Reflections in Nature: The cabbage butterfly feeds on cabbage plants

I’ve been doing a lot of front porch sitting lately. It seems I have run into a heart problem and awaiting open heart surgery. Of course, while sitting on the front porch I have been watching our local wildlife.

The little white butterflies with black markings on their wings that have been flitting around have aroused my curiosity, and after researching I found they are cabbage butterflies. I have always assumed that insects are named after the plant they feed on, and in this instance, it is true since the cabbage butterflies do feed heavily on cabbage plants.

A female has two black dots on her fore wings, while the male has only one. I read in my insect book that this butterfly has ultraviolet colors, which are invisible to us. The males use their flashing wings to find females.

In early spring, the cabbage butterflies appear and continue throughout September. Although we most often hear about the monarch’s migration, there are other butterflies that migrate. Butterflies — such as the painted lady, red admiral and clouded yellow — also migrate. The cabbage butterfly can migrate a distance of over 100 miles.

The cabbage butterfly is another species that was introduced accidentally in 1860 to this continent (near Quebec, Canada) from Europe. Its correct name is the European Cabbage Butterfly.vEight years after reaching Canada, the cabbage butterfly crossed the border into the United States.

During one summer, three generations are born in our area, whilevin the southern states, as many as five generations could be produced.

These butterflies spend their time looking for plants of the cabbage family on which to deposit their eggs. No other plant will do. If you were to move the hatched-out caterpillars onto other plants, except the nasturtium, they would refuse to eat and eventually die. Although the nasturtium plant is not related to the cabbage family, it gives off the same pungent oil that smells exactly as the oil contained in the cabbage plant.

One day as I watched several pairs of cabbage butterflies flitting about, I noticed that they were in pairs. The butterflies are nectar-drinkers, and in our yard, they seem to prefer lobelia, a small blue flower that is planted in Mary Alice’s hanging baskets. While close, I was able to catch a female and examine her under a 10x hand lens. All insects when viewed closely are ugly, and this female was quite ugly. Long hairs covered her body, slender antennas, with knobs on the ends and large compound eyes. After handling the female, my fingers were coated with a fine dust, which was presumably from the body.

The female will lay her eggs on members of the cabbage plant family, such as mustard, wild radish, pepperwort, and many others in the crucifer family and related plants. She could lay a couple hundred bright orange-yellow eggs, all of which are arranged in a straight row. In one week’s time, the row of eggs will hatch at the same time. The caterpillar chews its way out of the bag (shell) in which it was born. Naturalists believe that this enables the caterpillar to immediately make the silk, which is needed to help prevent the caterpillar from slipping on the plant’s waxed surface.

At this time, the caterpillar goes through a molt and changes color. After this molt, three or four days of rest are needed. Now, the caterpillar begins to eat continuously, both day and night, causing a great amount of damage to a cabbage patch.

In early days, a stake attached to a horse’s skull (bleached white from the sun) was driven into the ground. A mare’s skull was preferred over a stallion’s. This was a method used to kill off the caterpillars. Later eggshells were used in place of skulls. The reasoning behind both ideas was that butterflies would be attracted by the whiteness of either the skull or eggshells. After being tricked, this is where the caterpillars would lay their eggs, a place where they would receive no protection and not end up being broiled by the sun. If the caterpillars did hatch out, they would find no nourishment and die. However, this really didn’t work, and today cabbage patches are sprayed with chemicals for protection. The caterpillars do have some natural enemies, such as wasps and birds.

After feeding for about one month, the caterpillar straps itself to some support and turns into a chrysalis. Later, it becomes a butterfly and the whole process begins anew. Through the past years, I have been concerned that the government has not listed the monarch butterfly as endangered, and the reason for this is that there are other species that are at greater risk.

In 1995, the monarch butterflies were hit hard by a snowstorm in their wintering grounds located in the mountains of Mexico. The monarchs had been recovering from a previous snowstorm that occurred ten years earlier. Researchers at Cornell University have discovered that half of the monarch caterpillars that were fed milkweed leaves dusted with Bt corn pollen died within four days, while those fed normal corn pollen leaves survived.

Bio-engineered Bt corn, which was planted on 16 million acres this year, is a pest-resistant corn that carries a gene from a bacterium that kills corn borers eating the toxin-expressing plants. This could be a big problem since milkweed plants often grow in or near cornfields. Also, logging is occurring in the traditional wintering areas of the monarch butterflies and this is also affecting their population.

This tiny insect migrates over 2,000 miles and lands on the same trees that its ancestors left in the spring. The monarchs that migrate south are the fourth and fifth generations and all earlier generations have died. One of the many marvels of nature is that these tiny butterflies migrate alone to a place they have never been before, and land on the very same trees that earlier generations left in the spring.

If you see a monarch butterfly, stop and think about this tiny insect and the journey it will make. I’m sure you will marvel at its ability.


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