Worms and Flowers

Butterfly vs. Bt

Posted in Scientific by Lzyjo on September 29, 2009

PhotobucketI know, I’m not Sherlock Holmes, but there is a serious problem afoot that needs some investigating. Here is the first clue: On the East Coast the most prevalent butterflies are the Eastern Tiger Swallowtail in both its black and yellow forms. These pictures were taken last year in the middle of June.  One of their favorite flowers in these parts are the milk thistles. There are a ton of these thistles and they bloom a lot, but this year, not one butterfly on their flowers. Not one. In fact I saw two butterflies this entire summer. A black one quickly darted away from me while I was picking blackberries and a Yellow Tiger Swallowtail also darted away from me closer to the yard.

Second Clue: Bt, Bacillus thuringiensis, is a naturally occurring soil-dwelling bacteria and biological insecticide. Bt is a living organism very similar to Anthrax.  Bt, like anthrax, produces endospores a virtually indestructible  enclosure that protects the organism’s DNA. Endospores remain dormant until favorable conditions are met, then they replicates their own DNA, producing other compounds and toxins during the process. One of these is a crystal protein toxin produced by Bt’s cry gene. This cry toxin specifically effects larvae in many orders of the insect family. Bt lives in the soil and on plant material, specifically plant material that caterpillars need to eat. When caterpillars or any insect larvae ingest the cry toxin it becomes activated due to the pH in their guts. The toxin basically causes the cells in the thin gut lining to explode, quickly and effectively killing the insect. This is exactly how Bt insecticides and genetically modified Bt crops work.Photobucket

I lifted the following paragraph from Wikipedia’s Bt page. “Because of their specificity, these pesticides are regarded as environmentally friendly, with little or no effect on humans, wildlife, pollinators, and most other beneficial insects”

oh, except, ants, beetles, butterflies,  flies, mosquitoes, moths,  nematodes and so on…

Granted, we don’t want mosquitoes with West Nile Virus flying all over the country, but do we really prefer Bt killing every insect in sight like an invisible grim reaper?

Sources:

Wikipedia Bt]

UPDATED INFO: Bt Correction

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8 Responses

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  1. deb said, on September 29, 2009 at 6:41 AM

    Here in the Piedmont region of Georgia I have been noticing Extra butterflies this summer. There’s a planter full of lantana and purslane where they congregate sometimes vying with the humming birds. Maybe it’s a weather thing too.

    Interesting!! You have all the butterflies and hummers!! My lantana has been left alone, I hardly see bees on it. Maybe something else is going on here. Thanks for stopping by!

  2. Lizzy said, on September 29, 2009 at 6:53 AM

    How creepy. Poor butterflies!

    It’s sad and frighting, isn’t it?!

  3. tina said, on September 29, 2009 at 7:29 AM

    Hmmmm, bears further investigation for sure.

    I’m worried for sure. Doubtless it is caused by a combination of factors, which need to be uncovered. Thank you for stopping by, Tina!

  4. Daphne Gould said, on September 29, 2009 at 9:05 AM

    The Bt that works on mosquitoes doesn’t affect butterflies. It is a different strain. You can buy four different strains for different targets. The one that works on mosquitoes works on black flies and fungus gnats, but not caterpillars. So as long as the mosquito sprayer only uses the one strain, the caterpillars should be fine. Of course if they use some kind of Bt mix it would wreak havoc with the caterpillars. I too didn’t have any swallowtail larvae this year. I saw the eggs on my dill, but I never saw any caterpillars. I usually find them in their first instar when they are tiny then watch them grow up, but saw none at all.

    Interesting, thank you for the clarification, I did not know there were different strains. Wikipedia can be so off sometimes! I have never used the mosquito dunks myself. I couldn’t believe they left my fennel entirely untouched, I grew it just for them, believing that they preferred fennel to parsley. I hope next year is better!!

  5. Bt. Correction. « Worms and Flowers said, on September 29, 2009 at 3:41 PM

    […] Posted in Pests by Lzyjo on September 29, 2009 Just an update on my last post Butterfly vs. Bt. Luckily, Daphne from Daphne’s Dandelions saved us all from the misinformation on […]

  6. Frederic Kuzyk said, on September 30, 2009 at 8:48 AM

    Thank you for explaining in simple words the sad effect of GM Bt crops.
    Great news for us all on the GMO front! Federal Judge rules against Monsanto’s GM sugar beets, mentioning USDA failures. Read http://twitter.com/fredkzk/status/4320223934 or http://bit.ly/9KD6v

    Very sad, thank you for sharing the links!

  7. Carol said, on October 1, 2009 at 1:07 AM

    Great and Important post! There are so many things we can do to cut down on mosquitoes… poisons and war … I see them both in a similar way.

    You’re absolutely right, why not get rid of the standing water, instead of putting poison in it?! Thanks for stopping by!

  8. […] insecticide preparations popular among organic gardeners. This has led to the suspicion among some observers that Bti may be the culprit behind the recent unfortunate decline in butterfly populations on the […]


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