget-me-nots

Last Week’s Trivia Answer: Baltimore orioles differ from most passerine birds in our area by having only one brood each summer. In fact, they are often the first birds to head south for their wintering areas after getting their broods self-sufficient.

The milkweed tussock moth caterpillar feeds on milkweed leaves and ingests the toxins found there. It makes no effort to hide using its bright coloration to warn off predators. Its bristles will cause you to have an itchy feeling if you brush against one.
The spiny oak slug caterpillar makes no attempt to blend in. Its numerous spines will deter predators, but if you touch one, it will leave a noticeable stinging sensation.
Another caterpillar with stinging spines is the saddleback caterpillar. You will feel the sting if you brush against one. BARRY REED PHOTOS
Rather pretty, the bright colors and bristles do advertise the stinging hairs of the white-marked tussock moth caterpillar.
One of our most familiar and favorite butterflies is the monarch. It carries with it the toxins it ingested from milkweed leaves as a caterpillar. Birds know its warning coloration pattern and will avoid eating it. The next challenge for the monarch butterfly is hoping its wintering areas in Mexico will stop being threatened.