Posted by: Sandy Steinman | February 22, 2019

What Is Causing Monarch Butterfly Population Decline?

The answer is not what you may think. The Davis Enterprise has an article by Art Shapiro, a top California Butterfly expert, on the plight of Monarch and other butterflies in California. He finds that most species are experiencing significant population declines. He also reports that the cause of the declines are not understood. Although it was widely believed that the lack of milkweed plants was the cause of the Monarch population decline, this has proved to not be the cause. Read article at Commentary: So the monarch is endangered — now what?


  1. […] via What Is Causing Monarch Butterfly Population Decline? — Natural History Wanderings […]


  2. I understand that this guy has a lot of credentials but his argument that we don’t know what to do to protect insects seems a bit lacking. He has kind of/sort of ruled out climate change or at least drought as being a prime factor based on a small sampling. ok. Maybe. He wonders if there even is a milkweed ‘shortage’ but the sheer percentage of space that has been altered for human use should speak to the issue. Clearly, there is less space supporting wild flowers of all kinds than there was available even 50 years ago. But most of all, particularly over here in the continental US common sense offers a reasonable hypothesis. If you drench pretty much the entire area where they fly over with herbicides and pesticides, of course insects and wildflowers are going to die. That is the whole point of pesticide and herbicide use. If big agriculture and the use of GMO products isn’t the prime factor that would come as quite a surprise. Either way, big ag loses. If they are killing the insects they are accelerating this mass extinction event. If they aren’t then their use is not effective and so farmers can safely stop using these products.


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