For struggling butterflies, if it’s not one pesticide, it’s another

Monarch butterfly populations keep going down, down, down. Occasionally there’s a flutter of good news, which is then followed by more of the bad. Eastern monarch butterflies, which winter in Mexico, are down by 80% since the 1980’s. Their Western brethren, which winter in California, are faring worse, down by 90% during the same time period. 

Monarchs need milkweed – as in, it’s the only thing that young monarch caterpillars munch on. Research over the years has pointed at glyphosate as the reason for the monarch’s struggles, and it stands to reason. Glyphosate is the key active ingredient in Roundup, a weed-killer that kills, among other plants, milkweed. 

New report looks at all types of Midwest butterflies

But a new report finds that the newest, latest bad-boy pesticide driving down all butterfly populations in the Midwest is a class of insecticides called neonicotinoids or “neonics.” We’ve discussed neonics extensively here because declines in native bees and agriculture’s honeybees are linked to neonics. 

Neonics are intended to kill insects. Typically this insecticide is coated onto seeds as a strategy to protect the seed. But the chemical doesn’t stay put. It disperses throughout the growing plant, plus it gets into the nearby dirt, dust and water. Bees, butterflies and birds are exposed. 

Where do we go from here?

A few thoughts on what this new research means: 

1. It’s more evidence that we must tackle the use of neonics. We’ve helped pass laws and policies in 10 states (MD, CT, VT, ME, MA, NJ, NY, RI, CO and CA) to limit the sale of neonics. We’ve supported new laws in New York and Vermont, which restrict neonics on seeds. We need more states to follow their lead.
2. Glyphosate isn’t off the hook. As Dr. Leslie Ries, one of the authors from the latest report, points out, the damage from glyphosate is “still anchoring monarchs at lower populations than in the past.”
3. For all pollinators, we need to keep an eye on the overall cocktail of chemicals that they are exposed to. Glyphosate kills milkweed and perturbs the gut microbes of bees.  Neonics cause brain damage in young bees and make it harder for bees to navigate and reproduce, and neonics harm butterflies. These are two problematic pesticides but are only two of more than 800 pesticides registered for use in the U.S. To address this overall problem, we need to incentivize sustainable farming practices such as crop rotations, prairie strips and more.

The size of the problem can overwhelm. But we’re seeing progress, particularly in the states. Join us in calling on more states to take the next step – passing laws to address bee- and butterfly-killing neonic pesticides.