[permaculture] New research links pesticides to monarch butterfly declines

Lawrence London lfljvenaura at gmail.com
Sun Apr 5 02:56:21 EDT 2015

New research links pesticides to monarch butterfly declines
*Sunday, 5 April 2015, 12:14 pm*
*Press Release: Bioscience Resource

*New research links neonicotinoid pesticides to monarch butterfly declines*

By Jonathan Latham, PhD

USDA researchers have identified the neonicotinoid insecticide clothianidin
as a likely contributor to monarch butterfly declines in North America. The
USDA research is published in the journal *Science of Nature* and was
published online on April 3rd (*Pecenka and Lundgren 2015

Monarch butterfly populations (*Danaus Plexippus*) have declined
precipitously in North America in the last twenty years. This decline has
commonly been linked to loss of milkweeds (*Asclepias* species) from
farmer’s fields. Monarch caterpillars are dependent on milkweeds. The
ability of farmers to kill them with the Monsanto herbicide Roundup
(glyphosate) has therefore led to this herbicide being considered as a
major contributor to the decline of the monarch butterfly.


However, industrial farming methods include other known or potential causes
of monarch disappearances. One of these is the known toxicity of Bt
insecticides found in GMO crops. For instance, in 2006 pollen from
Syngenta’s BT176 corn (no longer on the US market) was *shown
<http://www.independentsciencenews.org/news/bt-maize-pollen/>* to have a
lethal dose of 14 pollen grains towards caterpillars of European
Swallowtail butterflies. Pollen from GMO crops falls on the milkweeds where
monarchs feed and individual maize plants produce millions of pollen

Neonicotinoids have been strongly implicated in pollinator declines
worldwide. As shown by a report from a task force of the International
Union of Nature Conservation based in Switzerland. Neonicotinoids, such as
clothianidin (Bayer), are a particular hazard because, unlike most
pesticides, they are soluble molecules. From soil or seed treatments they
can reach nectar and are found in pollen. Neonicotinoids are now the most
widely used pesticides in the world (Goulson 2013). Up to now there has
been negligible research on the effects of neonicotinoids on butterflies
and this new research is therefore the first to link neonicotinoids to the
survival and reproduction of any butterfly.

In their experiments the USDA researchers showed that clothianidin can have
effects on monarch caterpillars at doses as low as 1 part per billion. The
effects seen in their experiments were on caterpillar size, caterpillar
weight, and caterpillar survival. The lethal dose (LC50) they found to be
15 parts per billion. The caterpillars in their experiments were exposed to
clothianidin-treated food for only 36hrs, however. The researchers
therefore noted that in agricultural environments caterpillar exposure
would likely be greater than in their experiments. Furthermore, that
butterfly caterpillars would be exposed in nature to other pesticides,
including other neonicotinoids.

In sampling experiments from agricultural areas in South Dakota the
researchers found that milkweeds had on average over 1ppb clothianidin.

On this basis the USDA researchers concluded that “neonicotinoids could
negatively affect larval monarch populations.”

This new report is therefore the first to link neonicotinoids to monarch
butterfly survival and reproduction. Neonicotinoids are neurotoxins that
are partially banned in the EU.
“These results are very worrisome, but it is also crucial not to get lost
in the specifics of chemical toxicology and individual species declines”
says Allison Wilson, Science Director of the*Bioscience Resource Project
<http://www.bioscienceresource.org/>*, a non-profit public interest science
organization. “Industrial agriculture is a lethal combination of methods
that is causing the extinction of thousands of species worldwide. It is
affecting birds, amphibians, bats and other pollinators besides
butterflies. Many ecosystems are staring down the barrel.”

“The saddest irony is that, though industrial agriculture experts call
their methods ‘scientific’, using toxins to kill pests runs contrary to all
biological understanding, including the sciences of ecology, of evolution,
and of complex systems. The proof of this is that the very *best results in
all of agriculture
come from farming methods that reject all industrial inputs. Agribusiness
would very much like that not to be known.”

“The best news is that there is a simple way to transfer to sustainable
agricultural methods: remove the subsidies for industrial farming.”

Pecenka J and Lundgren J (2015) *Non-target effects of clothianidin on
monarch butterflies
<http://link.springer.com/article/10.1007/s00114-015-1270-y>*. Science and
Nature 102: 19IUCN Task Force (2014) *Systemic pesticides pose global
threat to biodiversity and ecosystem services
Goulson D. (2013) *An overview of the environmental risks posed by
neonicotinoid insecticides
Journal of Applied Ecology 50: 977–987.

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