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End of the Butterfly?

As long as there have been humans, we have gazed at beautiful butterflies, but climate change may alter all that. Rising carbon dioxide levels associated with global warming may affect interactions between plants and the insects that eat them, altering the course of plant evolution. This is particularly true of milkweed, the food that the caterpillars that turn into beautiful Monarch butterflies eat. The plant tastes bitter to other insects, but Monarchs have no problem with it. But if higher CO2 levels make the plant less bitter, other insects would no longer hesitate to feed on milkweed, leaving less for the Monarchs, which might eventually disappear.

Plant defenses---and insect eating patterns---also respond to environmental factors such as rising carbon dioxide. This suggests that elevated carbon dioxide could affect plant evolution by altering the "selection pressure" that plant-eating insects exert on plants. Selection pressure, the driving force of evolution, induces changes in the genetic composition of a population. It works like this: if insects inflict too much damage on plants, the plants can't reproduce as successfully. This sets up a situation in which any plants that, by chance, have inherited insect-deterring traits are at an advantage. Because of that advantage, such traits are likely to spread through the population, urged on by "pressure" from the insects. Researcher Rachel Vannette found that milkweed grown in a high CO2 environment had as much as 50% less of its insect-repelling toxins. Vannette says, "That's a big difference if you're a caterpillar." Will the plants' changing defense strategies help or hinder monarchs? "We don't know yet," Vannette says, "but that's a question we're investigating."

So far, thank goodness, butterflies seem to be doing all right. Researcher Craig Wilson says that despite recent cold snaps that brought record-setting low temperatures over much of Texas, the outlook for the annual Monarch butterfly invasion to the state looks promising “and better than expected.” He says the numbers of Monarchs entering the state over the next few weeks should be very strong: “The numbers are better than expected and the Monarch appears to have recovered to 2008-09 levels in their over-wintering sites in Mexico.”

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Plant Butterfly, Hummingbird, and Bee friendly plants on your property. This needs to include plants that the larva eat. They don't kill the plants and they will grow new leaves. Wildlife refuges are a great source of nectar from the wildflowers that grow there. We need more wildlife refuges. When you buy plants make sure they are nectar bearing. Most of the new strains of flowers aren't. Buying from native nurseries increases the chance of getting nectar plants. Plants that have a fragrance are nectar bearing. We want our gardens to be predator proof. There is always something that eats the predators. One upside to wildflowers is that you do not need to fertilize them because they are used to growing in the wild without fertilizer.

I can't remember the last time I saw milkweed!!! When I was a child our Indiana acre in the back was filled with it growing naturally and there were monarchs everywhere. We also had woolly worms, june bugs, stink bugs and what we used to call pinching bugs - I guess they were hard shell catapillars!!! I remember bats swooping at night in the fields and millions of fireflys. At night the chorus of insects was deafening and our front door screen was filled with bugs. It's sad to think all of this is no longer here because of insecticides and altered habitats. The kids now a days just don't realize what a wonderful, noisy, beautiful world our earth used to be!!!

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