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Milkweed, only food source for monarch caterpillars, ubiquitously contaminated:
New evidence identifies 64 pesticide residues in milkweed, the main food for monarch butterflies in the west. Milkweed samples from all of the locations studied in California's Central Valley were contaminated with pesticides, sometimes at levels harmful to monarchs and other insects.
The study raises alarms for remaining western monarchs, a population already at a precariously small size. Over the last few decades their overwintering numbers have plummeted to less than 1% of the population size than in the 1980s—which is a critically low level.
[...] "We expected to find some pesticides in these plants, but we were rather surprised by the depth and extent of the contamination," said Matt Forister, a butterfly expert, biology professor at the University of Nevada, Reno and co-author of the paper. "From roadsides, from yards, from wildlife refuges, even from plants bought at stores—doesn't matter from where—it's all loaded with chemicals. We have previously suggested that pesticides are involved in the decline of low elevation butterflies in California, but the ubiquity and diversity of pesticides we found in these milkweeds was a surprise."
[...] While this is only a first look at the possible risks these pesticides pose to western monarchs, the findings indicate the troubling reality that key breeding grounds for western monarchs are contaminated with pesticides at harmful levels.
"One might expect to see sad looking, droopy plants that are full of pesticides, but they are all big beautiful looking plants, with the pesticides hiding in plain sight," Forister, who has been a professor int he University's College of Science since 2008, said.
Journal Reference
Halsch, Christopher A., Code, Aimee, Hoyle, Sarah M., et al. Pesticide Contamination of Milkweeds Across the Agricultural, Urban, and Open Spaces of Low-Elevation Northern California, Frontiers in Ecology and Evolution (DOI: 10.3389/fevo.2020.00162)
(Score: 5, Insightful) by VLM on Tuesday June 09 2020, @01:20PM (1 child)
I'd extend your remarks with plants don't have a fast circulatory system or excretion system like animals, so once its sprayed with something that doesn't oxidize or photo-dissociate in UV or otherwise is persistent, its just not going away.
Animals at least slowly pee out lead and other heavy metals, strange organic chemicals. Maybe too slowly sometimes but at least the rate isn't near zero.
Mammal livers pretty much laugh at Carbaryl compounds and wipe it out of the blood about as well as alcohol. It has nothing chemically to do with alcohol but mammal livers perform "about as well" on it as alcohol. Mammals can withstand pretty similar dose percentages before death like a large fraction of a percent. On the other hand plants can't get rid of it at all so after application it sits around for weeks, which is great if you're killing pests and bad if its killing other non-pests. And insect brains have no defensive mammal liver so bugs rapidly croak. Of course being broad spectrum has its problems so its been banned in a lot of countries because it kills most everything but birds and mammals for a long time after application.
I haven't bothered to read the story but wouldn't be surprised to read its about Carbaryl and its zillions of consumer marketed versions or any similar pesticide.
Broad spectrum and persistent is always going to sell well to people not trying to feed bugs, and will also be problematic to someone sometimes, for the same reasons.
Really the solution is to promote and subsidize non-persistent pesticides and expand the industry vastly to treat everything all the time multiple times, but nothing is about rational science now, everything is about who can be the shittiest virtue signaller, so the fact that the best thing for the environment AND butterflies would be increasing pesticide use (of shorter persistence pesticides) is just not going to sell at protest marches.
(Score: 0) by Anonymous Coward on Tuesday June 09 2020, @02:51PM
Carbaryl has been around forever. These declines have not. I would imagine it's a problem of newer pesticides.