As stated in my previous posts (links are below), there are many factors causing a rapid decline in the Monarch Butterfly population. Logging of their wintering sites in Mexico continues to be a major factor as well as diversion of water sources. What are the factors that are contributing to the decline in the United States? The Monarch caterpillar only feeds on one plant, the Milkweed. As with any animal that solely relies on one food source, this puts it at great risk. Of course the more homes we build in wild areas, the more milkweed is destroyed. However, there seems to be another culprit in the Monarch Butterfly demise – GMO-corn. I certainly would like to follow up on this research and if I find anything contrary or further supporting, I will amend this post, but in a study published in the journal Nature May 20, 1999, (a top tier scientific journal and the feather in any researcher’s cap), and reported in the Cornell News, the pollen from BT-corn (corn carrying a gene from the bacterium, Bacillus thuringiensis which makes it resistant to the European corn borer) kills Monarch caterpillars in a research study.
In the laboratory tests, monarchs fed milkweed leaves dusted with so-called transformed pollen from a Bt-corn hybrid ate less, grew more slowly and suffered a higher mortality rate, the researchers report. Nearly half of these larvae died, while all of the monarch caterpillars fed leaves dusted with nontransformed corn pollen or fed leaves without corn pollen survived the study.
The toxin in the transformed pollen, the researchers say, goes into the gut of the caterpillar, where it binds to specific sites. When the toxin binds, the gut wall changes from a protective layer to an open sieve so that pathogens usually kept within the gut and excreted are released into the insect’s body. As a result, the caterpillar quickly sickens and dies.
The butterflies overwinter in Mexico and by the spring begin migrating north. The first generation of the year crosses into Texas, other Gulf Coast states and Florida, seeking milkweed on which to lay their eggs and feed. By late May or early June, the second generation of adults has emerged and heads north to areas including the Midwest Corn Belt. Monarch caterpillars are feeding on milkweed during the period when corn is shedding pollen, Losey says. Thus “they may be in the right place at the right time to be exposed to Bt-corn pollen.”
As in everything, it comes down to a battle between what is good (or perceived good) for humans and what is good for the environment. It is even more imperative that we give Monarch butterflies safe-alternative locations to lay their eggs away from corn fields! Please consider planting milkweed in your yard!! Plants start shipping in May! See my blog posts below to find out where to purchase milkweed.
You can find my other blog posts about Monarch butterflies here.
How to Raise Monarch Butterflies Part 1
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