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Poisonous Pollen: Another Problem for Monarchs?

Recently, scientists have created a new kind of corn. It has a special gene called a Bt gene. The Bt gene kills insects like the corn borer that harm the corn and destroy the farmers' crops. This saves the farmers a lot of money.

But, there is a problem. The corn produces pollen that is poisonous to monarch caterpillars. The pollen is carried by the wind and lands on the milkweed plants growing by the corn fields. The monarch caterpillars eat the milkweed plants and the pollen that has landed there. Then, many of the caterpillars die.
Scientists disagree on just how harmful Bt pollen is to the monarch caterpillars. However, one study showed that the Bt pollen from the special corn killed over half of the monarch caterpillars who ate it. As more kinds of crops are created with the Bt gene, monarchs may be facing even bigger problems.

Click on the small monarch to learn more about milkweed plants.

 

 
Winter Storms Cause Many Monarch Deaths
The monarch population has suffered during the 2001-2002 overwintering season in Mexico. This winter, monarchs faced deadly weather. It was both cold and wet. On January 12-13, 2002, a huge rain storm struck. It knocked many monarchs out of the trees and to the ground. The rain soon turned to snow and covered the fallen monarchs. Temperatures below freezing followed. Millions of monarch butterflies froze to death as a result of the wet and cold.
Monarchs are able to withstand colder temperatures as long as they are dry. They can also survive being wet if the temperature is not too cold. But they can't survive cold temperatures and wet weather at the same time. Scientists believe that 80% of the monarch population was killed in this storm. Piles of dead monarchs lined the ground after the storm had passed, leaving the monarch population smaller than it has ever been.
But, the weather may not have been the only cause of these monarch deaths. Logging companies have cut down many of the trees surrounding the monarch's overwintering area. Because there are less trees to offer protection from the rain and snow, the weather is becoming worse than it has been in past years. More dense forests could have provided the monarch butterflies increased protection from the snow, preventing many monarch deaths.